ABSTRACT
From time immemorial, natural substances have played a vital role in the field of drug discovery, contributing to the development of potent medications used in modern medicine. This research delves into the in vitro antimicrobial and antimalarial properties of specific natural herbs and spices commonly used in traditional Nigerian cuisine, namely Xylopia aethiopica, Chrysobalanus icaco, and Glycyrrhiza glabra. A successive extraction process was employed utilizing n-hexane and dichloromethane as solvents, resulting in extracts labeled as follows: Xylopia aethiopica (XA-H, XA-D), Chrysobalanus icaco(CI-H, CI-D), and Glycyrrhiza glabra (GG-H, GG-D). Phytochemical screening unveiled the presence of alkaloids, phenols, flavonoids, saponins, tannins, terpenoids, carbohydrates, and reducing sugars within these extracts. The subsequent in vitro antimicrobial assessment was conducted using American type cell cultures, involving pathogenic fungi, bacteria, and specific resistant microorganisms such as Vancomycin-resistant enterococcus and Methicillin-resistant Staphylococcus aureus. In addition, an in vitro antimalarial evaluation was performed using the Plasmodium lactate dehydrogenase (pLDH) assay, which measures the activity of the lactate dehydrogenase enzyme found in plasmodium to measure the effectiveness of the crude extracts against both chloroquine-sensitive and resistant strains of the parasite. Furthermore, an in vitro cytotoxicity test was executed employing VERO cell lines (monkey kidney fibroblast). The outcomes of our investigation revealed that all plant samples exhibited negligible antimicrobial activity. Conversely, the in vitro antimalarial assay demonstrated significant inhibition of the pLDH enzyme by all plant samples, indicating their antimalarial potential. Notably, GG-H, GG-D, XA-H, and XA-D displayed greater potency and selectivity indices comparable to artemisinin and chloroquine (>9). GG-H and XA-D, in particular, demonstrated remarkable results, with IC50 values significantly lower than the lowest test concentrations employed. In conclusion, our findings suggest that none of the plant samples possess antimicrobial properties under the experimental conditions employed in this study. However, all of them exhibit promising antimalarial activity, with Xylopia aethiopica demonstrating the highest potency. Consequently, further in vivo investigations are warranted to confirm the antimalarial potential and elucidate the active constituents within these plant extracts.
