Study on combined antimicrobial activity of some biologically active constituents from wild Moringa peregrina Forssk.

Abstract

Three plants were used in this study: Moringa pregrina, Achillea fragrantissimaand Coleome droserifolia. Six active constituents were separated from n-hexane and ethyl acetate fractions of Moringa pregrina. These active constituents were lupeol acetate, α-amyrin, β-amyrin, β-sitosterol, β-sitosterol-3-O- β-D-glucoside and apignin were assayed individually and in combination against pathogenic bacteria and fungi. All constituents were proved to be more antibacterial than antifungal agents. Aspergillus flavus and Fusarium solani were completely resistant to all constituents. α-amyrin was the most effective antibacterial compound. The least relative activity was achieved by β-sitosterol against Bacillus subtilis compared to ampicillin. Reasonable antifungal activity was recorded in case of lupeol acetate, α-amyrin and β-amyrin, while β-sitosterol and β-sitosterol-3-O- β-D-glucoside, revealed no antifungal activity. Apignin missed both antifungal and antibacterial activities. Low MICs were detected by α-amyrin, β-amyrin and β-sitosterol-3-O-β-D-glucoside against all tested bacteria. Concerning fungi, β-sitosterol and β-sitosterol-3-O-β-D-glucoside showed no antimycotic activity. Lupeol acetate, α-amyrin and β-amyrin, however, have slightly high MICs for all tested dermatophytic fungi compared to that of fluconazole. Among ninety nine assayed combination mixtures, thirty seven synergistic combination mixtures were detected which exerts 37 synergisms against different pathogens with FICI less than 0.5, which indicates high efficacy of combination mixtures over monotherapy treatments. Key words: Combined antimicrobial therapy, active constituents, Moringa peregrina, Achillea fragrantissima, Coleome droserifolia.