Dammarane-type saponins from Gynostemma pentaphyllum.

Seven dammarane glycosides, gypenosides GC1 to GC7, together with ten known compounds, gypenosides V, XIV, XLII-XLVI, gynosaponins TN-1, -2, and gymnemaside VI, were isolated from the methanol extract of the aerial parts of Gynostemma pentaphyllum. Their structures were elucidated by both analysis of 1D and 2D NMR spectra and chemical degradation.

Platelet-activating factor (PAF) receptor binding antagonists from Alpinia officinarum.

The bioassay-guided purification of ether extracts of Alpinia officinarum led to the isolation of two new compounds 6-hydroxy-1,7-diphenyl-4-en-3-heptanone (1) and 6-(2-hydroxy-phenyl)-4-methoxy-2-pyrone (4) as well as three known compounds 1,7-diphenyl-4-en-3-heptanone (2), 1,7-diphenyl-5-methoxy-3-heptanone (3), and apigenin (5). Their structures were established on the basis of spectral methods. All three diarylheptanoids 1, 2, and 3 exhibited potent PAF receptor binding inhibitory activities with an IC(50) of 1.3, 5.0, and 1.6 microM, respectively. These studies have identified diarylheptanoids as a novel class of potent PAF antagonists.

The inhibitory effect of triterpenoid glycosides originating from Sanguisorba officinalis on tissue factor activity and the production of TNF-alpha.

We examined the inhibitory effects of novel triterpene glycoside compounds [ziyu-glycoside II (ZY-II) and its methyl ester (ZYM-201)], which originated from the roots of sanguisorba officinalis L. (Rosaceae), on tissue factor (TF) activity and tumor necrosis factor (TNF)-alpha production. In in vitro TF activity tests, ZY-II but not ZYM-201 strongly blocked lung TF activity with an IC50 value of 0.46 microM. By contrast, only ZYM-201 dose-dependently inhibited in vivo TF activity with an ED50 value of 1.7 mg/kg, when orally administered. Furthermore, ZYM-201 diminished both in vitro and in vivo TNF-alpha production with IC50 or ED50 values of 69.4 microM and 87.4 mg/kg, respectively. Therefore, these results suggest either that ZYM-201 may be developed as a potent inhibitor of both TF- and TNF-alpha-mediated diseases such as atherosclerosis and septic shock, or it may be a lead compound to be derivatized for further improvement of its curative efficacy.

Preventive effect of Ginkgo biloba extract (GBB) on the lipopolysaccharide-induced expressions of inducible nitric oxide synthase and cyclooxygenase-2 via suppression of nuclear factor-kappaB in RAW 264.7 cells.

During our ongoing efforts to identify bioactive natural products with anti-inflammatory activity, we produced an extract from Ginkgo biloba (GBB) which contains higher levels of the active principles terpene and biflavonoid than EGb, the standard commercially available extract. In the present study, we examined and compared the effects of these two extracts on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by the RAW 264.7 macrophage cell line. Our data indicate that GBB is a more potent inhibitor of NO and PGE2 production than EGb 761, and it also significantly decreased tumor necrosis factor (TNF)-alpha release. Consistent with these observations, the protein and mRNA expression levels of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) were found to be inhibited by GBB in a dose-dependent manner. Furthermore, GBB inhibited the LPS-induced DNA binding activity of nuclear factor-kappaB (NF-kappaB), which was associated with the prevention of IkappaB degradation, and subsequently with decreased p65 protein level in the nucleus. These results suggest that GBB inhibits LPS-induced iNOS, COX-2 and TNF-alpha expressions through the down-regulation of NF-kappaB-DNA binding activity.

Control of cytokine gene expression by PG101, a water-soluble extract prepared from Lentinus lepideus.

