Antibacterial and hemolytic activity of extracts and compounds obtained from epicarps and seeds of Garcinia madruno(Kunth) Hammel / Actividad antimicrobiana y hemolítica de extractos y compuestos obtenidos del epicarpio y las semillas de Garcinia madruno (Kunth) Hammel

This paper describes the evaluation of the antimicrobial and hemolytic activity of the hexane, dichloromethane, ethyl acetate and methanol extracts from seeds and epicarps of Garcinia madruno; as well garcinol, morelloflavone and volkensiflavone isolated from the same species. In the preliminary test of bacterial susceptibility, hexane extracts from seeds and epicarps and the three compounds tested only displayed inhibitory growth effect against Gram-positive bacteria. The minimum inhibitory concentrations of extract and compounds ranging from 86.6 to 1253.4 µg/mL. The hemolytic activity was assessed; however, except for the methanol extract from seeds, none of the samples studied induced hemolysis. Thus, our results suggest that extracts and compounds from G. madruno have the potential to be used in the control of pathologies associated to Gram-positive bacteria. This is the first report of the antimicrobial and hemolytic activity of extracts of different polarity obtained from seeds and epicarps of this edible species.

El presente artículo describe la evaluación de la actividad antimicrobiana y hemolítica de los extractos de hexano, diclorometano, acetato de etilo y metanol, obtenidos de la semilla y el epicarpio de Garcinia madruno; así como de garcinol, morelloflavona y volkensiflavona; aislados de la misma especie. En el ensayo de susceptibilidad bacteriana, tanto el extracto de hexano obtenido a partir de la semilla y el epicarpio, y los tres compuestos aislados, únicamente mostraron actividad inhibitoria del crecimiento contra bacterias Gram-positivas. La concentración mínima inhibitoria presentó valores entre 86.6 y 1253.4 µg/mL. También se estableció la actividad hemolítica; sin embargo, con excepción del extracto metanólico obtenido a partir de las semillas, ninguna de las muestras evaluadas indujo hemólisis. Por lo tanto, los resultados sugieren que los extractos y compuestos de G. madruno tienen el potencial de ser usados en el control de bacterias Gram-positivas asociadas a diversas patologías. Este es el primer reporte de actividad antimicrobiana y hemolítica de extractos de diferente polaridad obtenidos de las semillas y epicarpios de esta especie comestible.

Interacción in silico de las moléculas Agatisflavona, Amentoflavona y Punicalina con la Importina α 1 humana / In silico interaction of Agathisflavone, Amentoflavone and Punicalin molecules with human Importin α1

RESUMEN Varios virus con genoma de ARN en fases iniciales de la infección realizan la translocación de proteínas al interior del núcleo de la célula hospedera mediante la vía de las importinas α1. Este transporte es fundamental para el éxito de la replicación viral y se ha convertido en un blanco para la búsqueda y desarrollo de nuevos antivirales. El objetivo de este estudio fue determinar y caracterizar interacciones entre la Agatisflavona, Amentoflavona, Punicalina con el sitio mayor de unión de las Importinas α1 humanas mediante el análisis in silico del acoplamiento molecular y simulaciones de dinámica molecular. Las pruebas de acoplamiento molecular se realizaron entre estos fitoconstituyentes y la estructura de la importina α1 humana. Las afinidades de interacción fueron detectadas con la Agatisflavona, Amentoflavona y Punicalina (ΔG b = -8,8, -9,1 y -8,8 kcal.mol-1 respectivamente), con afinidades de interacción específicamente a los dominios ARM2-ARM5 (sitio mayor de unión) de las importinas α1. Las simulaciones de dinámica molecular revelaron interacciones significativamente favorables (P<0,001) con los ligandos Agatisflavona y Amentoflavona (ΔG b = -18,60±0,35 y -22,55±2,41 kcal.mol-1) mientras que la Punicalina registró mayores valores de energía de interacción (ΔG b = -5,33±1,72 kcal.mol-1). Los hallazgos obtenidos en este estudio computacional sugieren que las moléculas Agatisflavona y Amentoflavona presentan interacciones favorables con el sitio mayor de unión de las Importinas α1, en comparación a lo registrado con la Punicalina, sin embargo, se recomienda realizar ensayos in vitro a modo de confirmar estas observaciones.

