2011 Volume 5 Pages 22-25
Vegetables and fruits are good sources of free radical scavengers or antioxidants. To evaluate the free radical scavenging activity of a plant extract, a few simple steps using the 1,1-diphenyl-2- picryl hydrazyl (DPPH) assay can be followed. Any plant part can be processed to produce crude extracts which can be used for testing. Using this technique, a small class of tertiary students determined the antioxidant property of ethanolic crude leaf extracts of some endemic and indigenous plants. The plants used were Ardisia pyramidalis Roth (Myrsinaceae), Baccaurea tetrandra (Baill.) Mull.Arg. (Phyllanthaceae), Chisocheton pentandrus (Blanco) Merr. (Meliaceae), Ficus septica Burm. (Moraceae), Parameria laevigata (Juss.) Moldenke (Apocynaceae),Parartocarpus venenosus (Zoll. & Moritzi) Becc. (Moraceae), Streptocaulon baumii Decne. (Asclepiadaceae), Uncaria perrottetii (A. Rich) Merr. (Rubiaceae), and Voacanga globosa (Blanco) Merr. (Apocynaceae). Crude leaf extracts of U. perrottetti and B. tetrandra were observed to possess a high free radical scavenging activity with values beyond 90% of that of gallic acid. These were fractionated further, and subsequent assays showed that ethyl acetate fractions for both plants had high free radical scavenging activity indicating that they contain potential chemopreventive agents against many diseases such as cancer, cardiovascular disorders and aging. Free radical scavenging activities demonstrated by leaf extracts of A. pyramidalis and C. pentandrus did not reach 70% of that of gallic acid. All the rest of the plant extracts showed very low or no free radical scavenging activity.
