New compounds with antimicrobial activities from Elaeodendron buchananii stem bark

Abstract

The plant species Elaeodendron buchananii Loes is widely used in folklore medicine to manage microbial infections in Kenya. Previous studies on the plant fruits and root bark revealed the presence of steroids and terpenoids. The present phytochemical analysis of the plant stem bark has led to the isolation of four new triterpenes characterized as methyl 3β-acetoxy-11α, 19α, 28-trihydroxyurs-12-en-23-oic acid (1), 3β, 11α, 19α-trihydroxyurs-12-en-23, 28-dioic acid (2), 3β-acetoxy-19α, 23, 28-trihydroxyurs-12-ene (3) and 3-oxo-19α, 28-dihydroxyurs-12-en-24-oic acid (4), together with ten known ones (5–14), whose structures were elucidated using spectroscopic techniques. The isolate canophyllol (8) showed promising antibacterial activity against N. meningitides with MIC value of 31.25 μg/ml.

Keywords:

• Elaeodendron buchananii
• Celastraceae
• triterpenes
• antimicrobial activities

Acknowledgments

The authors are grateful to Mr. Mutiso (Taxonomist) of Botany department, University of Nairobi for identification and collection of the plant materials and Mr. James Odhiambo of the Jaramogi Odinga Teaching and Referral Hospital in Kisumu County, Kenya for provision of microbes and conducting the bioassay experiments. The Institute of Organic Chemistry, University of Saarland, Germany is acknowledged for the spectroscopic data.