Mineral Profiling and Antimicrobial Effects of the West Indian Cherry (Malpighia emarginata DC.) Fruit Extracts Against Selected Pathogenic Bacteria

Abstract

Bioactive compounds are found throughout the cherry fruit and these compounds give the fruits their antimicrobial properties. The objective of this study was to determine the mineral profile of M. emarginata for four maturity stages. The mineral potassium (K), phosphorus (P), and magnesium (Mg) content was evaluated by spectrophotometry. The highest amount of K was found in the half-green (HG) stage and the lowest in the full-ripe (FR). The highest concertation of P and Mg was found in the full-green (FG) stage and the lowest in the full-ripe. For P, there was an increase from the FG to the HG maturity stage, then the concentration declined until maturity, as it related to the concentration of Mg and K, there was a decline in the concentration as the fruit progressed maturity. Additionally, the antibacterial activity of the fruit extract was conducted on E. coli and S. aureus using the Kirby Bauer disc diffusion method at different concentrations of plant extracts.  The ethanolic extracts (EE) (zone of inhibition 13.4 ± 1.9 to 21.8 ± 0.6) showed more antimicrobial activity than the aqueous extract (AE) with zones of inhibition diameters (mm) which ranged from 0 ± 0 to 18.2 ± 0.8.  Both AE and EE were effective against S. aureus bacteria strain except the AE (crude) which had no zone of inhibition. All tested microorganisms were susceptible to the antibiotic ciprofloxacin. This study suggests that other types of solvents were used to investigate the antibacterial activities of the M. emarginata extract on a wider array of bacteria as the fruit demonstrated antimicrobial properties.