Antimicrobial activity of the methanolic leaf extract of Prosopis laevigata

Abstract

The appearance of antimicrobial-resistant pathogens has highlighted the need to search for new compounds that can effectively combat infectious diseases. A potential source of these compounds are the secondary metabolites of species that have been reported as effective traditional treatments of such diseases. Prosopis laevigata is a medicinal plant, and its chemical constituents have shown potential antimicrobial activity. In this study, the antimicrobial activities of the methanolic extract of the leaves of Prosopis laevigata against different bacterial and fungal strains of medical and agronomic interest were investigated in vitro. In addition, the chemical composition of this extract was investigated by HPLC–DAD, GC‒MS, and HPLC‒MS. The methanolic leaf extract contained 67 mg of GAE/g of total phenols (6.7%), 2.6 mg of QE/g of flavonoids (0.26%), and 11.87 mg of AE/g of total alkaloids (1.18%). Phenolic acids and catechol were the compounds identified by HPLC–DAD. The methanolic extract had strong antimicrobial activity, especially against Staphylococcus aureus (MIC = 0.62 mg/mL), Escherichia coli (MIC = 0.62 mg/mL), Candida tropicalis (MIC = 0.08 mg/mL) and Fusarium moniliforme (MIC = 4.62 mg/mL). These results suggest that the extract of P. laevigata leaves could be a source of antimicrobial molecules. However, it is necessary to delve into its chemical composition.

Isolation and Characterization of Antimicrobial Constituent(s) from the Stem of Cissus populnea Guill. & Perr.

“…Thus, the findings of this study were in close agreement with those reported for the antimicrobial activity of stigmasterol and β-sitosterol from the roots of C. populnea [17] and β-sitosterol from the leaves of the plant, C. populnea [8]. Even though there is limited information on the mechanism of antimicrobial activity of stigmasterol and β-sitosterol, some studies have shown that the compounds have a broad spectrum of antibacterial and antifungal properties [30,31]. Stigmasterol has been reported to inhibit the growth of C. albicans, viruses and tropicalis at low concentrations [32].…”

“…Antimicrobial activity of C4C5 was determined using agar well diffusion method as described by Yusuf et al [30]. A quantity (0.001 mg) of C4C5 was weighed and dissolved in 10 cm 3 of DMSO to obtain a concentration of 100 µg/cm 3 each.…”

“…The MIC for each microbial sample was determined using broth dilution technique [30,38]. Mueller Hinton broth and sabouraud dextrose broth were prepared according to the manufacturer's instruction; the medium was dispensed in screw-capped test tubes and sterilized at 121 • C for 15 min and allowed to cool.…”

“…Incubation was made at 37 • C for 24 h for the bacteria and at 30 • C for 48 h for fungi. The test tubes containing the inoculated broth were observed for turbidity (growth) and the lowest concentration of the compound in the sterile broth which shows no turbidity was recorded as the minimum inhibition concentration [39] The MBC/MFC was carried out to determine whether the test microbes were killed or whether only their growth was inhibited [30,38]. Mueller Hinton agar and sabouraud dextrose agar were prepared, sterilized at 121 • C for 15 min and transferred into sterile petri dishes to cool and solidify.…”

Phytochemical Properties and In vitro Antimicrobial Activity of Methanolic Leaf Extract of Durio zibethinus Murr. on Selected Clinical Isolates

“…The method described by Jensen et al [19,20] was adopted with minor modifications. Into sterile test tubes was placed 1 mL of nutrient broth.…”