More than 20% of the world's biodiversity is located in Brazilian forests and only a few plant extracts have been evaluated for potential antibacterial activity. In the present study, 705 organic and aqueous extracts of plants obtained from different Amazon Rain Forest and Atlantic Forest plants were screened for antibacterial activity at 100 µg/ml, using a microdilution broth assay against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli. One extract, VO581, was active against S. aureus (minimum inhibitory concentration (MIC) = 140 µg/ml and minimal bactericidal concentration (MBC) = 160 µg/ml, organic extract obtained from stems) and two extracts were active against E. faecalis, SM053 (MIC = 80 µg/ml and MBC = 90 µg/ml, organic extract obtained from aerial parts), and MY841 (MIC = 30 µg/ml and MBC = 50 µg/ml, organic extract obtained from stems). The most active fractions are being fractionated to identify their active substances. Higher concentrations of other extracts are currently being evaluated against the same microorganisms. Correspondence
Twelve extracts obtained from nine plants belonging to six different genera of Clusiaceae were analyzed against Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus and Enterococcus faecalis) bacteria using the microdilution broth assay. Tovomita aff. longifolia, T. brasiliensis, Clusia columnaris, Garcinia madruno, Haploclathra paniculata, and Caraipa grandifolia extracts showed significant results against the bacteria. The organic extract obtained from the leaves of T. aff. longifolia showed minimal inhibitory concentration (MIC) = 70 µg/ml and minimal bactericidal concentration (MBC) = 90 µg/ml against E. faecalis and the organic extract made with the stem of C. columnaris showed MIC = 180 µg/ml and MBC = 270 µg/ml against P. aeruginosa. None of the antibacterial extracts showed lethal activity against brine shrimp nauplii. On the other hand, both aqueous and organic extracts obtained from the aerial organs of Vismia guianensis that were cytotoxic to brine shrimp nauplii did not show a significant antibacterial activity in the assay.Key words: antibacterial -cytotoxicity -Clusiaceae -Amazon rain forest -Brazil Natural products are considered an important source of new antibacterial agents. Drugs derived from unmodified natural products or drugs semi-synthetically obtained from natural sources corresponded to 78% of the new drugs approved by the FDA between 1983 and 1994(Cragg et al. 1997). This evidence contributes to support and quantify the importance of screening natural products. Previous screening works were done with more than 700 Amazon rain forest plant extracts, and results can be seen elsewhere (Frana & Suffredini 2002, Suffredini et al. 2002a, b 2004, Nepomuceno et al. 2003.Less than 20% of the Angiospermae have been screened for biological activity, and taking the Brazilian rain forests in concern, not much has been done so far. Brazil is home to more than 20% of the world's biodiversity, and the Amazon rain forest concentrates 17% of the biodiversity found within the country (Wilson & Peter 1988). For this reason, our research team has been systematically studying the antibacterial activity of organic and aqueous plant extracts obtained from plants native to the rain forest against Gram-positive Staphylococcus aureus ATCC 29213 (Sau) and Enterococcus faecalis ATCC 29212 (Efae) and Gram-negative Pseudomonas aeruginosa ATCC 27853 (Psa) and Escherichia coli ATCC 25922 (Ecol) with the aim of discovering new natural product compounds that can be used as antibiotics. Twelve aqueous and organic extracts obtained from plants belonging to six different genera of Clusiaceae (Vismia, Garcinia, Haploclathra, Tovomita, Caraipa, and Clusia) were submitted to the determination of the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) using the microdilution broth assay (Suffredini et al. 2004). The extracts were also tested against brine shrimp nauplii in order to evaluate their potential as cytotoxic agents and to determine if ...
Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare malignant liver neoplasm, commonly observed in adolescents and young adults of both genders. The disease is more common in Caucasians and in patients without a prior history of liver disease. The best treatment option is a surgical resection associated with liver hilum lymph node dissection. However, there is no established systemic drug treatment for patients with locally advanced or metastatic disease. We report on a patient with advanced FLHCC, initially considered unresectable due to invasion of the right and the middle hepatic veins and circumferential involvement of the left hepatic vein. Following the treatment with gemcitabine-oxaliplatin systemic chemotherapy, the patient exhibited a significant tumor reduction. As a result, a complete resection was performed with an extended right hepatectomy associated with a partial resection of the inferior vena cava, a wedge resection in segment 2, and lymphadenectomy of the hepatic hilum. The case was unusual due to the significant tumor downstaging with gemcitabine-oxaliplatin, potentially enabling curative resection. More studies are needed to confirm the efficacy of the systemic drug treatment for FLHCC.
Younes RN, Varella AD, Suffredini IB. Discovery of new antitumoral and antibacterial drugs from brazilian plant extracts using high throughput screening. Clinics. 2007;62(6):763-8.Plants have played a significant role in the treatment of cancer and infectious diseases for the last four decades. The discovery and introduction to market of paclitaxel, the vinca alkaloids, etoposide, and many antibacterial drugs support drug discovery programs based on natural products. Natural products have been rediscovered as important tools for drug development despite advances in combinatorial chemistry, due to the complex molecular structures able to interact with mammalian cell targets. The Brazilian flora, the most diverse in the world, has become an interesting spot to prospect for new chemical leads or hits due to its species diversity and associated chemical richness. Screening programs have been established in Brazil as a strategy to identify potentially active substances. High throughput screening techniques allow for the analysis of large numbers of extracts in a relatively short period of time, and can be considered one of the most efficient ways of finding new leads from natural products. An updated review of the current status of the biological screening program is presented and recent results from new antitumoral and antibacterial chemical leads are discussed.
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