Identification of compounds with potential angiotensin converting enzyme inhibitory activity in Adansonia digitata L. fruit pulp

Abstract

The study employed bioassay-guided fractionation to identify novel angiotensin-converting enzyme inhibitory compounds from Adansonia digitata fruit pulp, potentially responsible for its antihypertensive effects. A. digitata Fruit pulp was extracted using the solvents n-hexane, ethylacetate, methanol, and water. The percentage weight, in vitro Angiotensin Converting Enzyme (ACE) inhibitory activities and IC₅₀ values of the extracts were determined. Fractionation and phytocompound identification were performed by thin layer chromatography (TLC), column chromatography techniques, and gas chromatography-mass spectrometry (GC-MS) techniques. The yields obtained from solvent extractions using n-hexane, ethylacetate, methanol, and water were 0.14%, 1.17%, 4.30%, and 21.80%, respectively. The IC₅₀ values of Ramipril®, n-hexane, ethylacetate, methanol, and water extracts were found to be 101.40μg/ml, 116.70μg/ml, 40.53μg/ml, 47.25μg/ml, and 81.05μg/ml, in that order. The most potent ACE inhibitory activity was found in methanol extract of A. digitata Fruit (MEADF), which was chosen for bioassay-guided fractionation. From the assay, two fractions (Fraction I and III), among others, showed low IC₅₀s of 11.77±0.10 μg/ml and 11.96±0.16 μg/ml, respectively, and significant ACE inhibitory activity. The most relatively abundant compounds found in Fractions I and III) were 9, 12, octadecadienoic acid methyl ester (conjugated linoleic acid isomers), cis-Vaccenic acid, 3H-Pyrazol-3-one, 4-benzoyl-2, 4-dihydro-5-methyl-2-phenyl (a pyrazole), and Hexadecanoic acid methyl ester (aromatic acid ester).

The study reveals valuable compounds in the methanol extract of Baobab fruit pulp, which could be a promising source for developing antihypertensive foods.