Biological properties and chemical composition of essential oil from Nectandra megapotamica (Spreng.) Mez. leaves (Lauraceae).

Nectandra megapotamica is a tree species that naturally occurs in the Atlantic Forest, Brazil. This paper aims to investigate the chemical composition and in vitro antibacterial, antileishmanial and antiproliferative activities of essential oil from N. megapotamica leaves (NM-EO). It displayed high antibacterial activity against Streptococcus mutans, S. sobrinus, Prevotella nigrescens and Bacteroides fragilis. NM-EO also exhibited high antileishmanial activity against promastigote forms of Leishmania amazonensis. Its antiproliferative activity was evaluated against the following cells: GM07429A (normal cell), MCF-7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma) and M059J (human glioblastoma). Its major components, which were determined by GC-FID and GC-MS, were α-bisabolol (13.7%), bicyclogermacrene (10.9%), (E,E)-farnesene (10.6%), Z-caryophyllene (9.5%) and (E)-ß-farnesene (7.0%). These results suggest that N. megapotamica, a Brazilian plant, shows initial evidence of a new and alternative source of substances of medicinal interest.

Nectandra as a renewable source for (+)-α-bisabolol, an antibiofilm and anti-Trichomonas vaginalis compound.

Essential oils, mixtures of volatile compounds, are targets of research for new antimicrobial drugs. In order to verify the potential from species of the Nectandra genus, the present study evaluated the essential oils from Nectandra amazonum, Nectandra cuspidata, Nectandra gardineri, Nectandra hihua and Nectandra megapotamica to prospect samples with high concentration of a component and its antibacterial, antibiofilm and anti-Trichomonas vaginalis activities. The essential oils from the leaves and barks were extracted by steam distillation and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The concentrations of 10 and 100 µg/mL of the essential oil were evaluated and the inhibition of bacterial growth and biofilm formation were measured, while for the evaluation of anti-T. vaginalis trophozoite viability, the concentrations from 7.8 to 1000 µg/mL were tested. Seventy-three compounds were identified from essential oils, highlighted bicyclogermacrene (up to 49.9%), elemicin (up to 42.4%), intermedeol (up to 58.2%), (E)-asarone (up to 45.9%) and (+)-α-bisabolol (up to 93.7%). The essential oil from N. megapotamica leaves presented 93.7% of (+)-α-bisabolol and demonstrated the high capacity of inhibition of the biofilm formation, in particular, against Staphylococcus aureus methicillin resistant (MRSA) and Pseudomonas aeruginosa. This sample also had significant activity against T. vaginalis (IC50 of 98.7 µg/mL) and demonstrated cytotoxic and hemolytic effects in Vero cells and human erythrocytes. In general, the Nectandra genus revealed high chemical variability and a N. megapotamica specimen accumulated a compound on high concentration with great potential for biotechnological exploration as a new antibiofilm and anti-T. vaginalis.

Influence of Monoterpenes in Biological Activities of Nectandra megapotamica (Spreng.) Mez Essential Oils.

Investigating the influence of seasonal variations on biological activities is important for pharmacological studies and metabolic engineering. Therefore, this study was conducted to determine the variation of the chemical composition of essential oils obtained from Nectandra megapotamica leaves, collected at different stages of plant development, as well as its influence on the biological activities. A total of 38 compounds were identified that accounted for 97⁻99.2% of the chemical composition of the oils. Major differences were observed in the monoterpenic fraction, representing 5.1% of the compounds identified in the productive rest phase to 37.1% in the blooming phase. Bicyclogermacrene and germacrene D were the predominant compounds identified in the oil of all collections. Furthermore, limonene, ß-pinene, and spathulenol were identified predominantly in the samples of blooming and fruiting phases. The oils exhibited significant antichemotactic activity and different effects in scavenging the radical 2,2-diphenyl-1-picrylhydrazyl. Variations were also observed in the antifungal activity, with the minimum inhibitory concentrations ranging from 125 to 500 µg/mL. These results demonstrate the influence of monoterpenes, primarily limonene, α-pinene, and ß-pinene, on the bioactivities of the oil. Studies investigating the variations in the chemical composition of essential oil may offer a strategy to produce a compound or a group of compounds of interest to industries with a specific pharmacological focus.

Neolignans from Nectandra megapotamica (Lauraceae) Display in vitro Cytotoxic Activity and Induce Apoptosis in Leukemia Cells.