A water-soluble extract from Lentinus lepideus mycelium, named PG101, has been shown to control the expression of various cytokines [M. Jin, H.J. Jung, J.J. Choi, H.Jeon, J.H. Oh, B. Kim, S.S. Shin, J.K. Lee, K. Yoon, S. Kim, Activation of selective transcription factors and cytokines by water-soluble extract from Lentinus lepideus, Exp. Biol. Med. (Maywood) 228 (2003) 749-758]. To understand its molecular mechanism(s), PG101-mediated activation of cytokines was studied at the RNA and protein levels. Results from Northern blot analysis indicated that the steady-state RNA levels of TNF-alpha and seven other cytokines were highly increased in human peripheral blood mononuclear cells treated with PG101. The RNA level of TNF-alpha, MIP-1alpha, MIP-1beta, MIP-3alpha, and IL-8 was not affected by the presence of cycloheximide, an inhibitor of the translation process, suggesting that they are the direct targets of PG101. A significantly high protein level of TNF-alpha, MIP-1alpha, and IL-8 remained detectable, even when cells were cultured with actinomycin D, 2h prior to the PG101 treatment. Our data indicate that PG101 controls selective cellular proteins, which play key roles in the innate immune system, at the transcriptional and post-translational levels.

Neuroprotective effects of naturally occurring biflavonoids.

We examined neuroprotective effects of naturally occurring biflavonoids on oxidative stress-induced and amyloid beta peptide-induced cell death in neuronal cells. Among the nine biflavonoids tested, amentoflavone, ginkgetin, and isoginkgetin exhibited strong neuroprotection against cytotoxic insults induced by oxidative stress and amyloid beta, suggesting their therapeutic potential against neurodegenerative diseases, including ischemic stroke and Alzheimer's disease.

A new antipsychotic effective neolignan from Firmiana simplex.

A new neolignan, named simplidin was isolated from the the n-butanol extract of stem of Firmiana simplex, together with six known compounds, scopoletin (1), syrigaresinol (2), aquillochin (3), nitidanin (4), tamarixetin 3-rhamnoside (6), and quercitrin (7). On the basis of spectral and chemical evidence, simplidin (5) was determined to be rel-(7R,8R)-4,5,9,9'-tetrahydroxy-3,3'-dimethoxy-7-O-5',8-O-4'-neolignan. All the six compounds were also isolated for the first time from this plant.

Inhibition of calmodulin-dependent protein kinase II by cyclic and linear peptide alkaloids from Zizyphus species.

The effects of sedative peptide alkaloids from Zizyphus species on calmodulin- dependent protein kinase II were investigated. Protein kinase II activity was assayed on the basis of its ability to activate tryptophan 5-monooxygenase as its substrate in the presence of calmodulin. All thirteen alkaloids tested were stronger inhibitors than chlorpromazine (IC50, 98 microM) on calmodulin-dependent protein kinase II. Among them, the most potent inhibitor was daechuine S27 (IC50 2.95 microM), which was stronger than pimozide (IC50, 15.0 microM).

Tissue factor inhibitory sesquiterpene glycoside from Eriobotrya japonica.

Tissue factor (TF, tissue thromboplastin) is a membrane bound glycoprotein, which accelerates the blood clotting, activating both the intrinsic and the extrinsic pathways to serve as a cofactor for activated factor VII (VIIa). The TF-factor VIIa complex (TF/VIIa) proteolytically activates factors IX and X, which leads to the generation of thrombin and fibrin clots. In order to isolate TF inhibitors, by means of a bioassay-directed chromatographic separation technique, from the leaves of Eriobotrya japonica Lindley (Rosaceae), a known sesquiterpene glycoside (2) and ferulic acid (3) were isolated as inhibitors that were evaluated using a single-clotting assay method for determining TF activity. Another sesquiterpene glycoside (1) was also isolated but was inactive in the assay system. Compound 3 was yielded by alkaline hydrolysis of compound 2. The structures of compounds 1, 2, and 3 were identified by means of spectral analysis as 3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-glucopyranosyl nerolidol (1), 3-O-alpha-L-rhamnopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-(4-trans-feruloyl)-rhamnopyranosyl-(1-->6)]-beta-D-glucopyranosyl nerolidol (2) and ferulic acid (3), respectively. Compounds 2 and 3 inhibited 50% of the TF activity at concentrations of 2 and 369 microM/TF units, respectively.

