Metabolite profiling of eastern teaberry (Gaultheria procumbens L.) lipophilic leaf extracts with hyaluronidase and lipoxygenase inhibitory activity

Abstract

The phytochemical profile and anti-inflammatory activity of Gaultheria procumbens dry lipophilic leaf extracts were evaluated. Forty compounds were identified by GC-MS, representing 86.36% and 81.97% of the petroleum ether (PE) and chloroform (CHE) extracts, respectively, with ursolic acid (28.82%), oleanolic acid (10.11%), methyl benzoate (10.03%), and methyl salicylate (6.88%) dominating in CHE, and methyl benzoate (21.59%), docosane (18.86%), and octacosane (11.72%) prevailing in PE. Three components of CHE were fully identified after flash chromatography isolation and spectroscopic studies as (6S,9R)-vomifoliol (4.35%), 8-demethyl-latifolin (1.13%), and 8-demethylsideroxylin (2.25%). Hyaluronidase and lipoxygenase inhibitory activity was tested for CHE (IC50 = 282.15 ± 10.38 μg/mL and 899.97 ± 31.17 μg/mL, respectively), PE (IC50 = 401.82 ± 16.12 μg/mL and 738.49 ± 15.92 μg/mL), and nine of the main constituents versus heparin (IC50 = 366.24 ± 14.72 μg/mL) and indomethacin (IC50 = 92.60 ± 3.71 μg/mL) as positive controls.With the best activity/concentration relationships, ursolic and oleanolic acids were recommended as analytical markers for the extracts and plant material. Seasonal variation of both markers following foliar development was investigated by UHPLC-PDA. The highest levels of ursolic (5.36-5.87 mg/g DW of the leaves) and oleanolic (1.14-1.26 mg/g DW) acids were observed between August and October, indicating the optimal season for harvesting.