Effect of Pergularia daemia (Forssk) and Momordica charantia L. (bitter gourd) leaf extracts on some enteric bacterial species

Abstract

Medicinal plants are potential sources of new antimicrobial molecules. This study was undertaken to determine the effects of Pergularia daemia (Forssk) and Momordica charantia (bitter gourd) leaf extracts on some enteric bacterial species. Plant leaves were collected from Kerker village of Jos East Local Government Area of Plateau State. Plants were identified, the leaves were shade-dried, pulverized into fine powder. Proximate analysis was carried out using AOAC methods. Extracts were obtained through cold maceration techniques. The extracts were used for phytochemical screening; antibacterial activity was carried out using well diffusion methods. Minimum inhibitory concentration and maximum bactericidal concentration was determined using broth dilution method. The results of proximate analysis showed that the plants powder were rich in carbohydrates, M. charantia 55.59± 0.02 and P. daemia 31.38 ± 0.03, followed by crude fiber and crude fat 19. 62± 0.04 and 16.69± 0.22 in P. daemia compared to 10.66 ± 0.03 and 10.78± 0.03 in M. charantia while ash content and moisture were moderate with 12.86±0.12 in M. charantia and 7.53 ± 0.02 in P. daemia. The phytochemicals showed the presence of alkaloids, phenols, flavonoids, tannins and terpenoids in all plant extracts. The antibacterial activity showed that the extracts have a broad spectrum of activity on the test organisms as compared to the standard drug gentamicin. There was a significant difference at p<0.05. Shigella flexneri was the most susceptible to methanolic and aqueous extracts with 22.53± 0.10 at 500 mg/ml as compared to standard drug gentamicin 32.33± 0.18, followed by E. coli with 21.13± 0.13 at 500 mg/ml as compared to the control 29.60±0.15 and Salmonella typhi with 20.47±0.14 at the concentration of 500 mg/ml as compared to standard drug with 38.50±0.36. The results of minimum inhibitory concentration showed that Shigella flexneri was the most susceptible with the MIC of 31.25 mg/ml and 62.5 mg/ml for both methanolic and aqueous extracts of P. daemia while salmonella typhi was the most susceptible with the MIC of 62.5 mg/ml and 125 mg/ml for M. charantia respectively. The presence of alkaloids, saponins, tannins and terpenoids showed that the plants leaves have antibacterial activity. The results of this study support the use of these plants as therapeutic agents for diarrhoea caused by S. flexneri and E. coli.