Antioxidant properties of selected parts of Syringa vulgaris L.

Abstract

Abstract Introduction: Antioxidants, in addition to their general positive effect on health, inhibit the aging of the skin. Many plant extracts are a valuable source of natural antioxidants that can be used in the production of cosmetics and cosmetology. Syringa vulgaris L. is a plant that contains flavonoids, one of the most important groups of natural compounds that eliminate free radicals. The aim of this study was to determine and compare the anti-oxidant activity of the extracts prepared from selected S. vulgaris L. parts. We analyzed the influence of the solvent and the extraction time on the antioxidant potential of extracts. Materials and methods: Alcoholic extracts from selected parts of S. vulgaris L. were prepared by ultrasound-assisted extraction, for 15, 30, and 60 min, and their antioxidant activity was evaluated. The analysis of the antioxidant potential was performed by 2,2-diphenyl--1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline--6-sulfonic acid) – ABTS methods using a spectrophotometer. The raw material used to prepare extracts comprised dried leaves and flowers harvested during flowering and dried fruits harvested during fruiting. The solvents applied were methanol, ethanol, isopropanol, and n-propanol at concentrations of 40%, 70%, and 100%. Results: The highest mean antioxidant activity evaluated using the ABTS method was 96.4% radical scavenging activity (RSA) for the leaf extract of S. vulgaris L., prepared in 70% methanol for 15 min. The highest antioxidant potential of the leaf extract determined using the DPPH method was 87.9% for concentrated ethanol applied for the same time. The lowest antioxidant activity was 1.36% RSA in a fruit extract extracted for 30 min, prepared in 99% n-propanol, determined by the ABTS method, and 6.3% RSA as evaluated using the DPPH method. The antioxidant potential was markedly lower for the fruit extracts. Conclusions: The best antioxidant properties were demonstrated by the extracts made from the leaves of S. vulgaris evaluated using both methods. The lowest results were obtained for fruit extracts. The type of extractant used and the duration of the ultrasonically assisted extraction affected the ability of the obtained extracts to neutralize free radicals. The results show that S. vulgaris is a valuable source of antioxidants, especially its leaves and flowers.