Omani medicinal plant in the focus of phytochemistry
IPB scientists and partners from Dhofar University recently took a closer phytochemical look at the Omani medicinal plant Terminalia dhofarica. Terminalia is rich in antioxidant and anti-inflammatory polyphenols. The plant's leaves and bark are used in traditional medicine in Oman for healing wounds and as an antiseptic in skin care. Terminalia dhofarica belongs to the plant genus Terminalia, which is widespread in South Asia, the Arabian Peninsula and West Africa. Many Terminalia species are important ethnomedicinal plants in this region with a wide range of applications against stomach complaints, skin infections, diabetes and respiratory diseases. In contrast to most Terminalia medicinal plant species, however, Terminalia dhofarica was hardly studied phytochemically, which means that very little is known about the exact composition of its ingredients and their effect on humans or pathogenic organisms.
The IPB chemists have now started to close this gap. Their study in Molecules is the first comprehensive phytochemical characterization of this species. To do so, they analyzed the most important constituents of the leaves using ultra-high-performance liquid chromatography followed by high-resolution electrospray ionization mass spectrometry (UHPLC-ESI-HRMS) and nuclear magnetic resonance spectroscopy (NMR) and tested their antibacterial efficacy. The main focus of the investigations was on natural polyphenolics. The scientists were able to isolate and structurally identify a total of 13 different polyphenols from the plant. Nine of the compounds found never before have been described for Terminalia dhofarica. In antimicrobial activity tests, the substances showed a moderate effect against microbes, including plant pathogens that cause wheat leaf blight and potato late blight. The plant contains further constituents with potential, e.g. with anti-inflammatory properties. The results support the traditional medicinal use of the plants for topical applications like wound healing and as an antiseptic, the scientists conclude, but significant systemic effects should not be expected.
