Chemical composition, antioxidant, anti-melanogenic and anti-inflammatory activities of Glechoma hederacea (Lamiaceae) essential oil

Essential oils show important biological activities, which account for the development of aromatherapy used in complementary and alternative medicine. The aim of this study was to evaluate the chemical composition and the antioxidant, anti-melanogenic, and anti-inflammatory properties of Glechoma hederacea essential oil (GHEO). The essential oil composition was analyzed by gas chromatography and mass spectrometry. The most abundant compound in GH-EO was trans-3-pinanone (41.4%), and other major compounds were 4,5,6,7-Tetrahydro-5-isopropenyl-3,6-beta-dimethyl-6-alpha-vinylbenzofuran (10.8%), beta-caryophyllene (10.2%), and spathulenol (4.3%). Our results indicated that GH-EO shows strong lipid peroxidation inhibitory activity for the moderation of beta-carotene bleaching. GH-EO can markedly decrease melanin production and tyrosinase activity in alpha-melanin-stimulating-hormone (alpha-MSH)-stimulated B16 cells. The results also demonstrated that the activity of GH-EO on melanogenesis might be the result of its potent antioxidative ability (P < 0.05), which was reflected in the decreased cellular oxidant and malondialdehyde (MDA) levels and in the recovered activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD) in alpha-MSH stimulated B16 cells. GH-EO may suppress the inflammatory responses of LPS-stimulated RAW 264.7 macrophages, including nitric oxide (NO) production, by regulating the expression of the inflammation-related enzymes inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1), and the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha), which decreases LPS-induced MDA levels and DNA damage.