Phytochemical screening and antibacterial activity of crude extract of Phyllanthus amarus plant against Salmonella typhi and Staphylococcus aureus isolated from patients attending Mulago hospital

Abstract

Apart from being used for the treatment of Malaria fevers, herbal preparation of Ugandan Phyllanthus amarus whole plant is widely used by local communities in central Uganda for the treatment of typhoid and skin infections. However, phytochemical composition studies regarding crude extracts and efficacy studies of the Ugandan Phyllanthus amarus against Salmonella typhi and staphylococcus aureus is lacking. Therefore, the present study was aimed to evaluate the phytochemical composition and antibacterial activity of Phyllanthus amarus crude extracts against Salmonella typhi and Staphylococcus aureus isolated from patients attending Mulago Hospital. The antibacterial activity was carried out by agar well diffusion technique against the bacterial pathogens and the zones of inhibition were measured in mm diameter and the minimum inhibition concentration was calculated on every organism. Phytochemical analysis was done by using different reagents to confirm the presence of different bioactive compounds. In the study, Phyllanthus amarus extract was found to be effective against the S. aureus and no effect against S. typhi, the methanolic extract showed highest zone of inhibition in S. aureus 20.75 ± 0.25mm and highest minimum inhibition concentration was 0.125g/ml. S. typhi exhibited resistance to all the three extracts of the plant with zone of inhibition of 6.00 ± 0.51mm. Generally, the methanol extract had a high antimicrobial effect than the ethanolic and aqueous extract against S. aureus and it was found that S. aureus trended to be more susceptible than S. typhi. Phytochemical investigations revealed the presence of flavonoids, tannins, alkaloids, terpenoids, phenols, saponins and glycosides. The finding that Phyllanthus amarus has phytochemicals and antibacterial effect serves to suggest that there is a potential in discovering novel antimicrobial agents from the plant. This however needs further investigation of the extracts against different microorganisms and also determine the mechanism of action by which this plant crude extract inhibits S. aureus.