ABSTRACT
For centuries oak wood (Quercus robur) has been used in aging of wines and spirits, which is based on pleasant flavors given to beverages by phenolics transferred to the liquid during the maturation process. Other metabolites, such as triterpenoids, can also be released. Searching for extractable triterpenoids in oak heartwood, 12 new, 1-12, and five known, 13-17, oleanane types were isolated and characterized. Their cytotoxicities were tested against cancer cells (PC3 and MCF-7) and lymphocytes. Breast cancer cells (MCF-7) were the most affected by triterpenoids, with roburgenic acid, 4, being the most active compound (IC50 = 19.7 µM). Selectivity was observed for compounds 1-3, 8, 9, and 16, exhibiting an IC50 > 200 µM against lymphocytes, while active against cancer cells. A galloyl unit attached to the triterpenoid moiety was established as the key feature for such effect. These results highlight the occurrence of triterpenoids in oak heartwood and their relevance for chemoprevention of breast cancer.
Subject(s)
Plant Extracts/chemistry , Quercus/chemistry , Triterpenes/chemistry , Wood/chemistry , Alcoholic Beverages/analysis , Cell Line, Tumor , Cell Proliferation/drug effects , Chromatography, High Pressure Liquid , Flavoring Agents/chemistry , Flavoring Agents/pharmacology , Gas Chromatography-Mass Spectrometry , Humans , Plant Extracts/pharmacology , Triterpenes/pharmacologyABSTRACT
For centuries wood containers have been used in aging of wines and spirits, due to the pleasant flavors they give to the beverages. Together with oak, sweet chestnut wood (Castanea sativa) have been often used for such purpose. The maturation process involves the transfer of secondary metabolites, mainly phenolics, from the wood to the liquid. At the same time, other metabolites, such as triterpenoids and their glycosides, can also be released. Searching for the extractable triterpenoids from sweet chestnut heartwood (C. sativa), two new ursane-type triterpenoid saponins named chestnoside A (1) and chestnoside B (2), together with two known oleanen-type analogs (3 and 4) were isolated and characterized. The cytotoxicity of isolated compounds was tested against two cancer cell lines (PC3 and MCF-7), and normal lymphocytes. Breast cancer cells (MCF-7) were more affected by tested compounds than prostate cancer cells (PC3). Chestnoside B (2) exhibited the strongest cytotoxicity with an IC50 of 12.3 µM against MCF-7 cells, lower than those of positive controls, while it was moderately active against normal lymphocytes (IC50 = 67.2 µM). These results highlight the occurrence of triterpenoid saponins in sweet chestnut heartwood and their potential for the chemoprevention of breast cancer.
