Anti-inflammatory activity of the functional groups present in Hippophae rhamnoides (Seabuckthorn) leaf extract

Immunomodulators salvage the immune response by enhancing or reducing its capacity to the required level. Plant extracts are extensively used as immunomodulators because of their easy availability, simple methods of preparation and minimum side effects with maximum efficacy.

The present study was conducted to assess the immunomodulatory activities of phyto constituents present in Seabuckthorn leaves. The aqueous–alcoholic leaf extract was subjected to successive and parallel extraction in the presence of polar and non-polar solvents for fractionation of compounds. Based on the yield, three fractions were selected viz. parallel methanol (PM), successive chloroform (SC) and successive methanol (SM) and screened for in vitro immunomodulatory activities. Peritoneal macrophages were isolated from Balb/c mice and cultured with or without LPS to evaluate the immunomodulatory effect of the three fractions on cell viability, hemolytic activity, nitric oxide (NO) production, cytokine levels, iNOS and COX-2 expressions.

The results revealed that none of the three fractions induced hemolysis. Cells treated with PM fraction significantly suppressed LPS-induced NO production and pro-inflammatory cytokines such as TNF-α, IL-6 and IFN-γ as compared to SC and SM treatment. The iNOS and COX-2 expressions were also significantly reduced after treatment with PM fraction.

The decrease in LPS-induced NO production, pro-inflammatory cytokine secretion, iNOS and COX-2 expression signifies anti-inflammatory properties of PM fraction containing tannins, proteins and carbohydrate groups. Hence, this plant-derived immunomodulator can be used as a therapeutic agent in inflammatory diseases.