Pâmela S. Silva

Cytogenotoxicity of Cymbopogon citratus (DC) Stapf (lemon grass) aqueous extracts in vegetal test systems

The lemon grass, Cymbopogon citratus (DC) Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce) root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous extracts (5; 10; 20 and 30 mg/mL). The percentage of germination, root development and cellular behavior were analyzed, and the results showed that the highest concentration of aqueous extracts reduced the mitotic index, the seed germination and the root development of lettuce. The extracts have also induced chromosome aberrations and cellular death in the roots cells of L. sativa.

Cytotoxic and genotoxic effects of two medicinal species of Verbenaceae

Abstract Lantana camara L. and Lippia alba (Mill.) N. E. Br. are two important species of Verbenaceae family and are commonly used in folk medicine in many countries of Central and Southern America. The aim of this study was to investigate, for the first time, the cytotoxic and genotoxic effects of aqueous extracts from leaves of both species on Lactuca sativa (lettuce) root tip meristem cells using a cytogenetic approach. Seeds of lettuce were separately treated during 72h with different concentrations of L. camara and L. alba aqueous extracts (5, 10, 20 and 30g/L). The percentage of germination, root development and cellular behavior were analyzed and the results showed that the highest concentration of aqueous extracts reduced the mitotic index, the seeds germination and the root development of lettuce. The extracts also induced chromosome aberrations and cellular death in roots cells of L. sativa. The cytogenotoxicity of L. camara and L. alba extracts was comparatively described.

Chromosome banding and essential oils composition of Brazilian accessions of Lippia alba (Verbenaceae)

The essential oil components and a karyotypic analysis of five Lippia alba (Verbenaceae) accessions from Brazil were performed with the objective of investigating the variation among different populations. The chemistry analysis allowed the grouping of the accessions in two main chemotypes: neral chemotype (LaCat, LaJF and LaRJ) and linalool chemotype (LaGua and LaVC). However, large karyotypic differences, verified by different chromosome banding techniques, were not detected. The results presented the same chromosome number for all accessions (2n = 30) with 10 metacentric chromosomes and 5 submetacentric. The chromosome banding showed great blocks of constitutive heterochromatin (C-bands) around the centromeric region, which was rich in AT bases (DAPI+), while the CMA bands were observed only in terminal regions of six chromosomes. Through Ag-NOR techniques, only two active pairs of NORs were detected on the three pairs of secondary constrictions (the NOR activity is discussed). This work relates the pattern of heterochromatin for Lippia alba for the first time.

Chemical composition of the essential oil and hexanic fraction of Lippia and Lantana species

A comparison between two extraction approaches of volatiles compounds from six species of Verbenaceae collected at Serra do Cipo, Minas Gerais, Brazil was done. The essential oil and hexanic fraction of leaves from two Lantana and four Lippia species collected in two different seasons were analyzed by GC/MS. Among various identified compounds from both extraction methods the majority of species showed major amounts of β-caryophyllene followed by germacrene D, bicyclogermacrene and α-pinene. Few differences were observed between the composition of essential oil and the hexanic fraction regarding the two studied genera. These results suggest that the analysis of hexanic fraction can be used, as an alternative way, to analyze the volatile compounds of the essential oil.

An increment in the Duranta repens L. (Verbenaceae) knowledge: DNA content, karyology, meiosis and palynology

Abstract Meiotic behavior, pollen morphology, interphasic nucleus pattern and karyotype description for Duranta repens (Verbenaceae) are presented. The species had semi-reticulate interphasic nucleus and in mitotic metaphase, chromosome number was 2n = 34 (32 m + 2 sm), with secondary constriction in one chromosome pair. Additionally to the A complement, we observed B chromosomes, varying to 0–3 in some cells of several individuals. Meiotic behavior was regular and pollen grains were isopolar and tricolporate, being classified as prolate-spheroidal with psilate-perfurate exine ornamentation.