Antimicrobial Potential of Root Extracts of Cryptolepis sanguinolenta: Antibacterial and Antifungal Activities

Abstract

Cryptolepis sanguinolenta is a West African medicinal plant widely used in traditional medicine, particularly in Senegal, for the treatment of colic and intestinal infections. Despite its importance in traditional medicine, scientific validation of its antimicrobial and antifungal properties is still needed. The objective of this study was to evaluate the antibacterial and antifungal activities of various extracts from the roots of C. sanguinolenta, as well as to isolate and characterize its main bioactive compound. Root extracts were obtained by successive maceration using solvents of increasing polarity (cyclohexane, ethyl acetate, ethanol, and water). Cryptolepine was isolated from the ethanolic extract, and its structure was elucidated by proton and carbon NMR as well as by DEPT 135 spectroscopy. Antimicrobial activity was evaluated in vitro against bacterial strains (Escherichia coli, Staphylococcus aureus), yeasts (Candida albicans, Kluyveromyces marxianus, Saccharomyces cerevisiae), and molds (Penicillium chrysogenum, Aspergillus niger). Minimum inhibitory concentrations (MICs) were determined. Among the extracts tested, the ethanolic extract showed the strongest antimicrobial activity, with MIC values of 1.25 mg/mL against E. coli and S. aureus. The isolated cryptolepine exhibited more pronounced activity, with MIC values of 0.625 mg/mL against these same bacteria. Regarding fungi, the ethanolic extract and cryptolepine exhibited comparable activity against the tested species, with MIC values of 1.25 mg/mL for most strains, with the exception of K. marxianus, which proved to be more sensitive (MIC of 0.625 mg/mL for the extract and 0.313 mg/mL for cryptolepine). These results confirm that C. sanguinolenta, particularly its ethanolic root extract and isolated cryptolepine, possesses promising in vitro antimicrobial properties. Further phytochemical, mechanistic, and in vivo studies are needed to confirm its therapeutic potential and support its development as a source of plant-derived antimicrobial agents.