Kyung Seop Ahn

Characteristic immunostimulation by angelan isolated from Angelica gigas Nakai.

The immunopharmacological characteristics of angelan, a polysaccharide purified from Angelica gigas Nakai, were investigated in relation to the specificity to immune cells. The treatment of angelan increased the expression of IL-2, IL-4, IL-6, and IFN-gamma. The expression of IL-6 and IFN-gamma was rapidly augmented but that of IL-2 responded later. In the case of IL-4, angelan stimulated at early time after exposure but down-regulated thereafter. These results suggested that macrophages and natural killer cells involved in nonspecific immunity were primarily activated and helper T cells were secondarily affected by angelan. Angelan also had lympho-proliferative potential to B cells, specifically. The specificity of angelan was also elucidated in a cell fractionation experiment. The activated B cells by angelan also increased antibody production. The direct activation of B cells, macrophages, and accessory cells and the indirect activation of helper T cells coordinately increased immune functions such as in vitro and in vivo T-dependent immunization and antibody production. The experiment of host resistance to syngeneic tumors also showed that angelan potentiated the immune functions. In conclusion, angelan, a purified polysaccharide from an oriental herbal drug, showed characteristic immunostimulation, which was different from clinically used polysaccharides such as lentinan and PSK.

Activation of NF-κB/Rel in angelan-stimulated macrophages

In our previous studies we showed that the primary target cell of angelan, a polysaccharide purified from Angelica gigas Nakai, is a macrophage (Han et al., 1998). In the present study we examined the effect of angelan on iNOS, IL-1β, and TNF-α transcription in mouse macrophage line RAW 264.7. We show that angelan produces a marked induction of iNOS, IL-1β, and TNF-α transcription by RAW 264.7 cells. Since these gene transcriptions have been recently shown to be under the control of NF-κB/Rel family of transcription factors, we assessed the effect of angelan on NF-κB/Rel using a electrophoretic mobility shift assay. Treatment of RAW 264.7 cells with angelan produced strong induction of NF-κB/Rel binding. Treatment of RAW 264.7 cells with angelan slightly induced AP-1 binding activity, whereas Oct binding was not affected by angelan. Angelan stimulated macrophages to activate NF-κB/Rel, whereas neither B-cells nor T-cells were affected by the angelan. In conclusion, we demonstrate that the stimulation effect of angelan on macrophage is mediated by specific activation of NF-κB/Rel.

Differential activation of murine macrophages by angelan and LPS

In our previous studies, we showed that angelan, a polysaccharide purified from Angelica gigas Nakai, is a potent LPS-mimetic in murine macrophages [Jeon, Y.J., Han, S.B., Ahn, K.S., Kim, H.M., 1999. Activation of NF-kB/Rel in angelan-stimulated macrophages. Immunopharmacology 43, 1-9]. Angelan stimulates murine macrophage to produce cytokines including iNOS and activate NF-kappaB/Rel. In the present study, we investigated the role of CD14 and complement receptor type 3 (CR3) in mediating NO production and NF-kappaB/Rel activation induced by angelan and LPS. Three major differences between angelan and LPS were observed. First, angelan does not require serum proteins for NO response and NF-kappaB/Rel activation, while the activation by LPS requires serum proteins. Second, blocking of either CD14 or CR3 decreased angelan-induced NO response, while LPS-mediated NO production was inhibited by anti-CD14 mAb only. Third, angelan induced strong NF-kappaB/Rel and slight AP-1 DNA binding, whereas LPS potently activated both NF-kappaB/Rel and AP-1. Both angelan and LPS degraded IkappaB proteins and subsequently induced the mobilization of NF-kappaB/Rel proteins (p65, c-rel and p50) into nucleus. This suggests that macrophages display a common signaling machinery leading to the NF-kappaB/Rel activation in response to different stimulants. In conclusion, angelan and LPS use the membrane receptor CD14 and CR3 differentially for signaling NF-kappaB/Rel activation and NO production.

In vitro anticomplementary activity of hederagenin saponins isolated from roots ofDipsacus asper

Anticomplementary activity of hederagenin and related saponins isolated fromDipsacus asper was investigatedin vitro. HN saponin F (3) was most potent with IC50 value of 3.7×10−5 M followed by 3-O-β-D-glucopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-β-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyrano side (8), 3-O-β-L-arabinopyranosyl hederagenin 28-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyrano side (5) dipsacus saponin A (4), and hederagenin (1) on the classical pathway (CP) of complement system, while the saponins3–5, did not show the inhibition of hemolysis and rather increase the hemolysis on the alternative pathway (AP). However, all of C-3 monodesmosides [prosapogenin CP (2), dipsacus saponin B (6), and dipsacus saponin C (7)] evoked hemolysis directly on the erythrocytes.

Enantioselective syntheses of decursinol angelate and decursin

Abstract The practical enantioselective syntheses of decursinol angelate and decursin were achieved in eight steps from resorcinol. The stereochemistry was addressed using the catalytic asymmetric epoxidation of 7-acetoxy-2,2-dimethylchromene by chiral (salen)Mn complexes as the key step.

Immunostimulating polysaccharide from cell culture of Angelica gigas Nakai

An immunostimulating polysaccharide was produced extracellularly by suspension cell culture of Angelica gigas Nakai. The polysaccharide was larger in molecular weight than that obtained from the extract of A. gigas root. It was mainly composed of arabinose, galactose, galacturonic acid, protein, Ca2+ and Mg2+, and stimulated the mixed lymphocyte reaction activity as potently as the polysaccharide obtained from the plant root.

