%0 Journal Article %T Canthium parviflorum Leaves: Antioxidant Activity in Food and Biological Systems, pH, and Temperature Stability %A Vanitha Reddy Palvai %A Sowmya Mahalingu %A Asna Urooj %J Chinese Journal of Biology %D 2014 %R 10.1155/2014/813201 %X Canthium parviflorum leaves were analyzed for their proximate and phytochemical composition. The leaves were extracted with methanol (ME) and analyzed for antioxidant activity by radical scavenging method, reducing power, ferric reducing capacity, and in vitro inhibition of Fenton¡¯s reagent induced oxidation in oil emulsion and microsomes. In addition, the effect of high temperature (100¡ãC, 15 and 30£¿min) and pH (4.5, 7, and 9) on the antioxidant activity of ME was investigated. The leaves were rich in polyphenols, flavonoids ¦Â-carotene, glutathione, ¦Á-tocopherol, and ascorbic acid. The ME exhibited varying degree of antioxidant activity in a dose dependent manner. The RSA was 68%¨C500£¿¦Ìg. Reducing potency was 0.34 and FRAP was 1.377. Canthium exhibited greater inhibition of oxidation in microsomes (73%) than in the oil emulsion (21%). Heat treatment resulted in reduction of radical scavenging activity of extract from 68% to 40%. At pH 4.5 and 7 methanol extract exhibited some percent of antioxidant activity which ranged between 18 and 32%. Data indicates Canthium as a good source of antioxidants and methanol extract exhibited good antioxidant activity. 1. Introduction In recent years, secondary plant metabolites with unknown pharmacological activities have been extensively investigated as a source of medicinal agents. Natural antioxidants present in food and other biological materials have attracted considerable interest because of their presumed safety and potential nutritional and therapeutic effects. The increasing interest in the search for natural replacements for synthetic antioxidants has led to the antioxidant evaluation of a number of plant sources [1] especially spices and herbs [2]. Screening active compounds from plants has led to the discovery of new medicinal drugs which have efficient protection and treatment roles against various degenerative diseases. In recent years, a large number of plants have been screened as a viable source of natural antioxidants such as tocopherol, vitamin C, carotenoids, and phenolic compounds which are responsible for maintenance of health [3, 4]. At present time, medicinal plants as rich source of natural bioactive components are given priority to study their antioxidant activity and explore their utilization in treatment of diabetes mellitus, dyslipidemia, and cardiovascular diseases. Our team has explored some medicinal plants, namely, Moringa oleifera [5], Morus indica [6], Aegle marmelos [7], Raphanus sativus [8], and Psidium guajava [9], for their antioxidant activity and stability. Before exploring a %U http://www.hindawi.com/journals/cjb/2014/813201/