Upper respiratory infection, especially in infants and children, is a common disease worldwide. Respiratory syncytial virus (RSV) has been recognized as a major cause of such infections.1) The nucleoside analog ribavirin has been used widely for treating RSV infections in healthcare settings such as hospitals and nursing homes. However, the treatment protocol, the potentially severe side effects and the emergence of drug-resistant mutants during long-term medication with this drug have often limited its administration to patients. 2)Therefore, the development of new antiviral agents with different mechanisms is most desirable. Traditional medicines utilizing natural products have been shown to contain antiviral compounds. [3][4][5][6][7] We screened for such compounds from natural products. In this paper, we report the isolation of active compounds from the whole herb of Selaginella sinensis (Selaginellaceae) and the content determination of amentoflavone in nine different species of Selaginella. Antiviral Assays The antiviral activity of test sample against RSV was measured by the plaque reduction assay. 8,9) Briefly, two-days old confluent monolayers of Hep 2 cells were infected with RSV at 100 plaque-forming units (PFU) per well in 0.5 ml maintenance medium . The inoculated cultures were incubated at 37°C in a CO 2 incubator with gentle agitation at 10-15 intervals to ensure uniform virus adsorption. Following 1 h virus adsorption, the inoculum was removed and 1.5 ml of agarose overlay medium containing 0.6% agarose in DMEM and 2% FBS were added to each well. When the agarose overlay became well-solidified, 1.5 ml of diluted test samples in maintenance medium were added to each well. A minimum of three different concentrations of each test sample was tested. One well per plate was added with 1.5 ml of maintenance medium without the test sample as control. The culture plates were incubated in the humidified CO 2 incubator for 4-5 d. The cultures were then fixed with 10% formalin in PBS and subsequently stained with 1% crystal violet in 20% ethanol upon removal of the agarose overlay. The number of plaques per well was enumerated macroscopically. The 50% inhibitory concentration (IC 50 ) was determined as the concentration of the test sample that reduced 50% of the plaque formation in the control wells. MATERIALS AND METHODS MaterialsExtraction and Isolation of Main Compound from the Herb of S. sinensis Air dried herb (5.0 kg) was extracted by refluxing with 90 l ethanol for three times, each time for 2 h. The ethanol solution was filtered and evaporated under reduced pressure to give a brownish ethanol extract (660 g). The ethanol extract was dissolved in water containing 0.5 N HCl and filtered. The precipitate was dissolved in water containing 0.5 N NaOH and filtered. The basic solution was adjusted to pH 1-3 with HCl, stayed overnight and filtered. The precipitate was washed with water to give a yellowish powder (195 g). Then this yellowish powder was extracted with chloroform, ethyl acetate and methanol by ...

Oleuropein is a phenolic secoiridoid glucoside widespread in members of the family Oleaceae. It has been shown to possess a wide range of biological activities. It increased coronary blood flow and showed antiarrhythmic and spasmolytic effects.1,2) Oleuropein exhibited hypoglycemic effect and increased tolerance of orally administered glucose. It also showed anti-oxidative and anti-inflammatory properties. [3][4][5][6][7] Other reported effects of oleuropein included the potentiation of cellular and organismal protection through the macrophage-mediated response, 4) the inhibition of platelet aggregation and eicosanoid production, 8) reduction of the low density lipoproteins (LDL) level, 9) the potent and protective antioxidant action on LDL, 10) the inhibitory effects on cytochrome P450 and 17b-hydroxysteroid dehydrogenase activity, 11) potent cytotoxic effects on tumor cell lines including P-388, L-1210. 12) inhibitory effects on of lipoxygenase activity, 13) and antibacterial functions. 14-18) Recently, oleuropein was also claimed in a U.S. patent to have potent antiviral activities against herpes mononucleosis, hepatitis virus, rotovirus, bovine rhinovirus, canine parvovirus and feline leukaemia virus. 19) On the other hand, But and his research team recently reported the isolation of oleuropein (4), lucidumoside C (1) and other secoiridoid glucosides from the fruits of Ligustrum lucidum, another member of Oleaceae.3) They demonstrated strong anti-oxidative effects in these secoiridoid glucosides (Table 1). Oleuropein and lucidumoside C were found to have stronger anti-oxidative potency than trolox, their IC 50 being 25.0, 9.3, and 55.0 mM, respectively. Based on such anti-oxidative capabilities and also the antiviral effects claimed in the U.S. patent, the authors suggested that "it would be interesting to check if oleuropein's antiviral effect is related to its anti-oxidant property and also if lucidumoside C has stronger antiviral function". 3)This suggestion actually posed two important questions: 1) is anti-oxidative potency of a compound correlated with its antiviral potency? and 2) is anti-oxidation a mechanism against viruses?In the present paper, we present the in vitro evaluation of six secoiridoid glucosides from the fruits of Ligustrum lucidum against herpes simplex type 1 virus (HSV-1), influenza type A virus (Flu A), respiratory syncytial virus (RSV) and parainfluenza type 3 virus (Para 3). The relationship of antiviral activities of secoiridoid glucosides with their anti-oxidative effects were analysed. Results and DiscussionThe six secoiridoid glucosides isolated from L. lucidum did not show any antiviral activities against Flu A and HSV-1, except oleoside dimethylester (2) which showed a little antiviral activity against HSV-1 (Tables 2, 3).The in vitro antiviral activities of the six isolated compounds against RSV are summarized in Table 4. Oleuropein showed potent anti-RSV activity with an IC 50 value of 23.4 mg/ml and a large therapeutic index comparable to that of ribavirin, an approved d...

From the antibacterial fraction of the roots of Garcinia kola, 3؆,4,4ٟ,5,5؆,7,7؆-heptahydroxy-3,8؆-biflavanone (GB1) was isolated as the major constituent, whose interesting conformations were studied on the basis of its 1D and 2D NMR spectra obtained at different temperatures and in different solvents. GB1 showed antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) with MIC of 32 and 128 m mg/ml, respectively.

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