Essential oil composition and cytotoxic activity in twospecies ofthe plant genus Vismia (Hypericaceae) from the Venezuelan Andes

Introduction: The Vismia genus belongs to the Hypericaceae family and comprises around 57 species of which 17 have been located in Venezuela. Previous investigations have been carried out in extracts as well as pure isolated compounds, revealing antimicrobial, antioxidant and anti-HIV, among other, biological activities. Objective: This investigation aims to determine the cytotoxic activity of essential oils from leaves of Vismia baccifera Triana & Planch (VBJ and VBV) and Vismia macrophylla Kunth (VM) collected in three different locations of the Venezuelan Andean region. Methods: Essential oils obtained by hydrodistillation were analyzed using gas chromatography-mass spectrometry (GC-MS) and their cytotoxic activity was analyzed following the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. Human tumor cell lines from SKBr3, MCF-7 and PANC-1, two breast carcinomas and one pancreatic adenocarcinoma of ductal type, were tested with the oil samples and human dermis fibroblasts were used as non-tumor cells. Results: β-caryophyllene and trans-caryophyllene were present as major components in VBJ and VBV, respectively, while γ-bisabolene was the main component in the VM sample. Anticancer activity was observed on V. baccifera essential oil against SKBr3, MCF-7 and PANC-1. The selectivity index showed that VBV is highly selective against the SKBr3 cell line and has no activity against non-tumor cells. Conclusions: These results are considered a contribution to natural products research and may provide supportive data for future studies on cancer.

Introducción: El género Vismia pertenece a la familia Hypericaceae y comprende alrededor de 57 especies de las cuales 17 han sido ubicadas en Venezuela. Se han realizado investigaciones previas tanto en extractos como en compuestos puros aislados revelando actividad antimicrobiana, antioxidante y anti-VIH, entre otras actividades biológicas. Objetivo: El propósito de esta investigación es determinar la actividad citotóxica de los aceites esenciales de las hojas de Vismia baccifera Triana & Planch (VBJ y VBV) y Vismia macrophylla Kunth (VM) recolectadas en tres localidades de la región andina venezolana. Métodos: Aceites esenciales obtenidos por hidrodestilación fueron analizados por cromatografía de gases-espectrometría de masas y su actividad citotóxica fue analizada siguiendo el método MTT (bromuro de 3-[4,5-dimetiltiazol-2-il]-2,5-difeniltetrazolio). Los aceites esenciales fueron ensayados frente a células tumorales humanas SKBr3, MCF-7 y PANC-1, dos carcinomas de mama y un adenocarcinoma pancreático del tipo ductal, usando cultivos primarios de fibroblastos de dermis humana como células no tumorales. Resultados: β-cariofileno y trans-cariofileno estuvieron presentes como compuestos mayoritarios en VBJ y VBV, respectivamente, mientras que γ-bisaboleno fue el componente principal en la muestra VM. El aceite esencial de V. baccifera mostró actividad anticancerígena frente a SKBr3, MCF-7 y PANC-1. El índice de selectividad reveló que VBV es altamente selectivo frente a la línea celular SKBr3 y no presenta actividad contra las células no tumorales. Conclusiones: Estos resultados se consideran una contribución a la investigación de los productos naturales y los datos pueden ser de utilidad en futuras investigaciones sobre el cáncer.

