Phytochemical Study and Antimicrobial Activity of<i> Murraya paniculata </i>(L.) Extracts

The present study focused on the phytochemistry and antimicrobial potential of the stems of M. paniculata, an ornamental and medicinal plant used in Benin for oral care and hygiene. The objective of this work was to determine the chemical composition and antimicrobial activity of the aqueous and ethanolic extracts, as well as the decoction of this plant. For this purpose, the total phenolic compounds and flavonoid content were determined by the Folin-Ciocalteu and aluminum trichloride methods, respectively. The antioxidant activity was assessed using the DPPH and FRAP methods. The antimicrobial tests were conducted using antibiograms and the determination of MIC and MBC. The identification of bioactive molecules was performed by HPLC. The results reveal that the three extracts are rich in phenolic compounds. The ethanolic extract exhibits the highest content of total phenolic compounds with a value of 109.678 ± 0.757 μg GAE/mg DE, while the decoction has the highest flavonoid content, measuring 150.538 ± 2.020 μg QE/g DE. The antioxidant activity demonstrated that the decoction possesses the best activity according to the DPPH method, with an IC50 of 0.181 ± 0.015 mg/ml, while the aqueous extract proved to be the most effective by the FRAP method, with a reducing power of 74.022 ± 1.152 mg E AG/g DE and 153.009 ± 3.127 mg EC/g DE. Only the decoction displayed activity against the tested microorganisms, showing an inhibition diameter of 23.333 ± 11.666 mm on Staphylococcus aureus, whereas vancomycin, the reference compound, had an inhibition diameter of 17.666 ± 0.577 mm. The MICs of the decoction on the various strains range from 3.125 to 25.000 mg/ml. Tannic acid is the major bioactive compound identified in the three extracts, with the highest content found in the decoction. The traditional use of this plant could be well justified by the results obtained.