Malaria is one of the most important tropical diseases and mainly affects populations living in developing countries. Reduced sensitivity of Plasmodium sp. to formerly recommended antimalarial drugs places an increasing burden on malaria control programs as well as on national health systems in endemic countries. The present study aims to evaluate the antimalarial activity of betulinic acid and its derivative compounds, betulonic acid, betulinic acid acetate, betulinic acid methyl ester, and betulinic acid methyl ester acetate. These substances showed antiplasmodial activity against chloroquine-resistant Plasmodium falciparum parasites in vitro, with IC(50) values of 9.89, 10.01, 5.99, 51.58, and 45.79 microM, respectively. Mice infected with Plasmodium berghei and treated with betulinic acid acetate had a dose-dependent reduction of parasitemia. Our results indicate that betulinic acid and its derivative compounds are candidates for the development of new antimalarial drugs.

Betulinic acid (BA) is a lupane-type triterpene with a number of biological activities already reported. While potent anti-HIV and antitumoral activities were attributed to BA, it is considered to have a moderate anti-inflammatory activity. Here we evaluated the effects of BA in a mouse model of endotoxic shock. Endotoxemia was induced through intraperitoneally LPS administration, nitric oxide (NO) and cytokines were assessed by Griess method and ELISA, respectively. Treatment of BALB/c mice with BA at 67 mg/kg caused a 100% survival against a lethal dose of lipopolysaccharide (LPS). BA treatment caused a reduction in TNF-α production induced by LPS but did not alter IL-6 production. Moreover, BA treatment increased significantly the serum levels of IL-10 compared to vehicle-treated, LPS-challenged mice. To investigate the role of IL-10 in BA-induced protection, wild-type and IL-10(-/-) mice were studied. In contrast to the observations in IL-10(+/+) mice, BA did not protect IL-10(-/-) mice against a lethal LPS challenge. Addition of BA inhibited the production of pro-inflammatory mediators by macrophages stimulated with LPS, while promoting a significant increase in IL-10 production. BA-treated peritoneal exudate macrophages produced lower concentrations of TNF-α and NO and higher concentrations of IL-10 upon LPS stimulation. Similarly, macrophages obtained from BA-treated mice produced less pro-inflammatory mediators and increased IL-10 when compared to non-stimulated macrophages obtained from vehicle-treated mice. In conclusion, we have shown that BA has a potent anti-inflammatory activity in vivo, protecting mice against LPS by modulating TNF-α production by macrophages in vivo through a mechanism dependent on IL-10.

