Phytochemical screening and antibacterial activities of Momordica charantia and Vernonia amygdalina extracts on some selected enteric isolates

Background:This research focuses on herbal medicine,an ancient healthcare practice,exploring the antibacterial attributes of fresh and dried leaf extracts from Momordica charantia(commonly known as Bitter melon)and Vernonia amygdalina(Bitter leaf).The study specifically investigates their effects on different bacterial strains associated with gastroenteritis.Methods:Four enteric bacterial isolates-Klebsiella pneumoniae,Salmonella typhi,Escherichia coli,and Proteus mirabilis-were obtained from the Medical Laboratory Unit at Babcock University Teaching Hospital in Ilishan-Remo,Ogun State.Phytochemical screening and antibacterial testing were conducted using standard biochemical techniques and the Punch-hole agar diffusion method,respectively.Results:Qualitative phytochemical screening of the plant extracts revealed the presence of flavonoids,glycosides,and saponin in both plants,excluding terpenoids.Alkaloids were identified only in Vernonia amygdalina.Despite these phytochemicals,neither plant displayed inhibitory effects on the tested bacterial isolates(Escherichia coli,Proteus mirabilis,Klebsiella pneumoniae,and Salmonella typhi)when tested individually or in combination.Intriguingly,combining the fresh and dried leaf extracts of Momordica charantia and Vernonia amygdalina with a standard drug resulted in smaller mean zone diameters of inhibition(Escherichia coli range:14 mm–16 mm,Proteus mirabilis range:31 mm–35 mm,Klebsiella pneumoniae range:13 mm–22 mm,and Salmonella typhi range:35 mm–38 mm)compared to the drug tested alone(16 mm–45 mm).Conclusion:Despite previous indications of antibacterial properties in various extracts of V.amygdalina and M.charantia leaves,our study presents contradictory results,prompting the need for further investigation despite the presence of significant phytochemicals.