Source of materialThe title compound, guatambuine, a pyrido [4,3-b]carbazole alkaloid, was isolated from the chloroform fraction of the ethanol extract from the stem of Aspidosperma subincanum, a tree of the Apocynaceae family. The crystals of the guatambuine were obtained by recrystallization from MeOH at room temperature.
Experimental detailsH atoms attached to C atoms were located on stereochemical grounds and refined with fixed bond lengths and angles, each riding on a carrier atom, with an isotropic displacement parameter amounting to 1.5 (for methyl) or 1.2 (for the other H atoms) times the value of the equivalent isotropic displacement parameter of the atoms to which they are bonded. The H atom attached to the N atom was refined freely.
DiscussionThe title compound, 1,2,5-trimethyl-1,2,3,4-tetrahydropyrido [4,3-b]carbazole, belongs to the class of indole alkaloids, a large group of biologically active compounds of naturally occurrence. The indole alkaloids have numerous biological activities such as antitumor, anti-microbial, anti-hypertensive and stimulant for the central nervous system [1]. The occurrence of the indole alkaloids is described at the Apocynaceae, Rubiaceae, and Loganiaceae families [2]. Among the Apocynaceae, the genus Aspidosperma is especially rich in indole alkaloids [3]. Aspidosperma subincanum is a Brazilian medicinal plant used in the treatment of general debility, digestive tract disorders, dysentery and against fever [4]. Previous separate investigations of this plant revealed the presence of more than 15 indole alkaloids [5]. In our search for structurally unique and biologically interesting compounds from Brazilian medicinal plants we are working with the stem and stem bark of A. subincanum. From the ethanolic extract of stem of A. subincanum we isolated guatambuine or N-methyltetrahydroolivacine, which has received considerable interest as result of this anti-tumor activity [6]. Guatambuine was isolated previously from others Aspidosperma species [7].
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.