Bioactivity Assessment of Murdannia nudiflora (L.) Brenan: Nitric Oxide Inhibition and Anti-ulcer Potentials of its Isolated Compounds and ExtractFractions

Introduction: Murdannia nudiflora (L.) Brenan, a medicinal herb, has traditionally been used for the treatment of gastrointestinal disorders, but scientific evidence for its bioactivity remains limited. This study aimed to evaluate the nitric oxide (NO) inhibitory activity and antipeptic ulcer potential of M. nudiflora extracts and isolated compounds. Methods: Successive solvent extraction was performed to obtain fractions, followed by chromatographic isolation of metabolites. The fractions and purified compounds were tested for NO inhibition in LPS-stimulated RAW 264.7 macrophages. The most active fraction was further evaluated for acute toxicity in Swiss albino mice (both sexes, 6-8 weeks, 18-22 g) and tested for antiulcer activity in Wistar rats (both sexes, 180-220 g) using the cysteamine-induced peptic ulcer model. Results: The ethyl acetate fraction of M. nudiflora (MNC2) exhibited the strongest NO inhibitory activity. From the MNC2, six compounds were isolated for the first time from this genus, including indole-3-carbaldehyde (1), loliolide (2), macommelinol (3), indole-3-carboxylic acid (4), blumenol A (5), and benzoic acid (6), and their NO inhibitory activities were subsequently evaluated. Among these, compound 3 showed the most potent NO inhibition (IC50 = 16.89 ± 0.77 μM), stronger than butein, a flavonoid used as the positive control (IC50 = 21.19 ± 0.36 μM). MNC2 was also found to be relatively safe, with an LD50 value above 25000 mg/kg/day in acute toxicity studies. In vivo, MNC2 significantly reduced the ulcer index and improved histopathology in cysteamine- treated rats. Discussion: The findings suggest that the anti-ulcer effect of M. nudiflora may be associated with inhibition of NO production, while additional mechanisms such as antioxidant, cytoprotective, and acid-regulatory pathways could also contribute. Conclusion: This is the first report of macommelinol exhibiting significant biological activity and the first evidence of gastroprotective effects of M. nudiflora, supporting its potential as a source of anti-ulcer agents.