Antimicrobial and cytotoxic activities of medicinal plants of the Brazilian cerrado, using Brazilian cachaca as extractor liquid

Ethnopharmacological importance: Many species of plants in the Brazilian cerrado (savanna) are widely used in ethnomedicine. However, the safety and effectiveness of medicinal plants used in communities with little or no access to manufactured drugs should be evaluated. Aim of the study: Evaluate the antimicrobial and cytotoxic activities of extracts from eight plant species, obtained using Brazilian cachaca as the extractor liquid. Materials and methods: The extracts were tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Candida parapsilosis, promastigote forms of Leishmania amazonensis, and poliovirus. In addition, cytotoxic activity was assayed in Vero cells and in human erythrocytes. Results: The plant species Curatella americana, Sclerolobium aureum, and Plathymenia reticulata showed the best activity against yeasts, especially the crude extract of C. americana and its ethyl-acetate fraction. Kielmeyera lathrophyton showed a minimum inhibitory concentration of 250 mu g/ml against S. aureus, and was inactive against Gram-negative bacteria. The extract obtained from Annona coriacea showed the best activity against the promastigote forms of Leishmania amazonensis (IC(50) = 175 mu g/ml). Only C. americana showed potential for antipoliovirus activity. The concentrations of the crude extracts that showed toxicity to VERO cells had CC(50) between 31 and 470 mu g/ml, and the lyophilized Brazilian cachaca showed a CC(50) of 307 mu g/ml. None of the extracts showed toxicity against human erythrocytes. Conclusions: Among the plant species studied. C americana proved to be effective against microorganisms, especially as an antifungal. The results will help in the search for alternative drugs to be used in pharmacotherapy, and will contribute to establish safe and effective use of phytomedicines in the treatment of infectious diseases. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

Effect of doxorubicin on cytokine production by lymphocytes and the Th1/Th2 balance

Doxorubicin (DOXO) is a potent chemotherapeutic used mainly against solid tumours; however, it has several side effects that can limit its clinical use. On the other hand, the effect of DOXO upon lymphocyte function is controversial. Some studies demonstrate that DOXO administration in vitro suppresses T-cell activation, while the cellular function has been shown to increase in vitro. The objective of this study was to investigate the effect of DOXO on lymphocyte cytokine production in rats. The animals were divided into: SAL (control, n = 10) and DOX (DOXO treated, n = 10). The DOX group received only one DOXO dose at 15 kg Kg(-1) by intraperitoneal injection. Forty-eight hours after DOXO administration, the animals were killed by decapitation. IL-2 production was significantly enhanced (p < 0.05) in lymphocytes from rats treated with DOXO (169.17 +/- 21.73 pg mL 10(5) cell) as compared to cells from SAL (45.92 +/- 10.53 pg mL 10(5) cell). The administration of DOXO decreased (<0.05) IL-4 production in the DOXO group (29.85 +/- 13.09 pg mL 10(5) cell) relative to the SAL group (75.08 +/- 15.31 pg mL 10(5) cell). The IL-2/IL-4 ratio was higher (<0.05) in the DOX group (5.99 +/- 0.44), as compared to SAL group (0.73 +/- 0.12). In conclusion, our results suggest that a dose of DOXO promotes an alteration in the Th1/Th2 balance, promoting a shift towards a Th1-dominant cytokine response. (C) 2010 Elsevier Masson SAS. All rights reserved.

Inhibitory activity of limonene against Leishmania parasites in vitro and in vivo

Limonene is a monoterpene that has antitumoral, antibiotic and antiprotozoal activity. In this study we demonstrate the activity of limonene against Leishmania species in vitro and in vivo. Limonene killed Leishmania amazonensis promastigotes and amastigotes with 50% inhibitory concentrations of 252.0 +/- 49.0 and 147.0 +/- 46.0 mu M, respectively. Limonene was also effective against Leishmania major, Leishmania braziliensis and Leishmania chagasi promastigotes. The treatment of L. amazonensis-infected macrophages with 300 mu M limonene resulted in 78% reduction in infection rates. L. amazonensis-infected mice treated topically or intrarectally with limonene had significant reduction of lesion sizes. A significant decrease in the parasite load was shown in the lesions treated topically with limonene by histopathological examination. The intrarectal treatment was highly effective in decreasing the parasite burden, healing established lesions and suppressing the dissemination of ulcers. Limonene presents low toxicity in humans and has been shown to be effective as an agent for enhancing the percutaneous permeation of drugs. Our results suggest that limonene should be tested in different experimental models of infection by Leishmania. (C) 2009 Elsevier Masson SAS. All rights reserved.