Abstract:
The burden of chronic diseases is rapidly increasing worldwide. Diet and nutrition are important factors in the promotion and
maintenance of good health throughout the entire life course. Physiological and biochemical alterations in the human body may
result in overproduction of free radicals leading to oxidative damage to biomolecules (e.g. lipids, proteins, DNA). Use of
medicinal plant based products has increased recently because of their exerted beneficial properties such as antioxidant,
anticancer, hypoglycaemic and hypolipidaemic activities. The present study was designed to assess the in vitro antioxidant
activity and free radical scavenging capacity of ten medicinal plants which are extensively used in the Ayurvedic treatment
systems in Sri Lanka. Water extracts were prepared and evaluated for their free-radical scavenging capacity and antioxidant
activity using a number of chemical assays; DPPH, ABTS and FRAP. The total Phenolic (TPC) and Total Flavonoid Content
(TFC) were also assessed. The TPC and TFC values of the extracts varied from 295.94±3.65 – 5.22±0.08 (mg Gallic Acid
Equivalent (GAE)/g dry weight) and 115.01±1.69 – 0.97±0.002 (mg Catechin Equivalent (CE)/g dry weight) respectively. The
DPPH and ABTS radical scavenging activities were higher for the Nelli (Phyllanthus emblica) extract while the least activity was
observed in Venivel (Cosciniumfenestratum) extract. The FRAP activity of the extracts was well proved with the DPPH· and
ABTS radical scavenging activities. A positive, significant linear relationship between antioxidant activity and TPC and TFC
content showed that phenolic compounds and flavonoids were the dominant antioxidant components in the medicinal herbs
studied.
