Swertia species are the valuable medicinal plants. These are the biological sources of useful xanthones, triterpenoids, flavonoids, steroids, sugars and alkaloids. Naturally occurring xanthones are now a day emerged as an important class of organic compounds due to their remarkable pharmacological and other biological applications. In the present study, the allelopathic effect of xanthone extract of three Swertia species was studies with reference to catalase, peroxidase and polyphenol oxidase activity under two different conditions i.e. under lab condition and culture condition. Treatment of xanthone extract was administered with three concentrations, 0.05%, 0.1% and 0.5%. Advancement in the studied enzyme activity was investigated in the culture condition. The activities of Catalase and peroxidase were observed to be enhanced in the experimental set of lab condition but polyphenol activities were decreased.
