Characterization of pharmacological properties and isolation of two bioactive compounds (ursolic acid and palmitoleic acid) from the stem bark extract of Lannea coromandelica

The current research aimed to conduct a bioassay-guided isolation of bioactive compounds from the stem bark of Lannea coromandelica. Using column chromatography and NMR spectroscopy, two compounds -ursolic acid and palmitoleic acid- were isolated from the plant’s stem bark. The methanolic stem bark extract possessed higher total phenolic, flavonoid, and antioxidant capacity content than the n-hexane extract. The IC50 value of the methanol and n-hexane stem bark extracts for DPPH free radical scavenging potential was found to be 37.37 and 27.726 μg/mL, respectively, while for nitric oxide, the IC50 value was 14.615 and 22.136 μg/mL, respectively. The n-hexane extract exhibited higher antidiabetic effectiveness (46% blood glucose reduction) than the methanolic extract (37.8% blood glucose reduction) after 3 hours of glucose administration in mice model at a dose of 400 mg/kg body weight (p 0.001). The methanolic extract demonstrated the highest anti-diarrheal action at a dose of 400 mg/kg body weight (88.70% inhibition of defecation, p 0.001). Furthermore, the n-hexane extract showed the highest analgesic activity (70.5% inhibition of writhing, p 0.01).