Potential antioxidants and tyrosinase inhibitors from leaf extracts of Zanthxylum spp

Background: Zanthoxylum is a genus of about 250 species of deciduous and evergreen trees and shrubs in the citrus or rue family,Rutaceae, native to warm temperature and subtropical areas worldwide. The genus Zanthoxylum has been credited with a long list of ethnompharmacological properties.Objectives: In the present study, in vitro anti-oxidant and anti-tyrosinase properties of extracts of Zanthoxylum piperitum and Zanthoxylum schinifolium leaves extracts were evaluated using various assays.Methods: Z. piperitum and Z. schinifolium leaves harvested at the mature green stage were collected at Baek-un Mt. Chollanamdo,S. Korea in August 2009. The extracts of Z. piperitum and Z. schinifolium leaves using methanol, n-hexane, chloroform, ethyacetate or butanol as solvents were evaluated for their tyrosinase inhibition, anti-oxidant and anti-microbial properties. The antityrosinase and anti-oxidant potentials were determined by in vitro mushroom tyrosinase assay and the free radical scaening activity methods.Results: Both of these results showed the strong inhibition abilities at a dosage of 100.0 'g/mL. Particularly, higher activity was exhibited by Z. piperitum with 92.8% and 80.1% inhibition of butanol and ethyl acetate extracts, while 78.2% and 57.8% inhibitions by Z. schinifolium respectively. However, both butanol extracts exhibited higher DPPH radical scavening activity than the corresponding methanol, n-hexane, chloroform, and ethyl acetate extracts. In addition, extracts of Z. piperitum leaves showed morepotent anti-tyrosinase activity than Z. schinifolium leaves. Anti-microbial activities against Gram(+) and Gram(-) bacteria demonstrated good inhibition at 34.8 - 43.6 'g/mL. These results obtained from biological assays showed that extracts of Z. piperitum and Z. schinifolium leaves possessed multiple bioactivities, including anti-tyrosinase, anti-oxidants,anti-microorganism and cell proliferation.The data exhibited the high potential of applying extracts of Z. piperitum and Z. schinifolium leaves in cosmoceutical lines.