Two New Dihydrochalcone Glucosides from Balanophora subcupularis

Two new dihydrochalcone glucosides, phloretin-4 '-O-(4 ''-O-galloyl)-beta-D-glucoside (1) and phloretin-4 '-O-(3 ''-O-galloyl)-beta-D-glucoside (2), were isolated from the fresh aerial part of Balanophora subcupularis P.C.Tam, together with eight known flavonoid glycosides, phloretin-4 '-O-(6 ''-O-galloyl)-beta-D-glucoside (3), trilobatin (4), 3-hydroxyphloretin-4 '-O-beta-D-glucoside (5), phloretin-4 '-O-(4 '',6 ''-O-Sa-hexahydroxydiphenoyl)-beta-D-glucoside (6), naringenin-7-O-beta-D-glucoside (7), eriodictyol-7-O-beta-D-glucoside (8), kaempferol-7-O-beta-D-glucoside (9), and quercetin-7-O-beta-D-glucoside (10). All of the compounds were elucidated by spectroscopic methods. Their antioxidant activities were examined by DPPH and ABTS assay. Compounds 1-3, 5, 6, and 10 showed significant radical scavenging activities compared with ascorbic acid.