Isolation and characterization of secondary metabolites from Gaultheria tenuifolia berries

Abstract

Gaultheria berries (Ericaceae) are consumed as food or used in folk medicine throughout the world. In the present study, Gaultheria tenuifolia berries were studied to describe their polyphenol and iridoid composition, aroma volatiles, and cytoprotective effects. In total, 14 metabolites were isolated using a combination of countercurrent chromatography and Sephadex LH-20, namely, cyanidin-3-O-β-galactoside, cyanidin-3-O-β-arabinoside, 3-O-caffeoylquinic acid, 5-O-caffeoylshikimic acid, quercetin, quercetin-3-O-β-glucuronide, quercetin-3-O-β-rutinoside, quercetin-3-O-β-glucoside, quercetin-3-O-β-arabinoside, quercetin-3-O-β-rhamnoside, 6α-hydroxydihydromonotropein-10-trans-cinnamate, monotropein-10-trans-cinnamate, and an (epi)-catechin dimer and trimer. Other flavan-3-ols, proanthocyanidins, and iridoids were tentatively identified by spectroscopic and spectrometric means in the fruit extracts. The tentative volatile organic compound characterization pointed to methyl salicylate as responsible for the aroma of this species. The extracts showed significant cytoprotective effects in an oxidative stress model in human gastric epithelial cells. This is the first report on the isolation, characterization, and potential biological activity of secondary metabolites from G. tenuifolia berries and insights on its possible application as a functional food. PRACTICAL APPLICATION: Berries are desirable fruit species because of their phytochemical composition and pleasant taste. Gaultheria berries are special due to their high content of iridoids and the presence of salicylic acid derivatives. Aroma of native berries is relevant for the development of new products reflecting the local identity and use of fruits. The present work involves cooperation of academia and industry on the constituents of the native products. The results provided in this article could be useful for the introduction of this species in the food and nutraceutical industries.

Keywords: Gaultheria; antioxidant; counter-current chromatography; fruit; liquid chromatography; polyphenols; volatiles.