Raphael F Queiroz
University of the Southwest, Brazil
Title: A new tropane alkaloid from Erythroxylum macrocalyx (Erythroxylaceae) and bioactivities of their chemical constituents
Biography
Biography: Raphael F Queiroz
Abstract
Statement of Problem: The genus Erythroxylum P. Browne is the major representative of the Erythroxylaceae family, comprising around 240 species widespread in neotropical regions. Erythroxylum species are characterized mainly by presence of tropane alkaloids, flavonoids and terpenoids which confer to these species several pharmacological activities. Considering the occurrence of E. macrocalyx Mart. in Brazilian Northeast and the lack of knowledge concerning its chemical constituents and respective biological properties, the aim of this work was to perform a phytochemical investigation of the branches from E. macrocalyx beyond to evaluate their antiproliferative and antibacterial activities. Methodology: The structures were established by analyses of 1D- and 2D-NMR and MS data, as well as, by comparison with literature data for known compounds. The structure of the compound 2 was also confirmed by X-ray crystallography.
The isolated compounds were tested for their in vitro antibacterial and antiproliferative activities. The antiproliferative activity of the substances 2-9 was evaluated against tumor (HepG2, HL-60, MCF-7 and HCT116) and non-tumor (MRC-5 and human lymphoblast) cell lines. Findings: The compound (5) 6β-benzoyloxy-3α-(4-hydroxy-3,5-dimethoxybenzoyloxy)tropane was the most active showing IC50 value of 3.66 μg/mL against HepG2 cell line but no cytotoxic effect on human lymphoblast (IC50 >25 μg/mL). Conclusion & Significance: A new tropane alkaloid, 7β-acetoxy-6β-benzoyloxytropan-3α-ol (1), was isolated, together with eight known substances [four tropane alkaloids (2-5), one flavonol glycoside (6) and three triterpenes (7-9)] of the branches from E. macrocalyx. In addition, the tropane compound [5] was a promising antiproliferative prototype for further mechanistic studies.