Cladogynos orientalis Zipp. extracts inhibit cell culture-derived hepatitis C virus genotype 2a replication in Huh-7 cells through NS5B inhibition

Objective: To evaluate the potential anti-hepatitis C virus (HCV) activities of Cladogynos orientalis Zipp. ex Span and to investigate the molecular mode of action. Methods: Ethanolic and water extracts from various parts of Cladogynos orientalis were examined for cytotoxicity by MTT assay. Sub-cytotoxic concentrations of the extracts were used for further determining anti-HCV activity using cell culture-derived HCV genotype 2a propagated in HepaRG cell line. Immunofluorescence assay was performed to observe the effect on viruses at the pre-entry step. Mode of action at the post-entry step was investigated for the viral RNA and protein expressions by real time RT-PCR and Western blotting assays, respectively. Results: Although Cladogynos orientalis water extracts exhibited lower cytotoxicity than ethanolic extracts, all ethanolic extracts from roots, stems, and leaves of Cladogynos orientalis exhibited higher anti-HCV activities than water extracts. The highest anti-HCV activity was observed in infected cells treated with the extracts 5 h after absorption. No extracts showed pre-viral entry effect. At the post-viral entry step, only leaf ethanolic extracts inhibited NS5B expression, while all extracts did not inhibit HCV NS3 expression. Conclusions: Cladogynos orientalis ethanolic extracts could be further studied and the major active compound needs to be identified as a promising source for anti-HCV agents.

Antioxidant activity of Acanthopanax trifoliatus

The aim of this study was to investigate the antioxidant activity of extracts of various parts of Acanthopanax trifoliatus obtained by different extraction methods. The total phenolic and flavonoid contents of the extracts were also determined. The leaves, stems, stembark, roots and root bark of A. trifoliatus were extracted separately using decoction, maceration and refluxing methods. The extracts were analysed for free-radical-scavenging activity using the 1,1-diphenyl-2-picryl-hydrazyl scavenging assay and the thiobarbituric-acid-reactive substance method for the inhibition of lipid peroxidation of a rat brain homogenate. Total phenolic and total flavonoid contents of the extracts were measured by UV spectrophotometry. The leaf decoction extracts possessed a significantly stronger antioxidant activity as revealed by both methods. Total phenolic and flavonoid contents of the extracts were measured by UV spectrophotometry. The leaf decoction extracts possessed a significantly stronger antioxidant activity as revealed by both methods. Total phenolic and flavonoid contents of the extracts ranged from 2.16 to 21.79 g% chlorogenic acid equivalent and from 0.37 to 9.61 g% rutin equivalent, respectively. Analysis of the leaf decoction extract, which exhibited the most potent antioxidant activity, by thin-layer chromatography revealed flavonoid and polyphenolic compounds corresponding to rutin and chlorogenic acid. The leaf aqueous extracts showed a high level of antioxidative activity and contained high levels of both phenolic and flavonoid compounds. The magnitude of antioxidant activity corresponded with the level of phenolic and flavonoid compounds

Comparison of free radical scavenging activity of siamese neem tree [azadirachta indica A. juss var. siamensis valeton] leaf extracts prepared by different methods of extraction

The aim of this study was to investigate the antioxidant activity of the aqueous extracts of leaves of Siamese neem tree [Azadirachta indica A. Juss var. siamensis Valeton] from several extracting and drying methods using 2,2-diphenyl-1-picrylhydrazyl [DPPH]-scavenging assay. The leaves of Siamese neem tree were extracted using percolation, decoction, maceration, soxhlet extraction, freeze drying or spray drying methods. The extract was tested for antioxidant activity using DPPH-scavenging assay. Thin-layer chromatography of the extract from decoction was also investigated. The freeze drying method gave the highest yield [51.50%, w/w] of crude extract, while decoction gave the most effective DPPH-scavenging activity [EC[50]: 31.4 micro g/ml]. Thin-layer chromatography analysis was used to screen the leaf extract obtained using decoction, and the chromatogram showed spots corresponding to quercetin and rutin flavonoids which exhibited antioxidant activities [EC[50]: 2.29 and 34.67 micro g/ml, respectively]. Siamese neem tree leaf extracts possessed free radical scavenging activity against the DPPH radical. The most active extract was obtained with the leaf decoction method. It showed antioxidant activity with EC[50] of 31.4 micro g/ml