About this Research Topic
Hypericum is an important genus of the family Hypericaceae, which includes about 484 species of herbs, shrubs and trees. Being the home for many important bioactive compounds, these species have a long traditional value as medicinal plants. Currently, several species of this genus has been used in ailments as knowledge-based medicine in many countries. In the recent past, several pharmacological studies have been performed using crude extracts to evaluate the traditional knowledge. Results of those studies have revealed that extract of Hypericum exert several pharmacological properties including antidepressant, antimicrobial, antitumour and wound healing effects. Phytochemical analyses revealed that these species produce a broad spectrum of valuable compounds, mainly naphthodianthrones (hypericin and pseudohypericin), phloroglucinols (hyperforin and adhyperforin), flavonoids (hyperoside, rutin and quercitrin), benzophenones/xanthones (garcinol and gambogic acid), and essential oils.
Noticeably, Hypericum extracts have been used to treat mild to moderate depression from ancient to present times and the antidepressant efficacy of Hypericum extracts has been accounted for its hyperforin content, which is known to inhibit the uptake of aminergic transmitters such as serotonin and noradrenaline into synaptic nerve endings. Neurodegenerative diseases and inflammatory responses are also linked with Reactive Oxygen Species (ROS) production. A wide range of flavonoids present in Hypericum extracts, namely, rutin, quercetin, and quercitrin exhibit antioxidant/free radical scavenging activity. Hypericin, beside hyperforin, is the active molecule responsible for the antitumor ability of Hypericum extracts and is seen as a potent candidate to treat brain tumour. Recent attempts of using hypericin in patients with recurrent malignant brain tumours showed promising results. Collectively, Hypericum species contains multiple bioactive constituents, suggesting their potential to occupy a huge portion of phytomedicine market.
Today, studies on medicinal plants are rapidly increasing because of the search for new active molecules, and for the improvement in the production of plants or molecules for the herbal pharmaceutical industries. In the post genomic era, application of molecular biology and genomic tools revolutionized our understanding of major biosynthetic pathways, phytochemistry, pharmacology of Hypericum species and individual compounds. This special issue mainly focuses on the recent advancements made in the understanding of biosynthetic pathways, application of biotechnology, molecular biology, genomics, pharmacology and related areas. Although this topic is primarily targeted to the members of the HYPEXPLOR consortium (www.hypexplor.com), in the framework of the 7th annual Hypericum meeting putatively scheduled for 2015- 2016 at Poznan, Poland, contributions from other authors are also equally welcomed.
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