Phytochemical Screening and Antimicrobial Properties of Leaf Extracts from <i>Newbouldia laevis</i> (P. Beauv) and <i>Flueggea</i> <i>virosa</i> (Roxb. ex Willd.)

Using plants to treat human diseases is very old and has evolved throughout human history<i>. Flueggea virosa</i> and <i>Newbouldia laevis</i> are two plant species acclimatized in Benin and used in Africa to treat several diseases such as malaria, liver diseases; fever, migraine, diarrhea, dysentery, intestinal worms, diabetes, sexually transmitted diseases, etc. In this work, we studied methanolic and hydroethanolic leaf extracts from those species. Phytochemical screening was determined by the Hounton and Raman methods, and the antimicrobial activity of the leaf extracts was evaluated by the microdilution method. The antimicrobial properties of the leaf extracts were examined on five bacteria strains. The phytochemical analysis revealed the presence of alkaloids, polyphenols, tannins, flavonoids, anthocyanins, coumarins, mucilages, reducing compounds, and bound anthracene derivatives (O-heterosides and C-heterosides). Quinonine derivatives were absent in the leaves of <i>Flueggea virosa</i>, but present in the leaves of <i>Newbouldia laevis</i>. In addition, the leaves of <i>Flueggea virosa</i> contained saponosides, triterpenoids compared to those of <i>Newbouldia laevis</i>. Moreover, <i>Flueggea virosa</i> leaves enclosed no cardenolides, cyanogenic derivatives as well as, free leuco-anthocyanins and anthracene derivatives. Evaluation of antimicrobial activity in the five strains included in this study showed better results (minimum inhibitory concentrations between 31.2 and 1000 μg/mL), specifically with the methanolic extract from <i>Flueggea virosa</i> leaves that showed a Minimum Inhibitory Concentration (MIC) equal to 31.2 μg/mL against the reference strain of <i>Staphylococcus aureus</i> ATCC 12600. Among the two plants, <i>Flueggea virosa</i> extracts showed more interesting antimicrobial activity then those of <i>Newbouldia laevis</i> on strains.