In vitro antioxidant activity and qualitative phytochemical analysis of two Vismia (Hypericaceae) species collected in Los Andes, Venezuela / Actividad antioxidante in vitro y análisis fitoquímico cualitativo de dos especies de Vismia (Hypericaceae) recolectadas en Los Andes, Venezuela

Abstract:Vismia genus is distributed mainly in tropical and subtropical regions of Central, South America and some areas of Africa. According to previous investigations, antioxidant potential of Vismia species might be related to anthrones, anthraquinones, flavonoids and phenol derivatives biosynthesized by these plants. In this investigation, phytochemical screening of Vismia baccifera (VB) from Mérida-Venezuela and Vismia macrophylla (VM) from Táchira-Venezuela methanolic extracts, carried out using various chemical assays, revealed an abundant presence of anthraquinones in both species analyzed. Glycosides were also present while flavones and dehydroflavones were observed abundantly in VB but moderated in VM. Triterpenes were also detected and steroids showed to be abundant in VM but moderate in VB. On the other hand, antioxidant capacity measured by the DPPH assay showed that VM possesses a stronger antioxidant activity than VB with IC50 5.50 µg mL-1. Phenol and flavonoid assays carried out by Folin-Ciocalteu and colorimetric test also revealed that methanol extracts of both species contain high concentrations of these metabolites. A relationship between the antioxidant activity, total phenol and flavonoids content of the extracts analyzed was demonstrated in this investigation since those samples with higher phenolic concentrations showed likewise higher antioxidant activity. Rev. Biol. Trop. 64 (4): 1431-1439. Epub 2016 December 01.

Resumen:El género Vismia esta distribuido principalmente en las regiones tropicales y subtropicales de Centro, Sur América y algunas zonas de África. De acuerdo a reportes previos, el potencial antioxidante de las especies de Vismia puede estar relacionado con antronas, antraquinonas, flavonoides y derivados fenólicos biosintetizados por estas plantas. En la presente investigación, el tamizaje fitoquímico de los extractos metanólicos de Vismia baccifera (VB) de Mérida-Venezuela y Vismia macrophylla (VM) de Táchira-Venezuela realizado con diferentes ensayos químicos reveló abundante presencia de antraquinonas en ambas especies analizadas. Glucósidos también estuvieron presentes mientras que flavonas y dehidroflavonas fueron observados abundantemente en VB pero con presencia moderada en VM. Triterpenos y esteroides también fueron detectados mostrando ser abundantes en VM y moderados en VB. Por otro lado, la actividad antioxidante determinada por el método DPPH reveló que VM posee actividad antioxidante más fuerte que VB con un IC50 de 5.50 µg mL-1. El ensayo del contenido de fenoles y flavonoides realizado con los métodos de Folin-Ciocalteu y test colorimétrico también demostró que los extractos metanólicos de ambas especies contienen altas concentraciones de estos metabolitos. En este estudio se observó una relación entre la actividad antioxidante, el contenido de fenoles y de flavonoides en los extractos analizados ya que las muestras que presentaron concentraciones más altas de fenoles y flavonoides también mostraron una mayor actividad antioxidante.

In vitro antioxidant activity and qualitative phytochemical analysis of two Vismia (Hypericaceae) species collected in Los Andes, Venezuela.

Vismia genus is distributed mainly in tropical and subtropical regions of Central, South America and some areas of Africa. According to previous investigations, antioxidant potential of Vismia species might be related to anthrones, anthraquinones, flavonoids and phenol derivatives biosynthesized by these plants. In this investigation, phytochemical screening of Vismia baccifera (VB) from Mérida-Venezuela and Vismia macrophylla (VM) from Táchira-Venezuela methanolic extracts, carried out using various chemical assays, revealed an abundant presence of anthraquinones in both species analyzed. Glycosides were also present while flavones and dehydroflavones were observed abundantly in VB but moderated in VM. Triterpenes were also detected and steroids showed to be abundant in VM but moderate in VB. On the other hand, antioxidant capacity measured by the DPPH assay showed that VM possesses a stronger antioxidant activity than VB with IC50 5.50 µg mL-1. Phenol and flavonoid assays carried out by Folin-Ciocalteu and colorimetric test also revealed that methanol extracts of both species contain high concentrations of these metabolites. A relationship between the antioxidant activity, total phenol and flavonoids content of the extracts analyzed was demonstrated in this investigation since those samples with higher phenolic concentrations showed likewise higher antioxidant activity.

