Phytochemical study of Joannesia princeps Vell. (Euphorbiaceae) leaves

Joannesia princeps Vell. (Euphorbiaceae family, Jatropheae tribe) is an endemic species of subtropical and coastal regions of Brazil, but it can also be cultivated in Africa and Asia [1]. Several secondary metabolites have been isolated from different parts of the plant, such as lignans, neolignans, sesquineolignans, that have been obtained from the methanol extract of the seeds [1], while sesquiterpenes, diterpenes, triterpenes, steroids, proanthocyanidins, and phenolic compounds from the root bark [2]. J. princeps leaves have shown antibacterial, antioxidant [3] and anti-inflammatory activities [4], however to our knowledge, their complete phytochemical characterization was never carried out. A phytochemical approach led to the isolation of twenty eight compounds from chloroform-methanol and methanol extracts of J. princeps leaves, including two α-ionones, three glycosylated monoterpenes, eight phenolic compounds, two gallotannins, twelve flavonoids, and one lignan. The structural determination of the isolated compounds was performed by spectroscopic data and comparison with the literature. All compounds were isolated from this species and from Joannesia genus for the first time. Some chemotaxonomic considerations were then highlighted: the presence of the ellagic acid derivative corilagin in the Jatropheae tribe has been reported only once in Jatropha curcas L. [5]. Since this class of compounds were found in different Euphorbiaceae species [6] they might be useful as chemotaxonomic markers. To our knowledge, this is the first report of methylbrevifolin carboxylate, isolariciresinol-9’-O-β-D-xylopyranoside, and brevifolin carboxylic acid in the Jatropheae tribe. The isolation of myricetin 3-O-rutinoside, 2’’-O-galloylorientin, and the flavone C-glycosides isovitexin 2’’-O-β-D-xylopyranoside, isovitexin 2’’-O-α-L-rhamnopyranoside, and isoorientin 2’’-O-β-D-xylopyranoside, is reported now for the first time in a plant of the Jatropheae tribe, and more generally in the Euphorbiaceae family.