Mutagenic activity of airborne particulate matter (PM10) in a sugarcane farming area (Araraquara city, southeast Brazil).

Brazil contains 25% of the total land planted with sugarcane in the world and is thus one of the major producers. The annual burning of sugarcane fields prior to harvesting emits huge amounts of pyrogenic particles. Biomass burning is an important primary and secondary source of aerosol particles. The presence of carbonaceous particles in the inhalable size range makes it important to study this fraction in view of the possible effects on human health and the climate. In this study, the mutagenic activity associated with inhalable airborne particulate matter (PM(10)) collected on air filters in a sugarcane-growing area near the city of Araraquara (SE Brazil) was determined. The extracts were dissolved in dimethylsulfoxide and tested for mutagenicity by the Ames plate incorporation test with Salmonella typhimurium YG1024 in the presence and absence of the S9 mixture. To assess the association between mutagenicity and PM(10), samples were collected in sugarcane harvesting and non-harvesting periods of the year. Significant mutagenicity was detected in organic solvent extracts of all samples, with differences between the two periods. The highest values of mutagenic potency (13.45 and 5.72 revertants/m(3) of air in the absence and presence of the S9 mixture, respectively) were observed during the harvest. In this period, a Teflon™-coated glass-fiber air filter trapped 67.0 µg of particulate matter per m(3) of air. In the non-harvest period, on the same type of filter, only 20.9 µg of particulate matter was found per m(3). The mutagenic potencies at this time were 1.30 and 1.04 revertants/m(3) of air, in the absence and presence of the S9 mixture, respectively. Period, concentration of PM(10) and mutagenicity were associated with each other. For routine monitoring of mutagenicity in the atmosphere, the use of YG1024 tester strain without metabolic activation (S9) is recommended.

Mutagenic and cytotoxic effect of planifolin: a naphthopyranone dimer isolated from Paepalanthus planifolius.

A naphthopyranone dimer, named planifolin, was isolated from a methylene chloride extract of the capitula of Paepalanthus planifolius Koern. The molecule (C(31)H(26)O(10)) appeared to be made up of two monomeric portions, semi-vioxanthin and paepalantine (an isocoumarin), linked by an ether bond, and it may possess several kinds of biological activity that can be related to its polyphenolic structure. Short-term tests that detect genetic damage can afford the information needed to evaluate carcinogenic risks of chemicals to humans. The Ames test, recommended for testing the mutagenicity of chemical compounds with potential pharmacological application, was used in the present study. The mutagenic activity was evaluated in Salmonella typhimurium strains TA100, TA98, TA102 and TA97a and the cytotoxic effect in McCoy cells. The in vitro cytotoxicity of planifolin to McCoy cells, tested in microculture with neutral red, showed a significant cytotoxic index (CI(50)) of 12.83 microg/mL. Planifolin showed mutagenic activity for TA100, TA98 and TA97a. The results indicate that this new naphthopyranone dimer causes mutations by substitution and by addition and deletion of bases in the sequence of DNA. Moreover, its mutagenic potential was increased by metabolic activation.

Avaliaçäo do extrato de Momordica charantia em Salmonella typhimurium: mutagenicidade e antimutagenicidade / Evaluation of the Momordica charantia extract in Salmonella typhimurium: mutagenicity and antimutagenicity

Nos últimos anos, alguns compostos naturais têm sido descritos como supressores do processo de mutagênese em bactérias, os antimutagênicos. A literatura referencia que, na maioria dos países, a populaçäo faz uso de plantas medicinais. A planta Momordica charantia (Cucurbitaceae) é originária da Africa, sendo usada popularmente como purgativo, anti-reumático, para problemas de pele, queimaduras e hemorróidas. O presente teve como objetivo avaliar as atividades mutagênica e antimutagênica do extrato etanólico de M. charantia em ensaios com Salmonella/microssomo, utilizando as linhagens TA100, TA98 e TA102. Verificou-se que esse extrato näo apresentou atividade mutagênica em diferentes concentraçöes (0,64, 1,27, 2,55 e 3,84 mg/placa), mas atuou como antimutagênico contra as mutaçöes induzidas pela azida sódica (TA100, -S9), 4-nitro-fenilenodiamina (TA98, -S9), daunomicina (TA102, -S9), 2-antramina (TA100 e TA98, +S9) e 2-aminofluoreno (TA102, +S9). Quando foi utilizada a ativaçäo metabólica (+S9), a porcentagem de inibiçäo da mutagenicidade variou de 31 por cento-96 por cento, ao passo que em ausência de metabolizaçäo (-S9) a porcentagem de inibiçäo da mutagenicidade máxima obtida ficou em torno de 40 por cento. Desse modo, podemos concluir que os metabólitos presentes no extrato têm potencial para proteger o material genético dos danos induzidos pelos diferentes agentes químicos.