Chemical composition, antioxidative and enzyme inhibition activities of chickweed herb (Stelaria media L., Vill.) ethanolic and aqueous extracts

Abstract

The aim of the study was an attempt of justification of chickweed’s herb (Stelaria media L., Vill.) traditional use as anti-inflammatory agent in the treatment of skin diseases. In the study a phytochemical characterization and potential anti-inflammatory effect of the aqueous and ethanolic extracts of chickweed herb were investigated in vitro, by determining their antioxidant and enzyme inhibition activities. Moreover, the effect on reactive oxygen species (ROS) generation by human skin fibroblasts and keratinocytes after UV irradiation was determined. The main components of both extracts were apigenin glycosides. The content of flavonoids in the aqueous extract was 25.6mg/g of liophilized extract and in the ethanolic extract 63.9mg/g of liophilized extract. The ethanolic extract showed stronger scavenging activity against three of the tested radicals. The determined SC50 (the concentration required to inhibit radical formation by 50%) average values for hydrogen peroxide (H2O2), nitric oxide (NO) and peroxynitrite (ONOO−) were 132.83, 16.5, 11.9μg/mL, respectively. On the other hand, in xanthine-xanthine oxidase system activity of aqueous extract was more potent, with SC50 average value 62.75μg/mL, than activity of ethanolic extract. Scavenging of DPPH, and hyaluronidase and lipoxidase activity inhibition of both the extracts was weak, on the contrary to the strong inhibition of xanthine oxidase activity. Subsequently, the influence of the extracts on the human skin cells was examined. The study showed that the aqueous extract decreased intracellular ROS production by fibroblasts in a concentration-dependent manner. In the case of keratinocytes the aqueous extract also reduced intracellular ROS production, but not in a concentration-dependent manner. On the basis of this study it can be concluded that the possible anti-inflammatory activity on the skin of the extracts obtained from chickweed herb is due to their antioxidant activity, but not via an influence on activity of pro-inflammatory enzymes like hyaluronidase or lipoxygenase.