2003 ResumoEspécies nativas ou endêmicas do semi-árido brasileiro foram investigadas com o intuito de se descobrir novas drogas antimicrobianas. Os ensaios foram realizados contra cepas padrões de Staphylococcus aureus e Escherichia coli através do método de difusão em disco. Dos 137 extratos de vegetais avaliados, sete apresentaram atividade significativa contra o Staphylococcus aureus. Os extratos ativos foram preparados a partir de espécies pertencentes às famílias Leguminosae e Rutaceae e serão futuramente fracionados com o intuito de se chegar às moléculas ativas. AbstractSpecies native or endemic of the Brazilian semiarid were investigated with the intention of discovering new antibacterial drugs. The rehearsals were accomplished against standard strains of Staphylococcus aureus and Escherichia coli through the diffusion method in disk. Of the 137 extracts of appraised vegetables, seven presented significant activity against the Staphylococcus aureus. The active extracts were prepared starting from species belonging to the Leguminosae and Rutaceae families and they will be fractional hereafter with the intention of arriving to the active molecules.A origem do conhecimento do homem sobre as propriedades medicinais das plantas confunde-se com sua própria história. Há milênios os vegetais têm sido utilizados pelos seres humanos no tratamento de doenças. Porém, apenas recentemente as plantas tornaram-se objeto de estudo científico no que concerne às suas variadas propriedades medicinais, inclusive quanto à atividade antibacteriana.Nos últimos anos, a resistência de microorganismos patogênicos a múltiplas drogas tem aumentado devido ao uso indiscriminado de antimicrobianos, comumente comercializados e usados no tratamento de doenças infecciosas. Essa situação tem forçado os cientistas à busca de novas drogas. Os vegetais são uma excelente fonte de busca de novas drogas antimicrobianas, tendo em vista que a diversidade molecular dos produtos naturais é muito superior àquela derivada dos processos de síntese química.No semi-árido brasileiro, região que ocupa 11,5% do território nacional, estima-se haver oito mil espécies vegetais sendo que destas, 318 espécies de 42 famílias botânicas são endêmicas da caatinga 1 . Diante dessa vasta biodiversidade e da necessidade da descoberta de novas moléculas bioativas, é de fundamental importância o estudo farmacológico da flora dessa região, ainda pouco estudada sob esse aspecto.Para a realização do presente estudo, espécies vegetais endêmicas ou nativas desse bioma foram randomicamente coletadas, identificadas e utilizadas para o preparo de extratos a serem testados quanto à atividade antimicrobiana.Dentre os 137 extratos de vegetais avaliados, sete demonstraram atividade antibacteriana significativa contra Staphylococcus aureus. Nenhum dos extratos testados foi ativo contra Escherichia coli (Tabela 1).

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Inflammatory diseases have a high prevalence and has become of great interest due to the increase in life expectancy and the costs to the health care system worldwide. Chronic diseases require long-term treatment frequently using corticosteroids and non-steroidal anti-inflammatory drugs, which are associated with diverse side effects and risk of toxicity. Betulinic acid, a lupane-type pentacyclic triterpene, is a potential lead compound for the development of new anti-inflammatory treatments, and a large number of derivatives have been produced and tested. The potential of betulinic acid and its derivatives has been shown in a number of pre-clinical studies using different experimental models. Moreover, several molecular mechanisms of action have also been described. Here we reviewed the potential use of betulinic acid as a promissory lead compound with anti-inflammatory activity and the perspectives for its use in the treatment of inflammatory conditions.

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Ethyl acetate and chloroform extracts from aerial parts of Portulaca werdermannii and P. hirsutissima were tested in lymphoproliferation assays and axenic cultures of Leishmania amazonensis and Trypanosoma cruzi. Both extracts of P. werdermannii and P. hirsutissima had a potent inhibitory activity on lymphocyte proliferation. On the contrary, only the chloroformic extract of both plants inhibited L. amazonensis growth, without effect on T. cruzi cultures. These results indicate these Portulaca species as potential sources of new active molecules for the treatment of leishmaniasis and immune-mediated pathologies.

The ferrocenyl diphenol 1 [1,1-bis(4-hydroxyphenyl)-2-ferrocenyl-but-1-ene] displays strong cytotoxic effects against a variety of cancer cells. In the present study we have evaluated the immunomodulatory and antiparasitic activities of compound 1 and its protected dipalmitate analogue 2. We have furthermore compared the antiparasitic results of 1 and 2 with the organic analogue, 3 [1,1-bis(4-hydroxyphenyl)-2-phenyl-but-1-ene], where the ferrocenyl group has been replaced by a phenyl ring. When assayed against normal (noncancerous) splenocytes, all compounds were considered nontoxic. Compound 1 inhibited NO production by macrophages, inhibited concanavalin A-induced lymphoproliferation, and was active against Leishmania amazonensis and Trypanosoma cruzi. Compound 2 had lower activity in all assays performed. Surprisingly, compounds 1 and 2 exhibited similar and significant activity against Plasmodium falciparum, with IC 50 values of 3.50 and 1.33 mM, respectively. Compound 3 showed an inverse activity profile, being active against T. cruzi but far less active against P. falciparum. Drug Dev Res 71: 69-75, 2010.