Phytochemical Constituents and Antioxidative Activity of Schleichera oleosa Fruit doi.org/10.26538/tjnpr/v5i8.20

Abstract

Schleichera oleosa (Lour) Oken is a plant in the family Sapindaceae found in Thailand. Although the fruit of this plant is popularly consumed, there is a lack of information about its biological activities. This study determined the antioxidant activity of this fruit and identified the active constituents. The peel, juice, and seed parts of the fruit were separated and extracted with ethanol. Total carotenoid, phenolic, flavonoid, and anthocyanin contents were determined by standard spectrophotometric methods. Ascorbic acid and beta-carotene contents were determined by HPLC. Antioxidative activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azobis (3-ethylbenzothialzoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP), oxygen radical absorption capacity (ORAC), ferric thiocyanate, and metal chelating activity assays. The total carotenoid content was 11.90-343.57 mg/g extract as beta-carotene equivalents, total phenolic content was 4.06-9.91 mg/g extract as gallic acid equivalents, total flavonoid content was 2.19-9.18 mg/g extract as quercetin equivalents, and total anthocyanin content was 0.20-2.81 mg/g extract calculated as mg cyanindin-3-glucoside. Levels of ascorbic acid and beta-carotene were highest in the juice extract. Peel extract showed the highest antioxidative activity in the DPPH, ABTS, FRAP, and ORAC assays, while the juice extract showed the highest antioxidative activity in the ferric thiocyanate and metal chelating assays. Seed extract showed the least antioxidant activity. High levels of antioxidant compounds in extracts from the peel and juice parts of S. oleosa fruit corresponded with high antioxidant activities.