ABSTRACT Several RNA-viruses during early stages of infection perform the translocation of proteins into the nucleus of host cell by the importin α1 pathway. This transport is essential for viral replication success and has become a target to search and development new antivirals. The objective of this study was to determine and characterize interactions between Agathisflavone, Amentoflavone and Punicalin with the major binding site of human importins α1 by in silico analysis of molecular docking and molecular dynamics simulations. Molecular docking tests were performed between these phytoconstituents and the structure of human importin α1. Interaction's affinity was detected with the Agathisflavone, Amentoflavone and Punicalin (ΔG b = -8.8, -9.1 and -8.8 kcal.mol-1 respectively), with binding affinity to ARM 2-ARM 5 domains (major binding site) of importins α1. Molecular dynamics simulations revealed significantly favorable interactions (P<0.001) with the ligands Agatisflavone and Amentoflavone (ΔG b = -18.60 ± 0.35 and -22.55 ± 2.41 kcal.mol-1) meanwhile Punicalin showed higher values of interaction free energy (ΔG b = -5.33 ± 1.72 kcal.mol-1). The findings obtained suggest that Agathisflavone and Amentoflavone could favorably interact to the major binding site of Importins α1 compared to that registered with Punicalin, however, it is recommended to perform in vitro assays to confirm these observations.

Potential hepatic and renal toxicity induced by the biflavonoids from Ginkgo biloba / 中国天然药物

Evidence continues to grow on potential health risks associated with Ginkgo biloba and its constituents. While biflavonoid is a subclass of the flavonoid family in Ginkgo biloba with a plenty of pharmacological properties, the potential toxicological effects of biflavonoids remains largely unknown. Thus, the aim of this study was to investigate the in vitro and in vivo toxicological effects of the biflavonoids from Ginkgo biloba (i.e., amentoflavone, sciadopitysin, ginkgetin, isoginkgetin, and bilobetin). In the in vitro cytotoxicity test, the five biflavonoids all reduced cell viability in a dose-dependent manner in human renal tubular epithelial cells (HK-2) and human normal hepatocytes (L-02), indicating they might have potential liver and kidney toxicity. In the in vivo experiments, after intragastrical administration of these biflavonoids at 20 mg·kg·d for 7 days, serum biochemical analysis and histopathological examinations were performed. The activity of alkaline phosphatase was significantly increased after all the biflavonoid administrations and widespread hydropic degeneration of hepatocytes was observed in ginkgetin or bilobetin-treated mice. Moreover, the five biflavonoids all induced acute kidney injury in treated mice and the main pathological lesions were confirmed to the tubule, glomeruli, and interstitium injuries. As the in vitro and in vivo results suggested that these biflavonoids may be more toxic to the kidney than the liver, we further detected the mechanism of biflavonoids-induced nephrotoxicity. The increased TUNEL-positive cells were detected in kidney tissues of biflavonoids-treated mice, accompanied by elevated expression of proapoptotic protein BAX and unchanged levels of antiapoptotic protein BCL-2, indicating apoptosis was involved in biflavonoids-induced nephrotoxicity. Taken together, our results suggested that the five biflavonoids from Ginkgo biloba may have potential hepatic and renal toxicity and more attentions should be paid to ensure Ginkgo biloba preparations safety.

Kolaviron Protects the Prefrontal Cortex and Hippocampus against Histomorphological and Neurobehavioural Changes in Cuprizone Model of Multiple Sclerosis

Background: This study explored the efficacy of kolaviron—a biflavonoid complex isolatedfrom the seeds of Garcinia kola—in protecting against cuprizone (CPZ)-induced demyelination inboth the prefrontal cortex and the hippocampus of Wistar rats.Methodology: Thirty rats were treated to receive 0.5 mL phosphate-buffered saline (groupA, control), 0.5 mL corn oil (group B), 0.2% CPZ (group C), for 6 weeks, 0.2% CPZ for 3 weeks andthen 200 mg/kg of Kv for 3 weeks (group D), or 200 mg/kg of Kv for 3 weeks followed by 0.2%CPZ for 3 weeks (group E). Rats were assessed for exploratory functions and anxiety-like behaviourbefore being euthanised and perfused transcardially with 4% paraformaldehyde. Prefrontal andhippocampal thin sections were stained in hematoxylin and eosin and cresyl fast violet stains.Results: CPZ-induced demyelination resulted in behavioural impairment as seen byreduced exploratory activities, rearing behaviour, stretch attend posture, center square entry,and anxiogenic characteristics. Degenerative changes including pyknosis, karyorrhexis, neuronalhypertrophy, and reduced Nissl integrity were also seen. Animals treated with Kv showedsignificant improvement in behavioural outcomes and a comparatively normal cytoarchitecturalprofile.Conclusion: Kv provides protective roles against CPZ-induced neurotoxicity throughprevention of ribosomal protein degradation.