Chemical composition and evaluation of antibacterial activity of essential oils of Ageratina jahnii and Ageratina pichinchensis collected in Mérida, Venezuela / Composición química y evaluación de la actividad antibacteriana de los aceites esenciales de Ageratina jahnii y Ageratina pichinchensis recolectadas en Mérida,Venezuela

Essential oil from leaves of Ageratina jahnii (B.L.Rob.) R. M. King & H. Rob. and Ageratina pichinchensis (Kunth) R. M. King & H. Rob (Asteraceae) collected in January 2010 were analyzed by GC/MS. Oils extracted by hydrodistillation yielded 0.50 percent and 0.43 percent w/v, respectively. Fifteen and twenty five components were identified by comparison of their mass spectra with the Wiley GC-MS Library data and by their retention indices (RI). The major components identified in A. jahnii were beta-myrcene (37.6 percent, alpha-pinene (17.1 percent), limonene (8.8 percent and pentacosane (9.2 percent while for A. pichinchensis 8,9-epoxythymyl isobutyrate (20.2 percent, germacrene-D (19.8 percent, thymyl isobutyrate (10.8 percent, eupatoriochromene (6.5 percent) and encecalol (5.9 percent) were observed as main compounds. This is the first report regarding the essential oil composition and antibacterial activity of the essential oil of A. jahnii.

Aceites esenciales de las hojas de Ageratina jahnii (B.L.Rob.) R. M. King & H. Rob. y Ageratina pichinchensis (Kunth) R. M. King & H. Rob (Asteraceae) colectadas en enero 2010 fueron analizados por CG/EM. Los aceites extraídos por hidrodestilación produjeron 0,50 por ciento y 0,43 por ciento p/v de rendimiento, respectivamente. Quince y veinticinco compuestos fueron identificados por comparación de sus espectros de masas con la base de datos de la librería Wiley CG/EM y por sus índices de retención (IR). Los compuestos identificados como majoritarios en A. jahnii fueron beta-mirceno (37,6 por ciento), alfa-pineno (17,1 por ciento, limoneno (8.8 por ciento y pentacosano (9,2 por ciento mientras para A. pichinchensis isobutirato de 8,9-epoxitimilo (20,2 por ciento, germacreno-D (19,8 por ciento, isobutirato de timilo (10,8 por ciento), eupatoriocromeno (6,5 por ciento y encecalol (5,9 por ciento) fueron observados como compuestos mayoritarios. Este es el primer reporte sobre la composición química y actividad antibacteriana del aceite esencial de A. jahnii.

Composition of the essential oil of leaves and roots of Allium schoenoprasum L. (Alliaceae) / Composición del aceite esencial de hojas y raíces de Allium schoenoprasum L

Essential oil from leaves and roots of Allium schoenoprasum L. (Alliaceae) were analyzed by GC/MS. The oils extracted by hydrodistillation yielded 0.02 percent and 0.03 percent for leaves and roots, respectively. Five (99.12 percent leaves) and four (98.32 percent roots) components were identified being bis-(2-sulfhydryethyl)-disulfide (72.06 percent leaves, 56.47 percent roots) the major constituent on the two oil samples while 2,4,5-trithiahexane (5.45 percent leaves, 15.90 percent roots) and tris (methylthio)-methane (4.01 percent leaves, 12.81 percent roots) were detected in lower amounts.

Los aceites esenciales de hojas y raíces de Allium schoenoprasum L. (Alliaceae fueron analizados por CG/EM. La extracción por hidrodestilación mostró un rendimiento de 0.02 por ciento y 0.03 por ciento para las hojas y raíces, respectivamente. Cinco (99.12 por ciento hojas) y cuatro (98.32 por ciento raíces) compuestos fueron identificados siendo el bis-(2-sulfidietil)-disulfuro (72.06 por ciento hojas, 56.47 por ciento raíces) el compuesto mayoritario en los dos aceites mientras que 2,4,5-tritiahexano (5.45 por ciento hojas, 15.90 por ciento raíces) y tris (metilthio)-metano (4.01 por ciento hojas, 12.81 por ciento raíces) fueron observados en menores cantidades.

