Major Chemical Composition of Fruit Extracts of Morinda citrifolia L. and their Antibacterial, Antioxidant and Cytotoxicity Properties

Abstract

Morinda citrifolia L. has been reported as a medicinal plant for treatment of abscesses and microbial infections. Thus, this study was conduced to isolate and identify the major constituents of the ethanolic extract of M. citrifolia fruit and also to evaluate their antibacterial, antioxidant and cytotoxicity properties. Isolation procedures included silica gel 60 column chromatog. and thin layer chromatog. Identification of purified compounds was archived by spectroscopic methods. The antibacterial, antioxidant and cytotoxicity properties of purified compounds were carried out. On the basis of the spectral data, the major compounds were isolated and identified as rutin (1) and asperulosidic acid (2) with yield of 9.28 and 7.71% (w/v), resp. Antibacterial activity of crude extract and isolated compounds was evaluated by disk diffusion, MIC and MBC against Staphylococcus aureu, Bacillus subtilis, Escherichia coli, Salmonella typhimurium and methicillin-resistance Staphylococcus aureus SP6-106. The crude extract exhibited an antimicrobial activity at a dose level of 15 mg disk-1, while the isolated compounds exhibited an excellent antimicrobial activity at a dose level of 3.75μg disk-1 in all test micro-organisms for disk diffusion method. Compound 2 showed the lowest MIC (8μg mL-1) against S. aureus, while compound 1 showed the lowest MIC (16μg mL-1) against E. coli. However, compounds 1 and 2 had high MIC values (512μg mL-1) against B. subtilis. Compound 1 showed the lowest MBC (16μg mLμ-) against E. coli, while the compound 2 showed the lowest MBC (8μg mL-1) against S. aureus whereas these compounds had high MBC values (512μg mL-1) against B. subtilis. The compound 1 had the highest antioxidant activity with SC50 values of 68.45μg mL-1, while compound 2 and the crude extract had antioxidant activity with SC50 values of 103.32 and 150.22μg mL-1, resp. The cytotoxicity activity of the crude extract and isolated compounds was observed and showed weak cytotoxicity activity with IC50 values of 1352.67-2780.80 and 1524.19-2854.06μg mL-1 toward L929 and HEK293 cell lines, resp. It can be concluded that the major compounds isolated from the crude extract of M. citrifolia fruits in Nakorn Pathom, Thailand were rutin and asperulosidic acid, which have antibacterial, antioxidant and cytotoxicity properties. They may provide promising improvements in the therapeutic approach to infectious diseases and oxidative stress treatments.