mexican copalchis of the rubiaceae family: more than a century of pharmacological and chemical investigations

The term copalchi has been used in the scientific literature to define a group of plants of the rubiaceae and euphorbiaceae families with extremely bitter stem-barks, useful for treating diabetes and malaria. in this review we summarized the most relevant chemical and pharmacological works carried out in the last century with the copalchis of the rubiaceae family, namely hintonia latiflora, h. standleyana and exostema caribaeum. their major components are 4-phenylcoumarins 5,7,3′,4′- or 5,7,4′-substituted with oxygenated functionalities, with the former having the most common pattern. these along with a few cucurbitacins are responsible for the antidiabetic properties of both hintonia species. e. caribaeum contained mostly 4-phenylcoumarins, which apparently are the antimalarial constituents of these plants. toxicological reports on these plants are discussed. the quality control procedures (chromatographic and molecular) developed for the three species are summarized. these will be valuable for their unequivocal identification, which in turn will avoid their partial adulteration or substitution. future studies are required to solve the puzzle around the toxicity of the copalchis and for better understanding their pharmacological actions. finally, establishment of their metabolomics profiles will provide a better knowledge of their secondary metabolism and help map their biosynthesis pathways.