Influência do processo de desidratação sobre a atividade antimicrobiana do pólen apícola desidratado

O objetivo deste estudo foi investigar a influência do processo de conservação na ativi-dade antimicrobiana de amostras de pólen apícola do Brasil contra microorganismos isolados de fluidos biológicos e estirpes de referência.Amostras de pólen apícola foram coletadas durante os meses de abril/2012 e setem-bro/2012 em um apiário localizado no Estado de São Paulo, Brasil. Parte das amostras foi subme-tida a desidratação por aquecimento em estufa a 42ºC e parte a desidratação por liofilização. A atividade antimicrobiana foi determinada pelo método de microdiluição em placa [1], na Escola Superior Agrária de Bragança. Como material biológico foram utilizadas bactérias Gram-positi-vas (Streptococcus pyogenes ATCC; Streptococcus pyogenes ESA12; Staphylococcus aureus ATCC 6538™; Staphylococcus aureus ESA54), bactérias Gram-negativas (Escherichia coli ATCC 25922™; Escherichia coli ESA72; Klebsiella pneumoniae ATCC 13883™; Klebsiella spp) e leveduras (Candida albicans ATCC 10231™ e Candida albicans ESA109). Os resultados foram expressos em concentra-ção minima inibitória (CIM; p/v), que é a menor concentração de extrato de pólen apícola capaz de inibir o crescimento microbiano indicado por coloração com cloreto de trifenil tetrazolium (TTC).Todos os extratos apresentaram atividade antimicrobiana. A CIM para bactérias Gram--positivas variou entre 1,4 e 5,3%, enquanto que, para as bactérias Gram-negativas os valores obtidos oscilaram entre 2,5 e 7,0% e para as leveduras entre 16,7 e 25,8%. As amostras liofilizadas exerceram um efeito mais acentuado na inibição de crescimento de todos os microrganismos em estudo comparativamente com as amostras secas em estufa, sugerindo que o aquecimento pode ter alterado os compostos com propriedades antimicrobianas.Grande parte dos produtores de pólen apícola utiliza a desidratação por aquecimento em suas unidades de processamento, no entanto, este estudo indica que a liofilização pode ser uma alternativa ao processo atual que resulte num produto de maior potencial biológico. O consumo de pólen apícola é impulsionado pela demanda por produtos naturais com propriedades tera-pêuticas, portanto, quanto maior o potencial biológico deste produto, maior será a sua procura.info:eu-repo/semantics/publishedVersio

HPLC- MS Flavonoid determination and antioxidant capacity of Brazilian dehydrated bee pollen

Bee-pollen, produced by Apis mellifera bees, is an important source of proteins, lipids, vitamins and minerals for the hive, being considered one of nature's most completely nourishing foods. Its composition may vary according to the geographical region and its quality is influenced by harvest method and processing conditions. Although it has good nutritional components, beepollen contains significant amounts of polyphenols with recognized health benefits, including antioxidant activity. The present study aimed to evaluate the flavonoid composition, using HPLC-MS technique; and the antioxidant activity, using two different methods (DPPH and ORAC), of eight dehydrated bee-pollen samples collected in different Brazilian apiaries. The sample with the highest antioxidant capacity using DPPH method was produced in Rio Grande do Sul State (110.85 mol TE/g) while the sample with the least antioxidant capacity was collected in Bahia State (9.97 mol TE/g). The same sample from Rio Grande do Sul State presented the highest antioxidant capacity using ORAC method (542.00 mol TE/g), while the lowest value was observed in a sample from Mato Grosso State (133.70 mol TE/g). The flavonoid analysis using HPLC-MS revealed the following variations: catechin (0.69 to 0.75 mg/100 g); naringenine (4.57 to 18.36 mg/100 g); rutin (3.36 to 46.80 mg/100 g); quercetin (1.86 to 67.91 mg/100 g) and kaempferol (5.50 to 44.97 mg/100 g). In the sample with the highest antioxidant capacity (Rio Grande do Sul State) was observed 40 peaks in the HPLC-MS, while the samples with the lowest antioxidant capacities the number of peaks were 25 (Mato Grosso State) and 22 (Bahia State); therefore, the variety of compounds may have influenced the antioxidant capacity of the samples.info:eu-repo/semantics/publishedVersio

