Scientific rationale behind the medical application of Plumeria rubra in both infected and non-infectious diarrhoea is evaluated in the present manuscript. In-vivo and in-vitro experiments were conducted to examine the effect of a crude extract of P. rubra leaf on castor oil-induced diarrhoea, gastrointestinal movement, and fluid accumulation in the intestines.  Using an in-vitro assays, the antibacterial effectiveness of P. rubra was evaluated against several enteric and non-enteric harmful bacteria, and its phytochemical and antioxidant potential was also assessed.  P. rubra significantly decreased the severity of diarrhoea in rats with reductions of 39.20, 47.30 and 70.30%, which was observed at doses of 150, 300 and 450mg/kg, respectively. Intestinal secretions revealed decreases of 24.14, 28.09 and 38.90, respectively, while intestinal motility decreased by 32.11, 45.78 and 54.80% at dosages of 150, 300 and 450mg/kg, respectively. P. rubra exhibited bactericidal activity against various bacteria, including Escherichia coli (71.80%), Staphylococcus aureus (91.60%), Bacillus subtilis (84.24%), Pseudomonas aeruginosa (76.83%), at a concentration of 12.5mg/mL. The 10mg/mL exhibited bactericidal effects against all previously indicated pathogens. HPLC analysis revealed the presence of rutin, quercetin, kaempferol, plumericin and isoplumericin, while significant antioxidant activity was observed in DPPH, SOD and NO scavenging assays, with inhibition ranging from 78 to 86%. P. rubra demonstrated efficacy against both enteric and non-enteric pathogens that cause diarrhoea and justified its therapeutic usage and applications for both forms of diarrhoea.

To Cite This Article: Sun T, Ren J, Chen J, Deng H, Guo R, Xie X, Liu Y, Khan IA, Abbas A, Khan MK, Kamran M, Hailan WAQ and Mares M, 2026. In-vitro and in-vivo antibacterial effects of Plumeria rubra extract: A novel approach for treating infectious and non-infectious diarrhea. Pak Vet J, 46(5): 1333-1340. http://dx.doi.org/10.29261/pakvetj/2026.119