A new isoflavone glucoside and other compounds from Poiretia bahiana C. Mueller: Chemophenetics, fragmentation pattern and biogenetic implications.

The genus Poiretia belongs to the Fabaceae (Leguminosae) family and it encompasses twelve species of flowering plants. The chemistry of this genus is scarcely investigated, although some studies have demonstrated the potential of Poiretia species to produce important bioactive compounds. Herein, we describe the phytochemical investigation of P. bahiana C. Mueller leaves. A new isoflavone glucoside named as 2',4',5'-trimethoxyisoflavone-7-O-ß-D-glucopyranoside (1), along with six known isoflavones (2-7), two rotenones (8-9), cyclitol 3-O-methyl-chiro-inositol (10), the amino acid proline (11), a mixture of sitosterol (12) and stigmasterol (13), and a mixture of the triterpenes lupeol (14) and ß-amirine (15) were obtained from P. bahiana leaves. The structures were established by extensive analysis of their spectroscopic data, which included 1H NMR, 13C NMR, DEPT, and 2D-NMR (13C1H HETCOR and 13C1H COLOC). Two isoflavones (3 and 5) and two rotenones (8-9) exhibited antifungal activity against the plant pathogenic fungus Cladosporium sphaerospermum. Furthermore, the biogenetic implications of the oxygenation pattern of the B-ring of the isoflavones, and the chemophenetics and fragmentation pattern of the isoflavones and rotenones are discussed.

Modes of action of arjunolic acid and derivatives on Trypanosoma cruzi cells.

Chagas disease causes considerable morbimortality in the Americas, with circa 7 to 8 million infected people, causing at least 12,000 annual deaths and 100 million people at risk. Its chemotherapy is poorly selective and effective, associated to severe side effects and unresponsive cases. Thus, R&D on therapeutic alternatives is undoubtedly required. The Brazilian poorly studied biodiversity offers uncountable bioagents, which may be exploited for chemotherapy. The triterpene arjunolic acid (AA), reduced the Trypanosoma cruzi epimastigote in vitro proliferation with an apparent IC50 of 171 µM. Electron microscopy analysis revealed remarkable effects on the parasite surface and architecture. AA-treated parasites displayed minutely corrugated plasma membranes devoid of subpellicular microtubules as well as biogenesis of multiple basal bodies. As the AA effects appeared mainly restricted or originated at the parasite peripheral cytoplasm, including the cytoskeleton membrane linkage, we inferred that the compound targeted primarily the lipid bilayer; therefore, we performed synthetic modification to increase the molecule lipophilicity and thus membrane permeability. The methyl ester (MeAA) and tri-acetylated derivatives (3AcAA) had potentiated trypanocidal activity, producing IC50 values of 21.9 and 15.8 µM, respectively. Both derivatives were able to produce remarkable ultrastructural alterations in the parasites, including inner compartments such as Golgi apparatus and the endocytic/autophagic pathway. Parasites cultured with both derivatives displayed numerous and large autophagic vacuoles, altered flagellar length and cell body connection. These data indicate that synthetically-modified natural products comprise valuable tools in antiparasitic chemotherapy and that electron microscopy may be useful not only in determining the mechanisms of action but also in directing such modifications for rational drug design.

Antibacterial activity of the alkaloid-enriched extract from Prosopis juliflora pods and its influence on in vitro ruminal digestion.

The purpose of this study was to assess the in vitro antimicrobial activity of alkaloid-enriched extracts from Prosopis juliflora (Fabaceae) pods in order to evaluate them as feed additives for ruminants. As only the basic chloroformic extract (BCE), whose main constituents were juliprosopine (juliflorine), prosoflorine and juliprosine, showed Gram-positive antibacterial activity against Micrococcus luteus (MIC = 25 µg/mL), Staphylococcus aureus (MIC = 50 µg/mL) and Streptococcus mutans (MIC = 50 µg/mL), its influence on ruminal digestion was evaluated using a semi-automated in vitro gas production technique, with monensin as the positive control. Results showed that BCE has decreased gas production as efficiently as monensin after 36 h of fermentation, revealing its positive influence on gas production during ruminal digestion. Since P. juliflora is a very affordable plant, this study points out this alkaloid enriched extract from the pods of Prosopis juliflora as a potential feed additive to decrease gas production during ruminal digestion.

