title: Antioxidant activity of Siamese neem tree (VP1209).
abstract: Leaves, fruits, flowers and stem bark extracts from the Siamese neem tree (Azadirachta indica A. Juss var. siamensis Valeton, Meliaceae) were assessed for antioxidant activity in vitro using the 1,1-diphenyl-2-picryl hydrazyl (DPPH) scavenging assay, total antioxidant activity and inhibition of lipid peroxidation in Chago K1 cancer cell culture by the thiobarbituric acid reactive substances (TBARS) method. The results showed that leaf aqueous extract, flower and stem bark ethanol extracts exhibited higher free radical scavenging effect on the DPPH assay with 50% scavenging activity at 26.5, 27.9 and 30.6 microg/ml, respectively. The total antioxidant activity of these extracts was found to be 0.959, 0.988 and 1.064 mM of standard trolox, respectively. At 100 microg/ml, the flower ethanol and leaf aqueous extracts significantly decreased malondialdehyde (MDA) levels (46.0 and 50.6%, respectively) by the TBARS method. The results suggest that extracts from leaf, flower and stem bark of the Siamese neem tree have strong antioxidant potential. This report supports the ethnomedical use of young leaves and flowers of this plant as a vegetable bitter tonic to promote good health.
authors.affiliation: Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayuthaya Rd., Ratchatewi, Bangkok 10400, Thailand.
authors.forename: Pongtip
authors.initials: P
authors.lastname: Sithisarn
authors.forename: Roongtawan
authors.initials: R
authors.lastname: Supabphol
authors.forename: Wandee
authors.initials: W
authors.lastname: Gritsanapan
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000494:pharmacology; D000975:Antioxidants / Q000737:chemistry*; D031601:Azadirachta / Q000737:chemistry*; D001713:Biphenyl Compounds; D002460:Cell Line; D035264:Flowers / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D010851:Picrates / Q000737:chemistry; D024301:Plant Bark / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D013785:Thailand; D017392:Thiobarbituric Acid Reactive Substances / Q000737:chemistry; D014466:Ultraviolet Rays
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D010936:Plant Extracts; D017392:Thiobarbituric Acid Reactive Substances; C004931:1,1-diphenyl-2-picrylhydrazyl