Phytochemical Screening and Gram-Negative Antibacterial Activity of Carica Papaya leaves extracts

Abstract

The use of plants as potential sources of antibiotics needed to reduce Gram-negative antibiotic resistance has been investigated. The extraction of these plants is essential for isolating antibacterial agents with the aim of understanding their role in the treatment of Gram-negative bacterial infections. Therefore, this study was designed to identify the presence of some phytochemicals as well as their antibacterial activities against Gram-negative bacteria Pseudomonas aeruginosa. Carica papaya leaves were extracted successively with n-hexane and dichloromethane at varying pH’s using percolation method after which phytochemical screening was carried out on each extract. The qualitative analysis of the phytochemicals was carried out using standard experiment. The in-vitro antibacterial activity of the extracts was carried out against P. aeruginosa using disk diffusion assay. The results of phytochemical screening indicated the presence of steroid in all the four extracts. The leave extracts except for the dichloromethane at pH 9.15 inhibited the pathogen with the highest zone of inhibition being 22 mm. The minimum inhibitory concentration (MIC) was analyzed using disk diffusion assay with values ranging between 31.25 mgmL-1 to 250 mgmL-1 against the pathogen. There were variations in the lowest concentrations of the extracts causing the inhibitions. The dichloromethane at pH 8.3 extract that contained terpenoids was biologically active against P. aeruginosa at 250, 125, 62.5 and 31.25 mgmL-1 concentrations.