Sesquiterpene lactones from the leaves of Hedyosmum brasiliense (Chloranthaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Hedyosmum brasiliense Miq. is an endemic aromatic arborescent shrub that is the only representative of the Chloranthaceae in Brazil. There have been few studies seeking to determine its chemical constituents and/or pharmacological effects. This work describes the isolation and identification of sesquiterpene lactones from the leaves, including guaianolides, elemanolides and a lindenanolide. These were tested against Mycobacterium tuberculosis, together with podoandin, onoseriolide and some other common phenolics. The structures of the isolated compounds were determined based on extensive analysis of 1D and 2D NMR spectroscopic and MS data, as well as comparison with published data. The compounds found were the guaianolides, 1,2-epoxy-10 alpha-hydroxy-podoandin and 1-hydroxy-10,15-methylenepodoandin, the elemenolide 15-acetoxy-isogermafurenolide and the lindenanolide 8 alpha/beta,9 alpha-hydroxy-onoseriolide, along with the previously isolated guaianolide podoandin, the lindenanolide onoseriolide and the elemenolide 15-hydroxy-isogermafurenolide. The phenolic compounds isolated were scopoletin, vanillin, vanillic acid, protocatechuic aldehyde and ethyl caffeate. The isolated sesquiterpene lactones did not show anti-mycobacterial activity against isoniazid-sensitive M. tuberculosis cultures at concentrations of 1-30 mu M. (C) 2012 Elsevier Ltd. All rights reserved.87126132Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FINEPUFPRConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Isolation of anti-mycobacterial compounds from Curtisia dentata (Burm.f.) C.A.Sm (Curtisiaceae)

Abstract Background Tuberculosis is counted amongst the most infectious and lethal illnesses worldwide and remains one of the major threats to human health. The aim of the current study was to isolate and characterize anti-mycobacterial compounds present in Curtisia dentata (Burm.f.) C.A.Sm , a medicinal plant reportedly used in the treatment of tuberculosis, stomach ailments and sexually transmitted infections. Methods The bioassay guided principle was followed to isolate the anti-mycobacterial compounds. The crude ethanol extracts of the leaves was partitioned with various solvents four compounds such as β-sitosterol, betulinic acid, ursolic acid and lupeol were successfully isolated. The compounds and their derivatives were evaluated for anti-mycobacterial activity using Microplate Alamar Blue Assay (MABA) against Mycobacterium tuberculosis H37RV (ATCC 27294). Furthermore, the derivatives were investigated for their toxicity against HepG2 and HEK293 using the MTT assay. Results The methanol fraction had the lowest minimum inhibitory concentration (MIC) of 22.2 μg/ml against the selected Mycobacterium strain when compared to other fractions. Ursolic acid acetate (UAA) was the most active compound with MIC value of 3.4 μg/ml. The derivatives had varying degrees of toxicity, but were generally non-toxic to the selected cell lines. Derivatives also exhibited highest selectivity index and offers a higher safety margin. Conclusions The derivatives had better antimicrobial activity and low cytotoxic effects compared to isolated compounds. These increased their selectivity. It appears that acetylation of both betulinic acid and ursolic acid increased their activity against the selected Mycobacterium species. The results obtained in this study gives a clear indication that Curtisia dentata may serve as major source of new alternative medicines that may be used to treat TB. Furthermore, there is a need to explore the activity of these tested plant against other pathogenic Mycobacterium species