Research advances of Zanthoxylum bungeanum Maxim. polyphenols in inflammatory diseases

Zanthoxylum bungeanum Maxim., commonly known as Chinese prickly ash, is a well-known spice and traditional Chinese medicine ingredient with a rich history of use in treating inflammatory conditions. This review provides a comprehensive overview of the botanical classification, traditional applications, and anti-inflammatory effects of Z. bungeanum, with a specific focus on its polyphenolic components. These polyphenols have exhibited considerable promise, as evidenced by preclinical studies in animal models, suggesting their therapeutic potential in human inflammatory diseases such as ulcerative colitis, arthritis, asthma, chronic obstructive pulmonary disease, cardiovascular disease, and neurodegenerative conditions. This positions them as a promising class of natural compounds with the potential to enhance human well-being. However, further research is necessary to fully elucidate their mechanisms of action and develop safe and effective therapeutic applications.


Introduction
Chinese prickly ash, also known as Hua Jiao in Mandarin, belongs to the genus Zanthoxylum in the Rutaceae family (1).Widely cultivated in Asia, including China, Japan, India, and Korea (2), the genus comprises approximately 250 species, with 41 found in China (Table 1) (3).Chinese prickly ash, or Hua Jiao, is a popular spice and traditional Chinese medicine ingredient specifically derived from Zanthoxylum bungeanum Maxim.and Zanthoxylum schinifolium, according to the Pharmacopoeia of the People's Republic of China (4).This review, we will focus on Zanthoxylum bungeanum Maxim.(Z.bungeanum).
Zanthoxylum bungeanum Maxim., commonly known as Honghuajiao, is a deciduous shrub with a height range of 3-7 meters, bearing small, crimson fruits measuring 4-5 mm in diameter.The flowering period spans from April to May, while fruit ripening occurring between August and October.Z. bungeanum holds significant importance in both traditional Chinese medicine and cuisine.The earliest record of its use in China can be traced back to the "Book of Songs," a compilation of folk poetry from the Western Zhou period, underscoring a history of over two thousand years of utilization (5).The dried fruit follicles of Z. bungeanum are integral to Chinese cuisine, often incorporated for their distinctive flavor and numbing taste (1).Additionally, leaves at various stages of maturity serve as ingredients and seasonings in Chinese culinary practices (6).
In traditional Chinese medicine, Z. bungeanum is esteemed for its properties in warming the spleen and stomach, alleviating pain, and demonstrating anthelmintic and antipruritic effects (4).It is also recognized for promoting the flow of Qi and dispelling coldness (5).Decoctions of Z. bungeanum find primary application in treating conditions such as stomachaches accompanied by sensations of coldness and dampness, vomiting, intestinal disorders, diarrhea, ascarid infections, schistosomiasis, and rheumatic joint inflammations (5,7).Externally, the plant is used to address issues like bruises, eczema, and snakebites (2).
Z. bungeanum also features prominently in Indian and Nepalese folk medicine.Its decoction serves as an aromatic tonic for fevers, and as a carminative and stomachic remedy for dyspepsia, cholera, and toothaches (7).
Current research endeavors have demonstrated the pharmacological effects of Z. bungeanum on the gastrointestinal, neurological, and cardiovascular systems.Additionally, it exhibits anti-inflammatory and analgesic properties, along with displaying antioxidant, anti-tumor, antibacterial, antifungal, and insecticidal effects (2) (Figure 1).
Inflammation constitutes an adaptive response of the immune system to deleterious stimuli, encompassing pathogens, cellular injury, and toxic agents.Its principal role is protective, expelling these detrimental agents from the body and instigating the recovery process.However, unbridled inflammation can also be deleterious, culminating in conditions such as atherosclerosis, type 2 diabetes, and rheumatoid arthritis (8).Empirical evidence corroborates the noteworthy anti-inflammatory attributes of polyphenols.They possess the capacity to ameliorate inflammation in various diseases induced by inflammation, such as inflammatory bowel disease and acute pancreatitis (9).The molecular mechanisms underlying the anti-inflammatory activities of polyphenols involve scavenging free radicals, modulating the activity of inflammatory cells, inhibiting enzymes linked to pro-inflammatory attributes like COX2, iNOS, and LOX, suppressing NF-kB and AP-1, and impeding the activation of MAPK, protein kinase C, and Nrf2 (10).
In this review, we summarize the polyphenolic compounds present in Zanthoxylum bungeanum (Z.bungeanum) and the therapeutic effects of Z. bungeanum on inflammation, with a particular emphasis on the polyphenols.Recent research suggests that Z. bungeanum polyphenols have the potential to significantly contribute to the management and prevention of inflammatory conditions.Further indepth research is needed to promote their health benefits.
Investigation of the structure-activity relationships of Z. bungeanum polyphenols reveals a correlation between elevated antioxidant efficacy and the presence of a hydroxyl (-OH) group at both the 4' position on the B ring and the 7 position on the A ring.Moreover, adjacent -OH groups on the B and/or A rings significantly enhanced antioxidant capabilities.Additionally, the diverse structures of these polyphenols suggest that they may display different antioxidant capacities in solution or oil-in-water emulsion reactions (20).Z. bungeanum polyphenols have demonstrated effective radical scavenging activities in DPPH, ABTS (21), FRAP, lipid peroxidation inhibition assays (20), and superoxide anion (19).Furthermore, polyphenols have been reported to protect Escherichia coli under peroxide stress (20) and concurrently reduce reactive oxygen species (ROS) levels in HT-29 cells without inducing any cell toxicity (19).Moreover, polyphenols have a cell-protective impact, mitigating oxidative damage in PC12 cells caused by H2O2 (21).Constituents of Z. bungeanum and their pharmacological effects.

