RESUMEN
A new family of monothiooxalamides derived from 2-aminobenzimidazole was synthesized, and their structures were confirmed by 1H and 13C one-dimensional and 2D NMR experiments (COSY, HSQC, and HMBC). The antioxidant capacity was evaluated by free radical scavenging assays: 1,1-diphenyl-2-picrylhydrazyl (DPPHâ¢), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTSâ¢+), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and the Fe(II) chelating ability. Our work group has previously reported the synthesis and antioxidant activity of monothiooxalamides derived from 2-aminopyridine (I). In this study, the in vitro hemolytic activity of compounds from the 2-aminopyridine (I) and 2-aminobenzimidazole (II) families was evaluated against human red blood cells (RBCs). The concentration at which monothiooxalamides showed no hemolytic activity was chosen to assess their ability to inhibit free radical-induced membrane damage in human RBCs, acute toxicity in brine shrimp, and in vivo toxicity against Drosophila melanogaster. Compounds with morpholine fragments (1g, 1h, 2g, and 2h) showed time- and concentration-dependent protective effects against radical-induced oxidative hemolysis. Moreover, they had the lowest acute toxicity in the brine shrimp lethality assay and a significant increase in chelating activity compared with the other molecules. In particular, monothiooxalamide 2g showed lower toxicity and can be considered for further biological screening and application trials.
RESUMEN
Urbanization, livestock activities, and rainfall are factors that contribute to the contamination of inland water. This study aimed to determine the spatial and temporal variability of total coliforms (TCs) and fecal coliforms (FCs) in the surface water of San Pedro Lake as well as the gills and skin of Nile tilapia (Oreochromis niloticus) cultivated in the lake. The study consisted of seasonal sampling during an annual cycle. Using the multiple-tube fermentation technique, we quantified the microbial load of TCs in the lake and fish. The median of the TC and FC groups in surface water showed differences during the seasonal cycle, in which a significant correlation was observed between rainfall and bacterial load in the lake surface water. There was a significant seasonal difference between FCs and TCs in the gills as well as in skin FCs. Anthropogenic activities in the watershed combined with rainfall influence the bacterial load of San Pedro Lake. However, the water quality is still classified as excellent and uncontaminated according to Mexican regulations with lower FC values acceptable for higher FC values. In addition, the bacterial load in tilapia from San Pedro Lake does not pose a risk to human health. PRACTITIONER POINTS: Watershed livestock activities combined with rainfall increase fecal matter pollution in specific areas of the lake. San Pedro Lake displays satisfactory quality for aquatic life. The median fecal coliform population in lake fish (gills and skin) differs by season.
Asunto(s)
Lagos , Microbiología del Agua , Animales , Bacterias , Monitoreo del Ambiente , Branquias , Humanos , MéxicoRESUMEN
The effect of refrigerated 48h transport and 4 days storage on the quality and shelf life of the whole lion's paw scallop Nodipecten subnodosus gonad was evaluated. Proximal composition, adenosine 5´triphosphate (ATP) and related products, K-value, total volatile bases (TVB-N), trimethylamine (TMA-N), pH, fatty acid profile and microbiological analyses were quantified. Gonad holds a significant composition of essential fatty acids while levels of gonadal ATP were initially low; moreover, K-value of the gonad remained constant. With respect to TVB-N and TMA-N, only the former exceeded allowed limits. The pH level showed no significant variation during storage and, despite the high level of TVB-N, according to the TMA-N as well as microbiological analyses it was demonstrated innocuity after 4 days under the transportation and storage conditions utilized.
Avaliou-se o efeito do transporte em refrigeração por 48 horas e quatro dias de armazenamento sobre a qualidade e vida de prateleira da gônada do bivalve pata de leão, Nodipecten subnodosus. Determinou-se a composição centesimal, a adenosina 5'trifosfato (ATP) e afins, o índice K, bases voláteis totais (TVB-N), trimetilamina (TMA-N), pH, perfil de ácidos graxos e análise microbiológica. A Gônada apresentou uma importante composição de ácidos graxos essenciais e baixos níveis iniciais de ATP, enquanto o índice K manteve-se constante. Quanto a TVB -N e TMA- N, apenas as primeiras ultrapassaram os limites admissíveis. Os valores de pH não mostraram nenhuma mudança significativa durante o armazenamento e, apesar dos altos níveis de TVB -N, de acordo com a análise quantitativa e microbiológica TMA- N, a segurança do produto foi demonstrada após quatro dias sob as condições de transporte e armazenamento utilizado.