Phytochemical investigation of the roots extracts of Terminalia brownie and isolation of dimethyl terephthalate

Abstract

Terminalia brownie (T. brownie) is a plant traditionally used for treatment of human illnesses such as bronchitis, diarrhea, bacterial infections, fungal infections, viral infections, stomach ache, ulcers, sexually transmitted diseases, malaria, cough, hepatitis, jaundice and yellow fever. The objective of this study was to extract and isolate compounds from the root extract of T. brownie, and to characterize structures of isolated compounds. The successive extraction of the roots was carried out using solvent systems n-hexane, dichloromethane: methanol (1:1) and methanol that afford 0.9 g, 42.0 g and 11.0 g of crude extracts, respectively. Phytochemical screening of the dichloromethane: methanol (1:1) root extract of the plant revealed the presence of terpenoids, saponins, steroids, flavonoids, tannins, phenols, and glycosides. Column Chromatographic separation on silica gel of dichloromethane: methanol (1:1) extract using chloroform: methanol solvent system with gradual increase in polarity led to isolation of compound 19 (dimethyl terephthalate) for the first time from the genus. The structure of this compound was elucidated using spectroscopic techniques (UV-Vis, IR, and NMR). The present study concluded that the secondary metabolites found in the dichloromethane: methanol (1:1) root extract of T. brownii are almost similar with that of the secondary metabolites reported in the previous studies of leaf and bark extract of the plant, and other species of genus Terminaia.