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DOI: 10.1055/s-0032-1321247
Isolation of bioactive diterpenes from Tetradenia riparia by HSCCC
Tetradenia riparia (Hochst) Codd. (Lamiaceae) is a shrub originally from Africa where it is used in traditional medicine. In Brazil it is used in rituals and is commercialized in open markets. Literature reports diterpenes as constituents with interesting antimicrobial activity.
Fractionation of the dichloromethane extract of leaves of T. riparia (687,4mg) by HSCCC with the solvent system hexane-ethyl acetate-methanol- water (3:1.5:3:1.5) afforded the isolation of 7-α-hydroxyroyleanone, along with other 14 fractions, which were assayed against Mycobacterium tuberculosis by the microdilution method using resazurin as an indicator of cell viability. The best results were obtained for compound 1 and for the fraction containing a flavonoid derivative. Ibozol, obtained by further fractionation of fraction F4 with hexane-acetone-methanol-water in a second step (3:1.5:2.5:2) was also found to be active. Scale-up of this fractionation was performed with 1.5298g of the extract and the same chromatographic profile was obtained.