Functional Properties and Components of Koenigia alpina Extract

Koenigia alpina (All.) T.M.Schust. & Reveal (alpine knotweed) is a perennial herb belonging to the Polygonaceae family. Several studies have examined Polygonaceae species' potential applications as cosmeceutical materials; however, the potential of K. alpina as a cosmeceutical has not yet been studied.

Hydrogen peroxide (H₂O₂) and lipopolysaccharide were used to induce an inflammatory response in RAW 264.7 cells. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radicals and H₂O₂ were used to evaluate the free-radical scavenging activity of K. alpina extract and its protective effect against reactive oxygen species (ROS)-induced cell damage. The whitening, antiaging, and cell proliferation/migration effects of the extracts were evaluated via tyrosinase inhibition, collagenase/elastase inhibition, and wound healing assays, respectively. The anti-inflammatory effect was confirmed by evaluating nitric oxide (NO) production in RAW 264.7 cells. High-performance liquid chromatography (HPLC), UV, and MS/MS were used to determine the main components of the extract and fractions.

The ethyl acetate (EA) fraction and its aglycone fraction showed very high free-radical scavenging activities (47.5 and 47.1 µg/mL, respectively). The extract/fractions also showed significant tyrosinase inhibition (IC₅₀ = 0.38 mg/mL in EA fraction), collagenase inhibition (IC₅₀ = 0.21 mg/mL in EA fraction), and elastase inhibition (IC₅₀ = 0.57 mg/mL in aglycone fraction). NO production in lipopolysaccharide-induced RAW 264.7 cells was inhibited by the extract/fractions. The extract also promoted the closure of scratch wounds in HaCaT cells. The K. alpina extract/fractions contained cardamonin, quercetin, and quercitrin.

K. alpina extracts/fractions showed antioxidant, antiaging, whitening, and anti-inflammatory activities, suggesting they may have potential as antiaging cosmeceuticals.