Cancer chemopreventive theasaponin derivatives from the total tea seed saponin of Camellia sinensis

• Natural QR inducing agents were screened and identified from the hydrolysis products of the total tea seed saponin in Camellia sinensis.
• Compounds 7, 12 and 14 were selected as potential QR inducing agents with IR value at 2.87, 3.02 and 2.33.

Natural QR (quinine oxidoreductase) inducers play critical roles in cancer chemoprevention. Because tea seed saponins of Camellia sinensis exhibited significant QR inducing activities, this study aimed to find bioactive theasaponin derivatives by structure modification on the sugar part and acyl groups. Three kinds of hydrolysis methods were employed to afford 7 major acid hydrolysis products (1–7), 10 alkaline hydrolysates (8–17) and 2 derivatives (3, 18) by oxidative alkaline-degradation. They were elucidated as kaempferol (1), camelliagenin B (2), camelliagenin A (3), 21-O-angeloybarringtogenol C (4), 5-hydroxymethylfurfural (5), 16-O-angeloybarringtogenol (6), 23-aldehyde-16-O-angeloybarringtogenol (7), desacyl-assamsaponin D (8), desacyl-theasaponin A5 (9), desacyl-assamsaponin E (10), desacyl-theasaponin C1 (11), desacyl-theasaponin E (12), desacyl-theasaponin E13 (13), desacyl-assamsaponin F (14), desacyl-theasaponin F1 (15), desacyl-theasaponin G (16), desacyl-assamsaponin A (17), camelliagenin C (18) accordingly. By the QR inducing activity assay, compounds 7, 12 and 14 were selected as potential QR inducing agents with IR value at 2.87, 3.02 and 2.33.