Activation of mitogen-activated protein kinase pathways by angelan in murine macrophages

In our previous studies, we showed that angelan, a polysaccharide purified from Angelica gigas Nakai, specifically activated macrophages to induce cytokines including inducible nitric oxide synthase (iNOS) which has strong anti-tumor activities [Immunopharmacology, 1999; 43: 1.]. In the present study, we investigated the intracellular signal transduction pathways involved in the angelan-induced iNOS synthesis by murine macrophages. Protein tyrosine phosphorylation was induced within 5 min by angelan, and the blocking of protein tyrosine kinases (PTKs) inhibited down-stream pathways leading to iNOS production in response to angelan. Treament of RAW 264.7 cells with angelan resulted in significant activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and p38, while stress-activated protein kinase/c-Jun NH2 terminal kinase (SAPK/JNK) was not activated by angelan. The specific p38 inhibitor SB203580 abrogated the angelan-induced iNOS synthesis, whereas the selective mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1 (MEK-1) inhibitor PD98059 did not affect the iNOS induction. In conclusion, we demonstrate that PTK and p38 MAPK activation are required to transduce signals leading to iNOS expression in angelan-stimulated murine macrophages.

Anticomplement activities of oleanolic acid monodesmosides and bisdesmosides isolated fromTiarella polyphylla

Seven known oleanolic acid glycosides (1–7) were isolated from the MeOH extract ofTiarella polyphylla. The structures were identified to be 3-O-(β-D-glucopyranosyl) oleanolic acid (1), 3-O-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl] oleanolic acid (2), 3-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl] oleanolic acid (3), 3-O-[β-D-glucopyranosyl-(1→3)-β-D-glucopyranosyl] oleanolic acid 28-O-β-D-glucopyranosyl ester (4), 3-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl] lleanolic acid 28-O-β-D-glucopyranosyl ester (5), 3-O-[a-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl] oleanolic acid (6), and 3-O-[α-L-rhamnopyranosyl-(1→3)-β-D-glucuronopyranosyl] oleanolic acid 28-O-β-D-glucopyranosyl ester (7) on the basis of physicochemical and spectral data. These triterpene glycosides were tested for the anticomplement activity and hemolytic activity. Bisdesmosidic saponins,4, 5, and7, showed anticomplement activity; in contrast, monodesmosidic saponins,1–3, and6, showed direct hemolytic activity. Methyl esterified monodesmosidic saponins showed anticomplement activity at a low concentration and hemolytic activity at a high concentration.

Piscroside C, a novel iridoid glycoside isolated from Pseudolysimachion rotundum var. subinegrum suppresses airway inflammation induced by cigarette smoke.

ETHNOPHARMACOLOGICAL RELEVANCE Pseudolysimachion rotundum var. subintegrum (Speedwell, Plantaginaceae) is used as a traditional herbal medicine for treating bronchitis, cough and asthma in Korea, China, Russia, and Europe. AIM OF THE STUDY In this study, we investigated the protective effects of the novel iridoid glycoside, piscroside C (compound 1) isolated from the methanolic extract of P. rotundum var. subintegrum against inflammatory responses using a cigarette smoke induced chronic obstructive pulmonary disease (COPD) and TNF-α-stimulated human airway epithelial NCI-H292 cells. MATERIALS AND METHODS The novel iridoid glycoside piscroside C was isolated from the methanolic extract of P. rotundum var. subintegrum. The chemical structure was established by NMR, HRESIMS, and optical rotation. In in vivo experiment, the mice received 1h of cigarette smoke for 3 days. Piscroside C was administered to mice by oral gavage 1h before cigarette smoke exposure for 3 days. In in vitro experiment, we evaluated the effect of piscroside C on proinflammatory mediators in H292 cells stimulated with TNF-α. RESULTS Piscroside C significantly reduced the neutrophil influx, reactive oxygen species production, IL-6, TNF-α, and elastase activity in bronchoalveolar lavage fluid in COPD animals. In addition, piscroside C attenuated NF-κB and IκB phosphorylation, leading to reduced recruitment of inflammatory cells into the lung tissue. Consistent with the results of in vivo experiment, piscroside C significantly inhibited the expression of inflammatory cytokines (IL-6, IL-8 and IL-1β) by inhibiting NF-κB activation, as resulting decrease in the phosphorylation of IKKβ, IκBα and TAK1 in TNF-α-stimulated H292 cells. CONCLUSION These findings indicate that piscroside C effectively inhibits inflammatory responses, which is an important process in the development of COPD through suppression of IKK/NF-κB activation. Our study suggest that piscroside C might represent a useful therapeutic for the treatment of inflammatory airway disease.

Copper oxide nanoparticle induces inflammatory response and mucus production via MAPK signaling in human bronchial epithelial cells

Copper nanoparticles (CuONPs) can pose risks to industrial workers. With increase of its applications especially in electronic fields, it is necessary to assess the toxicity of CuONPs, including pulmonary toxicity. In this study, we investigated the effect of CuONPs on human epithelial cell line H292. CuONPs treatment caused a significant increase in IL-6 and IL-8 mRNA expression and protein levels in H292 cells in a concentration-dependent manner. The mRNA expression and protein levels of MUC5AC were consistent with those of proinflammatory mediators. Additionally, CuONPs treatment increased phosphorylation of mitogen-activated protein kinases (MAPKs), Erk, JNK, and p-38 compared to that of control in a concentration-dependent manner. However, co-treatment with CuONPs and each MAPK inhibitor significantly decreased the phosphorylation of each MAPK, resulting in decreased mRNA expression and protein levels of proinflammatory mediators and MUC5AC compared to that in H292 cells only treated with CuONPs. In summary, CuONPs-induced inflammatory mediators and MUC5AC associated with MAPKs phosphorylation. Our results will provide useful information on CuONPs-induced pulmonary toxicity.