Hong-Guang Jin

A new triterpenoid from Alisma orientale and their antibacterial effect

A new triterpenoid, named alisol Q 23-acetate, as well as fourteen known terpenes, alisol B 23-acetate (2), alisol B (3), alismol (4), 10-O-methyl-alismoxide (5), alismoxide (6), 11-deoxyalisol C (7), 13β,17β-epoxyalisol B 23-acetate (8), 4β,12-dihydroxyguaian-6,10-diene (9), alisol C 23-acetate (10), alisolide (11), 16β-methoxyalisol B monoacetate (12), alisol A (13), 16β-hydroxyalisol B 23-acetate (14), alisol A 24-acetate (15) were isolated from the rhizomes of Alisma orientale. The structures of compounds (1–15) were identified based on 1D and 2D NMR, including 1H-1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Among these isolates, antibacterial effect of compounds 2, 3, 10, and 15, major constituents of A. orientale was examined. The MIC values of compounds 2, 10, and 15 were 5–10 βg/mL against eight antibiotic resistant strains, which were lower than those from the positive controls (MICs of chloramphenicol and ampicillin were 5–80 μg/mL). Therefore, compounds 2, 10 and 15 exhibited the potent antibacterial activity.

The root barks of Morus alba and the flavonoid constituents inhibit airway inflammation

ETHNOPHARMACOLOGICAL RELEVANCE The root barks of Morus alba have been used in traditional medicine as an anti-inflammatory drug, especially for treating lung inflammatory disorders. AIM OF STUDY To find new alternative agents against airway inflammation and to establish the scientific rationale of the herbal medicine in clinical use, the root barks of Morus alba and its flavonoid constituents were examined for the first time for their pharmacological activity against lung inflammation. MATERIALS AND METHODS For in vivo evaluation, an animal model of lipopolysaccharide-induced airway inflammation in mice was used. An inhibitory action against the production of proinflammatory molecules in lung epithelial cells and lung macrophages was examined. RESULTS Against lipopolysaccharide-induced airway inflammation, the ethanol extract of the root barks of Morus alba clearly inhibited bronchitis-like symptoms, as determined by TNF-α production, inflammatory cells infiltration and histological observation at 200-400mg/kg/day by oral administration. In addition, Morus alba and their major flavonoid constituents including kuwanone E, kuwanone G and norartocarpanone significantly inhibited IL-6 production in lung epithelial cells (A549) and NO production in lung macrophages (MH-S). CONCLUSIONS Taken together, it is concluded that Morus alba and the major prenylated flavonoid constituents have a potential for new agents to control lung inflammation including bronchitis.

Anti-inflammatory Mechanism of 15,16-Epoxy-3α-hydroxylabda-8,13(16),14-trien-7-one via Inhibition of LPS-Induced Multicellular Signaling Pathways

Phytochemical investigation of Leonurus japonicus has led to the isolation of a labdane diterpene derivative, 15,16-epoxy-3α-hydroxylabda-8,13(16),14-trien-7-one (1), which was tested for its in vitro anti-inflammatory effects. The results demonstrated that 1 exhibits an inhibitory effect on LPS-stimulated RAW 264.7 macrophages. The anti-inflammatory action shown by 1 suppressed LPS-induced NF-κB activation, resulting in the down-regulation of iNOS and COX-2 protein expression, attributable to the inhibitory action of LPS-induced NO and PGE(2) production. Compound 1 inhibited LPS-induced phosphorylation and the degradation of inhibitory kappa B (IκBα) and decreased the nuclear translocation of p50 and p65. In addition, 1 exhibited an inhibitory effect on LPS-induced NF-κB-DNA and AP-1-DNA binding activity, using an electrophoretic mobility shift assay with NF-κB- and AP-1-specific (32)P-labeled probes. The LPS-induced mitogen-activated protein kinases (p-JNK, p-p38, and p-ERK) and p-Akt were inhibited after 30 and 10 min of LPS stimulation, respectively. In addition, TNF-α production was suppressed by 1.

Amentoflavone Stimulates Mitochondrial Dysfunction and Induces Apoptotic Cell Death in Candida albicans

Amentoflavone was isolated from an ethyl acetate extract of the whole plant of Selaginella tamariscina. It is a traditional herb for the therapy of chronic trachitis and exhibits some anti-tumor activity. Previously, we confirmed the antifungal effects of amentoflavone. The objective of this study was to investigate the antifungal mechanism(s) of amentoflavone, such as mitochondria-mediated apoptotic cell death. The cells that were treated with amentoflavone exhibited a series of cellular changes that were consistent with apoptosis: externalization of phosphatidylserine, DNA and nuclear fragmentation, accumulation of intracellular reactive oxygen species (ROS) and hydroxyl radicals, and activation of metacaspase. In addition, diagnostic markers of apoptosis, including the reduction of mitochondrial inner-membrane potential and the release of cytochrome c from mitochondria, were observed. These phenomena are important changes in mitochondria-mediated apoptosis. Furthermore, the effect of thiourea as hydroxyl radical scavenger on amentoflavone-induced apoptosis was evaluated. A hydroxyl radical is a more active ROS species. Mitochondrial dysfunction was inhibited, which was indicated by decreased levels of intracellular hydroxyl radicals. Taken together, our results present the first evidence that amentoflavone induces apoptosis in C. albicans cells and is associated with the mitochondrial dysfunction. Besides, amentoflavone-induced hydroxyl radicals may play a significant role in mitochondria-mediated apoptosis.

