Isolation and structure determination of terminalin A toxic condensed tannin from Terminalia oblongata.

Abstract

Terminalia oblongata (yellow wood) is a small deciduous tree growing over an area of central Queensland that supports a large proportion of this state's cattle population. Cattle and sheep that consume yellow wood leaves are poisoned and die. Severe losses of these animals can occur, and this problem is considered the main cause of economic loss to the cattle industry in the area apart from drought. A new toxic condensed tannin, terminalin was isolated from Terminalia oblongata. Its structure was deduced following NMR, IR, UV, MS analyses and in the knowledge that these data show good correlations to those obtained from the related punicalagin molecule which is present in the plant. Terminalin has a high toxicity (20 mg/kg) to white Quackenbush male mice and produces a vascular renal necrosis with slight liver necrosis, unlike punicalagin, which produces liver lesions but not kidney lesions. Similar results were obtained with sheep. A most interesting aspect is that there are two different specific toxins in the plant.