Berries from the Gaultheria genus (Ericaceae) are used worldwide as food and in traditional medicine [1]. Most studies have been carried out with Asian [2], North American and European species [3], [4]. Five edible Gaultheria species occurs in Chile [5] and little is known on their secondary metabolite chemistry. The aims of the present
work were to isolate the main secondary metabolites from Gaultheria phillyreifolia and G. poeppigii berries, and to evaluate their antioxidant activity. A combination of membrane chromatography
(MC) and counter-current chromatography (CCC) was used to isolate the main compounds.
The products were characterized by spectroscopic and spectrometric means. The antioxidant
activity was measured by different spectrophotometric assays. The fruit extracts were
submitted to MC to separate anthocyanins from copigments. Four anthocyanins were isolated
by CCC and identified as galactoside and arabinoside of cyanidin and delphinidin.
From the copigment fraction, CCC allowed the isolation of quercetin-3-arabinoside,
3-rutinoside and 3-rhamnoside, 3-caffeoylquinic acid and the iridoids monotropein-10-trans-coumarate, monotropein-10-trans-cinnamate and 6α-hydroxy-dihydromonotropein-10-trans-cinnamate. The latter two compounds are new natural products. Other 34 compounds
were tentatively identified by HPLC-DAD-ESI-MSn. The G. phillyreifolia samples showed better antioxidant activity in the FRAP, TEAC and CUPRAC assays. On
the other hand, the G. poeppigii samples showed better results in the DPPH and ORAC assays. The observed differences
between both species were validated by a Partial Least Square Discriminant Analysis
(PLS-DA). This is the first report on the isolation and characterization of secondary
metabolites from Chilean Gaultheria phillyreifolia and G. poeppigii berries.
Fig. 1
