Evaluación preliminar de la actividad antiviral del extracto de Laurencia obtusa frente a herpesvirus y virus dengue / Preliminary evaluation of the antiviral activity of Laurencia obtuse extract against herpesvirus and dengue virus

Introducción: los virus del herpes simplex y el virus dengue se encuentran entre los patógenos humanos de mayor importancia dados los altos niveles de morbilidad y mortalidad que provocan. El fallo en el desarrollo de vacunas para ambos virus, así como la ausencia de fármacos para el tratamiento del dengue y el surgimiento de nuevas variantes virales resistentes a las drogas existentes para los herpesvirus, incrementa la necesidad de buscar nuevas fuentes de compuestos con actividad antiviral. En este sentido las algas son una alternativa interesante debido a la diversidad de compuestos con actividad biológica que se han aislado de estos organismos. Objetivo: evaluar la actividad antiviral in vitro de un extracto hidroalcohólico del alga roja Laurencia obtusa frente a virus herpes simplex tipo1, herpes simplex tipo 2 y virus dengue. Métodos: se determinó el valor de concentración citotóxica media empleando el ensayo de reducción de MTT en células Vero y C6/36HT. El cálculo de la concentración efectiva media se realizó mediante inhibición del efecto citopático en células Vero o C6/36HT, dependiendo del virus. El índice selectivo se calculó a partir de la relación IS=CC50/CE50. Resultados: el extracto hidroalcohólico de L obtusa no es tóxico en las células Vero y C6/36HT, en el rango de concentraciones evaluadas. El extracto inhibió la replicación in vitro de los virus HHV 1 y HHV 2 en células Vero con valores de IS>29 y 42, respectivamente. Por otra parte no se observó inhibición de la replicación de DENV-2 en células C6/36HT. Conclusiones: el extracto hidroalcohólico de L. obtusa posee actividad antiviral frente a HHV 1 y HHV 2 pudiera ser empleado en el desarrollo de fármacos antiherpéticos novedosos. Este trabajo constituye el primer informe sobre la actividad antiviral de esta especie de alga(AU)

Introduction: herpes simplex and dengue viruses are the most important human pathogens with high levels of morbidity and mortality. Lack of vaccine development for these viruses, non-existence of drugs for dengue treatment and the emergence of new herpes virus variants resistant to drugs currently in use reinforce the need for new sources of antiviral drugs. Algae remain an interesting alternative in this regard, due to the diversity of compounds with biological activity found in these organisms. Objective: to evaluate the in vitro antiviral activity of a hydroalcoholic extract of the red seaweed Laurencia obtusa against herpes simplex type 1, herpes simplex type 2 and dengue virus. Methods: the mean cytotoxic concentration was determined by using the MTT reduction assay in Vero and C6/36HT cells. Mean effective concentration was estimated with the cytopathic effect inhibition in Vero or C6/36HT cells depending on the virus. Selective index (SI) =CC50/EC50 was calculated. Results: hydroalcoholic extract from L.obtusa was not toxic at the evaluated concentrations The extract managed to inhibit HHV 1 y HHV 2 virus replication in Vero cells with SI values higher than 29 and 42, respectively. On the other hand there was no inhibition of DENV-2 replication in C6/36HT cells. Conclusions: hydroalcoholic extract from L. obtusa showed in vitro antiviral activity against HHV 1 and HHV 2 and could be employed as a source for new antiviral compounds. This is the first report on the antiviral activity of this alga species(AU)

Actividad antiviral de un extracto acuoso del alga roja Laurencia obtusa frente a virus influenza A y B / Antiviral activity of an aqueous extract from the red alga Laurencia obtusa against influenza A and B viruses

(au)INTRODUCCIÓN: la terapia antiviral frente a las infecciones provocadas por virus influenza se basa en empleo de inhibidores de las proteínas M2 y neuraminidasa (NA). Sin embargo, la emergencia de cepas estacionales resistentes a ambos grupos de fármacos motiva la búsqueda de nuevos fármacos anti-influenza. Los extractos de algas pueden ser utilizados como fuente para la obtención de estos compuestos, teniendo en cuenta la diversidad de metabolitos descrita en estos organismos. OBJETIVO: evaluar la actividad antiviral in vitro de un extracto acuoso del alga roja Laurencia obtusa frente a virus influenza A (H1N1), A (H3N2) e influenza B. MÉTODOS: se evaluó la citotoxicidad en células MDCK, mediante cálculo de la viabilidad celular, en presencia de concentraciones crecientes del extracto. Los efectos sobre la replicación viral se cuantificaron mediante determinación de los niveles de la hemaglutinina (HA) y de la inhibición del efecto citopático (ECP). El índice selectivo (IS) se calculó a partir de la relación IS=CC50/CE 50. RESULTADOS: el extracto acuoso de Laurencia obtusa posee actividad antiviral in vitro frente a virus influenza B, A (H3N2) y A (H1N1) con valores de IS de 7,73; 11,79 y 12,95; respectivamente. CONCLUSIONES: Laurencia obtusa inhibe la replicación de virus influenza de elevada importancia clínica. La realización de ensayos secundarios de caracterización de la actividad biológica, así como de caracterización molecular del extracto, podrían permitir el desarrollo de novedosos compuestos antivirales. Este trabajo constituye el primer informe de actividad inhibitoria de esta especie de macroalga frente a virus influenza.compuestos antivirales. Este trabajo constituye el primer informe de actividad inhibitoria de esta especie de macroalga frente a virus influenza(AU)

