Anti-aging potential, anti-tyrosinase and antibacterial activities of extracts and compounds isolated from Rosa chinensis cv. 'JinBian '

Rosa chinensis cv. 'JinBian', a cultivar of Rosa chinensis Jacq., is one of major raw material of rose tea and possesses sufficient plant resources in China. However, the studies on the chemical constituents and cosmetic activities of R. chinensis cv. 'JinBian' are almost blank. The main purpose of this study was to evaluate the antiaging, skin-whitening, and antibacterial potentials of extracts and chemical constituents of the flower by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, elastase inhibition, anti-tyrosinase, and antibacterial assays. Bioassay results suggested both 95 % and 65 % ethanol extracts possessed significant antioxidant, elastase inhibition, and anti-tyrosinase activities. The combined active extract was studied with bioassay-guided fractionation to give a new compound, kaempferol 3-O-alpha-L-rhamnopyranosyl (1 -> 6)-(2",3"-O-digalloyl)-beta-D-glucopyranoside (1) and fourteen known compounds (2-15). All compounds were firstly isolated from this species and subjected to the above mentioned bioassays. Ten compounds exhibited antioxidant activities with DPPH radical scavenging rate from 63.40 %-94.04 % under the concentration of 100 mu g/mL. The antioxidant activities of 1, 2-phenylethyl 1-O-beta-D-(6'-O-galloyl)-glucopyranoside (12), vomifoliol (14), and 4, 4'-dimethoxy-3'-hydroxy-7, 9': 7', 9-diepoxylignan-3-O-beta-D-glucopyranoside (15) were firstly found with DPPH radical scavenging rate of 83.24 %, 91.10 %, 63.40 %, and 77.75 %, respectively. The moderate elastase inhibitory activities of 12, ethyl gallate (13), and 15 were firstly found with the inhibitory rate of 43.69 %, 43.25 %, and 35.34 % at the concentration of 100 mu g/mL. Multiflorin B (3), 12, and 13 showed strong tyrosinase inhibitory activities with the inhibition rate at 43.83 %-55.80 %, comparing with the positive control, alpha-arbutin (22.15 %). In addition, 1 showed significant antibacterial activity against Staphylococcus aureus with the MIC50 of 8.51 +/- 0.26 mu g/mL. Compounds 2-4 and 12-14 showed moderate antibacterial activities against S. aureus. Compounds 6 and 13 also exhibited moderate inhibitory effects against Klebsiella pneumoniae. Above results manifested that R. chinensis cv. 'JinBian' possessed potential application values in the development of natural anti-aging, skin-whitening and antibacterial products.