Re-processing of pharmaceutical herb residues using isolated probiotics from plant sources and their beneficial effects on diarrhea

This study aims to use hot aqueous extract of herbal residue (HRE) to enhance bacterial growth and possess anti-diarrheal effects. In this study, lactobacillus species L. brevis (SAM-1), Lactobacillus plantarum (SAM-2), and Lactobacillus herbinensis (SAM-3) were isolated from date palm sap (collected in winter season). Square Pharmaceuticals PLC, Bangladesh provided herbal residues ‘Adovas’ which is non-sedating herbal cough syrup with sixteen common herbs including Adhatoda vasica. In our observation, HRE increased the number of colonies in MRS media. In the anti-diarrheal study by castor oil and magnesium sulphate-induced diarrheal mouse model, SAM-1 and 2 with or without HRE showed almost similar results. After initial morphological characterization, tests such as resistance to low pH, bile salt and survival capability in gastric simulated fluid (GSF) were performed to confirm them as a probiotic candidate. All three isolates were gram-positive bacteria and could grow in a mesophilic range of temperatures. The isolates were catalase-negative and were able to coagulate milk after overnight incubation. As the isolates exhibited resistance to low pH and could tolerate bile salts, they may survive in the stomach and intestine, thus making them a promising probiotic candidate. The isolated probiotics and HRE inhibited diarrheal and restored the body's electrolytes. Interestingly, SAM-2 showed higher efficacy than the standard drug (Loperamide), while SAM-1 showed a similar effect and SAM-3, had less effect than Loperamide. The findings suggest that probiotics and herbal residue could contribute to diarrhoeal disease prevention, which might be an alternative to a synthetic standard drug (Loperamide).