INTRODUCTION: antiviral therapy against infections caused by influenza viruses is based on the use of inhibitors of M2 protein and neuraminidase (NA). However, the emergence of seasonal strains resistant to both drug groups has led to the search for new anti-influenza medications. Extracts from algae may be used as a source of compounds, considering the diversity of metabolites described for these organisms. OBJECTIVE: evaluate the in vitro antiviral activity of an aqueous extract from the red alga Laurencia obtusa against influenza A (H1N1), A (H3N2) and B viruses. METHODS: cytotoxicity was evaluated in MDCK cells by cell viability estimation in the presence of growing concentrations of the extract. The effects over viral replication were quantified by determining hemagglutinin (HA) levels and inhibition of the cytopathic effect (CPE). The selective index (SI) was estimated by SI=CC50/CE50. RESULTS: the aqueous extract of Laurencia obtusa showed in vitro antiviral activity against influenza B, A (H3N2) and A (H1N1) viruses with SI values of 7.73, 11.79 and 12.95, respectively. CONCLUSIONS: Laurencia obtusa inhibits the replication of influenza viruses, a fact of great clinical importance. Secondary assays to characterize the biological activity and molecular composition of the extract may lead to the development of novel antiviral compounds. The present paper is the first report on the inhibitory activity of this macroalga species against influenza viruses(AU)

Studies on chemical constituents of Laurencia saitoi / 中国中药杂志

In order to search for bioactive natural products from marine algae, the chemical constituents of red alga Laurencia saitoi was separated by the combination of normal phase silica gel, Sephadex LH-20 column chromatography and recrystallization. Seven compounds: aplysistatin (1), 5-acetoxypalisadin B (2), palisadin B (3), palisadin A (4), pacifigorgiol (5), stigmast4-en-3alpha, 6beta-diol (6), 2, 3, 5, 6-Tetrabromoindole (7), were isolated and their structures were elucidated by spectroscopic methods including 1H-NMR, 13C-NMR and MS techniques. All compounds were isolated from L. saitoi for the first time. Cytotoxicities of purified compounds were evaluated by MTT method, however, all of them were found inactive (IC50 >10 mg x L(-1).

Studies on chemical constituents of Laurencia tristicha ( II ) / 中国中药杂志

<p><b>OBJECTIVE</b>To search for chemical constituents with structural diversity from Laurencia tristicha to supply for biological assay.</p><p><b>METHOD</b>Compounds were isolated by means of column chromatography over normal phase silica gel and Sephadex LH-20, recrystallization and HPLC. Structures were identified by spectroscopic methods including 1D NMR, IR and MS. Cytotoxicities of the purified compounds were evaluated by MTT method.</p><p><b>RESULT</b>Seven compounds were isolated from L. tristicha. Their structures were elucidated as cholesterol (1), cholesta- 5-en-3beta, 7alpha-diol (2), beta-stigmasterol (3), phytol (4), zeaxanthin (5), 4 -hydroxybenzaldehyde (6), indolyl-3-carbaldehyde (7). In the cytotoxic assay compound 2 was active against human cancer cell lines HCT-8, Bel-7402, BGc-823, A549 and HELA with IC50 values of 1.90, 2.02, 1.99, 6.52 and 1.20 microg x mL(-1), respectively. Compound 4 showed cytotoxicity against HCT-8 and HELA with IC50 value of 3.51 and 2.04 microg x mL(-1), and other compounds were inactive ( IC50 > 10 microg x mL(-1)).</p><p><b>CONCLUSION</b>Compounds 1-7 were isolated from L. tristicha for the first time. In additon, compounds 2 and 4 were cytotoxic against several human cancer cell lines.</p>