Identification of Triterpenes from the Leaves of Jacaranda puberula

Abstract

The Bignoniaceae family of flowering plants is made up of approximately 100–125 genera and 860 species, and plants belonging to this family are especially common in the tropical regions of South America. Flowering plants belonging to this particular family contain a wide variety of chemical constituents, including naphthoquinones (lapachol type), iridoid glycosides, alkaloids, flavones, triterpenes, polyphenols, and tannins. Although the genus Jacaranda contains 49 distinguished species, only 13 of these species have been reported in the scientific literature, with reports focusing primarily on the application of these plants in ethnobotanical medicine or their phytochemical evaluation [1]. Only six species from the Jacaranda genus have been subjected to phytochemical investigation [1]. Although Jacaranda puberula was recent reported to contain polyphenol compounds such as verbascoside and cis-caffeoyl aldehyde [2], our general knowledge and understanding of the phytochemical properties of the plants belonging to this genus is poor. Phytochemical investigation of plants belonging to this genus, however, has revealed that they contain a variety of different compounds, including triterpenes (e.g., -sitosterol, lupenone, betulinic acid, ursolic acid, corosolic acid, oleanolic acid, and jacoumaric acid), quinones (e.g., jacaranone and hydroquinone), flavonoids (e.g., luteolin, quercetin, apigenin, and isoquercitrin), fatty acids (e.g., triacontanoic acid and 8Z,10E,12Z-octadocatrienoic acid), acetosides (e.g., E-acetoside, Z-acetoside, and isoacetoside), and a novel phenylethanoid dimer known asjacraninoside A [1]. Herein, we report for the first time the identification of several pentacyclic triterpenes, including ursolic acid (1), oleanolic acid (2), corosolic acid (3), and maslinic acid (4) from Jacaranda puberula. Furthermore, the work described in this study represents the first reported account of maslinic acid (4) being identified in a species belonging to this genus. We therefore believe that the results of this study will improve our overall understanding of the phytochemical properties of plants belonging to the Jacaranda genus, which are interesting from both biological and chemical perspectives. The identification of triterpenes in the current study is particularly interesting in view of their contribution to the biological properties of species belonging to the Bignoniaceae family. Phytochemical analysis of J. puberula confirmed that this species belonged to Tecomeaea species of the Bignoniaceae family of flowering plants. In accordance with the evolution of species belonging to this family, significant quantities of secondary metabolites derived from acetate-mevalonate were detected in J. puberula, including iridoid glycosides and pentacyclic triterpene derivatives. Tecomeaea, which is the second most studied species belonging to this family, has been found to contain a wide variety of different terpene-based compounds. Taken together, these features are considered by many to indicate the general high level of evolutionary advancement in flowering plants [3].