Chemical constituents of Rourea doniana

The chromatography fractionation of the hexane, chloroform and ethyl acetate extracts from the leaves and stems of Rourea doniana Baker, Connaraceae, resulted in the isolation of five triterpenes (lupeol, lupenone, α-amyrenone, β-amyrenone, and taraxerol), a flavonol (7,4'-dimethylkaempferol), a coumarin (scopoletin) and four phytosteroids (β-sitosterol, stigmasterol, β-sitosteryl-3-O-β- D-glucopyranoside and stigmasteryl-3-O-β-D-glucopyranoside). All compounds are being for the first time in this species and all triterpenes and the flavonol are being described for the first time in the family Connaraceae. These compounds were identified on basis of their IR and NMR (¹H, 13C, DEPT, HSQC, HMBC, and NOESY) spectral data and by comparison with literature data.

Studies on the antimicrobial activity and brine shrimp toxicity of Zeyheria tuberculosa (Vell.) Bur. (Bignoniaceae) extracts and their main constituents.

BACKGROUND: Due to the indiscriminate use of antimicrobial drugs, the emergence of human pathogenic microorganisms resistant to major classes of antibiotics has been increased and has caused many clinical problems in the treatment of infectious diseases. Thus, the aim of this study was to evaluate for the first time the in vitro antimicrobial activity and brine shrimp lethality of extracts and isolated compounds from Zeyheria tuberculosa (Vell.) Bur., a species used in Brazilian folk medicine for treatment of cancer and skin diseases. METHODS: Using the disc diffusion method, bioautography assay and brine shrimp toxicity test (Artemia salina Leach), we studied the antimicrobial activity and lethality of extracts and isolated compounds against three microorganisms strains, including Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria and yeasts (Candida albicans). RESULTS: In this study, the extracts inhibited S. aureus (8.0 +/- 0.0 to 14.0 +/- 0.0 mm) and C. albicans (15.3 +/- 0.68 to 25.6 +/- 0.4 mm) growth. In the brine shrimp test, only two of them showed toxic effects (LC50 29.55 to 398.05 microg/mL) and some extracts were non-toxic or showed weak lethality (LC50 705.02 to > 1000 microg/mL). From these extracts, four flavones [5,6,7,8-tetramethoxyflavone (1), 5,6,7-trimethoxyflavone (2), 4'-hydroxy-5,6,7,8-tetramethoxyflavone (3), and 4'-hydroxy-5,6,7-trimethoxyflavone (4)] were isolated through bioassay-guided fractionation and identified based on the 1D and 2D NMR spectral data. By bioautography assays, compounds 1 [S. aureus (16.0 +/- 0.0 mm) and C. albicans (20.0 +/- 0.0 mm)] and 3 [S. aureus (10.3 +/- 0.6 mm) and C. albicans (19.7 +/- 0.6 mm)] inhibited both microorganisms while 2 inhibited only S. aureus (11.7 +/- 0.6 mm). Compound 4 did not restrain the growth of any tested microorganism. CONCLUSION: Our results showed that extracts and isolated flavones from Z. tuberculosa may be particularly useful against two pathogenic microorganisms, S. aureus and C. albicans. These results may justify the popular use this species since some fractions tested had antimicrobial activity and others showed significant toxic effects on brine shrimps. However, in order to evaluate possible clinical application in therapy of infectious diseases, further studies about the safety and toxicity of isolated compounds are needed.

Constituintes químicos das folhas e caule de Croton sellowii (Euphorbiaceae) / Chemical constituents from the leaves and stems of Croton sellowii (Euphorbiaceae)

O presente trabalho descreve o isolamento de terpenóides (sitosterol, estigmasterol, cicloart-25-eno-3b,24b-diol, cicloart-25-eno-3b,24a-diol e ácido betulônico), flavonóides (artemetina, crisosplenetina, casticina, penduletina e tilirosídeo) e fenilpropanóide (treo-7-etoxi-8-hidroxi-diidroanol) nas folhas e caule de Croton sellowii Baill. Todos os compostos isolados estão sendo descritos pela primeira vez nesta espécie e foram identificados com base na análise de dados espectrais (IV, UV e RMN, incluindo APT, DEPT, COSY, NOESY, HMQC e HMBC), bem como pela comparação com dados descritos na literatura.

This work describes the isolation of terpenoids (sitosterol, stigmasterol, cycloart-25-ene-3b,24b-diol, cycloart-25-ene-3b,24a-diol and betulonic acid), flavonoids (artemetin, crysosplenetin, casticin, penduletin and tiliroside) and phenylpropanoid (threo-7-ethoxy-8-hydroxy-dihydroanol) from the leaves and stems of Croton sellowii Baill. All isolated compounds are being described for the first time in this species and were identified on basis of the spectral data (IR, UV, and NMR, including APT, DEPT, COSY, NOESY, HMQC and HMBC), and by comparison with literature data.