Inflammatory diseases and polyphenols in Z. bungeanum
A combination of polyphenols found in Zanthoxylum bungeanum has demonstrated anti-inflammatory effectiveness in both in vivo and in vitro experiments.The ethyl acetate fraction of Z. bungeanum has been identified as the primary active component in enhancing cognitive function in aging mice with D-galactoseinduced cognitive decline.This fraction contains several polyphenols, such as hyperoside, chlorogenic acid, quercetin-3b-d-glucoside, rutin, and epicatechin.It aids in reducing neuroinflammation, inhibiting the NLRP3/caspase-1 pathway, GSDMD, and downstream pyroptosis, both in the mouse model and in BV-2 cells subjected to LPS and ATP treatment, leading to overall cognitive improvements (25).
The treatment with Z. bungeanum pericarp extract (ZBE), predominantly composed of rutin, isoquercitrin, and quercitrin, has demonstrated effectiveness in protecting mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC).It has been observed to mitigate body weight loss, prevent colonic shortening, Polyphenols identified in Z. bungeanum.
reduce disease activity index scores, and inhibit myeloperoxidase activity.ZBE is found to inhibit caspase-1, ASC, NLRP3, TLR4, subsequent MAPK and NF-kB pathways, and the production of TNFa, IL-12, and IL-1b, both in vitro in the LPS-triggered J774.1 cell model and in vivo.Concurrently, activation of PPARg is detected (13).
In the subsequent section, we will individually discuss the research pertaining to the anti-inflammatory effects of each polyphenolic component found in Z. bungeanum.We will categorize the 40 polyphenolic constituents of Z. bungeanum into various groups based on their chemical compositions: flavonoids, flavonoid glycosides, glycosides, phenylpropanoid, anthocyanin, and nonglycosides (Figure 2).Please note that we do not aim to provide an exhaustive or comprehensive list of all antiinflammatory studies for each component here.Instead, we have selected those with high citation counts or the most recent research to provide an overview of the association between inflammation and polyphenols in Z. bungeanum.

Rutin
Rutin is a flavonoid with well-established anti-inflammatory properties (26) Administered at doses of 50-100 mg/kg, rutin exhibits protective effects against hepatotoxicity induced by cyclophosphamide (CP), a potent anticancer agent, in rats.This protection is associated with decreased levels of pro-inflammatory cytokines and signaling molecules, including IL-6, TNFa, iNOS, COX2, p38-MAPK, and NF-kB.Histopathological analysis reveals substantial structural damage to the liver caused by CP, effectively reversed through prior administration of rutin (27).Rutin has also demonstrated the preservation of the vascular barrier integrity in human umbilical vein endothelial cells stimulated by LPS and in an acetic acid-induced mouse mode (28).It effectively reduced hyperpermeability induced by LPS, TNFa, and HMGB1, and suppressed both TNFa production and NF-kB activation triggered by LPS (28).Beyond its anti-inflammatory and vascular protective effects, rutin has demonstrated neuroprotective and anti-colitic properties.In a rat model of spinal cord injury, rutin administration significantly attenuated histological alterations and reduced tissue damage.This was associated with decreased levels of oxidative stress markers, pro-inflammatory cytokines, and caspase-1 (29).In a mouse model of DSS-induced colitis, rutin significantly improved several key indicators of disease severity, including the disease activity score, colon length, and the integrity of goblet cells and colon epithelium.Rutin also reduced the expression of a range of oxidative-inflammatory markers, including IgE, IgM, iNOS, HO-1, and ICAM-1, and restored the balance among effector cells, regulatory cells, and B cells.The study revealed a substantial increase in the activation of the PI3K/Akt/ GSK3b/MAPKs/NF-kB and p38/MK2 pathways during DSS-induced colitis in the animal subjects, a condition that rutin treatment effectively mitigated.In silico studies supported the specificity of rutin's interaction with these pathways (30).
In terms of pharmacokinetics, orally administered rutin is absorbed in the small intestine, transferred to the liver via the bloodstream, and eliminated through bile and the kidneys (31).Major metabolites include sulfates and glucuronides of quercetin (32).In rats, Zhang et al. reported elimination rate half-life, area under the curve, and plasma clearance values of 3.345 minutes, 5750 mg min/ml, and 5.891 mL/min/kg, respectively (33).Intravenous rutin accumulates in the liver, with a significant portion then transferred to the small intestine, and is also detected in the lung post-injection (31).Interactions between rutin and drugs were studied as well.Rutin reduces the anticoagulant effect of racemic warfarin by 31% when co-administered orally.This outcome was ascribed to a noteworthy 77% rise in the unbound formation clearance of both oxidative and reductive metabolites, coupled with an elevation in the unbound renal clearance of the more potent S-enantiomer of warfarin (34).Rutin also significantly decreases the oral Cmax and AUC of cyclosporine by 63.2% and 57.2%, respectively, through the activation of Pgp transporter and CYP3A enzyme (35).

Hyperoside
Hyperoside is another flavonoid known for its antiinflammatory properties.In mouse peritoneal macrophages subjected to LPS stimulation, hyperoside inhibited TNFa, IL-6, and NO production by 32.3%, 41.3%, and 30%, respectively.Moreover, hyperoside reduced NF-kB activation and IkB-a degradation (36).This compound also exhibits antineuroinflammation effect in vitro and in vivo (37,38).In the LPS-induced HT22 murine neuronal cell line, hyperoside enhances cell survival and mitigates inflammation, oxidative stress, and apoptosis.This effect is achieved by amplifying SIRT1, triggering the activation of both Wnt/b-catenin and sonic hedgehog pathways (38).In rats, 50 mg/kg hyperoside protected against cerebral ischemia-reperfusion injury by mitigating oxidative stress, inflammation, and cell death.Rats treated with hyperoside exhibited significantly enhanced neurological function and a substantial reduction in the ratio of cerebral infarction volume (37).
Hyperoside also attenuate several vascular inflammatory responses initiated by elevated glucose levels in human umbilical vein endothelial cells and mice.These responses include vascular permeability, monocyte attachment, CAMs expression, ROS formation, and NF-kB activation (39).Furthermore, hyperoside's anti-arthritic properties have also been verified both in vitro and in vivo.It can suppress inflammation and prevent cartilage breakdown by influencing the PI3K/AKT/NF-kB and MAPK signaling pathways, as well as the interplay between the Nrf2/HO-1 and NF-kB signaling pathways (40).Hyperoside also inhibited OVAinduced airway hyperresponsiveness in mice through activation of Nrf2/HO-1 (41).In a rat model of antiphospholipid syndrome (APS), hyperoside at a dose of 40 mg/kg led to increased fetal weight, reduction of fetal resorption rates, and reduced pregnancy loss by modulating the mTOR/S6K and TLR4/MyD88/NF-kB signaling pathways (42).

