Antioxidant, Anti-inflammatory and Cytotoxic Activity of Schinus terebinthifolia Fruit and Isolation of a New Immunomodulatory Polyphenolic Compound

Abstract

Background: The fruit of Schinus terebinthifolia Raddi is used in ethnomedicine for the treatment of different ailments. Materials and Methods: We studied the phytochemical profile of S. terebinthifolia fruit and evaluated its properties, including its antioxidant, anti-inflammatory, analgesic, cytotoxic and antimicrobial activity. Results: Phytochemical investigation of S. terebinthifolia fruit showed an estimated total phenolic content of 67 mg of gallic acid equivalent (GAE)/g, with respect to gallic acid, while the flavonoid content was 26 mg of quercetin equivalent (QE)/g, in terms of quercetin. Bioassay fractionation of methanolic extract of the fruit resulted in the isolation of a new molecule for the first time from this natural source: 4′,methoxy-6-vinyl-7- O-rhamnosyl-dihydromyricetin or 4′,methoxy-6-vinyl-7- O-rhamnosyl-ampelopsin (Compound 8). Seven other phenolic compounds were isolated, such as (1) gallic acid; (2) afzelin; (3) quercetin 3- O- β-D-glucopyranoside; (4) genistein 7- O- α-l-rhamnopyranoside; (5) ellagic acid; (6) kaempferol and (7) quercetin. The new compound was ascertained using UV, NMR and MS spectra and acid hydrolysis analysis. Significant antioxidant, cytotoxic, anti-inflammatory, analgesic and antimicrobial properties were observed in the alcohol extract, as well as proliferation inhibition in MCF-7 human cancer cell lines. Its activity in elevating glutathione levels in diabetic rats could be due to its anti-inflammatory and immunomodulatory properties. Conclusion: The new compound shows immunomodulatory effects that can be utilized to augment host responses, which is important in both cancer and infectious diseases and thus worth further pharmacological investigation.