Ellagitannins, ellagic acid derivatives and ampelopsin in antimicrobial root and stem bark extracts of some selected african species of Terminalia and Anogeissus leiocarpus
Terminalia sambesiaca, Terminalia kaiserana and Terminalia brownii are native to East and South African Miombo and dry woodlands. Anogeissus leiocarpus is found both in West and East Africa. Roots, stem bark and leaves are prepared to hot water decoctions and teas or mixed in maize porridge for infectious diseases and their symptoms, diarrhea and cough . Although ellagitannins and ellagic acid derivatives have been identified from several species of Terminalia, T. sambesiaca and T. kaiserana have not been studied before in this context. Ellagitannins  and ellagic acid derivatives  have been identified in A. leiocarpus and seven ellagic acid derivatives  are known from T. brownii, but since these species have given interesting antimicrobial profiles in our screenings they should be studied in detail for active compounds. Our data obtained using MS-QTOF indicate that methanol extracts of the roots of T. sambesiaca contain the ellagitannins corilagin, terchebulin and its isomer along with several unknown ellagitannins as well as ellagic acid glycosides. Root extracts of T. kaiserana contain punicalin, punicalagin and its isomer as well as terchebulin, castalagin and terflavin-A together with unknown ellagitannins and several ellagic acid derivatives. Ellagic acid derivatives and ellagitannins were identified from the roots of T. brownii and stem bark of A. leiocarpus. Ampelopsin was found for the first time in A. leiocarpus. All species possess promising antibacterial, antimycobacterial and antifungal activities. MIC as low as 39 – 78 µg/ml was recorded for some root and stem bark extracts of T. brownii and A. leiocarpus against P. aeruginosa and S. aureus.
Acknowledgements: This study has been supported by Finnish Medical Association and Swedish Cultural Foundation in Finland.
Keywords: Terminalia, Anogeissus, Africa, antimicrobial, ellagitannins, ellagic acid derivatives