Quercitrin
Quercitrin demonstrates the ability to attenuate carbon tetrachloride (CCl4) induced brain injury by suppressing ROS, MDA, TNFa, and IL-6 (43).Furthermore, it exhibits protective effects against skin damage induced by UVB damage.This protection is achieved through the reduction of ROS, NF-kB activation, and DNA damage triggered by UVB exposure.Quercitrin also restores the diminished expression of catalase and the GSH/GSSG ratio due to UVB exposure (17).In a study involving mice with Alzheimer's disease, quercitrin inhibits the activation and proliferation of microglia, decreases the accumulation of amyloid-b plaques, and improves cognitive impairment by inhibiting inflammation.Specifically, this compound inhibits the level of IL-1a, IL-17A, IL-6, and G-CSF in peripheral blood, as well as IL-1a, IL-4, IL-6, Eotaxin, CXCL-1, MIP-1a, MIP-1b and G-CSF in the brain, thereby alleviating systemic inflammation in the 5XFAD mice (44).
Quercetin and quercitrin, common flavonoids in vegetables, are frequently compared (45).Theoretical calculations clarify that the oxygen atom located on the B rings could serve as the primary site for alterations in electron cloud density, providing insights into how quercetin and quercitrin exert their anti-inflammatory and ROS scavenging effects (46).In LPS-stimulated RAW264.7 cells, both compounds markedly decrease NO and ROS production, as well as the expression of TNFa, IL-1b, and IL-6 (46).However, Comalada et al. reported that unlike quercitrin, quercetin can reduce the expression of cytokines and iNOS by inhibiting the NF-kB pathway in vitro in bone marrow-derived macrophages, without affecting c-Jun N-terminal kinase activity.The group revealed that quercitrin's in vivo impact in a rat colitis model induced by DSS may be attributed to the liberation of quercetin, which occurs following the breakdown of glycosides by intestinal microbiota.In other words, quercitrin releases quercetin to exert its anti-inflammatory influence, achieved by inhibiting the NF-kB pathway (45).

Isoquercitrin
Isoquercitrin has undergone tested in an LPS-stimulated RAW264.7 cell model, revealing its ability to decrease NO production, downregulate the expression of PGE2, COX2, iNOS, and NF-kB p65 protein, and reduce the mRNA levels of IL-1, IL-6, PTGES2, and MCP-1 (47).Moreover, at a dosage of 20 mg/kg, isoquercitrin has demonstrated the capacity to protect denervated muscle from atrophy.This protective effect is achieved by reducing the levels of IL-1b, TNFa, and IL-6 and inactivating the JAK/ STAT3 signaling pathway in the target muscle (48).

Vitexin
Vitexin exhibits anti-inflammatory properties in the OVAinduced mouse allergic asthma model at doses of ranging from 0.2 to 5 mg/kg.Specifically, vitexin mitigates the migration of eosinophils, neutrophils, and mononuclear cells prompted by OVA within bronchoalveolar lavage fluid (BALF).Examination of lung tissue reveals that vitexin effectively suppresses the invasion of leukocytes, mucus production, and development of pulmonary edema.It also moderates the escalation of Th2 cytokines in BALF and reduces the concentration of IgE in the plasma (49).Vitexin has also demonstrated anti-inflammatory effects in chronic cerebral hypoperfusion injury in a rat model of persistent bilateral common carotid artery occlusion and in HT22 mouse hippocampal neuronal cells exposed to oxygen and glucose deprivation followed by reoxygenation injury.The findings confirm vitexin's ability to modulate Epac and NLRP3.Additionally, in the rat model, vitexin has shown the potential in diminishing the severity of ongoing pathological harm in the cortex and hippocampus and preventing further decline in cognitive function (18).Moreover, vitexin inhibits inflammatory pain in various mouse models of inflammation-related pain, including acetic acid-induced writhing, pain-like behavior prompted by phenyl-p-benzoquinone, capsaicin, complete Freund's adjuvant (CFA), and both phases of the formalin test.It also alleviates mechanical and thermal hyperalgesia triggered by capsaicin, carrageenan, and chronic CF.TRPV1 is considered the key target (50).Additionally, vitexin alleviates liver inflammation in a DSS-induced colitis model by inhibiting the TLR4/NF-kB signaling pathway activation.Administration of vitexin results in lower ALT and TC levels in the livers of mice suffering from liver injury.It also reduces the release of IL-6, TNFa, and IL-1b induced by DSS (51).Furthermore, vitexin inhibits the movement of neutrophils toward areas of inflammation by suppressing the p38, ERK1/2, and JNK pathways (52).

Isovitexin
Isovitexin effectively alleviates contact dermatitis in mice triggered by ginkgolic acids, leading to a significant reduction in ear swelling, splenomegaly, and inflammatory cell infiltration.Subsequent investigations have revealed that isovitexin can impede the MAPK and STAT signaling pathways, along with the phosphorylation of SHP2 (53).In the mouse models of kidney injury induced by cyclophosphamide (CP) (54), liver injury triggered by LPS/d-galactosamine (55), and acute lung injury induced by LPS (56), isovitexin demonstrates its therapeutic effects via inhibiting NF-kB activation and inducing Nrf2 and HO-1 expression.In the kidney injury model, isovitexin mitigates CP-induced increases in serum BUN and creatinine, and curbs TNFa, IL-1b, and IL-6 (54).Isovitexin substantially diminishes liver injury, evidenced by reduced histopathological changes and lower AST and ALT levels.It also reduces TNFa levels, MPO activity, and MDA content (55).Pretreatment with isovitexin significantly alleviates acute lung injury, as demonstrated by reduced histopathological changes, diminished granulocyte infiltration, and subdued endothelial activation.Additionally, it lowers VCAM-1 and ICAM-1 expression, reduces MPO and MDA levels, and enhances GSH and SOD (56).

Afzelin
Afzelin performs anti-inflammatory effect in two in vitro experiments (60, 61).In human keratinocytes exposed to particulate matter (PM), a widespread airborne contaminant, afzelin mitigates inflammation and ROS production.It also inhibits p38 kinase, as well as the transcription factors c-Fos and c-Jun (61).The inhibitory effect of afzelin on the p38 kinase pathway contributes to its protective effect of human keratinocytes and epidermal equivalent models exposed to UVB, resulting in a reduction of IL-6, TNFa, and PGE2 release induced by UVB (60).

Quercetin
Quercetin stands out as one of the extensively researched polyphenols in Z. bungeanum.showcasing therapeutic potential in addressing inflammatory conditions, particularly arthritis (62,63).In a study involving women with rheumatoid arthritis, a daily supplement of 500mg quercetin over 8 weeks resulted in significant improvements in the clinical symptoms, disease activity, hs-TNFa levels, and health assessment questionnaire outcomes (62).For rabbits with surgically-induced osteoarthritis (OA), a 4-week gavage treatment of 25 mg/kg quercetin demonstrated increased SOD and TIMP-1 expressions, reduced MMP-13 expression, and mitigation of OA degeneration, comparable to the effects observed in the celecoxib-treated group (63).Quercetin's impact extends to inflammation-based pain models, as intraperitoneal and oral administrations significantly suppressed pain induced by phenylp-benzoquinone and acetic acid.It also mitigated the second phase of pain intensity escalation caused by formalin and carrageenin.This compound further demonstrated its efficacy in curtailing hypernociception stimulated by TNFa and CXCL1, along with reducing carrageenin-induced IL-1b production (15).Moreover, in RAW264.7 cells stimulated with LPS, quercetin significantly reduced the production of NO, inducible NO synthase, and IL-6.It also hindered the relocation of NF-kB to the cell nucleus and suppressed the activation of Erk1/2 and JNK.In DNCB-induced atopic dermatitis mouse model, quercetin exhibited antiinflammatory effects, as evidenced by improvements in ear thickness, serum IgE levels, and histological analysis (64).
Regarding the pharmacokinetic aspects of quercetin, initial metabolism occurs in the small intestine through processes like glucuronidation and O-methylation.The subsequent breakdown and processing take place in the liver after reaching it through the hepatic portal vein.Notably, gut bacteria, especially clostridium orbiscindens, play a role in the breakdown process in the large intestine.Key metabolites found in human plasma include quercetin-3-glucuronide, quercetin-3-sulfate, and isorhamnetin-3glucosidic acid.Quercetin distribution involves various organs (lungs, kidneys, heart, and liver), with the lungs exhibiting the highest concentrations.Conjugates are predominantly present in the blood and are excreted in urine (65).
Pharmacokinetic and pharmacodynamic interactions between quercetin and drugs have been unveiled in studies.Competitive binding to serum albumin influence on cytochrome P450, glycoproteins, and other factors modify drug profiles, affecting treatment outcomes for infectious diseases, cardiovascular diseases, diabetes, and cancer (65).For example, quercetin competes with erlotinib for binding to bovine serum albumin, potentially contributing to increased adverse events associated with erlotinib use (66).Additionally, combined treatment with quercetin and methotrexate significantly reduces inflammatory mediators in collagen-induced arthritis mice, suggesting quercetin's potential as an adjuvant to enhance anti-rheumatic monotherapy (67).

Epicatechin
Epicatechin exhibits dose-dependent reduction in TNFainduced increase of JNK, p38, and ERK1/2 phosphorylation, nuclear AP-1-DNA interaction, activation of the NF-kB signaling pathway, nuclear NF-kB-DNA binding, p65 nuclear translocation, and PPARg expression in 3T3-L1 adipocytes (68).A dosage of 20 mg/kg epicatechin proves effective in mitigating inflammation in the renal cortex of fructose-fed rats (69), while a higher dose of 80 mg/kg demonstrates efficacy in alleviating LPS-induced renal inflammation in rats (70).In both studies, downregulation of TNFa, iNOS and IL-6 are observed (69,70).Furthermore, a dosage of 15 mg/kg epicatechin exhibits anti-inflammatory properties in mice experiencing LPS-induced acute lung injury, achieved by directly impeding the function of the p38-MAPK signaling pathway (71).Epicatechin also shows significant effects in mitigating atherosclerosis, specifically reducing severe lesions by 27% in ApoE*3-Leiden mice, without affecting plasma lipids.Additionally, it successfully countered diet-induced increases in inflammatory markers such as serum amyloid A and human Creactive protein (72).
Concerning the pharmacokinetic parameters, orally administered epicatechin is initially absorbed in the duodenum, with the majority (70%) being absorbed in the lower intestine after catabolism by the gut microbiome.Over 80% of ingested epicatechin is absorbed, and the gut microbiome plays a crucial role in its metabolism, yielding more than 20 identifiable metabolites.These metabolites are then mainly excreted through urine (73).

Catechin
Catechin mitigates coronary heart disease in rats induced by pituitrin injection and a high-fat diet by inhibiting, lipoproteinassociated phospholipase A2, C-reactive protein, TNFa, and IL-6.Simultaneously, catechin treatment also demonstrates the inhibition of NF-kB and upregulation of FXR, p-STAT3, and p-Akt expression levels (74).High fructose consumption over a six-week period in rats induces a series of metabolic problems, including insulin resistance, dyslipidemia, obesity, reduced plasma adiponectin, and inflammation of adipose tissue.Supplementing their diet with 20 mg/kg/day of catechin effectively enhances all these parameters.In the TNFa induced 3T3-L1 adipocyte model, catechin inhibits inflammation by suppressing MAPKs, JNK and p38 activation, and preventing PPAR-g reduction (75).At a dose of 75-300 mg/kg, catechin alleviates allergic symptoms such as sneezing and nose rubbing in mice suffering from OVA-induced allergic rhinitis.It reduces the levels of ovalbumin-specific IgE, IL-5, IL-13, restoring the balance between Th2 and Th1 cells.The potential mechanism of action involves the inhibition of TSLP expression in epithelial cells through the modulation of the NF-kB/ TSLP pathway by catechin (76).

