Bioassay-guided isolation and identification of anti-ulcer ecdysteroids from the seeds of Sphenocentrum jollyanum Pierre (Menispermaceae)

Abstract

Sphenocentrum jollyanum seeds (MeOH extract and n butanol fraction) exhibited urease inhibitory activity (IC₅₀ 40.0 ± 0.92, 28.6 ± 0.41). The Ethyl acetate (EtOAc) fraction gave significant antacid activity with an increase in the baseline pH value of 1.2 to 1.61 ± 0.00 and 1.53 ± 0.00 at 50 and 100 mg, respectively, compared to the antacid activity of sodium bicarbonate (1.53 ± 0.00, 1.47 ± 0.00). Five known ecdysteroid compounds isolated from S. jollyanum ethyl acetate and n butanol fractions are Pinnatasterone (1), Polypodine B (2), 20-hydroxyecdysone (3), 20, 26-dihydroxyecdysone, (4) and Atrotosterone A (5). The compounds' structures were determined using extensive 1D and 2D NMR experiments, and the molecular mass for each of the compounds was confirmed by FAB-MS. Compounds 1-5 were evaluated for their urease inhibitory and antacid activities. Fractions were active in comparison with the standard drug acetohydroxamic acid, and sodium bicarbonate, respectively. Compounds 2, 3 and 1 showed significant urease inhibitory activity (IC₅₀ 7.0 ± 0.56, 13.8 ± 0.49 and 14.1 ± 0.59), respectively. The activity of compounds 4 and 5 were moderate compared to that of acetohydroxamic acid (IC₅₀ value 20.3 ± 0.43). Very few compounds have been isolated from this plant despite the numerous biological activities reported for it. The antacid and urease inhibitory activities of this plant and isolated compounds are described for the first time.

Keywords: Antacid activity; Bioactive compounds; Ecdysteroids; Medicinal plants; Urease inhibition assay.