Antitumor effects of flavanol glycosides against human cancer cell lines.

R1–R5 (name, no.)	IC50 (μM)
	HL-60	U937	SK-MEL-1
R1 = R2 = R3 = R4 = Ac, R4 = H (kaempferol tetraacetate, 132a)	45	48	37
R1 = R2 = R3 = R5 = Ac, R4 = OAc (quercetin pentaacetate, 133a)	38	25	58
R1 = β-d-Gal Ac, R2 = R3 = R5 = H, R4 = H (trifolin heptaacetate, 134a)	21	10	15
R1 = β-d-Gal OMe, R2 = R3 = R5 = Me, R4 = H (heptamethyltrifolin, 134b)	88	>100	>100
R1 = β-d-Gal Ac, R2 = R3 = R5 = Ac, R4 = OAc (hyperoside acetate, 135a)	15	19	23
R1 = 2-O-acetyl-β-d-Gal, R2 = R3 = R5 = H, R4 = OH (2′′-acetylhyperoside, 136)	>100	>100	>100
R1 = 6-O-acetyl-β-d-Gal, R2 = R3 = R5 = H, R4 = OH (6′′-acetylhyperoside, 137)	>100	>100	>100
R1 = β-d-Gal Ac, R3 = β-d-Glu Ac, R2 = R5 = Ac, R4 = H (glucotrifolin acetate, 138a)	>100	>100	>100