Antioxidant, mutagenic, antimutagenic activities, and phenolic compounds of Liquidambar orientalis Mill. var. orientalis
ABSTRACT The ethanolic extract of the leaves of Liquidambar orientalis var. orientalis, an endemic tree species in Turkey, has medicinal and cosmetic properties; this extract was isolated, and its antioxidant, mutagenic, and antimutagenic activities were investigated. The antioxidant activity was determined by the inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, total antioxidant activity, and phenolic compounds. The mutagenic and antimutagenic activities were investigated by Ames Salmonella/microsome mutagenicity test. The IC50 value for DPPH radicals was 3.11 ± 0.024 mg/ml. The total antioxidant activity increased with an increase in the concentration of the extracts (0.5, 2.5, 5, 10, and 20 mg/ml), which contained linoleic acid emulsion. The total phenolic content was 333.14 ± 7.96 mg gallic acid equivalent/g extract. HPLC analysis of the phenolic compounds showed the presence of protocatechuic acid (12.232 ± 0.118 mg/g extract), (−)-epicatechin (7.954 ± 0.493 mg/g extract) and gallic acid (3.258 ± 0.035 mg/g extract) as a major phenolic acids in L. orientalis var. orientalis.
The results showed that the ethanolic extract can be considered genotoxically safe, because it does not have any mutagenic effect at the tested concentrations. As a result, the ethanolic extract of the leaves exhibited antimutagenic effects at 2.5, 0.25, and 0.025 mg/plate concentrations. To our knowledge, this is the first study of the antioxidant, mutagenic, and antimutagenic activity of the ethanolic extract of the leaves of L. orientalis var. orientalis. Also, phenolic compounds of this plant are unknown. These activities are an important topic in the medical field as well as in the food industry.