Phenolic Compounds and Seed Oil Composition of Ziziphus mauritiana L. Fruit

Ber is a tropical fruit which grows from the tree species, Ziziphus mauritiana Lamk. The pericarp of this fruit is consumed either fresh or dried while its seeds are usually discarded as waste. The present study was undertaken to evaluate the antioxidant activity and phenolic content of the fruit, and to evaluate if any potential value-added phytochemicals can be extracted from seed waste. The edible portion of the fruit was extracted with 60% aqueous methanol by sonication and then assayed for total phenolic content, antioxidant activity, and individual phenolic compounds by HPLC-DAD. The seed oil extracted with n-hexane was assayed for fatty acid composition, sterols, and tocopherols content by GC-MS. The total phenolic content of the fresh fruit was 12.8 mg/g as gallic acid equivalent, with an antioxidant activity of 0.5 mu mol/g as quercetin equivalent by Folin-Ciocalteu and DPPH assays respectively Hydroxybenzoic acid, vanillin, ortho- and para-coumaric acid, epicatechin, quercetin, and naringenin were tentatively identified by matching retention time and UV spectra with those of commercial reference standards. GC-MS analysis of the TMS derivative of fruit extract showed the presence of following compounds: propanoic, hexanoic, heptanoic, octanoic, nonanoic, decanoic, dodecanoic, n-pentadecanoic, hexadecanoic, benzoic, and trihydroxybenzoic acids. In addition, D-fructose, galactofuranoside, gluconic acid, and beta-sitosterol were also detected. In seed oil of ber, the fatty acids such as, hexanoic, octanoic, 7-octadecenoic, 9,12-octadecendoic, eicosanoic, 11-eicosenoic, and docosanoic acid with 7-octadecenoic acid, were found to make up 55% of total fatty acids. Squalene, gamma-tocopherol and stigmasterol were identified as minor constituents in the unsaponifiable fraction of seed oil. Current study shows that ber fruit is a good source of healthy phytochemicals.