Phytochemical Investigation, Antimicrobial, and Antioxidant Evaluation of Stembark Extract of Tamarindus Indica

Abstract

Tamarindus indica is one of the tropical medicinal plants that has been attributed curative potential of numerous diseases. Nonetheless, not much research has been done on T. indica's phytochemical analysis, antibacterial, and, antioxidant activities. Thus, the aim of this work is to examine the phytochemical components of T. indica stembark and assess its antioxidant and antibacterial properties. Using a 1:1 methanol to chloroform ratio and cold maceration for 24 hours, the extraction was carried out three times. To separate the pure compounds from the crude extract, column chromatography was used. Spectroscopic techniques (IR, 1HNMR,13CNMR, and DEPT-135) were used to elucidate the structures of the isolated compounds. The antimicrobial activity of the crude extract and isolated compounds from T. indica was carried out against four bacterial strains and one fungal strain; Bacillus cereus (ATCC25923), Salmonella typhimurium (ATCC13311), Escherichia coli (ATCC25922), Staphylococcus aureus (ATCC25923) and Candida albican (ATCC14053) using the disk diffusion method. The free radical scavenging ability of the extracts was tested by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Two new compounds, methyl octadecanoate and hylodiglyceride, and two known compounds, β-sitosterol and lupeol were isolated through the fractionation of the crude extract on silica gel column chromatography, followed by purification on Sephadex LH-20 and small column chromatography. The antimicrobial activity result showed that compound TI-D had significant antimicrobial activity among the tested compounds. Isolated compounds exhibited lower antimicrobial activity than that of the crude extract. The antioxidant activity result showed that stembark extract of T. indica had significant antioxidant activity. Comparing of T. indica with standard ascorbic acid the stembark extract, this study showed that they both had comparable free radical scavenging activities. The results suggest that T. indica used in this study has thepotential for the production of drugs against microbial infections. Further study on the use of different organic solvents for the extraction and isolation of more bioactive compounds is recommended.