Unveiling Urease Inhibitory Properties and Phytochemical Screening for the Therapeutic Potential of Extracts and Fractions of Khaya grandifoliola C.DC. and Entada africana Guill. et Perr

Abstract

Urease is an enzyme that plays a significant role in the pathogenesis of Helicobacter pylori responsible for numerous health issues, among which chronic gastritis, peptic ulcer disease, gastric neoplasia and even stomach cancer. Therefore, targeting urease represents a key strategy to attenuate gastritis induced by H. pylori. Khaya grandifoliola (KG) and Entada africana (EA) were prepared using methylene chloride/methanol (1:1, v/v). After that, the extracts were fractionated using a gradient of solvent and the anti-urease activities of crude extracts and fractions was evaluated. Mechanism of inhibition of urease by the most active fractions was determined using kinetic method. Polyphenols and flavonoids contents were determined. Extracts and fractions of KG and EA exhibited a significant inhibition of urease activity. The half inhibitory concentration (IC50) of KG (31.61 ± 0.23 µg/mL) and EA (35.70 ± 0.14 µg/mL) showed no significantly difference (P > 0.05) to the reference Thiourea (30.37 ± 0.30 µg/mL). In addition, the kinetic study revealed that the methanolic fraction (FMeOH) of KG and EA strongly inhibited the activity of urease with IC50 values of 31.60 ± 1.25 and 29.00 ± 1.05 µg/mL respectively. These fractions exhibited mixed-type inhibition with Kic and Kia values of 9.96 and 91.15 µg/mL for KG and 13.24 and 226.59 µg/mL for EA respectively. Both extracts contain phenolic compounds. Overall, this study indicated a high anti-urease activity of the methanolic fraction of KG and EA.  Each fraction exerts a mixed inhibition on urease activity.