The medicinal properties and phytochemistry of plants of the genus Terminalia (Combretaceae)

Plants of the genus Terminalia are amongst the most widely used plants for traditional medicinal purposes worldwide. Many species are used for their antibacterial, antifungal, antiprotozoal, antiviral, antidiarrhoeal, analgesic, antimalarial, antioxidant, antiinflammatory and anticancer activities. Wound healing and cardiovascular effects have also been credited to some species. Many Terminalia species have multiple beneficial effects for multiple diseases and ailments. Indeed, the Indian species Terminalia chebula is known as the king of plants in Ayurveda due to its broad range of medicinal uses. However, apart from the reported ethnopharmacological uses of many Terminalia species, surprisingly few studies have rigorously examined this important genus for their medical properties/mechanisms and phytochemistry. This is likely due to the high tannin content common to many Terminalia species and the perception that these tannins may be responsible for much of their beneficial properties. As the complexities of tannins make them poor candidates for drug design, most interest in Terminalia species has been for their pharmacognostic and nutraceutical value and they have often been overlooked as potentials for drug discovery. However, recent reports have identified many other interesting phytochemicals and demonstrated that these may be responsible for several of the reported bioactivities of the Terminalia species used in traditional medicinal systems. The last decade has seen a large increase in the number of studies into the use of Terminalia species as therapeutic agents. Several species used in Ayurvedic medicine (Terminalia arjuna, Terminalia bellerica, Terminalia catappa, T. chebula) in particular have received much recent attention. Similarly, recent reports have also highlighted the medicinal potential of species from Africa, Australia and the Americas. The aim of this report is to summarise the recent research into the medicinal properties, phytochemistry and therapeutic mechanisms of Terminalia species and thus to highlight and direct future areas of research into the medicinal activities of this important genus.