Studies on Chemicai Constituents of Fritillaria thunbergii Miq.

In our previous paper, it was reported that peimine, peiminine and a new alkaloid, Zhebeinine, were isolated from the bulbs of Fritillaria thunbergii Miq. In consecutive investigation of the plant, an additional new alkloid, 5α, 14α-cevanine-3β-hydroxy-6-one, named zhebei rine(2) and a known eduardine (1) were isolated and the structure of zhebeirine was determined on the basis of spectral analysis. Eduardine(1) was firstly isolated from the bulbs.     

Studies on Chemical Constituents of Fritillaria yuminensis

Six compounds were isolated from the bulbs of Fritillaria yuminensis X. Z. Duan. They were elucidated as 5α, 14α-cevanine-3α-hydroxy-6-one ( Ⅰ ), 5α, 14α-cevanine-3-one-6β-O-β-D-glucoside ( Ⅱ ), imperialine ( Ⅲ ), delavinone ( Ⅳ ), tortifolisine ( Ⅴ ) and adenosine( Ⅵ ) by means of spectral analysis and chemical reaction. They all were firstly isolated from this plant. Among them, compound Ⅰ and Ⅱ, named yubeinine and yubeiside respectively, were new compounds.     

New Steroidal Saponin of Stem and Leaf of Fritillaria ussuriensis Maxim

A new steroidal saponin, pingpeisaponin, was isolated from stem and leaf of Fritillaria ussuriensis Maxim by column chromatographic technique. On the basis of the IR, MS, 1H NMR and 13C NMR spectra of pingpei saponin, the structure has been established as 24α-hydroxyl diosgenin-3-O-α-L-rhomno-pyranosyl-(l-2)-β-D-glucopyranoside.     

Two steroidal alkaloids from fritillaria harelinii

Two new steroidal alkaloids named harepermine and hareperminside have been isolated from the bulbs of Fritillaria harelinii together with a known alkaloid, peiminine. The structure of the alkaloids were found to be 3β, 6β-dihydroxy-5α, 14α,17β-cevanine and its 3-O-glucoside on the basis of spectroscopic evidence.     

Studies on the Chemical Constituents of Fritillaria pallidiflora Schrenk

Six steroid alkaloids, imperialine (Ⅰ), imperialine-3β-D-glucoside (Ⅱ), peimissine (Ⅲ), imperialine N-oxide (Ⅳ), cycloparnine (Ⅴ), and cycloposine (Ⅵ) were isolated from the bulbs of Fritillaria pallidiflora Schrenk. Their structures were determined from spectral data and chemical evidences. Imperialine N-oxide was first obtained from nature.     

Studies of Songbeinone,A New Fritillaria Alkaloid Identified from the Bulb of Fritillaria unibracteata

A compound C was isolated from the dry bulbs of Fritillaria unibracteata Hsiao et K. C: Hsia which belongs to a main resource species of traditional Chinese drug “Chuan Bei-mu” in Chinese Pharmacopoeia (1990 ed.). It was identified as D/E cis(22R, 25S)-20-deoxy-3β-hydroxyl-6-carbonyl-5α, 14α, 17β-cevanine by means of spectroscopic methods. It is a new alkaloid of 5α-cevanine group of isosteroidal alkaloids being attributed to the characteristic constituents of this genus, named as songbeinone.     

Neuroprotective Kaurane Diterpenes from Fritillaria ebeiensis

The new kaurane diterpene, ent-3β-butanoyloxykaur-15-en-17-ol, and four known kaurane diterpenes were isolated from the bulbs of Fritillaria ebeiensis. Their structures were elucidated on the basis of extensive spectroscopic analyses (IR, ESI-MS, HR-ESI-MS, 1-D and 2-D NMR). All the isolates showed neuroprotective effects against MPP(+)-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.     

Camtschatcanidine,an alkaloid from Fritillaria camtschatcensis

From the hydrolysed glycoalkaloid fraction from bulbs of mature Fritillaria camtschatcensis in addition to already reported alkaloids a new solanidanine alkaloid, 22 R,25 S-solanid-5-ene-3β,27-diol (camtschatcanidine), was isolated and its structure elucidated by spectral analysis and its conversion to solanidine. Also veralkamine was identified from the same plant.     

