Background: Human respiratory syncytial virus (hRSV) is a leading cause of severe lower respiratory infection and a major public health threat worldwide. To date, no vaccine or effective therapeutic agent has been developed. In a screen for potential therapeutic agents against hRSV, we discovered that an extract of Rosmarinus officinalis exerted a strong inhibitory effect against hRSV infection. Subsequent studies identified carnosic acid as a bioactive constituent responsible for anti-hRSV activity. Carnosic acid has been shown to exhibit potent antioxidant and anti-cancer activities. Anti-RSV activity of carnosic acid was further investigated in this study. Methods: Effects of extracts from various plants and subfractions from R. officinalis on hRSV replication were determined by microneutralization assay and plaque assay. Several constituents were isolated from ethyl acetate fraction of R. officinalis and their anti-RSV activities were assessed by plaque assay as well as reverse-transcription quantitative PCR to determine the synthesis of viral RNAs. Results: Among the tested bioactive constituents of R. officinalis, carnosic acid displayed the most potent anti-hRSV activity and was effective against both A- and B-type viruses. Carnosic acid efficiently suppressed the replication of hRSV in a concentration-dependent manner. Carnosic acid effectively suppressed viral gene expression without inducing type-I interferon production or affecting cell viability, suggesting that it may directly affect viral factors. A time course analysis showed that addition of carnosic acid 8 hours after infection still effectively blocked the expression of hRSV genes, further suggesting that carnosic acid directly inhibited the replication of hRSV. Conclusions: The current study demonstrates that carnosic acid, a natural compound that has already been shown to be safe for human consumption, has anti-viral activity against hRSV, efficiently blocking the replication of this virus. Carnosic acid inhibited both A- and B- type hRSV, while it did not affect the replication of influenza A virus, suggesting that its antiviral activity is hRSV-specific. Collectively, this study suggests the need for further evaluation of carnosic acid as a potential treatment for hRSV.

Alzheimer's disease (AD) is a neurodegenerative disorder associated with progressive memory loss and neuronal cell death. Although numerous previous studies have been focused on disease progression or reverse pathological symptoms, therapeutic strategies for AD are limited. Alternatively, the identification of traditional herbal medicines or their active compounds has received much attention. The aims of the present study were to characterize the ameliorating effects of spinosin, a C-glucosylflavone isolated from Zizyphus jujuba var. spinosa, on memory impairment or the pathological changes induced through amyloid-β1-42 oligomer (AβO) in mice. Memory impairment was induced by intracerebroventricular injection of AβO (50 μM) and spinosin (5, 10, and 20 mg/kg) was administered for 7 days. In the behavioral tasks, the subchronic administration of spinosin (20 mg/kg, p.o.) significantly ameliorated AβO-induced cognitive impairment in the passive avoidance task or the Y-maze task. To identify the effects of spinosin on the pathological changes induced through AβO, immunohistochemistry and Western blot analyses were performed. Spinosin treatment also reduced the number of activated microglia and astrocytes observed after AβO injection. In addition, spinosin rescued the AβO-induced decrease in choline acetyltransferase expression levels. These results suggest that spinosin ameliorated memory impairment induced through AβO, and these effects were regulated, in part, through neuroprotective activity via the anti-inflammatory effects of spinosin. Therefore, spinosin might be a useful agent against the amyloid b protein-induced cognitive dysfunction observed in AD patients.

The present investigation of the chemical constituents of the stem barks of Ailanthus altissima has resulted in the isolation of six canthinone-type alkaloids, including a new compound, (R)-5-(1-hydroxyethyl)-canthine-6-one (1), and five known compounds (2–6). Moreover, four phenyl propanoids (7–10), two lignans (11 and 12), two triterpenoids (13 and 14) and a fatty acid (15) having previously known chemical structures were isolated during the same course of this study. The structure of the new compound was elucidated by physical (m.p., [α]_D) and spectroscopic data (¹H-NMR, ¹³C-NMR, 2D NMR, and HR-DART-MS) interpretation and its absolute configuration was determined by electronic circular dichroism (ECD) data and quantum chemical calculations. The inflammatory activities of the isolates were screened on lipopolysaccharide (LPS)-induced nitric oxide (NO), a proinflammatory mediator, in RAW 264.7 cells. Among these isolated compounds, six compounds exhibited significant inhibition of NO production, with IC₅₀ values in the range of 5.92 ± 0.9 to 15.09 ± 1.8 μM.