Assessment of renal and hepato-protective potential of guava leaves in male Sprague dawley rats.

Present research project was an attempt to explore the functional/nutraceutical worth of guava leaves from two locally grown varieties (Ruby & Safeda). For the purpose, guava leaves extract was fed to experimental male Sprague Dawley rats to explore the nutraceutical potential of guava leaves against hepatotoxicity. Two studies were performed on two types of rats i.e. study I (normal rats), study II (hepatotoxic rats). In both studies, 250 mg/kg each of pink guava leaves extracts (T1) and white guava leaves extracts (T2) was added in the feed. Feed intake and body weights of the rats were recorded. At the end of the first and eighth week of study, the blood samples of the rats were analyzed to check the effect of guava leaves extracts on renal functioning (Alkaline Phosphatase, Alanine Transaminase and Aspartate Transaminase) as well as liver functioning parameters including urea and creatinine. In both studies, comparatively higher feed consumption was observed in the control group than the rest of the treatments. At the end of study I, the highest weight (207±9.21 g) was observed in T0 whereas, during study II, the maximum value (202±5.58 g) was found in T2 (rats consuming white guava leaves extract) that indicates its effectiveness against hepatotoxicity. Regarding renal functioning tests, pink guava leaves were more effective in decreasing urea and creatinine levels in rats as compared to the white guava leaves in both study plans. Likewise, in each of study trial, pink guava leaves were more effective in reducing AST, ALT and ALP than white guava leaves and control. From the present investigation, it is deduced that guava leaves were effective against hepatotoxicity.

Estimativa da viabilidade polínica de araçazeiro (Psidium cattleianum Sabine) através de distintos métodos de coloração / Estimation of pollen viability of strawberry guava (Psidium cattleianum Sabine) through distinct staining methods

RESUMO A análise histoquímica dos grãos de pólen através do uso de corantes permite a determinação de sua viabilidade polínica. O objetivo deste estudo foi comparar a eficiência dos corantes orceína acética 2% e reativo de Alexander modificado, para estimar a viabilidade polínica de vinte acessos de araçazeiro (Psidium cattleianum Sabine) – uma árvore de frutos muito apreciados que também é utilizada para fins medicinais. Botões florais na pré-antese foram coletados e fixados em etanol:ácido acético (3:1) por 24 horas, após os botões foram transferidos para etanol 70% e mantidos sob refrigeração. A técnica de esmagamento das anteras foi utilizada no preparo das lâminas. Para cada acesso foram preparadas 2 lâminas por corante e analisados 500 grãos de pólen por lâmina. A viabilidade polínica foi estimada através da porcentagem de grãos de pólen viáveis. De modo geral, observou-se que os grãos de pólen corados com orceína acética 2% apresentaram viabilidade alta, acima de 98,1%, e os acessos não diferiram entre si. A viabilidade polínica através da coloração com a solução de Alexander variou de 43% (acesso Silveira Martins 1) a 97% (acesso Candelária 1), mostrando que provavelmente exista variabilidade genética entre os acessos. Em apenas dois acessos não houve diferença significativa entre os valores de viabilidade encontrados através dos dois corantes testados. Conclui-se então que a orceína acética 2% superestimou a viabilidade polínica de P. cattleianum e que o reativo de Alexander é o mais preciso, devido a sua dupla coloração (verde de malaquita + fucsina ácida). Assim, indica-se o reativo de Alexander para análise de estimativa da viabilidade polínica de genótipos de araçá envolvidos em um programa de melhoramento genético.

ABSTRACT The histochemical analysis of pollen grains through the use of stains makes it possible to determine their pollen viability. The purpose of this study was to compare the efficiency of 2% acetic orcein and Alexander’s stain modified, in estimating the pollen viability of twenty strawberry guava accessions (Psidium cattleianum Sabine) – a valued fruit tree which is used for medicinal purposes. Pre-anthesis flower buds were collected and fixed in ethanol:acetic acid (3:1 v/v) for 24 hours at room temperature, subsequently they were stored in 70% ethanol under refrigeration. The anther squash technique was performed for slide preparation. In each accession two slides per stain and 500 pollen grains were analyzed. The pollen viability was estimated according to the percentage of viable pollen grains. Overall, it was observed that pollen grains stained with 2% acetic orcein evinced a high viability, higher than 98,1%, and the accessions did not differ. The pollen viability estimated with Alexander’s stain varied from 43% (accession of Silveira Martins 1) to 97% (accession of Candelária 1), indicating that there is probably genetic variability among the accessions. There was no significant difference among the levels of viability found by means of the two stains in only two accessions. In conclusion, 2% acetic orcein overestimated the pollen viability of P. cattleianum, whereas the Alexander’s stain is in turn more accurate due to its two stains (green malachite and fuchsine). Thus, it is indicated Alexander’s stain for analysis estimation of pollen viability of strawberry guava genotypes involved in a genetic improvement program.