Naringenin
Naringenin significantly inhibits paw swelling and pathological changes in the joint tissue in the SD rat model of complete Freund's adjuvant-induced arthritis.Additionally, IL-1b, TNFa, and IL-6 in serum are notably suppressed (14).Naringenin demonstrates neuroprotective effects by ameliorating neuroinflammation through the inhibition of p38-MAPK and STAT-1.In neuroglial cells induced by LPS/IFN-g, this compound reduces the production of TNFa and NO, along with the expression of iNOS, thereby preventing neuron death induced by inflammation (77).Furthermore, naringenin inhibits pain behavior in mice triggered by various inflammatory stimuli, including acute pain caused by the use of acetic acid, PBQ, formalin, capsaicin, and CFA, as well as the provocation of mechanical hyperalgesia through subplantar injection of capsaicin, CFA, carrageenan, or PGE2.The mechanism of naringenin involves the activation of NF-kB and the inhibition of IL-1b, IL-33, TNFa, and oxidative stress.Additionally, naringenin activates the analgesic NO-cyclic GMP-PKG-ATP sensitive K+ channel pathway (78).Naringenin also exhibits anti-inflammatory effects in respiratory inflammation.In a murine COPD model, characterized by 90 days of cigarette smoke exposure-induced initiation, 20-80mg/kg of naringenin significantly improves pulmonary function, reduced inflammatory cells, and inhibits IL-8, TNFa, and MMP-9 in mouse BALF and serum.Suppression of the NF-kB pathway is also observed in mice treated with naringenin (79).
Delving into the pharmacokinetic characteristics, orally administrated naringenin exhibits limited absorption in the human gastrointestinal tract, yielding a modest 15% oral bioavailability.The absorption process encompasses both passive diffusion and active transport mechanisms.Once absorbed, naringenin swiftly distribute to vital organs such as the liver, cerebrum, kidney, spleen, and heart, suggesting potential neuroprotection within the central nervous system.Remarkably, naringenin demonstrates high permeability across blood-brain barrier models.The enterohepatic recycling of naringenin plays a crucial role, contributing to hepatic conjugate excretion in bile and participating in the enteric excretion of phase II conjugation.Post-absorption, Naringenin undergoes a significant metabolic process involving glucuronidation, resulting in the detection of 98% of naringenin−o−b−d−glucuronide in plasma.Before absorption in the caecum, naringenin undergoes hydrolysis by beta-glucosidase in the small intestine.Further metabolism by intestinal bacterial microflora produces p−hydroxybenzoic acid, p −hydroxyphenylpropionic acid, and p−coumaric acid, which manifest in plasma and urine.Ultimately, flavonoid excretion primarily occurs through two pathways: the biliary and urinary pathways (80).

Kaempferol
In OVA challenged asthmatic mouse models, oral intake of kaempferol mitigated the increase in eosinophil major basic protein and eotaxin-1 expression, achieve through the transactivation inhibition of NF-kB.Consequently, this reduction leads to decreased accumulation of eosinophils in the airways and lung tissue (16).Furthermore, kaempferol demonstrates the ability to control vascular inflammation in an atherosclerosis rabbit model with a high-cholesterol diet for ten weeks.Following treatment with kaempferol, decreased levels of IL-1b, TNFa, and MDA, an increase in serum SOD activity, and a reduction in the gene and protein expression of aortic E-selectin, ICAM-1, VCAM-1, and MCP-1 are observed (81).In a rat model simulating cerebral ischemia/ reperfusion by occluding the middle cerebral artery for 60 minutes and then reperfusion, kaempferol is administered at doses of 25-100 mg/kg.The treatment significantly reduces the volume of cerebral infarction following cerebral ischemiareperfusion, alleviated inflammation, and prevented the breakdown of the blood-brain barrier, thereby improving the neurological outcome on the 7th day after cerebral ischemia reperfusion.Additionally, reduced nuclear translocation and phosphorylation of the transcription factor NF-kB p65 are observed (82).What's more, kaempferol exerts a protective effect on osteoarthritis chondrocytes by regulating the XIST/miR-130a/ STAT3 axis, thereby inhibiting inflammation and extracellular matrix degradation (83).
Limited absorption and minimal oral bioavailability are observed with kaempferol.Its lipophilic nature allows for passive absorption, diffusion facilitation, and active transport.Metabolism in the liver results in the formation of glucuronic acid and sulfate conjugates, while intestinal enzymes in the small intestine contribute to its processing.Aglycogens, produced through the metabolism of kaempferol by colonic microbiota, are further transformed into 4-hydroxyphenylacetic acid, 4-methylphenol, and phloroglucinol.These metabolites undergo absorption into the systemic circulation, distribution to tissues, and eventual excretion in feces or urine (84).
Notably, the administration of a 12 mg/kg kaempferol dose demonstrated a substantial improvement in oral etoposide bioavailability in rats, showing a 64% enhancement compared to lower doses of 47% and 15%.At the highest dose, 12 mg/kg kaempferol exhibited a 26% increase in intravenous etoposide bioavailability.This intriguing finding suggests potential hepatic CYP3A4 inhibition and implicates kaempferol in reducing the unpredictable oral bioavailability of etoposide (85).