Nectandra megapotamica (Spreng.) Mez. (Lauraceae) is a well-known Brazilian medicinal plant that has been used in folk medicine to treat several diseases. In continuation of our ongoing efforts to discover new bioactive natural products from the Brazilian flora, this study describes the identification of cytotoxic compounds from the MeOH extract of N. megapotamica (Lauraceae) leaves using bioactivity-guided fractionation. This approach resulted in the isolation and characterization of eight tetrahydrofuran neolignans: calopeptin (1), machilin-G (2), machilin-I (3), aristolignin (4), nectandrin A (5), veraguensin (6), ganschisandrin (7), and galgravin (8). Different assays were conducted to evaluate their cytotoxic activities and to determine the possible mechanism(s) related to the activity displayed against human leukemia cells. The most active compounds 4, 5 and 8 gave IC50 values of 14.2 ± 0.7, 16.9 ± 0.8 and 16.5 ± 0.8 µg/mL, respectively, against human leukemia (HL-60) tumor cells. Moreover, these compounds induced specific apoptotic hallmarks, such as plasma membrane bleb formation, nuclear DNA condensation, specific chromatin fragmentation, phosphatidyl-serine exposure on the external leaflet of the plasma membrane, cleavage of PARP as well as mitochondrial damage, which as a whole could be related to the intrinsic apoptotic pathway.

Variabilidad de la composición química del aceite esencial de nectandra megapotamica (spreng. ) mez (lauraceae) / Variability of chemical composition of essential oil from nectandra megapotamica (spreng. ) mez (lauraceae)

Este trabajo describe la variabilidad química del aceite esencial (AE) de N. megapotamica, utilizando análisis multivariado. Se colectaron hojas de tres individuos en una población en Santa Maria, Brasil, en cada estación durante un año y se clasificaron en hojas jóvenes y viejas. Los AE se obtuvieron por hidrodestilación y la composición química fue determinada por cromatografía de gases acoplada a espectrometría de masas. Se realizó un análisis de agrupamiento jerárquico para formación de grupos químicos (GQ) y análisis de componentes principales (ACP) para verificar cuáles constituyentes influenciaron la formación de grupos. Inicialmente se observaron dos agrupamientos en el dendrograma debido a concentraciones de α-pineno y biciclogermacreno, constituyentes mayoritarios. En el segundo corte se discriminaron cinco GQ, siendo este también el número de componentes principales con valores propios superiores a 1. Los isómeros de asarona se observaron solamente en el AE de dos individuos (GQ5), constituyendo los principales elementos de diferenciación.

This work describes the chemical variability of the essential oils (EO) of N. megapotamica using multivariate analysis. Leaves of three individuals of a population in Santa Maria-RS were collected per season for a year, and classified into young and old. The EO were obtained by hydrodistillation and the chemical composition was determined by gas chromatography coupled to mass spectrometry (GC/MS). Cluster analysis (HCA) were performed for formation of chemical groups (CG), and principal component analysis was done (PCA) to determine which constituents influenced the formation of groups. Initially, two clusters were observed in the dendrogram, due to the concentration of α-pinene and bicyclogermacrene, major constituents of the EO. The second section showed five different CG, which is also the number of principal components with eigenvalues greater than 1. The occurrence of isomers of asarone was observed only in EO of two individuals (CG5), containing the main elements of differentiation.

Identificação de plantas hospedeiras da broca do abacate, Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) no Rio Grande do Sul / Identification of host plants of the avocado borer, Stenoma catenifer Walsingham (Lepidoptera: Elachistidae) in Rio Grande do Sul

Frutos de Nectandra megapotamica Mez e de Cinnamomum camphora (L.) (Lauraceae) foram coletados no Rio Grande do Sul, em 2004. Nove espécies pertencentes a cinco famílias de insetos foram coletadas: duas espécies de Drosophila (Diptera: Drosophilidae), seis espécies de Coleoptera: Heilipus sp. e Conotrachelus sp. (Curculionidae), Hypothenemus sp. (Scolytidae) e três espécies de Carpophilus (Nitidulidae), e uma de Lepidoptera (Elachistidae). Os espécimes pertencentes à família Elachistidae foram identificados como Stenoma catenifer Walsingham, a broca do abacate. S. catenifer emergiu do início de abril até meados de maio. A infestação nos frutos foi baixa. Duas novas plantas hospedeiras dessa praga foram identificadas.

Fruits of Nectandra megapotamica Mez and Cinnamomum camphora (L.) (Lauraceae) were collected in Rio Grande do Sul, Brazil, in 2004. Species of five families of insects were found inside the fruits: two fly species (Diptera: Drosophilidae: Drosophila spp.), six beetle species, Heilipus sp., Conotrachelus sp. (Curculionidae), Hypothenemus sp. (Scolytidae) and three species of Carpophilus (Nitidulidae), and moths (Lepidoptera: Elachistidae). The moth especimes were identified as Stenoma catenifer Walsingham, the avocado borer. The occurrence of the moth was predominant from early April until middle May. The natural larval infestation level was low. Two new host plant of the pest were identified.