Phenolic profile and antioxidant capacity from 56 brazilian dehydrated bee-pollen

Bee-pollen is a food produced by bees from the flower pollen, to be a source of proteins, lipids, vitamins and minerals for the hive [1]. Its composition varies according to the region where it is produced, and its quality is influenced by the collection and processing conditions [2, 3]. Besides nutritional substances, bee-pollen contains significant amounts of polyphenols with recognized health benefits, including antioxidant activity [4]. The present study aimed to evaluate the polyphenolic profile and antioxidant activity of 56 dehydrated bee-pollen samples by high performance liquid chromatography and in vitro assays. Bee-pollens samples, collected during November 2011 to December 2013 from apiaries located in different Brazilian regions, were extracted with stirring for 30 minutes with ethanol 70% at 70 ºC and analyzed. The total phenolic content ranged from 6.5 ± 0.2 to 29.2 ± 0.3 mg gallic acid equivalent/g dry sample and flavonoid content ranged from 0.35 ± 0.01 to 17.5 ± 0.1 mg quercetin equivalent/g dry sample. The antioxidant activity assays, with values of 9.4 ± 0.4 to 155 ± 5 mol Trolox equivalent/g dry sample for DPPH and 133 ± 2 to 563 ± 15 mol TE/g for ORAC methods, revealed the antioxidant capacity of bee-pollen extracts. Regarding, the characterization of the phenolic composition from the several extracts by HPLC-PAD it was possible to observe that rutin, quercetin and vanillic acid were the main phenolic compounds found in the Brazilian dehydrated bee-pollen analyzed. On the other hand, caffeic acid was found in less amounts in the majority of samples studied. Among the identified polyphenols, only quercetin seems to have influenced positively in the antioxidant capacity of the samples. The Pearson’s Correlation analysis indicated high correlation between quercetin and ORAC values (r=0.6570, p=0.000) and medium correlation between quercetin and DPPH values (r=0.4873, p=0.000). In conclusion, bee-pollen characteristics vary according to the botanical origin and the Brazilian region where the sample was produced. This is a product with high antioxidant potential, therefore other tests, especially bioavailability assays, should be performed.The authors are grateful to State of São Paulo Research Foundation (FAPESP) for financial support (FAPESP process 2011/51741-5) and scholarship granted to AAM De-Melo (FAPESP process 2011/11746-8 and FAPESP process 2013/23179-6). Manuela M. Moreira (SFRH/BPD/97049/2013) is grateful for the postdoctoral fellowship financed by POPH-QREN – Tipologia 4.1 – Formação Avançada, subsidized by Fundo Social Europeu and Ministério da Ciência, Tecnologia e Ensino Superior.info:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Efect of Gamma irradiation on the microbiological quality of dehydrated bee-pollen

The objective of this study was to determinate some microbiological parameters of seven dehydrated bee-pollen collected from September to December of2012, in Brazil, before and after irradiation, in order to observe if the conservation process influenced the final microbiological load. All bee-pollen samples were collected in the same apiary and processed as usual; then one parcel of each one was gamma-irradiated to achieve dose of 5.0 kGy with a cobalt-60 source (by EMBRARAD/Empresa Brasileira de Radia~aes Ltda, Cotia, SAo Paulo, Brasil). The bee-pollen samples were analysed to enumerate aerobic mesophilic and psychotrophs bacteria, Staphylococcus aureus, total coliforms and yeasts and molds and to determine the presence or absent of sulphite-reducing Clostridium spores and Salmonella. Each sample ( 10 g) was homogenised and serial dilutions were inoculated on specific medium. Afterwards, incubations were performed depending on the microorganism (Estevinho et al., 2012). Results were expressed as colonyforming units per gram of dehydrated bee-pollen (CFU.g-1) for mesophilic, psychotrophs, Staphylococcus aureus, total coliforms and yeasts and molds or as presence or absent for sulphite-reducing Clostridium spores and Salmonella.info:eu-repo/semantics/publishedVersio

Antimicrobial activity of dehydrated bee-pollen produced in four Brasilian States against microorganisms with clinical importance

The objective of this study was to determine the antimicrobial activity of eight dehydrated bee pollen samples collected from April to July 2012 in four Brazilian States: Sergipe Bahia; Rio Grande do Sul and São Paulo