Antirheumatoid arthritis effect of Rhus verniciflua and of the active component, sulfuretin.

Oral administration of the MeOH extract of Rhus verniciflua or of an EtOAc fraction containing an EtOAc-soluble portion of the MeOH extract slightly decreased rheumatoid arthritis (RA) and C-reactive protein (CRP) factors in Freund's complete adjuvant reagent FCA-treated rats, indicating that they are active extracts for rheumatoid arthritis, the EtOAc extract being more active. Treatment with these two extracts prevented histological changes such as synovial cell proliferation, inflammatory cell infiltration and fat necrosis compared with an FCA-treated group. Oral administration (30 mg/kg) of sulfuretin and fustin, which were isolated from the EtOAc extract by activity-guided separation, significantly decreased RA and CRP factors, the former being more active than the latter. Treatment with the EtOAc fraction ( p. o.) containing sulfuretin significantly decreased malondialdehyde (MDA) formation, and highly increased the activities of superoxide dismutase, catalase and glutathione peroxidase. Inhibition of xanthine oxidase and aldehyde oxidase in FCA-treated rats was also evident. Since treatment with sulfuretin and the EtOAc extract decreased the concentration of infiltrated mast cells in the rat knee exhibiting rheumatoid arthritis, we suggest that the Rhus verniciflua extract, which contains sulfuretin as an active component, may prevent rheumatoid syndromes by inhibiting reactive oxygen species.

Peroxynitrite scavenging activity of lithospermate B from Salvia miltiorrhiza.

Peroxynitrite (ONOO-) is produced by the reaction of superoxide (O2-) with nitric oxide. ONOO- damages proteins through nitration or oxidation. For protection from ONOO- induced protein modifications, ONOO- scavengers should be supplemented. Evidence was obtained that lithospermate B extracted from Salvia miltiorrhiza showed the strongest scavenging activity among its constituents. Its ONOO- scavenging activity is via an electron donation mechanism. A dihydroxyl group and a double bond seem to be essential structure requirements. The data from the experiments further confirmed a protective effect of lithospermate B on bovine serum albumin and low-density lipoprotein against ONOO-. This study demonstrated that lithospermate B with hydroxyl groups and double bonds exerts an anti-nitration effect by scavenging ONOO-.

A new in vitro tissue factor inhibitory triterpene from the fruits of Chaenomeles sinensis.

Tissue factor (TF, tissue thromboplastin) accelerates the blood clotting, activating both the intrinsic and the extrinsic pathways to serve as a cofactor. In order to isolate TF inhibitors from the fruits of Chaenomeles sinensis, an activity-guided purification was carried out to yield four triterpenoid compounds. One compound was new and its structure was elucidated as 28-O-beta- D-glucopyranosyl-2alpha,3beta-dihydroxyolean-12-ene-24,28-dioic acid (2), named chaenomeloside A by means of spectral analysis and chemical conversion. Other compounds were trachelosperoside A-1 (1), oleanolic acid (3) and ursolic acid (4). Compound 2 and its aglycone 2a, named chaenomelogenin A inhibited by 50 % the TF activity at concentrations of 0.036 and 0.028 mM/unit of TF, respectively. Compound 1 isolated for the first time from this plant as well as 3 and 4 were inactive.

Peroxynitrite scavenging activity of herb extracts.