Isorhamnetin
Isorhamnetin possesses the ability to inhibit inflammation and provide renal protection.In a rat model of type 2 diabetes induced by a high-fat diet and streptozotocin, isorhamnetin significantly improved the renal function.The study reported that Isorhamnetin inhibited NF-kB signaling activity, resulting in reductions in IL-1b, IL-6, TNFa, TGF-b1, and ICAM-1 levels, as well as the mitigation of oxidative stress in diabetic rats and glomerular mesangial cells (86).Research conducted by Dou's team demonstrated that isorhamnetin exerts beneficial effects on TNBS-and DSS-induced mouse inflammatory bowel disease (IBD) by upregulating xenobiotic metabolism mediated by PXR and concomitantly downregulating NF-kB signaling.Isorhamnetin inhibited the expression of IL-6 and TNFa, as well as the mRNA levels of ICAM-1, iNOS, TNFa, COX2, IL-6, IL-2, through the aforementioned pathways (87).Isorhamnetin has been found to inhibit neuroinflammation.In BV2 microglial cells stimulated with LPS, isorhamnetin significantly inhibits NO and PEG2, as well as IL-1b, TNFa, iNOS and COX2.Research on its antiinflammatory mechanism indicates that isorhamnetin controls neuroinflammation by inhibiting the TLR4/MyD88/NF-kB pathway (88).Moreover, isorhamnetin exhibits efficacy in asthma.In TNFa-induced human bronchial epithelial cell line BEAS-2B, isorhamnetin at concentrations of 20-40 mM can reduce cellular proliferation and notably suppress the expression of CXCL10, IL-1b, IL-6, and IL-8.Furthermore, treatment with isorhamnetin downregulates the phosphorylation of the NF-kB and MAPK pathways in this model (89).

Glycosides
Arbutin significantly enhances kidney function in rats experiencing LPS-induced acute kidney damage.It reduces inflammation and cell death by modulating the PI3K/Akt/Nrf2 pathway after LPS exposure both in vivo and in vitro.Moreover, the Akt inhibitor GDC effectively inhibits this arbutin-induced improvement in vitro (91).Additionally, arbutin protects mice from isoproterenol (ISO)-induced cardiac hypertrophy.Pretreatment with arbutin notably inhibits the TLR4/NF-kB pathway, resulting in decreased IL-6 and TNFa (92).In a DSSinduced mouse colitis model, arbutin significantly mitigates symptoms such as elevated disease activity index, loss of body weight, and increased colon weight-to-length ratio.This antiinflammatory impact is contingent upon the control of JAK2 and the suppression of IL-1b, TNFa, and IL-6.Arbutin also suppresses inflammatory responses in epithelial (IEC6) and immune (RAW264.7)cells triggered by LPS.However, these benefits, both in vitro and in vivo, can be negated by the JAK2 inhibitor AG490 (93).In addressing metabolic issues, arbutin is found to suppress high-glucose-induced inflammation in adult human retinal pigment epithelial cells via upregulation of SIRT1, which provides a novel therapeutic target for diabetic retinopathy management (94).In arbutin-treated LPS-triggered BV2 murine microglial cells, inhibition of NO production, and reduced expression of COX2 and iNOS are observed.Arbutin significantly diminishes the expression of IL-1b, IL-6, MCP-1, and TNFa.Additionally, it impedes the nuclear transcriptional and translocation activity of NF-kB (95).
Jin's group developed arbutin-loaded gelatine methacryloyl-Liposome microspheres (GM-Lipo@ARB), offering extended arbutin release and notable cartilage targeting.The microspheres decrease inflammation in IL-1b-stimulated arthritic chondrocytes and maintain cartilage matrix equilibrium through NF-kB inhibition and Nrf2 pathway activation.Application of the GM-Lipo@ARB lessens inflammation and oxidative stress in articular cartilage, effectively decelerating osteoarthritis progression in a mouse model (96).

Phenylpropanoid
The anti-inflammatory effects of chlorogenic acid (CGA) have been investigated in LPS-stimulated RAW 264.7 macrophages and BV2 microglial cells.CGA inhibits the production of NO, IL-1b, IL-6, TNFa, CXCL1, COX2, and iNOS.A possible mechanism of action involves the reduction of ninjurin1 level and nuclear translocation of NF-kB (97).CGA also downregulates the TLR4/MyD88/NF-kB signaling pathway (98,99).Through this pathway, CGA can potently inhibit CCl4-induced liver fibrosis in rats (98), and alleviate renal inflammation in a mouse model of hyperuricemia induced by hypoxanthine and potassium oxonate (99).Animal experiments have confirmed that the systemic administration of CGA can help alleviate both inflammatory and neuropathic pain (100).
The hydrophilic nature of CGA essentially impedes its passage through the lipophilic membrane barrier, resulting in low absorption.Absorption likely occurs in the stomach rather than the small intestine.Caffeic acid is detected in plasma and urine 1.5 hours after a CGA-supplemented meal, along with derivatives like ferulic acid and isoferulic acid.These derivatives result from CGA hydrolysis in the small intestinal mucosa.CGAs' absorption and metabolism are relatively low, constituting about one-third of total intake in the upper gastrointestinal tract.The remaining two-thirds reach the colon, where intense microbial metabolism occurs.Microflora-derived esterase hydrolyzes CGA, producing microbial metabolites, comprising 57.4% of the total CGA consumed, emphasizing the crucial role of gut microbiota in CGA metabolism and biological properties (101).

Anthocyanin
Anthocyanins, a member of the polyphenolic family in Z. bungeanum, contribute to the crimson coloration of its fruit peel.(102).In total, five types of anthocyanins with clear chemical structure have been identified in Z. bungeanum (24,(102)(103)(104).
The anti-inflammatory efficacy of cyanidin 3-O-glucoside (C3G) has been demonstrated across various in vivo and in vitro models.C3G exhibits the ability to safeguard mice from chronic skin damage induced by UVB exposure, leading to notable improvements in UVB-induced epidermal hyperplasia, collagen fiber preservation, ROS levels, and the expression of COX-2 and IL-6 (105).Furthermore, C3G demonstrates protective effects in rats against cecal ligation and puncture (CLP)-induced acute lung injury (ALI), enhancing their survival rate.C3G treatment results in reduced serum levels of TNF-a, IL-1b, and IL-6, along with the inhibition of COX-2 protein expression and PGE2 production in the lung, potentially through the suppression of the NF-kB signaling pathway (106).C3G also exerts anti-neuroinflammatory effects.In LPS-stimulated BV2 microglia, C3G effectively suppresses microglial activation and the levels of neurotoxic mediators and pro-inflammatory cytokines.Moreover, there is observed suppression of the NF-kB and p38 MAPK signaling pathways (107).Additionally, in TNBS-challenged mice, C3G significantly ameliorates clinical symptoms and mitigates histological damage, possibly by protecting the intestinal barrier and suppressing inflammatory cytokine secretion (108).

