Sri Lankan black tea (Camellia sinensis L.) inhibits the methylglyoxal mediated protein glycation and potentiates its reversing activity in vitro

摘要

Objective: To evaluate inhibitory activity of methylglyoxal (MGO) mediated protein glycation and ability to potentiate its reversing activity and range of antioxidant properties of Sri Lankan low grown orthodox orange pekoe grade black tea. Methods: Freeze dried black tea brew (BTB) was used as the sample in this study. Anti-glycation and glycation reversing activity was studied in bovine serum albumin (BSA)-MGO model. Antioxidant properties were studied using total polyphenolic content, total flavonoid content, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power in vitro antioxidant assays. Results: The results demonstrated significant (P < 0.05) and dose dependant inhibition of BSA-MGO glycation [IC50: (164.30 ± 4.85) μg/mL], potentiating of its reversing activity [EC50:(235.39 ± 5.37) μg/mL] and marked antioxidant properties [total polyphenolic content: (119.55 ± 9.97) mg gallic acid equivalents/g BTB; total flavonoid content: (6.04 ± 1.26) mg quercetin equivalents/g BTB; 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, 1,1-diphenyl-2-picrylhydrazine and ferric reducing antioxidant power: (3.29 ± 0.06), (1.95 ± 0.15) and (1.31 ± 0.19) mmol Trolox equivalents/g BTB, respectively]. No correlations were observed between antioxidant activity and BSA-MGO glycation. Conclusions: The novel properties observed for Sri Lankan orange pekoe grade black tea indicate its usefulness as a supplementary beverage in managing MGO and advanced glycation end products related diseases and ailments.