Seasonal variability of the essential oil of Hesperozygis ringens (Benth.) Epling.

This study was developed to evaluate the effect of seasonality on the yield and chemical composition of the essential oil (EO) of Hesperozygis ringens (Benth.) Epling, a native species from the Brazilian Pampa. Leaves were collected from four specimens of a single population in each of the four seasons for a year and were extracted in triplicate by hydro-distillation for 2 hours. The yield of EO (% w/w) was calculated on fresh weight basis (FWB), and the 16 oil samples were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used as statistical tools to evaluate differences in chemical composition. The highest yields were obtained in autumn, spring and summer (2.32-4.38%), while the lowest yields were detected in winter, ranging from 1.15 to 1.91%. Oxygenated monoterpenoids were the predominant class of chemical constituents in the EO obtained in all seasons, showing the highest contents in autumn and summer, and pulegone was identified as a major compound, whose contents varied between 54.13 and 81.17%. The EO samples were divided into three chemical groups by HCA and PCA and were assigned to the same group, except for the three samples gathered in winter. The results showed a seasonal influence on the yield and chemical composition of the EO.

Seasonal variability of the essential oil of Hesperozygis ringens (Benth.) Epling. / Variabilidade sazonal do óleo essencial de Hesperozygis ringens (Benth.) Epling.

Abstract This study was developed to evaluate the effect of seasonality on the yield and chemical composition of the essential oil (EO) of Hesperozygis ringens (Benth.) Epling, a native species from the Brazilian Pampa. Leaves were collected from four specimens of a single population in each of the four seasons for a year and were extracted in triplicate by hydro-distillation for 2 hours. The yield of EO (% w/w) was calculated on fresh weight basis (FWB), and the 16 oil samples were analyzed by gas chromatography coupled to mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used as statistical tools to evaluate differences in chemical composition. The highest yields were obtained in autumn, spring and summer (2.32-4.38%), while the lowest yields were detected in winter, ranging from 1.15 to 1.91%. Oxygenated monoterpenoids were the predominant class of chemical constituents in the EO obtained in all seasons, showing the highest contents in autumn and summer, and pulegone was identified as a major compound, whose contents varied between 54.13 and 81.17%. The EO samples were divided into three chemical groups by HCA and PCA and were assigned to the same group, except for the three samples gathered in winter. The results showed a seasonal influence on the yield and chemical composition of the EO.

Resumo Este estudo foi desenvolvido a fim de avaliar o efeito da sazonalidade no rendimento e composição química do óleo essencial (OE) de Hesperozygis ringens (Benth.) Epling., uma espécie nativa do Pampa brasileiro. Folhas foram coletadas de quatro indivíduos de uma mesma população, em cada uma das quatro estações de um ano, e foram extraídas em triplicada por hidrodestilação durante 2 horas. O rendimento do OE (% m/m) foi calculado considerando a base fresca (BF) e as 16 amostras de óleo foram analisadas por cromatografia gasosa acoplada à espectrometria de massas (CG-EM) e cromatografia gasosa com detector de ionização de chamas (CG-DIC). Análise Hierárquica de Cluster (AHC) e Análise de Componentes Principais (ACP) foram utilizadas como ferramentas estatísticas para avaliar as diferenças na composição química. Os maiores rendimentos foram obtidos no outono, primavera e verão (2,32-4,38%), enquanto que os menores foram detectados no inverno, variando de 1,15 até 1,91%. Os monoterpenoides oxigenados foram a classe predominante dos constituintes do OE obtido em todas as estações, apresentando os maiores teores no outono e no verão, e a pulegona foi identificada como o constituinte majoritário, cujos teores variaram entre 54,13 e 81,17%. As amostras de OE foram divididas em três grupos químicos por AHC e ACP e foram classificadas no mesmo grupo, com exceção de três amostras coletadas no inverno. Os resultados demonstraram influência sazonal no rendimento e na composição química dos OE.

Study of the genetic diversity and structure of a natural population of Nectandra megapotamica (Spreng.) Mez. using RAPD markers.

Nectandra megapotamica (Spreng.) Mez. is a tree species that naturally occurs in the Atlantic Forest, Brazil. The aim of this study was to evaluate the genetic diversity and structure of a natural population of 12 N. megapotamica individuals using random amplified polymorphic DNA markers. Eleven primers were used in this study, producing 81 bands, of which 98.99% were polymorphic. Analysis using STRUCTURE defined three different clusters (K = 3), results that were consistent with those of principal coordinates analysis. Both Nei's genetic diversity (h = 0.33) and Shannon's diversity index (I = 0.49) were relatively high. Analysis of molecular variance indicated that 24.89% of the genetic variability was among clusters, while the remaining 75.11% was within clusters. The Mantel test showed a weak correlation between genetic and geographic distances (r = 0.25, P = 0.105). Overall, the results revealed high levels of genetic diversity within clusters and high genetic differentiation among clusters without any spatial pattern of genetic variability. In addition, gene flow was independent of the geographical distribution and was compatible with the hierarchical island model.

Larvicidal activity of Brazilian plant essential oils against Coenagrionidae larvae.

Odonate larvae can be serious pests that attack fish larvae, postlarvae, and fingerlings in fish culture tanks, causing significant loss in the supply and production of juveniles. This study reports a screen of the essential oils (EOs) of Nectandra megapotamica (Sprengel) Mez, Nectandra grandiflora Nees, Hesperozygis ringens (Bentham) Epling, Ocimum gratissimum L., Aloysia gratissima (Gillies & Hooker) Troncoso, and Lippia sidoides Chamisso against Coenagrionidae larvae. In addition, the most effective EO and its 50% lethal concentration (LC50) and chemical analysis are described. The larvae of Acanthagrion Selys, Homeoura Kennedy, Ischnura Charpentier, and Oxyagrion Selys were used to assess the EO effects. EO obtained from H. ringens, O. gratissimum, and L. sidoides showed the highest larvicidal effects at 19 h of treatment. The major constituents of the EO of H. ringens include pulegone and limonene, while eugenol and Z-beta-ocimene predominate in the EO of O. gratissimum, and carvacrol and rho-cymene were the major compounds of the EO of L. sidoides. Leaf EOs from H. ringens, O. gratissimum, and L. sidoides showed activity against Coenagrionidae larvae at similar concentrations with LC50s of 62.92, 75.05, and 51.65 microl liter(-1), respectively, and these were considered the most promising treatments.

Mucoepidermoid carcinoma of salivary glands: a clinicopathologic study of 46 cases.

Forty-six cases of mucoepidermoid carcinoma (MEC) of the salivary glands were reviewed with an emphasis on the clinicopathologic aspects and prognosis of the tumors. MEC occurred in a wide age range, with few cases being diagnosed in childhood. Its peak of incidence was in the fifth decade and it involved major and minor salivary glands with equal frequency; the parotid gland was the gland most commonly affected. Presence of a mass was the most common complaint of all 46 patients. About 64% of the patients presented with stages 3 and 4 disease. Three distinct histologic grades were found after analyzing cellular pleomorphism, mitotic activity, and presence of necrosis. This study showed that clinical staging and histologic grading are the most important factors influencing survival and they seem to be independent of each other. Other variables found to be important in prognosis were age, sex, and the development of recurrent disease after surgery. Surgery with total resection of the tumor was the most effective treatment in our cases and adjuvant radiotherapy proved to be of little value in improving survival of MEC in our series of cases, considering that the patients in whom this type of treatment was used had unfavorable clinicopathologic factors.