Non-glycosides
Research on the anti-inflammatory effects of quinic acid is limited.However, one study shown that quinic acid mitigates vascular inflammation in TNFa-stimulated vascular smooth muscle cells by reducing MAPK phosphorylation and inhibiting NF-kB activation (111).

Direct target of Z. bungeanum polyphenols
In the preceding sections, we primarily delineated the antiinflammatory pharmacological activities of Z. bungeanum polyphenols, highlighting their modulation of inflammation through signaling pathways, including NF-kB, MAPK, Nrf2/keap1, and the NLRP3 inflammasome (Figure 3).However, to date, limited research has been conducted on the direct targeting of proteins or genes associated with inflammation by Z. bungeanum polyphenols.In this section, we consolidate and summarize the pertinent studies investigating the direct interactions of Z. bungeanum polyphenols with inflammatory-related proteins or genes (Table 2).

Clinical trials of Z. bungeanum polyphenols
Currently, several clinical trials have utilized Z. bungeanum polyphenols; however, their application in inflammatory conditions remains limited.Table 3 below summarizes completed clinical studies on Z. bungeanum polyphenols to date.Notably, no severe adverse reactions associated with these polyphenols have been reported across these clinical investigations, providing a certain degree of evidence supporting their safety profile.
6 Inflammatory diseases and other compositions in Z. bungeanum

Alkaloids
Alkaloids, such as hydroxy-alpha-sanshool (HAS), constitute the characteristic compounds in Z. bungeanum, contributing to the notable sensation of numbness in the mouth (124).In a rat model of type 2 diabetes mellitus (T2DM), Zanthoxylum alkylamides (ZA), a mixed extract containing hydroxyl-g-sanshool, hydroxyl-bsanshool, and hydroxyl-a-sanshool, demonstrated the ability to control inflammation and address protein metabolism disorders, consequently ameliorating T2DM.The PI3K/Akt/forkhead box O signaling pathway and the TNFa/NF-kB pathway are implicated in this process (125).
Among the alkaloids in Z. bungeanum, HAS has been extensively studied for its anti-inflammatory effects.HAS exhibits a neuroprotective effect on H2O2-stimulated PC12 cells without inducing cytotoxicity in normal PC12 cells.The suppression of apoptosis is achieved by regulating the PI3K/Akt signaling pathway (126).Oral administration of HAS markedly improves spontaneous locomotion, cognitive function, and histopathological injuries in a mouse model of Alzheimer's disease induced by D-galactose and AlCl3.The therapeutic effect of HAS involves the mitigation of oxidative stress damage and the activation of the Nrf2/HO-1 signaling pathway (127).As one of the main active ingredients in the herbal medicine TU-100, HAS enhances the production of antimicrobial defense molecules (ADM) by intestinal epithelial cells.TU-100, administered orally, prevents weight loss and colon ulceration in both TNBS-induced type-1 model colitis and OXN-induced type-2 model colitis.This suggests that HAS possesses anti-inflammatory properties and could potentially serve as a beneficial treatment agent for UC through the promotion of ADM production (128).
Zanthoxylin, another major alkaloid of Z. bungeanum, exhibits anti-inflammatory and pain-relieving effects in a variety of animal models.In mice, zanthoxylin alleviates pain in both general and formaldehyde-induced pain models.Its mechanism of action involves binding to the a7nAChR receptor and activating the JAK2/STAT3 signaling pathway, thereby inhibiting inflammation and reducing the production of pro-inflammatory cytokines such as IL-6 and TNFa (129).
Zanthoxylum bungeanum Maxim seed (ZBMS), rich in oleic acid, linoleic acid, and a-linolenic acid, exhibits potential for treating asthma and stress-related disorders (132).ZBMS protects mice from histamine/acetylcholine-induced asthma, reduces citric acid-induced cough in guinea pigs, and increases swimming endurance and survival time in mice, indicating a positive antistress effect.In an OVA-induced airway inflammation mouse model, ZBMS treatment improved lung peak inspiratory airflow in a dose-dependent manner (132).
Another group examined ZBSO in an OVA-induced asthmatic mouse model, demonstrating its efficacy in alleviating airway inflammation, attenuates lung tissue injury and airway remodeling, and inhibits leukocytes and eosinophils infiltration into the airway.Molecule mechanism of polyphenols in Z. bungeanum and their anti-inflammatory effect.
ZBSO also reduces IL-5 and IL-4 in the bronchial airway, attenuates the induction of ICAM-1 and TNFa mRNA and protein expression levels, and alleviates ERK, JNK phosphorylation, c-fos and c-JUN induction in the lung tissue (133).ZBSO exhibits effective antiinflammatory properties in the wound healing process.In SD rat models with deep second-degree burns, topical ZBSO application resulted in decreased levels of TNFa, IL-6, and IL-1b in serum, elevated IkBa, and reduced p-IkBa and p-NF-kB p65 expression (134).In copper comb-induced rat burn model, ZBSO can reduce the level of thiobarbituric acid reactant, IL-6, TNFa, increase GSH level and promote wound recovery (135).ZBSO also inhibits inflammation in bone-destroying diseases.In RAW264.7 cells stimulated with NF-kB ligand (RANKL), ZBSO decreases NF-kB, TNFa, NFATc1, and TRAP, leading to the inhibition of osteoclastogenesis.Among the fatty acids in ZBSO, alpha-linolenic acid (ALA) exhibits the strongest effect.In ovariectomized