A new biphenyl and antimicrobial activity of extracts and compounds from Clusia burlemarxii.

Phytochemical investigation on Clusia burlemarxii (Clusiaceae) led to isolation and identification of nine compounds. Were isolated from leaves 3-O-α-L- rhamnopyranosylquercetin, 3-O-α-L-rhamnopyranosylkaempferol, 4-hydroxy-5,5-dimethyldihydrofuran-2-one, 2Z-δ-tocotrienoloic acid and friedelin and were isolated from trunk betulinic acid, protocatechuic acid, lyoniresinol, and a new biphenyl 2,2-dimethyl-3,5-dihydroxy-7-(4-hydroxyphenyl)chromane. The structures were determined by ¹H, ¹³C-NMR, DEPT, HMBC, HMQC, HRESIMS. The Minimal Inhibitory Concentration against Streptococcus mutans, Staphylococcus aureus, Bacillus subtilis, Micrococcus luteus, Escherichia coli, Salmonella choleraesuis, Pseudomonas aeruginosa, Aspergillus niger and Cladosporium cladosporioides was also determined. Extracts and compounds showed significant activity against tested Gram-positive bacteria, none activity against tested Gram-negative bacteria and fungi.

Xantonas, triterpenos e atividade antibacteriana do extrato em diclorometano de Kielmeyera cuspidata Saddi, Clusiaceae / Xanthones, triterpenes and antibacterial activity of dichloromethane extract of Kielmeyera cuspidata Saddi, Clusiaceae

Do extrato em diclorometano do tronco de Kielmeyera cuspidata Saddi, Clusiaceae, foram isoladas cinco xantonas, 1,6-diidroxi-3,5-dimetoxixantona, 2-hidroxi-1-metoxixantona, 2,3-metilenodioxixantona, 4-hidroxi-2,3-metilenodioxixantona e 3-hidroxi-2,4-dimetoxixantona e dois triterpenos, α-amirina e β-amirina. O extrato exibiu toxicidade para Artemia salina e atividade antibacteriana para Micrococcus luteus, Bacillus subitilis, Staphylococcus aureus e Streptococcus mutans, não sendo ativo para Escherichia coli, Pseudomonas aeruginosa e Salmonela choleraesuis.

From the dichloromethane extract of trunk of Kielmeyera cuspidata five xanthones were isolated, 1,6-dihydroxy-3,5-dimethoxyxanthone, 2-hydroxy-1-methoxyxanthone, 2,3-methylenedioxyxanthone, 4-hydroxy-2,3-methylenedioxyxanthone and 3-hydroxy-2,4-dimethoxyxanthone and two triterpenes α-amirin and β-amirin. The extract displayed toxicity against Artemia salina and exhibited antibacterial activity against Micrococcus luteus, Bacillus subitilis, Staphylococcus aureus and Streptococcus mutans and it was not active against Escherichia coli, Pseudomonas aeruginosa and Salmonela choleraesuis.

Preliminary studies on the volatile constitution of Mikania species / Estudos preliminares dos constituintes voláteis de espécies de Mikania

Volatile oils obtained from the aerial parts of three Mikania species plants were analyzed by GC-MS and NMR. Forty-six terpenes among monoterpenes, sesquiterpenes and diterpenes were identified by this methodology. The analysis classified Mikania hookriana as diterpene producer as the majority Mikania species occurring in Brazil.

Óleos voláteis obtidos das partes aéreas de plantas de três espécies de Mikania foram analisados por CG-EM e RMN. Quarenta e seis terpenos, entre monoterpenos, sesquiterpenos e diterpenos, foram identificados. A análise classificou Mikania hookeriana como produtora de diterpenos, de acordo com a maioria das espécies de Mikania que ocorrem no Brasil.