New Bioactive Polyphenols from Theobroma grandiflorum ("Cupuacu")

Activity-guided fractionation of Theobroma grandiflorum (“cupuacu”) seeds resulted in the identification of two new sulfated flavonoid glycosides, theograndins I (1) and II (2). In addition, nine known flavonoid antioxidants, (+)-catechin, (−)-epicatechin, isoscutellarein 8-O-β-d-glucuronide, hypolaetin 8-O-β-d-glucuronide, quercetin 3-O-β-d-glucuronide, quercetin 3-O-β-d-glucuronide 6‘ ‘-methyl ester, quercetin, kaempferol, and isoscutellarein 8-O-β-d-glucuronide 6‘ ‘-methyl ester, were identified. Theograndin II (2) displayed antioxidant activity (IC50 = 120.2 μM) in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical assay, as well as weak cytotoxicity in the HCT-116 and SW-480 human colon cancer cell lines with IC50 values of 143 and 125 μM, respectively. While 1 was less active as an antioxidant than 2, the known compounds were more potent in the DPPH assay (IC50 range 39.7−89.7 μM).