Anti-photoaging effects of solvent-partitioned fractions from Portulaca oleracea L. on UVB-stressed human keratinocytes.

In this study, the anti-photoaging activity of solvent-fractionated extracts from Portulaca oleracea L. was investigated in ultraviolet B-stressed keratinocytes. The results showed that the treatment of the fractions suppressed the generation of intracellular reactive oxygen species (ROS) and activated mRNA and protein expression levels of superoxide dismutase1 (SOD-1) and heme oxygenase1 (HO-1) enzymes via Nrf-2 pathway. The tested fractions down-regulated the expression of matrix metalloproteinases (MMPs) and up-regulated type Ⅰ procollagen production. Among the tested samples, the 85% aq. MeOH fraction was the most effective in suppressing MMPs and type Ⅰ procollagen degradation. Two homoisoflavonoids, portulacanone A (PA) and portulacanon D (PD), were isolated from the 85% aq. MeOH fraction. PA and PD successfully inhibited the secretionof MMP-1 and increased the production of type Ⅰ procollagen in UVB-stressed keratinocytes. Therefore, solvent-partitioned factions from P. oleracea and its active components, PA and PD, were suggested to have beneficial effects against photoaging. PRACTICAL APPLICATIONS: Portulaca oleracea L. is an edible nutrient-rich herb with high amounts of omega-3 and omega-6 fatty acids, ascorbic acid, and dietary minerals. P. oleracea has also been used as a botanical medicine for its potential health benefits such as antioxidant, antibacterial, and antiinflammatory properties. The current study suggested that the extracts from P. oleracea were able to prevent human keratinocytes from UVB-induced stress and damage. Due to its protective abilities, it can be used as an additive in the cosmeceutical industry to produce novel skin protectants. In addition, due to its intracellular antioxidant and MMP inhibitory effects, it can be a valuable source for nutraceutical development. Further studies that characterize the isolated flavonoids may also yield bioactive molecules to be utilized in cosmeceutical and nutraceutical industries as lead compounds. Nevertheless, P. oleracea can serve as a health beneficial addition to topical applications and dietary supplements against UVB-stimulated oxidative stress in skin cells.