Backhousia citriodora extract in protecting skin damage from photoaging

Abstract

The aim of this study was to evaluate the potential of Backhousia citriodora (B. citriodora) extract in protecting skin damage from photoaging effect caused by ultraviolet B (UVB) irradiation. Photoaging is skin premature aging caused by repetitive exposure of sun which contains ultraviolet rays that can lead to photoaging effects. The presence of antioxidants can slow down the photoaging effects because the antioxidants can act as neutralizer for the skin. Many studies had been carried out on plants for development of natural antioxidants. In this study, B. citriodora extract was used as a source of natural antioxidants and the percentage yield obtained from ultrasonic-assisted extraction was 20.6 % with total extract 5 g. The extract was tested for the most abundant bioactive compound existed in the extract by using gas chromatography-mass spectrometry. The extract consisted of geranial (23.2 %), neral (19.7 %), 2-methyl-2-pentanal (10.1 %), geranic acid (1.9 %) and linalool oxide trans (0.02 %). The bioactive compounds found have good potential in cosmetics application and attribute to antioxidant activity. B. citriodora extract showed strong antioxidant activity with IC50 values 2.59 ± 0.532 |ig/mL and 34.53 ± 1.14 |ig/mL in 2,2-diphenyl-1-picrylhydrazyl and 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid assays, respectively. The cytotoxicity of B. citriodora extract was evaluated by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay in both human skin fibroblast and immortalized human keratinocytes cells. The results showed high percentage of cell viability using low concentrations of B. citriodora extract. The skin collagen increased from 40 % to 80 % when tested by using sircol soluble collagen assay. B. citriodora extract restored the synthesis of collagen initially reduced by UVB irradiation. Next, B. citriodora extract inhibited the human matrix metalloproteinase- 1 (MMP-1) expression by 10%, indicated that B. citriodora extract inhibited the MMP- 1 expression under the experimental condition used. In elastase assay, B. citriodora extract had higher elastase inhibition rate (>80 %) at 0.05 |ig/mL compare to Epigallocatechin gallate (80 %). Therefore, it was concluded that B. citriodora extract can protect collagen and elastin from degradation, thus protect the skin from aging. The inflammatory cytokines were investigated using human tumour necrosis factor alpha (TNFa) and interleukin 6 (IL6). The TNFa and IL6 expression were reduced by 10 % and 70 %, respectively at concentration 7.81 |ig/mL. The data demonstrated that B. citriodora extract can be used as an anti-inflammatory agent at low concentration. These results suggested that B. citriodora extract could be used as a potential antiaging and anti-inflammatory agent in cosmeceutical products.