Phytochemical profile and antimicrobial activity of the leaves and stem bark of Symphonia globulifera L.f. and Allophylus abyssinicus (Hochst.) Radlk

Abstract IntroductionSymphonia globulifera and Allophylus abyssinicus are used in the management of skin rashes and sores, cough, malaria, digestive diseases, stomach ache, wounds, helminthic infections among others in Uganda, Kenya, Ethiopia, Cameroon. This study aimed at determining the phytochemical profile and antimicrobial activity of these two plants.Methods The stem bark and leaves of both plants were collected from Bwindi Impenetrable National Park, and air dried under shade at room temperature. Cold maceration, decoction and infusion with methanol, water and ethyl acetate as solvents were used in phytochemical extraction. Preliminary qualitative screening and thin layer chromatography were used for phytochemical profiling. Antimicrobial activity was analysed by Agar well diffusion assay, macro broth dilution assay and fractional inhibition concentration index. ResultsLeaves and stem bark of both plants have a diverse set of phytochemical compounds of variable polarity including, tannins, alkaloids, flavonoids, saponins, quinones, anthraquinones among others. Generally, methanol and water extracts of S. globulifera and A. abyssinicus had in-vitro bactericidal activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa but weak fungistatic activity against Candida albicans. Allophylus abyssinicus Leaf water and Symphonia globulifera Leaf methanol extract combination had a synergistic activity (ΣFICI=0.37) against S. aureus. Similarly, Allophylus abyssinicus stem bark water extract and A. abyssinicus leaf water extract combination had an additive effect (ΣFICI=1) against P. aeruginosa.ConclusionThe leaves and stem bark extracts of S. globulifera and A. abyssinicus possess antimicrobial bioactive compounds against both gram positive and gram-negative bacteria. They could therefore offer potential sources of novel antibiotics.