Antioxidant, antihypertensive, and anticancer activities of the flavonoid fractions from green, oolong, and black tea infusion waste

The flavonoid fractions from green (GTF), oolong (OTF) and black tea (BTF) infusion waste were comparatively studied on the antioxidant, antihypertensive and anticancer activities. HPLC-MS method was used to analyze the compositions of the flavonoid fractions. BTF exhibited the highest anti-hypertension effect and anticancer activities. Quercetin-3-O-rutinoside (QR) was highly related to angiotensin I-converting enzyme (ACE) inhibitory effect (r = 1.000), and BTF exhibited the highest ACE inhibitory effect with the IC50 value of 46.72 mu g/ml. BTF administration resulted in systolic decrease of 57.08 mmHg at 8 hr which was even higher than captopril (p < 0.05). The IC50 value of BTF on the growth of SMMC7721 cells was 52.31 mu g/ml. Quercetin-3-O-rutinoside, kaempferol 3-O-rutinoside, kaempferol 3-O-glucoside and patuletin O-glucoside might be the effective constituents in BTF by the principal components analysis. BTF might be good nutrition supplements in the treatment of hypertension and hepatocellular carcinoma.