Determinación de biflavonoides en diferentes partes de la especie Garcinia bakeriana (Urb) Borhidi / Determination of biflavonoids in different parts of Garcinia bakeriana (Urb) Borhidi

INTRODUCCIÓN: el género Garcinia produce una gran variedad de metabolitos secundarios representados por xantonas, acilfloroglucinoles y biflavonoides fundamentalmente. Sin embargo, existe muy poca información sobre la composición química de las especies cubanas pertenecientes a este género. OBJETIVO: determinar la presencia de 11 biflavonoides en las hojas, la corteza del tallo y el látex de Garcinia bakeriana (Urb) Borhidi. MÉTODOS : los extractos de las hojas, látex y la corteza del tallo de G. bakeriana fueron comparados empleando un método de cromatografía líquida de ultra alta eficacia (CLUAE) y 11 biflavonoides como sustancias de referencia. RESULTADOS: los biflavonoides GB-1A, GB-2A, glicósido de GB-2A, glicósido de morelloflavona, 4´´´metoxi- I3,II8-biapigenina, I3,II8-biapigenina, amentoflavona y 4´´´-metoxiamentoflavona fueron detectados como constituyentes de las hojas y la corteza del tallo de G. bakeriana. CONCLUSIONES: la especie G. bakeriana presenta biflavonoides como constituyentes de las hojas y la corteza del tallo. Además, la metodología de trabajo desarrollada contribuye al conocimiento de la composición química de la flora cubana y podría constituir una alternativa, rápida y de bajo consumo de disolventes, para el estudio comparativo de especies endémicas cubanas de escasa distribución y abundancia(AU)

INTRODUCTION: previous studies have revealed genus Garcinia to be a rich source of secondary metabolites, namely xanthones, acylphloroglucinols and bioflavonoids. However, the chemical composition of Cuban species in this genus is almost unknown. OBJECTIVE: to determine the presence of 11 biflavonoids in Garcinia bakeriana leaves, latex and stem bark. METHODS: leaves, latex and stem bark extracts of G. bakeriana were compared by using an ultra high performance liquid chromatography method (UPLC) and 11 biflavonoid standards. RESULTS: biflavonoids GB-1A, GB-2A, GB-2A glycoside, morelloflavone glycoside, 4´´´methoxy- I3,II8-biapigenin, I3,II8-biapigenin, amentoflavone y 4´´´-methoxyamentoflavone were detected as components in G. bakeriana leaves and stem bark. CONCLUSIONS: G. Bakeriana species has biflavonoids as components of its leaves and stem bark. The work methodology described in this paper helps to expand the knowledge about the chemical composition of the Cuban flora and may represent a rapid method with low dissolver consumption for the comparative study of poorly distributed and non abundant Cuban endemic species(AU)

Isolation and determination of biflavonoids in Ginkgo biloba leaves / 中草药

Objective: To purify the biflavonoids from Ginkgo biloba leaves and determine their contents in the leaves collected in different periods. Methods: Dichloromethane fraction of ethanol extract was used to purify biflavonoids through silica gel column and semi-preparative HPLC. The contents of four biflavonoids were simultaneously determined using RP-HPLC. Results: According to the reported 1H-NMR data, four compounds were identified as bilobetin (LB-1), ginkgetin (LB-2), isoginkgetin (LB-3), and sciadopitysin (LB-4). Content determination demonstrated that the biflavonoids accumulation decreased as the leaves collected from the beginning to the end of September, and the content difference can be as large as 30%. Conclusion: RP-HPLC method can be used in the quantitative determination of biflavonoids in G. biloba leaves. The semi-preparative condition can be used in the purification of biflavonoids from G. biloba leaves. The contents of four biflavonoids could be decreased significantly when the leaves turned yellow, which provides the useful information for the collection of G. biloba leaves. However, the mechanism and the accumulation of other kinds of compounds need further study.

