Chemical studies on the parasitic plant Thonningia sanguinea Vahl

Thonningia sanguinea Vahl plays an important role in traditional medicine in many African cultures. A study of the n-hexane fraction of the whole plant of T. sanguinea led to the isolation of two glucocerebroside molecular species TSC-1 and TSC-2, one β-sitosteryl-3β-d-glucopyranoside-6'-O-fatty acid ester molecular species, TSS-1, and seven known triterpenes (1-7). The ethyl acetate fraction also afforded five known lignans (8-12) and one known flavanone (13). Their structures were elucidated by means of chemical and spectroscopic methods (methanolysis, NMR and mass spectrometry). Spectral analyses of the glucocerebrosides revealed mainly sphingosine-type (TSC-1) and phytosphingosine-type (TSC-2) cerebrosides, with both possessing mainly 2-hydroxy fatty acid and β-d-glucopyranose moieties. TSS-1 was found to be a β-sitosterol-type with fatty acid methyl esters and β-d-glucopyranoside moieties. The classes of compounds isolated from this plant are well known for their interesting biological activities including antimicrobial, antioxidant, anticancer, antiinflammatory and analgesic. They may therefore be responsible in part or in whole for these activities, hence validating the traditional uses of the plant. To the best of our knowledge, this is the first report on the isolation of all these compounds from T. sanguinea.