Studies on Chemical Constituents of the Plant Fritillaria unibracteata

The plant Fritillaria unibracteata Hsiao et K. CHsia of the family Liliaceae is an elemental species of traditional Chinese drug "Chuan Beimu" in Chinese Pharmacopoeia. Four compounds(C, D, E,F) have been isolated from its medicinal part (dried bulb). The latter three compounds were identified as D/E cis(22R, 25s)-20- deoxy-3β,6β-dihydroxy-5α,14α, 17β-cevanine(D), β-sitcsterol (E), stearic acid and palmitic acid(F) by mean of spectroscopic methods. Compound D belongs to a new alkaloid of cevine group of isosteroidal alkaloids which is attributed to the characteristic constituent of this genus, named as songbeinine.     

披针叶胡颓子中的一个新木脂素

从披针叶胡颓子（Elaeagnus lanceolata）的干燥枝叶中分离得到19个化合物,其中isoamericanol B（1）为一新化合物,经波谱学方法鉴定其结构为rel-（7′Z）-（7β,8α）-3-methoxy-4,9′-dihydroxy-3′,7-epox-y-8,4′-oxyneolign-7′-ene。     

Regulatory domain of human protein kinase Cα dominantly inhibits protein kinase Cβ-I regulated growth and morphology in Saccharomyces cerevisiae

This study demonstrates that the isolated regulatory (R) domain (amino acids 1–270) of human protein kinase Cα (PKCα) is a potent inhibitor of PKCβ-I activity in a yeast expression system. The PKCα R domain fused to glutathione-S-transferase competitively inhibited the activity of yeast-expressed rat PKCβ-I in vitro (Ki = 0.2 μM) and was 400-fold more potent than a synthetic pseudosubstrate peptide corresponding to amino acids 19–36 from PKCα. In contrast, the fusion protein did not affect the activity of the purified catalytic subunit of cAMP-dependent protein kinase. The PKCα R domain (without glutathione-S-transferase [GST]) also was tested for its ability to inhibit PKCβ-I activity in vivo, in a yeast strain expressing rat PKCβ-I. Upon treatment with a PKC-activating phorbol ester, yeast cells expressing rat PKCβ-I were growth-inhibited and a fraction of the cells appeared as long chains. Coexpression of the R domain with rat PKCβ-I blocked the phorbol ester-induced inhibition of yeast cell growth and the phorbol ester-dependent alterations in yeast cell morphology. These results indicate that the R domain of PKCα acts as a dominant inhibitor of PKC activity in vivo and thus provides a useful genetic tool to assess the roles of PKC in various signal transduction processes. © 1996 Wiley-Liss, Inc.     

Fritillaria ussuriensis extract inhibits the production of inflammatory cytokine and MAPKs in mast cells

Fritillaria ussuriensis (FU, derived from the bulbs of various species of the genus Fritillaria, including Fritillaria thunbergii Miq.) is used in herbal medicine to treat conditions such as eczema, skin burns, and frostbite. In this study, we investigated the mechanism of the anti-allergy effect of FU. FU extract (80 mg/kg), orally administered to Sprague-Dawley (SD) rats, significantly inhibited the passive cutaneous anaphylaxis (PCA) reaction. It inhibited the compound 48/80-induced release of histamine from rat peritoneal mast cells in a concentration-dependent manner. Significant inhibitory effects of the FU extract on IL-6, IL-8, and TNF-α (1, 10, and 100 μg/mL) were observed in HMC-1 cells. Treatment with FU attenuated PMA plus A23187-induced phosphorylation of all three MAPKs, especially at concentrations of 10 and 100 μg/mL. Further, it (80 mg/kg) led to significant inhibition of mast-cell accumulation in ear tissue at the chronic phase. These results indicate that it inhibits allergic reactions.     

Isolation of 20 alpha and 20 beta 5 beta-pregnane-3 alpha,17 alpha,20,21-tetrol (hexahydro-Reichstein's compound-S) in a case of congenital adrenal hyperplasia

5β-Pregnane-3α, 17α, 20α, 21-tetrol (l) and 5β-pregnane-3α, 17α 20β, 21-tetrol (II) have been isolated and identified from the urine of a girl with congenital adrenal hyperplasia. The total 5β-pregnane-3α, 17α, 20(α+β),21-tetrol consisted of 60% of I and 40% of II. The final identity of the compounds was established by gas chromatography — mass spectrometry. The mass spectra of the two trimethylsilyl isomers were closely related to each other in contrast to the spectra of five other pairs of C₂₁-C-20(α and β)-hydroxy steroid-trimethylsilyl-ethers. The mass spectra of free I and II also exhibited many common features, but were less similar to each other than their trimethylsilyl derivatives.     

