Use of Frozen Leaves for Morpho-anatomical Characterization of Nectandra megapotamica (Spreng) Mez, Lauraceae

Abstract Nectandra megapotamica (Spreng.) Mez. it is a native tree species of the Atlantic Forest, commonly known as canela-preta. The species has some anti-inflammatory, antitumor and antirheumatic properties among others. In this work the use of frozen plant material for microscopy analysis was tested. In addition, the leaf morpho-anatomy of the species was characterized which allowed to perform a structural description and to identify structures of secretion and storage of essential oil. The plant material was prepared for analyzes in optical, fluorescence and scanning electron microscopy. The leaf anatomy shows glabrous epidermis, unistratified, paracytic stomata, absence of trichomes, polyhedral epidermal cells. Some typical family characteristics were observed as a closed arc-shaped bicollateral bundle vascular system and dorsiventral mesophyll. The structures of secretion and storage of essential oil were identified as secretory cavities.

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.