Phytochemical Profiling and Anti-Diarrhoea Activity of a Bi-herbal Aqueous Extract of Psidium guajava and Ocimum gratissimum

Diarrhoeal diseases remain a global health challenge, with rising antimicrobial resistance driving the need for plant-based therapies. This study evaluated the phytochemical composition and anti-diarrhoeal activity of a bi-herbal aqueous extract derived from Psidium guajava and Ocimum gratissimum. The phytochemical analyses were performed using standard methods. The in vitro anti-diarrhoeal activity of the extract was assessed against selected diarrhoeagenic microorganisms (Escherichia coli, Salmonella sp., Shigella dysenteriae, and Aspergillus niger) using the agar well diffusion technique. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Qualitative phytochemical screening revealed the presence of alkaloids, flavonoids, tannins, saponins, phenolics, terpenoids, glycosides, reducing sugars, and proteins. Quantitative analysis showed that proteins (2013.00 mg/100 g) and tannins (698.20 mg/100 g) were the most abundant constituents, while flavonoids, saponins, and phenolics were present in moderate amounts. The bi-herbal extract exhibited concentration-dependent antimicrobial activity, with zones of inhibition ranging from 1.00 to 1.70 cm across the tested organisms. The MIC was 16.67 mg/mL for all isolates, while the MBC was greater than 50 mg/mL, indicating predominantly bacteriostatic activity. The bi-herbal extract showed rich phytochemistry and inhibitory activity against diarrhoeagenic pathogens, indicating potential as a natural antidiarrhoeal agent, though further in vivo and mechanistic studies are needed.