Combined effects of interleukin-1α and transforming growth factor-β1 on modulation of human cardiac fibroblast function

During cardiac remodeling, cardiac fibroblasts (CF) are influenced by increased levels of interleukin-1α (IL-1α) and transforming growth factor-β1 (TGFβ1). The present study investigated the interaction between these two important cytokines on function of human CF and their differentiation to myofibroblasts (CMF). CF were isolated from human atrial appendage and exposed to IL-1α and/or TGFβ1 (both 0.1 ng/ml). mRNA expression levels of selected genes were determined after 6–24 h by real-time RT-PCR, while protein levels were analyzed at 24–48 h by ELISA or western blot. Activation of canonical signaling pathways (NFκB, Smad3, p38 MAPK) was determined by western blotting. Differentiation to CMF was examined by collagen gel contraction assays. Exposure of CF to IL-1α alone enhanced levels of IL-6, IL-8, matrix metalloproteinase-3 (MMP3) and collagen III (COL3A1), but reduced the CMF markers α-smooth muscle actin (αSMA) and connective tissue growth factor (CTGF/CCN2). By contrast, TGFβ1 alone had minor effects on IL-6, IL-8 and MMP3 levels, but significantly increased levels of the CMF markers αSMA, CTGF, COL1A1 and COL3A1. Co-stimulation with both IL-1α and TGFβ1 increased MMP3 expression synergistically. Furthermore, while TGFβ1 had no effect on IL-1α-induced IL-6 or IL-8 levels, co-stimulation inhibited the TGFβ1-induced increase in αSMA and blocked the gel contraction caused by TGFβ1. Combining IL-1α and TGFβ1 had no apparent effect on their canonical signaling pathways. In conclusion, IL-1α and TGFβ1 act synergistically to stimulate MMP3 expression in CF. Moreover, IL-1α has a dominant inhibitory effect on the phenotypic switch of CF to CMF induced by TGFβ1.     

Discovery of natural estrogen receptor modulators with structure-based virtual screening

Eleven compounds were identified as estrogen receptor modulators from an in-house natural product database (NPD) by structure-based virtual screening for ERα and ERβ. Among them, 3 compounds were confirmed as ER agonists and 8 compounds were confirmed as ER antagonists by yeast two-hybrid (Y2H) assay, with EC₅₀ values ranging from several micromolar to 100 micromolar. In this study, a novel series of cycloartane triterpenoids isolated from Schisandra glaucescens Diels was found to have ER antagonistic effect, the most potent antagonist of which exhibited activity with EC₅₀ value of 2.55 and 4.68 μM for ERα and ERβ, respectively. Moreover, the types of modulation and subtype selectivity were also investigated through molecular docking simulation.     

Identification of heterotrimeric G protein α and β subunits in rice

Like those in mammals, heterotrimeric G protein complexes have been implicated in signal transduction pathways in plants; however, the subunits themselves have not been isolated. In this study, the rice heterotrimeric G protein subunits α (Gα) and β (Gβ) were purified by affinity chromatography using anti-Gα and -Gβ antibodies and SDS-PAGE. Six and seven peptides, respectively, were identified by mass spectrometry and identified as the translation products of the Gα gene RGA1 and Gβ gene RGB1. During purification, the subunits dissociated easily from the G protein complex.     

Amino acid sequences of portions of the alpha and beta chains of bovine fibrinogen.

The N-terminal portions of the Aα and Bβ chains of bovine fibrinogen (CNBr Aα and Bβ), each of which contains an ArgGly bond that is hydrolyzed by thrombin, have been isolated by cyanogen bromide cleavage of fibrinogen and column chromatography of the resulting material. These peptides were digested with thrombin, releasing fibrinopeptide A and GlyProArg from CNBr Aα, and fibrinopeptide B from CNBr Bβ. The C-terminal peptides produced by digestion with thrombin (CNBr α and CNBr β) were purified, and the amino acid sequences of portions of these peptides (30 residues from the N-terminus of CNBr α and 32 residues from the N-terminus of CNBr β) were determined with an automatic sequenator using the Edman degradation.     

New class of steroidal alkaloids from Fritillaria imperialis

Two members of a new class of C-nor-D-homo steroidal alkaloids, impranine (1). and dihydroimpranine (2). along with a new pyridyl-pregnane-type steroidal alkaloid, fetisinine (3). and a known base, korsevine (4). were isolated from the bulbs of Fritillaria imperialis. The structures of the compounds were established on the basis of spectroscopic techniques and some chemical transformations. Compounds 1 and 2 form a new class of steroidal alkaloids, named as "impranane."