Avaliação da atividade antimicrobiana de extratos de Eugenia anomala e Psidium salutare (Myrtaceae) frente à Escherichia coli e Listeria monocytogenes / Evaluation of the antimicrobial activity of extracts of Eugenia anomala and Psidium salutare (Myrtaceae) against the Escherichia coli and Listeria monocytogenes

RESUMO As doenças transmitidas por alimentos ocorrem principalmente devido à ingestão de alimentos contaminados por microrganismos patogênicos, dentre eles a Escherichia coli e Listeria monocytogenes. Uma das alternativas estudadas para minimizar a contaminação de alimentos é o emprego de plantas, ou seus extratos, como agentes antimicrobianos de origem natural em produtos alimentícios. Desta forma o objetivo do presente estudo é fornecer dados científicos a respeito de duas plantas nativas do RS ainda não estudadas, Eugenia anomala e Psidium salutare, visando potencial emprego como agente antimicrobiano natural em alimentos. Para tanto, avaliou-se a atividade antimicrobiana de extratos de E. anomala e P. salutare contra E. coli e L. monocytogenes através da determinação da concentração inibitória mínima (CIM) pelo método de microdiluição em caldo, a capacidade antioxidante dos extratos por meio do método de redução do radical DPPH e a citotoxicidade in vitro empregando células CHO-K1. Os resultados obtidos mostraram que os extratos de acetato de etila e etanólico de ambas as espécies possuem ação antioxidante muito alta, de 94,08% e 93,86%, respectivamente. Apenas o extrato hexânico de P. salutare apresentou ação antimicrobiana moderada (CIM = 312,5 µg/mL). Todos os extratos apresentaram ação citotóxica sendo que os maiores percentuais foram do extrato clorofórmico de E. anomala (77,05%) e hexânico de P. salutare (76,79%), na concentração de 100 µg/mL. Assim, o presente estudo demonstrou que as espécies vegetais estudadas apresentam potencial para emprego como agente antimicrobiano destes microrganismos.

ABSTRACT The foodborne diseases occur mainly due to the ingestion of food contaminated by pathogenic microorganisms, including Escherichia coli and Listeria monocytogenes. One of the alternatives studied to minimize contamination of food is the use of plants or their extracts as antimicrobial agents naturally occurring in food products. The objective of this study is to provide scientific data on two native plants of RS have not studied Eugenia anomala and Psidium salutare for a potential use as a natural antimicrobial agent in food. To this end, we evaluated the antimicrobial activity of extracts of E. anomala and P. salutare against E. coli and L. monocytogenes by determining the minimum inhibitory concentration (MIC) by the broth microdilution method, the antioxidant capacity of the extract for means DPPH radical reduction method and in vitro cytotoxicity using CHO-K1 cells. The results showed that the ethyl acetate and ethanolic extracts of both species have very high antioxidant activity, of 94.08% and 93.86%, respectively. Only the hexane extract of P. salutare showed a moderate antimicrobial activity (MIC = 312.5 mg/mL). Moreover, all extracts showed cytotoxic action of which the highest percentages were the chloroform extract of E. anomala (77.05%) and hexane P. salutare (76.79%) at a concentration of 100 mg/mL. Thus, the present study showed that plant species have potential for use as an antimicrobial agent against these microorganisms.

Nutritional and nutraceutical comparison of Jamaican Psidium cattleianum (strawberry guava) and Psidium guajava (common guava) fruits.

Psidium cattleianum (strawberry guava) is one of many underutilised edible fruits that grow wild in Jamaica, and could potentially be commercially exploited to yield health and economic benefits. In this study, the total phenolics, proximate contents, and antioxidant, anti-inflammatory, and antimicrobial activities of P. cattleianum and P. guajava (common guava), a well-known species, were compared. Strawberry guavas were found to be superior to common guavas in antioxidant and antimicrobial activities, total phenolics and vitamin C content. They also possessed relatively high fibre content (24.9%). The hexane and ethyl acetate extracts of strawberry guavas showed cyclooxygenase-2 enzyme inhibitory activities of 18.3% and 26.5%, respectively (250 µg/mL), indicating anti-inflammatory activity. The EtOAc and MeOH extracts of P. guajava showed 56.4% (COX-2) and 44.1% (COX-1) inhibitory activity, respectively. Additionally, nine compounds were isolated from strawberry guava fruits, some of which demonstrated anti-inflammatory activity. These results indicate that strawberry guavas are beneficial for health.