Peroxynitrite (ONOO(-)) is a cytotoxicant with strong oxidizing properties toward various cellular constituents, including sulphydryls, lipids, amino acids and nucleotides and can cause cell death, lipid peroxidation, carcinogenesis and aging. The aim of this study was to characterize ONOO(-) scavenging constituents from herbs. Twenty-eight herbs were screened for their ONOO(-) scavenging activities with the use of a fluorometric method. The potency of scavenging activity following the addition of authentic ONOO(-) was in the following order: witch hazel bark > rosemary > jasmine tea > sage > slippery elm > black walnut leaf > Queen Anne's lace > Linden flower. The extracts exhibited dose-dependent ONOO(-) scavenging activities. We found that witch hazel (Hamamelis virginiana L.) bark showed the strongest effect for scavenging ONOO(-) of the 28 herbs. Hamamelitannin, the major active component of witch hazel bark, was shown to have a strong ability to scavenge ONOO(-). It is suggested that hamamelitannin might be developed as an effective peroxynitrite scavenger for the prevention of ONOO(-) involved diseases.

Antinociceptive and anti-rheumatoidal effects of Kalopanax pictus extract and its saponin components in experimental animals.

In the present study, we have attempted to elucidate the active components for rheumatoidal arthritis using chloroform (CHCl(3)), ethylacetate (EtOAc) and n-butanol (BuOH) fractions of the methanol extract (MeOH) of Kalopanax pictus. Kalopanaxsaponin-A and -I (KPS-A and -I, hederagenin monodesmoside) were isolated from EtOAc fraction and kalopanaxsaponin-B, -H and -K (KPS-B, -H and -K, hederagenin bisdesmosides) obtained from BuOH fraction, respectively. MeOH extract, EtOAc fraction (250, 500 mg/kg, p.o.) and KPS-A and -I (5, 10, 20 mg/kg, i.p.) exhibited significant antinociceptive effects, which were determined by acetic acid-induced writhing test and hot plate test. On Freund's complete adjuvant reagent-induced rheumatoidal arthritis in rats, the administration of EtOAc fraction and KPS-A and -I inhibited edema, agglutination, vascular permeability and trypsin inhibitor. In addition, LD(50) of the MeOH extract was shown to be 4.033 mg/kg. These results suggest that anti-rheumatoidal effects of KPS-A and -I contribute to the inhibition of kinin formation by suppression of trypsin inhibitor activity.

Tissue factor inhibitory flavonoids from the fruits of Chaenomeles sinensis.

Tissue factor (TF, tissue thromboplastin or coagulation factor III) accelerates the blood clotting, activating both the intrinsic and the extrinsic pathways to serve as a cofactor. In order to isolate TF inhibitors from the fruits of Chaenomeles sinensis, an activity-guided purification utilizing a bio-assay method of prothrombin time prolongation, was carried out to yield five active flavoniods such as hovetrichoside C (1) (IC50 = 14.0 microg), luteolin-7-O-beta-D-glucuronide (3) (IC50 = 31.9 microg), hyperin (4) (IC50 = 20.8 microg), avicularin (6) (IC50 = 54.8 microg) and quercitrin (10) (IC50 = 135.7 microg), along with other inactive compounds such as (+/-)-(2E,4E-O-beta-D-glucopyranosyl-4'-hydroxy-beta-ionylideneacetic acid ester (2), genistein-7-O-beta-D-glucopyranoside (5), luteolin-3'-methoxy-4'-O-beta-D-glucopyranoside (7), luteolin-7-O-beta-D-glucuronide methyl ester (8), tricetin-3'-methoxy-4'-O-beta-D-glucopyranoside (selagin-4'-O-beta-D-glucopyranoside) (9), (-)-epicatechin (11), luteolin-4'-O-beta-D-glucopyranoside (12) and apigenin-7-O-beta-D-glucuronide methyl ester (13). The structures of the isolated compounds were elucidated through spectral analysis. Among them, compounds 1 to 9,12 and 13 were isolated for the first time from the fruits of this plant and the compound 9 is a new flavonoid.