Investigation on the Biological Properties of Selected Medical Plant Hypericum Mysorense

Abstract

Cancer, cardiovascular and many viral diseases are the most dangerous diseases to human beings, thus research into these diseases has to be prioritized. Due to inefficiency, non-specificity, side-effects and tolerance or resistance produced against existing chemotherapeutic agents, new drug discovery against these diseases has taken central stage in research. Hypericum mysorense a plant belonging to Hypericum genus showed potent antioxidant activity. The flowering top and leaf extracts were most potent in vitro antioxidants compared to other extracts. These two extracts were tested for in vivo antioxidant and hepatoprotective activities. Among the two, flowering top extract showed potent antioxidant and hepatoprotective activity which was comparable to the standard drug silymarin. It suggests that the bioactive components are more in flowering tops which also had highest flavonol and phenolic content. Earlier studies by most research groups working on other species of Hypericum have concluded that hypericin and pseudohypericin are responsible for its biological activities. Recent reports from other research groups suggested the biological activity of Hypericum species is also because of compounds other than these two. In the present study we have mainly worked on its rich flavonoid content and tried to find out the bioactive component among them. Antioxidant based bioactive guided isolation from the flowering part of the plant yielded three flavonoids. Among them, two (quercetin and rutin) are well known potent flavonoid antioxidants. The third compound was identified as hyperoside which showed excellent in vitro antioxidant activity comparable to the standards used in the study. The pulse radiolysis studies of hyperoside showed its potent reactive oxygen and reactive nitrogen scavenging activity. The low reduction potential value at pH 7 revealed its better antioxidant activity than the standard antioxidant vitamin E. Hence the potent antioxidant activity of the flowering top extract may be due to its high flavonoid content.