Phenolic compounds with IL-6 inhibitory activity from Aster yomena

A new biflavonoid, named asteryomenin (1), as well as six known phenolic compounds, esculetin (2), 4-O-β-d-glucopyranoside-3-hydroxy methyl benzoate (3), caffeic acid (4), isoquercitrin (5), isorhamnetin-3-O-glucoside (6), and apigenin (7) were isolated from the aerial parts of Aster yomena. The structures of compounds (1–7) were identified based on 1D and 2D NMR, including 1H–1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compounds 2–7 were isolated from this plant for the first time. For these isolates, the inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell was examined. Among these isolates, compounds 4 and 7 appeared to have potent inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell, while compounds 1–3 and 5–6 showed moderate activity.

Structural implication in cytotoxic effects of sterols from Sellaginella tamariscina

A bioassay-guided fractionation of the CH2Cl2 extract of Selaginella tamariscina yielded six sterols 1–6 such as (4α, 5α)-4, 14-dimethylcholest-8-en-3-one (1), ergosta-4, 6, 8(14), 22-tetraene-3-one (2), ergosterol endoperoxide (3), 7β-hydroxycholesterol (4), 7β-hydroxysitosterol (5), and 7α-hydroxysitosterol (6). The structures of isolated compounds were determined using spectroscopic methods. Among these isolates, compounds 2–5 showed potent cytotoxicity against five human tumor cells, while compounds 1 and 6 did not. In the case of compounds 1 and 2, 3-oxo sterol derivatives, compound 1 was inactive, but compound 2 showed potent cytotoxicity. In addition, compound 5 exhibited potent cytotxicity, but, compound 6 which is the 7-epimer of compound 5 was weakly active against tumor cell lines. Therefore, in the case of oxysterol derivatives, the cytotoxicity appeared to be affected by the structural differences, i.e. the configuration of hydroxyl group and the number of conjugated double bond. Taken all together, the present study isolated six sterols from S. tamariscina for the first time based on a bioassay-guided fractionation and indicated that isolated oxysterols could exhibit the cytotoxic effects against tumor cells, suggesting that S. tamariscina might be a promising candidate for the development of anticancer agents.

Chalcones isolated from Angelica keiskei and their inhibition of IL-6 production in TNF-α-stimulated MG-63 cell

Six chalcone compounds, 2′,4′,4-trihydroxy-3′-[2-hydroxy-7-methyl-3-methylene-6-octaenyl]chalcone (1), 2′,4′,4-trihydroxy-3′-geranylchalcone (2), 2′,4′,4-trihydroxy-3′-[6-hydroxy-3,7-dimethyl-2,7-octadienyl]chalcone (3), 2′,4-dihydroxy-4′-methoxy-3′-[2-hydroperoxy-3-methyl-3-butenyl]chalcone (4), 2′,4-dihydroxy-4′-methoxy-3′-geranylchalcone (5), and 2′,4-dihydroxy-4′-methoxy-3′-[3-methyl-3-butenyl]chalcone (6) were isolated from the leaves of Angelica keiskei K (Umbelliferae). The structure of each isolated compound was determined using spectroscopic methods. Among the isolates, compounds 1–3 appeared to have potent inhibitory activity of IL-6 production in TNF-α-stimulated MG-63 cell, while compounds 4–6 did not. The distinct structural difference between compounds 1–3 and 4–6 was the presence of C-4′ hydroxyl group in the chalcone moiety. Our results imply that the inhibitory activity of IL-6 production in TNF-α-stimulated MG-63 cell may be affected by the presence of C-4′ hydroxyl group in the chalcone moiety.

A new megastigmane glycoside from Akebia quinata

A new megastigmane glycoside, 8S*,9R*-megastigman-3-one-4,6-diene-8,9-diol-9-O-β-d-glucopyranoside, named akequintoside D (1), as well as six known compounds, roseoside II (2), 3-O-caffeoylquinic acid (3), methyl-3-O-caffeoylquinate (4), 3,4,5-trimethoxyphenyl-β-d-glucopyranoside (5), cuneataside D (6), 3,4-dimethoxyphenyl-6-O-(α-l-rhamnopyranosyl)-β-d-glucopyranoside (7) were isolated from the stem of Akebia quinata. The structures of compounds (1-7) were identified based on 1D and 2D NMR, including 1H–1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.

Isolation of virus-cell fusion inhibitory components from the stem bark of Styrax japonica S. et Z

Five compounds, styraxjaponoside A (1), matairesinoside (2), egonol glucoside (3), dihydrodehydrodiconiferyl alcohol 9′-O-glucoside (4), and styraxjaponoside B (5) were isolated from the stem bark of Styrax japonica. Among them, compounds 1 and 5 showed significantly high virus-cell fusion inhibitory activity. In addition, compound 5 exhibited almost equivalent virus-cell fusion inhibitory activity to that of dextran sulfate, which is used as a positive control.