Extracts and compounds with anti-diabetic complications and anti-cancer activity from Castanea mollissina Blume (Chinese chestnut)

BACKGROUND: Castanea mollissima Blume (Chinese chestnut), as a food product is known for its various nutrients and functional values to the human health. The present study was carried out to analyze the anti-diabetic complications and anti-cancer activities of the bioactive compounds present in C. mollissima. METHODS: The kernels (CK), shells (CS) and involucres (CI) parts of C. Blume were extracted with 90% alcohol. The water suspension of these dried alcohol extracts were extracted using EtOAc and n-BuOH successively. The n-BuOH fraction of CI (CI-B) was isolated by silica gel column, Sephadex LH 20 column and preparative HPLC. The isolated compounds were identified by ¹H-NMR, ¹³C-NMR, HMBC, HMQC and ESI-Q-TOF MS, All the fractions and compounds isolated were evaluated on human recombinant aldose reductase (HR-AR) assay, advanced glycation end products (AGEs) formation assay and human COLO 320 DM colon cancer cells inhibitory assay. RESULTS: CI-B was found to show a significant inhibitory effect in above biological screenings. Six flavonoids and three polyphenolic acids were obtained from CI-B. They were identified as kaempferol (1), kaempferol-3-O-[6''-O-(E)-p-coumaroyl]-β-D-glucopyranoside (2), kaempferol-3-O-[6''-O-(E)-p-coumaroyl]-β-D-galactopyranoside (3), kaempferol-3-O-[2''-O-(E)-p-coumaroyl]-β-D-glucopyranoside (4), kaempferol-3-O-[2", 6"-di-O-(E)-p-coumaroyl]-β-D-glucopyranoside (5) and kaempferol-3-O-[2", 6"-di-O-(E)-p-coumaroyl]-β-D-galactopyranoside (6), casuariin (7), casuarinin (8) and castalagin (9). Compounds 2–9 were found to show higher activity than quercetin (positive control) in the AR assay. Compounds 3–6, 8, and 9 showed stronger inhibitory effects than amino guanidine (positive control) on AGEs production. Compounds 4–6, 7, and 8 showed much higher cytotoxic activity than 5-fluorouracil (positive control) against the human COLO 320 DM colon cancer cells. CONCLUSIONS: Our results suggest that flavonoids and polyphenolic acids possesses anti-diabetes complications and anti-cancer properties, and they were presumed to be the bioactive components of Castanea mollissima Blume.