Biological activity and characterization of leaf and seed lectins from Terminalia brownii: Insights into their analgesic and antiulcer properties

Abstract

Terminalia brownii Fresen, an African medicinal plant, is known for its analgesic, antiulcer, and antimicrobial properties, with its leaves, bark, and fruits deeply ingrained in indigenous healing practices. Two lectins, TerBLL (from leaves) and TerBSL (from seeds) of Terminalia brownii Fresen, were purified using salting-out and affinity chromatography on a fetuin-agarose column. The purified lectins were then assessed for protein yield, hemagglutination activity, and physicochemical properties. Both TerBLL and TerBSL have subunits with molecular weights of 57.3 and 65.7 kDa, respectively. TerBLL remains stable at 60–80 °C and is activated by Mn+2, while TerBSL is activated by Zn+2. These lectins maintain consistent activity under acidic conditions, with TerBLL demonstrating heightened activity at extreme alkaline pH. TerBLL retained 50 % of its activity in 2–8M urea, in contrast to the 13 % of TerBSL. Investigation of the properties of TerBLL revealed that it had antinociceptive effects, reducing abdominal pain and prolonging latency time in the hotplate assay, potentially through μ-opioid receptor blockade akin to that of morphine. TerBLL exhibits antiulcer activity at doses of 0.25 and 1 mg/kg, reducing ulcer formation by up to 33 %, comparable to that of pantoprazole (80 mg/kg). The physiochemical attributes of TerBLL, in addition to its pain-relieving and gastroprotective effects, underscore its therapeutic promise, which is consistent with its traditional use.