Polyphenol-rich extracts of African Combretum and Terminalia species show growth inhibition against Salmonella enterica and Bacillus cereus

Species of the genera Terminalia and Combretum occur in savanna woodlands in East, West and South Africa and are used in traditional medicine for various infections including food poisonings [ 1 ] [ 2 ] [ 3 ]. Accordingly, this study aimed to assess the effects against Salmonella enterica and Bacillus cereus of extracts made from various plant parts of Combretum and Terminalia spp. collected from Tanzania. In addition, we assessed the polyphenol composition of the active plant extracts, and identified the possible specialized metabolites causing the activities. Our results indicated that methanol and chloroform extracts of the leaves of C. adenogonium (MIC 156 and 78 μg/ml ), and methanol extracts of T. kaiserana and C. collinum (MIC 313 μg/ml for both) gave the strongest effects against B. cereus . Besides, the methanolic root extract of T. kaiserana and the leaf decoction of C. adenogonium were active against B. cereus (MIC 1250 and 2500 μg/ml). Only the methanol extract of the rootbark of C. zeyheri showed activity against S. enterica (MIC>2500 μg/ml) whereas all other screened extracts lacked the activity against this bacterium. Our UPLC/HRMS results (ESI- mode) indicated that a methanol extract of T. kaiserana roots contained e.g. punicalin (m/z 781.0591), castalagin (m/z 933.0136), ellagic acid rhamnoside (m/z 447.0510), methyl-flavogallonate (m/z 483.0253) and punicalagin (m/z 1083.0574), while a gallotannin (m/z 647.0890) was the most abundant metabolite in C. zeyheri roots. Our metabolite screening results indicate that Combretum and Terminalia spp. contain active polyphenolic compounds that could be used for the prevention of food poisonings. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany