Abstract

Extraction of nine plants selected from the family Euphorbiaceae, Lauraceae, Malvaceae and Balsaminaceae was done in petroleum ether, chloroform, ethyl acetate and methanol/n-butanol in order of increasing polarity using soxhlet apparatus. Total phenolic contents were determined with Folin-Ciocalteu reagent which ranged from 30.5 to 547.0 mg GAE/g of extract. Maximum phenolic contents were found in n-butanol extract of Ricinus communis. Antioxidant activities of these extracts were evaluated through DPPH^• radical scavenging, phosphomolybdate and ferric thiocyanate (FTC) methods. Methanolic extract of Cinnamomum zeylanicumand Cinnamomum tamala showed highest antiradical (96.8%) and phosphomolybdate (1.131) activity, respectively, while ethyl acetate extract of R. communis exhibited maximum lipid per-oxidation (FTC) activity (79.3%). IC₅₀ value of chloroform extract of C. tamala (2.2 μg/ml) was less than gallic acid (4.4 μg/ml), while ethyl acetate and methanol extracts of Abutilon bidentatum, Impatiens bicolorand Impatiens edgeworthii exhibited the IC₅₀ values in the range of 10.0 - 20.0 μg/ml.

Key words: Euphorbiaceae, Lauraceae, Malvaceae, Balsaminaceae, antioxidant assays, medicinal plants, total phenols.