In vitro antiviral activity of plant extracts from Asteraceae medicinal plants

Abstract

BackgroundDue to the high prevalence of viral infections having no specific treatment and the constant appearance of resistant viral strains, the development of novel antiviral agents is essential. The aim of this study was to evaluate the antiviral activity against bovine viral diarrhea virus, herpes simplex virus type 1 (HSV-1), poliovirus type 2 (PV-2) and vesicular stomatitis virus of organic (OE) and aqueous extracts (AE) from: Baccharis gaudichaudiana, B. spicata, Bidens subalternans, Pluchea sagittalis, Tagetes minuta and Tessaria absinthioides. A characterization of the antiviral activity of B. gaudichaudiana OE and AE and the bioassay-guided fractionation of the former and isolation of one active compound is also reported.MethodsThe antiviral activity of the OE and AE of the selected plants was evaluated by reduction of the viral cytopathic effect. Active extracts were then assessed by plaque reduction assays. The antiviral activity of the most active extracts was characterized by evaluating their effect on the pretreatment, the virucidal activity and the effect on the adsorption or post-adsorption period of the viral cycle. The bioassay-guided fractionation of B. gaudichaudiana OE was carried out by column chromatography followed by semipreparative high performance liquid chromatography fractionation of the most active fraction and isolation of an active compound. The antiviral activity of this compound was also evaluated by plaque assay.ResultsB. gaudichaudiana and B. spicata OE were active against PV-2 and VSV. T. absinthioides OE was only active against PV-2. The corresponding three AE were active against HSV-1. B. gaudichaudiana extracts (OE and AE) were the most selective ones with selectivity index (SI) values of 10.9 (PV-2) and >117 (HSV-1). For this reason, both extracts of B. gaudichaudiana were selected to characterize their antiviral effects. Further bioassay-guided fractionation of B. gaudichaudiana OE led to an active fraction, FC (EC50=3.1 μg/ml; SI= 37.9), which showed antiviral activity during the first 4 h of the viral replication cycle of PV-2 and from which the flavonoid apigenin (EC50 = 12.2 ± 3.3 μM) was isolated as a major compound.ConclusionsThe results showed that, among the species studied, B. gaudichaudiana seemed to be the most promising species as a source of antiviral agents.

Anti-HCV Activity from Semi-purified Methanolic Root Extracts ofValeriana wallichii

“…Traditional medicinal plants have been used to treat multiple diseases, often with unknown etiology, worldwide. In order to discover novel therapeutic agents, there is a scope to reconsider the age‐old cultural practices from diverse perspective and scrutinize these plants over a broad spectrum of pharmacological parameters (Kitazato et al ., ; Visintini Jaime et al ., ). V. wallichii is well‐recognized in traditional pharmacopeias in Asia for treatment of nervous disorders (Mathela et al ., ).…”

Flavonoids: promising natural compounds against viral infections

“…Apigenin is most commonly isolated in abundance from the family Asteraceae. The organic and aqueous extracts from Asteraceae plants with apigenin as a major compound were found to be active against HSV-1, poliovirus type 2 and hepatitis C virus (HCV) [85,127]. Apigenin isolated from sweet basil (Ocimum basilicum) showed a potent antiviral activity against adenoviruses (ADV) and hepatitis B virus in vitro [17].…”

In vitro anti influenza virus activity, antioxidant potential and total phenolic content of twelve Iranian medicinal plants

“…Results of the screening were expressed as positive (+), reduction of viral CPE was higher than 50% at all three concentrations tested, negative (−) without protection at all three concentrations tested, (++/−) reduction of viral CPE was higher than 50% at 100 and 50μg/mL, and +/−− reduction of viral CPE was higher than 50% only at 100μg/ mL [24].…”

“…Briefly, confluent MDCK cell monolayers were infected with 100µL (100TCID 50 ) of virus suspension and incubated at 37 o C for about one hour to allow virus adsorption and then the virus was removed and the cells were treated with 25, 50 and 100 μg/mL of each extracts [24] supplemented with 2 μg/mL TPCK and 0.3% BSA (200μL/well). The plates were incubated at 37°C in a humidified CO 2 atmosphere until 90% of viral CPE in the control virus was reached.…”

“…The antiviral activity of each plant extract was screened in 96-well culture plates by measuring the reduction of the viral cytopathic effect (CPE) [24]. Briefly, confluent MDCK cell monolayers were infected with 100µL (100TCID 50 ) of virus suspension and incubated at 37 o C for about one hour to allow virus adsorption and then the virus was removed and the cells were treated with 25, 50 and 100 μg/mL of each extracts [24] supplemented with 2 μg/mL TPCK and 0.3% BSA (200μL/well).…”