Chemical constituents from needles of Torreya nucifera

Abstract

Torreya nucifera (Linn.) Sieb. et Zucc. (Taxaceae), a species mainly distributed in Japan, Korea and China and it has long been extensively used in traditional medicines for the treatment of various diseases relating to oxidation and inflammation [1–3]. In this study, needles of T. nucifera were extracted with acetone-H2O (7:3, v/v), fractionated with hexane, chloroform and ethylacetate (EtOAc), and freeze dried to give some dark brown powders. The resulting EtOAc soluble fraction mixture was then repeatedly chromatographed on a Sephadex LH-20 open column using a series of aqueous methanol and ethanol-hexane mixtures as eluents. Most of the needle extractives were flavan and their methyl ether derivatives, such as (+)-catechin (1), (–)-epicatechin (2), (+)-gallocatechin (3), (–)-epigallocatechin (4), 3-O-methyl-(+)-catechin (5) and 3-O-methyl-(–)-epicatechin (6), as well as protocatechuic acid (7), one of benzoid acid. The structure elucidation and determination of the isolated compounds were based on physiochemical and spectroscopic methods, including 1H and 13C NMR, NOE and EI-MS analysis. Compounds 1, 3, 4, 5 and 7 were isolated from the needles of this species for the first time. Antioxidant potential of the isolates was assessed by DPPH free radical scavenging assay. Results indicated that EtOAc soluble fraction (IC50 13.8g/ml), compounds 1–4 and 7 (IC50 9.6, 9.4, 12.7, 9.5, and 12.9g/ml, respectively) exhibited significant scavenging effects, compared with positive control of curcumin (IC50 13.8g/ml. This indicates that T. nucifera needles could be a promising source for antioxidant-related-medicine exploitation.