Anti-elastase, anti-tyrosinase and anti-inflammatory activities of three compounds isolated from Psorospernum aurantiacum Engl. : in- silico and in- vitro assays

Abstract The hexane fraction of Psorospermum aurantiacum (PA) was found to prevent photoaging in skin cells lines. Therefore, this research aimed to evaluate the anti-skin aging potentials of compounds isolated from this bioactive fraction using in- silico and in- vitro models. Compounds were isolated by column chromatography and their structures were determined using spectroscopic techniques. A molecular docking was conducted to determine the interactions of compounds with selected targets: Elastase, 15-lipoxygenase, activator protein-1, Nuclear Factor Kappa B involved in skin aging processes. Furthermore, the in-vitro anti-elastase and anti-tyrosinase activities of compounds and their anti-inflammatory effect were evaluated on 15-lipoxygenase and nitric oxide (NO) production in lipopolysaccharide-stimulated RAW 264.7 macrophage cells. Chromatographic purification of PA yielded three known compounds namely 3-geranyloxyemodinanthrone (1), 3-geranyloxyemodine (2) and lupeol (3) were identified, and in-slico study showed that (3) (− 12.83 kcal/mol) had high affinity with elastase while (2) (− 8.98 kcal/mol) effectively interacted with lipoxygenase. The in vitro assays revealed that (1) possessed high anti-tyrosinase activity (IC50 = 65.00 µg/mL) and anti-lipoxygenase activity (IC50 = 35.35 µg/mL) as compared with vitamin C (IC50 = 48.85 µg/mL) and quercetin (IC50 = 26.79 µg/mL) respectively. Additionally, (3) showed a high percentage of elastase inhibition (88.09%) at 10 µg/mL and also inhibited NO production with IC50 of 28.74 µg/mL compared to quercetin (IC50 = 15.13 µg/ mL). Compounds 1 and 3 showed anti-elastase, anti-tyrosinase and anti-inflammatory properties through in vitro study. Molecular docking results confirmed the elastase inhibitory activity demonstrated by 3. These compounds could be incorporated skin care products after further studies.