Z. bungeanum essential oil
Z. bungeanum essential oil (ZBEO) is the primary source of the distinctive flavor of Sichuan pepper, with terpenoids being a major component of ZBEO (2).ZBEO has demonstrated anti-inflammatory effects in various skin disease models.In a guinea pig model of psoriasis, ZBEO treatment significantly improved Baker scores and reduced inflammatory cell infiltration (137).In a mouse model of ultraviolet-induced skin photoaging, topical application of ZBEO improved photoaging damage, reduced skin thickening, and attenuated inflammatory cell infiltration.ZBEO also inhibits the levels of MMP9, MMP1, and MMP3 in skin tissue, enhance the activity of CAT, SOD, and GSH-Px/GPX, and reduced the production of the lipid peroxidation byproduct MDA.Furthermore, ZBEO effectively suppress the expression of TNFa, IL-6, IL-1b, and IL-1a (138).In a HaCaT cell inflammatory model induced by Propionibacterium acnes (P.acnes), pretreatment with ZBEO reduced the levels of TNFa, IL-1b, IL-8, and IL-6, as well as the mRNA levels of TLR2, IL-8, IL-6, and NF-kB (139).
ZBEO inhibited enteritis and intestinal dysfunction caused by E. coli infection in mice.Histopathological observations indicated that ZBEO significantly improved the impairment of intestinal tissue structure, which could be associated with its inhibitory effect on the gene expression of inflammatory cytokines such as IL-8, TNFa, TLR4, and TLR2 (142).Atomized inhalation of ZBEO protects mouse from inflammation related colorectal cancer by reducing inflammation and cancer transformation.Furthermore, a decrease in AChE activity, an increase in ChAT activity, an increase in a7nAChR expression, and a decrease in IL-6 mRNA levels are observed in ZBEO treated group (143).

Other extractions
Z. bungeanum-cake-separated moxibustion (ZBCS-moxi) is a traditional Chinese therapy that has been employed for centuries to treat rheumatoid arthritis.A recent study assessed the antiinflammatory effects of ZBCS-moxi in a rat model of rheumatoid arthritis.The study found that rats treated with ZBCS-moxi for three weeks exhibited a significant reduction in paw volume, pannus formation, synovial hyperplasia of synovial membranes, and levels of TNFa and IL-1b in serum (144).
These findings suggest that Zanthoxylin and ZBCS-moxi may have therapeutic potential for the treatment of inflammation and pain.However, more research is needed to confirm these findings through clinical trials.

Discussion
Zanthoxylum bungeanum Maxim., or Chinese prickly ash, holds a rich history spanning over two millennia in traditional Chinese medicine (5).This herb has been extensively used orally and topically to address various ailments, including gastrointestinal discomfort, arthritis, and bruises (5,7).Its significance extends beyond China, finding a place in traditional medical practices in countries such as India and Nepal (7).Additionally, the unique flavor and numbing taste of the dried fruit follicles of Z. bungeanum have made it a significant ingredient in Chinese cuisine (1).Over time, research on and applications of Z. bungeanum have expanded significantly.Z. bungeanum exhibits diverse pharmacological activities such as antiinflammatory, analgesic, antibacterial, and anti-tumor properties, showcasing therapeutic effects on multiple organ systems, including the gastrointestinal tract, cardiovascular system, and nervous system (2).The plant contains over 140 compounds, including polyphenols, alkaloids, lignans, coumarin, fatty acids, and essential oils (2,11,12).Beyond its polyphenolic content, constituents like hydroxy-alphasanshool, a mixed extract of fatty acids, and essential oil extraction from Z. bungeanum, have proven anti-inflammatory efficacious in various systems, such as the nervous system (127) and digestive system (140,141).As research progresses, the application of Z. bungeanum in both medical and daily contexts continues to broaden, promising potential benefits to human health.
Polyphenols from Z. bungeanum emerge as a promising class of natural compounds with potential health benefits, particularly in preventing and treating inflammatory diseases.Numerous studies have highlighted their anti-inflammatory and antioxidant properties through a variety of mechanisms, including: • Inhibiting pro-inflammatory cytokine production, such as IL-1b, TNFa, and IL-6.• Suppressing the NF-kB and MAPK signaling pathway, central to inflammation.• Activating the Nrf2/HO-1 signaling pathway, protecting cells from oxidative damage.• Modulating the immune response, promoting regulatory T cells and suppressing inflammatory T cells.
While much of the current research on polyphenols of Z. bungeanum has been conducted in vitro or in animal models, promising preclinical data suggest therapeutic potential for a range of inflammatory diseases in humans, including ulcerative colitis, arthritis, asthma, chronic obstructive pulmonary disease, cardiovascular disease, and neurodegenerative diseases.In addition to their anti-inflammatory effects, polyphenols of Z. bungeanum have demonstrated other beneficial properties, such as anti-cancer, anti-diabetic, anti-bacterial, and neuroprotective effects.
Several clinical trials have tested Z. bungeanum polyphenols in non-inflammatory diseases, indicating the safety of these compound.Future research should prioritize human clinical trials to validate the clinical efficacy of polyphenols of Z. bungeanum on inflammatory diseases.Additionally, researchers should investigate: • Optimal dosages and long-term safety of polyphenols of Z. bungeanum.• Synergistic or antagonistic interactions of polyphenols of Z.
bungeanum with other bioactive substances.• Effects of polyphenols of Z. bungeanum on specific biomarkers of inflammation and disease activity.• Mechanisms by which polyphenols of Z. bungeanum exert their beneficial effects.
Ultimately, research outcomes may contribute to the development of novel therapeutic interventions and dietary recommendations that harness the power of polyphenols of Z. bungeanum to improve human health and well-being.For example, polyphenols of Z. bungeanum could be used to develop: • New drugs or dietary supplements for the prevention and treatment of inflammatory diseases.• Functional foods or fortified beverages that promote overall health and well-being.• Personalized nutrition plans that take into account individual genetic and environmental risk factors.
Overall, the polyphenols of Z. bungeanum are a promising class of natural compounds with the potential to play a significant role in human health and well-being.Further research is needed to fully elucidate their mechanisms of action and develop safe and effective therapies for human use.

TABLE 2
Direct target of Z. bungeanum polyphenols.