Flavonoids, benzophenones and a new euphane derivative from Clusia columnaris Engl / Flavonóides, benzofenonas e um novo eufano de Clusia columnaris Engl

The polyisoprenylated benzophenones machuone and clusiachromene A have been isolated from the fruits of Clusia columnaris. The hexane extract of the young branches with leaves afforded a new euphane derivative, whose structure was elucidated by spectroscopic methods. On the contrary, the most polar EtOAc and ButOH extracts were constituted of flavonoid C-glucosides (isovitexin, vitexin and vitexin-2"-xyloside) and seven biflavonoids of the so-called Garcinia group.

Dos frutos de Clusia columnaris foram isoladas as benzofenonas poliisopreniladas machuona e clusiacromeno A. Do extrato em hexano obtido de galhos e folhas novas, um novo triterpeno do tipo eufano foi isolado. Sua estrutura foi elucidada através de métodos espectroscópicos. Por outro lado, dos extratos mais polares - em acetato de etila e em butanol, foram isolados os flavonóides C-glicosilados isovitexina, vitexina e vitexina-2"-xilosídeo, além de sete bisflavonóides conhecidos como bisflavonóides do grupo da Garcinia.

Bioactive flavone dimers from Ouratea multiflora (Ochnaceae)

Chromatographic fractionation of the organic extract from leaves of Ouratea multiflora afforded the flavone dimers heveaflavone, amentoflavone-7'',4''''-dimethyl eter, podocarpusflavone-A and amentoflavone. Their structures were elucidated from spectral data, including 2D-NMR experiments of the natural substances. Biological activities of all isolates were evaluated, using antimicrobial assay against Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, cytotoxicity assay against mouse lymphoma (L5178) and KB cell lines, TLC screening for acetylcholinesterase inhibitors and antioxidant activity measured by DPPH test.

O fracionamento cromatográfico do extrato orgânico das folhas de Ouratea multiflora forneceu os flavonóides diméricos, heveaflavona, 7'',4''''-dimetilamentoflavona, podocarpusflavona-A e amentoflavona. Suas estruturas foram elucidadas com base nos dados espectrais, incluindo experimentos bidimensionais de RMN, das substâncias naturais. A atividade antibiótica de todos os isolados foi avaliada, usando-se as bacterias Gram-positivas Staphylococcus aureus and Bacillus subtilis. Teste de citotoxicidade nas linhagens de linfoma de ratos (L5178) e KB também foram conduzidos para avaliar os extratos e os flavonóides isolados. a triagem biológica para a avaliação de atividade antioxidante e inibidora de acetil colinesterase foram conduzidas pela técnica da bioautografia com DPPH e teste pelo teste de Ellman respectivamente.

Three biflavonoids from ethanol extract of the root of Daphne genkwa / 药学学报

Aim To investigate the chemical constituents of the secondary metabolites of the roots of Daphne genkwa. Methods The roots of D. genkwa were extracted with 95% ethanol at 60 - 70 ℃ for 7 days to obtain the crude extract. The crude extract was purified by silica gel and Sephadex LH-20 column chromatography as well as the HPLC techniques. The structures of the isolates were elucidated by combined spectroscopic methods including 1D and 2D NMR, MS, UV, IR and CD. Results Three new biflavonoids were isolated from the ethanol extract of the roots of D. genkwa and their structures were identified as daphnodorin H-3-methyl ether (1), daphnodorin H-3"-methyl ether (2) and daphnodorin G-3"-methyl ether (3). Conclusion Compounds 1, 2 and 3 are three new biflavonoids.

Chemical constituents from roots of Stellera chamaejasme / 中草药

Object To study the chemical constituents from the roots of Stellera chamaejasme L. Methods Chemical constituents were isolated by chromatographic methods and identified by physiochemical and spectral analysis. Results One lignan and three biflavonoids were purified and determined as bursehernin (Ⅰ), chamaejasmenin B (Ⅱ), isoneochamaejasmin A (Ⅲ),and (+)-chamaejasmin (Ⅳ). Conclusion Compound Ⅲ and Ⅳ are determined as new optical compounds. Compound I is first isolated from Stellera L. species.

Study on biflavonoids from stem bark of Daphne giraldii / 中草药

Object To isolate and identify the biflavonoids from the stem bark of Daphne giraldii Nitsche. Methods The flavonoids were isolated and purified by column chromatography on silica gel and Sephadex LH-20. Their structures were determined by spectroscopic methods, including IR, 1HNMR, 13 CNMR, HMBC and FAB-MS.Results Four biflavonoids daphnodorins A-D 1 (Ⅰ-Ⅳ) were isolated from the stem bark of D. giraldii. Conclusion The above four biflavonoids were isolated from the title plant only.