Phytochemistry and bioactivity of Acacia sensu stricto (Fabaceae: Mimosoideae)

Acacia sensu lato (Fabaceae: Mimosoideae) was recently retypified and divided into five genera worldwide: Acacia, Acaciella, Mariosousa, Senegalia and Vachellia. Acacia sensu stricto is now considered to be a large genus of predominantly Australian origin comprising seven sections: Acacia, Alatae, Botrycephalae, Juliflorae, Lycopodiifoliae, Plurinerves and Pulchellae. This review presents an overview of the current taxonomy of A. sensu stricto and the natural products isolated and identified from it. Further, the traditional uses of different species and known bioactivities of isolated natural products are summarised. The flavonoids and tannins are the best studied classes of natural products from Acacia with characteristic hydroxylation patterns of flavonoids isolated from the heartwood of species positioned in different sections of the genus. These compounds display a range of activities including antioxidant, enzyme inhibitory and antimicrobial effects. Peltogynoid compounds, differing from other flavonoids by the presence of a fourth ring, have been isolated from a small group of species, however, their biological activities remain to be defined. Only a limited number of terpenes and steroids have been identified, but complex triterpenoid saponins with various bioactivities are present across various sections. Despite their economic importance and the traditional use, only a limited number of species have been thoroughly studied for their chemical composition. Further investigation of the sections Alatae and Lycopodiifoliae would be of interest for bioactive compound research as these sections are largely unexplored.