Diversity of antioxidant properties among Madan (Syzygium cumini) trees in Belihuloya Region, Sri Lanka: Potential for improvement for community use

Abstract

Syzygium cumini (L.) Skeels, (Madan, Jambolan) is widely distributed in tropical and subtropical regions with high diversity and considered as underutilized fruit crop in all over the world. Though S. cumini is underutilized fruit crop it shows high potential of uses as multipurpose tree such as food crop (Fruit), medicinal plant, timber crop, tree for forestry etc. S. cumini traditionally uses as medicinal plant as treatment for various disease conditions. To improve the plant for promising uses it requires intensive study of diversity for different characters. In Sri Lanka it naturally growing in wide range of areas from North to South but pay remarkably low attention for use it as fruit crops or as medicinal plant. In Belihuloya region it grows naturally without having much intention to use as fruit crop. As the tree adapted to the condition in the region, improved varieties would have high potential to use by the community in the region. The present study is to investigate the diversity of antioxidant properties among S. cumini tree population in Belihuloya region. Phytochemical investigation was carried out on the crude ethanol and methanol extracts of the pericarp and seed of S. cumini fruit. The results showed that the methanol extracts were more active than ethanol extracts. The Folin-Ciocalteau method was used to find the Total Phenolic Content (TPC). Highest total phenolic content was recorded in methanol seed extracts and varies from 98.73±2.64 to 18.970±0.11 mg Gallic acid equivalent/ g of fruit among trees. The lowest TPC was recorded by ethanol pericarp extracts which is vary from 5.77±0.04 to 0.99±0.004 mg GAE/ g of fruit. Total Flavonoid Content (TFC) was detected using Aluminium chloride. Highest total flavonoid content was recorded in methanol seed extracts which was varied from 2.38±0.02 to 0.64±0.05 mg Quercetin equivalent/ g of fruit while lowest resulted by ethanol pericarp extracts range from 1.52±0.03 to 0.25±0.01 QE/g of fruit. 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) assay was done to find out the antioxidant activity. The highest IC₅₀ resulted by seed extracts which is range from 1.63±0.02 to 0.60±0.01 trolox/ g of extract. S. cumini trees exhibit wide range of antioxidant variability in their natural population in the region and this results will be source for consider the breeding for improve promising S. cumini varieties to the region.