Metabolite profile of Salix reticulata methanolic extract and its antiproliferative effect on immortalized human keratinocytes

Traditionally, Salix species (Salicaceae) have been used for their anti-inflammatory, analgesic and antipyretic properties. The pro-apoptotic effect of Salix extracts on cancer cells has been reported [1]. In the search for herbal remedies for skin diseases with cellular hyperproliferation, like psoriasis, such anti-inflammatory and pro-apoptotic effects would be highly desirable.

Salix reticulata L. is a mountain dwarf shrub. To our knowledge, no previous phytochemical investigation has been reported on this plant. In this study, the metabolite profile of the methanolic extract was characterized and its effect on immortalized human non-tumorigenic keratinocytes (HaCaT) was investigated.

The leaves were extracted successively by dichloromethane and methanol. Fractionation of the methanolic extract by a combination of column chromatography on Sephadex LH-20, and preparative and semipreparative HPLC afforded several flavonoids including luteolin and apigenin glycosides, and phenolic glucosides typical of Salix species such as triandrin and salicortin. Cell viability was determined using fluorescein diacetate-propidium iodide staining. Quantification of viable (green fluorescence) and inviable (red fluorescence) cells was performed using ImageJ software. Cell proliferation was assessed on HaCaT cells by a BrdU incorporation ELISA assay. Proliferation of HaCaT cells decreased with increasing concentrations of the extract. At a concentration of 200 µg/mL, BrdU incorporation was inhibited by 50%. Investigation of the possible molecular pathways leading to the observed anti-proliferative effect is ongoing.

References:

[1] Enayat S, Ceyhan MŞ, Başaran AA, Gürsel M, Banerjee S. Anticarcinogenic effects of the ethanolic extract of Salix aegyptiaca in colon cancer cells: involvement of Akt/PKB and MAPK pathways. Nutr Cancer 2013; 65: 1045 – 1058