NMR elucidation and crystal structure analysis of 1-hydroxy-3, 6-dimethoxy-8-methyl-9h-xanthen-9-one (lichexanthone) isolated from Vismia baccifera (Guttiferae) / Elucidación por RMN y análisis de la estructura cristalina de 1-hidroxi-3,6-dimetox1-8-methil-9h-xanten-9-ona (lichexanthone)

In the present investigation the structural analysis of 1-hydroxy-3,6-dimethoxy-8-methyl-9h-xanthen-9-one (lichexanthone) isolated from Vismia baccifera var. dealbata collected in Mérida-Venezuela, was established by NMR (1H and 13C), mass spectrometry and single crystal X-ray diffraction. Lichexanthone crystallizes in the monoclinic system, space group P21/c (No 14) with unit cell parameters a = 11.6405(5) Å; b = 7.5444(3) Å; c = 15.2341(6) Å; = 102.280(1)°; V = 1307.26(9) Å3; Z = 4. The structure refinement converged to R = 0.0397, wR2 = 0.1076, S = 1.04. Lichexanthone had been isolated before from Parmotrema sp and Ruprechtia tangarana (Polygonaceae). However, to the best of our knowledge, this is the first report of this compound obtained from V. baccifera var. dealbata (Guttiferae).

En la presente investigación el análisis estructural de 1-hidroxi-3,6-dimetoxi-8-metil-9h-xanten-9-ona (lichexanthone) aislada de Vismia baccifera var. dealbata colectada en Mérida-Venezuela, fue determinado por RMN (1H y 13C), espectrometría de masas y difracción de rayos X. La lichexanthona cristaliza en un sistema monoclínico con un grupo espacial P21/c (No 14) y parámetros de celda de a = 11.6405 (5) Å; b = 7.5444 (3) Å; c = 15.2341 (6) Å; = 102.280(1)°; V = 1307.26(9) Å3; Z = 4. El refinamiento de la estructura convergió a los valores de R = 0.0397, wR2 = 0.1076, S = 1.04. La lichexanthona ha sido aislada de Parmotrema sp y Ruprechtia tangarana (Polygonaceae). Sin embargo, para nuestro conocimiento, esta es la primera vez que se reporta el aislamiento de este compuesto en la especie V. baccifera var. dealbata (Guttiferae).

Relaxant activity of raspberry (Rubus idaeus) leaf extract in guinea-pig ileum in vitro.

Tea made from the leaves of Rubus idaeus L. (raspberry) has been used for centuries as a folk medicine to treat wounds, diarrhoea, colic pain and as a uterine relaxant. Extracts of dried raspberry leaves prepared with different solvents, (n-hexane, ethyl acetate, chloroform and methanol) were tested in vitro for relaxant activity on transmurally stimulated guinea-pig ileum. The methanol (MeOH) extract exhibited the largest response and also indicated that the active compounds are of a relatively polar nature. Hence the bulk of the leaves were extracted with methanol and the dried extract fractionated on a silica gel column, eluting with chloroform, mixtures of chloroform and methanol and finally methanol. Each fraction was examined by thin layer chromatography and tested for relaxant activity in an in vitro transmurally stimulated guinea-pig ileum preparation. The fractions eluted with chloroform (CHCl(3)) lacked relaxant activity. Samples eluted with CHCl(3)/MeOH (95:5) had moderate relaxant activity, while a second distinctive peak of activity eluted with a more polar solvent mixture (CHCl(3)/MeOH 50:50) provided strong dose dependent responses. Evidence was obtained that there are at least two components of raspberry leaf extract which exhibit relaxant activity in an in vitro gastrointestinal preparation.