Recent advances in pharmacognosy research in China

1. Progress made in pharmacognostic research by Chinese investigators in the last decade is summarized herein. 2. This review covers studies on herbal properties, resources, identification, physicochemical evaluation, cultivation, breeding, tissue culture, collection, processing, preparation, active principles and pharmacological activities of traditional and herbal Chinese drugs. 3. As a result of these research activities errors in species identification were spotted, new drug resources were revealed, new taxa were discovered, crude drugs were analyzed qualitatively and quantitatively, optimal conditions for cultivation and breeding of plants and animals used as drugs were formulated, the quality of some drugs was controlled, the drug processing procedures and storage conditions were evaluated, and the chemistry and pharmacology of a number of crude drugs were elucidated.

Expression of chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase in Escherichia coli

Chicken liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase was expressed in E. coli by using a pET3a T7 RNA polymerase-based expression system and was purified to homogeneity. The kinase and bisphosphatase of the expressed bifunctional enzyme had kinetic properties identical to those of the native chicken liver enzyme. However, the kinase activity of the chicken liver enzyme was 7-fold higher, while the bisphosphatase activity was 50 percent lower than those of the rat liver enzyme. Cys-256 of the rat liver bisphosphatase domain is not conserved in the chicken liver enzyme. A site-directed mutation was engineered at Cys-256 of the rat liver enzyme and the results indicate that the variation of this residue is not responsible for the difference in fructose-2,6-bisphosphatase activity between the rat and chicken liver enzymes. It is postulated that the difference in the kinase/bisphosphatase activity ratios of these two enzymes results from differences in their NH2-terminal regions.

Histological study on crude drugs pai-wei, pai-chein and indigenous species of Cynanchum in Taiwan

The botanical origins of Cynanchum species (Cynanchum spp.) on the Taiwan market have been established by histological studies in the present paper. The results showed that the Chinese crude drug Pai-wei on the Taiwan market was derived from the dried roots of Cynanchum atratum Bunge; that of Pai-chein was derived from the dried roots of C. stauntonii (Decne.) Hand.-Mazz; and the Wanling-shu used locally in Taiwan was derived from the dried roots of C. taiwanianum Yamazaki.

[Herbalogical study of Chinese drug guijiu and xiaoyelian]

Through a critical study of ancient Chinese herbals, it is concluded that the botanical origin of Guijiu should be Dysosma versipellis or D. pleiantha instead of Sinopodophyllum emodi, and that Xiaoyelian was originated from the latter. In Chinese Pharmacopoeia and many other books, the botanical origin of Xiaoyelian was erroneously referred to as Podophyllum emodi.

[Appearance and distribution of retinoic acid in the limb regeneration of Cynops orientalis]

Urodeles are the unique vertebrate which can regenerate their limbs in larvae and adult. The pattern formation of blastema cells in the limb regeneration is a central problem. Many evidence have been established to support the hypothesis that RA may be the morphogen in limb development. The limb development and regeneration are so similar morphogenetic processes that we suspect RA may also play an important role in the latter process. In order to give an answer to this question, we tested the limbs in different stages of regeneration with the specific antibody prepared against RA. The results indicated that RA appeared on day six and arrived its peak on day eight after amputation. During this time, the dedifferentiation of the stump is proceeding to the strongest degree and the distribution of RA showed a posterior-anterior gradient. If the stump is treated with RA for 24 hours at this stage, proximal distal duplication of the regenerate can be induced. These results and the fact that the close connection between apical epidermal cap and mesenchymal cells and abundant RA outside the epidermal cells suggest that RA may play an important role in the establishment of positional information of the blastema.

[Studies on injury-mechanism of trichosanthin on trophoblast cells and choriocarcinoma cells in culture]

For analysing the injurious mechanism of Trichosanthin (TCS) on trophoblast cells, cytotrophoblast cells were separated from placental villi in human early pregnancy and cultured on millipore filters coated with collagen in dual-environmental culture chambers. After 7-10 days culture the cells grew into confluent monolayer. A lot of multinucleated giant cells (synthetial like) could be found under light microscopy. Cytotrophoblast cells and the giant one were characterized as epithelial type by indirect immuno-fluorescent staining with anti-keratin. Because the procedure of separation of trophoblast cells is laborious and the choriocarcinoma cells (JAR) were as sensitive as trophoblast cells to trichosanthin, so the choriocarcinoma cells were used instead of the trophoblast cells in the later experiments. The internalization and distribution of TCS conjugated to 15 nm (in diameter) gold particles were examined. Electron microscopy showed that the TCS-gold particles were bound to the cell membrane and entered via coated pit and then internalized into coated vesicles (endosomes) within 30-60 minutes after treatment. Nevertheless, a number of free TCS-gold particles entered into the cell membrane nonspecifically. In the series of 60-120 minutes treatment, the TCS-gold particles presented in the multivesicular bodies. It is worthy to emphasize that the TCS-gold particles entered the cytosol from the endosomes and distributed nearby the rough endoplasmic reticulum (RER) and ribosomes within 120-180 minutes. In the meanwhile, the cells showed pathological changes markedly. With the same method, human liver carcinoma cells (BE 7402), kidney cells of African green monkey (CV-1) and rat embryonic liver epithelial cells (LW 13) were treated by TCS-gold particles as control. However, no particles had been found on the cell surface or in the cytosol within 60-120 minutes (see Table 1). In addition, trophoblast cells were treated by BSA-gold particles and transferrin-gold particles separately there still no particles could be found. (See Table 2). It is more interesting that TCS-Hepama-1-gold particles internalized into the choriocarcinoma cells with the same manner as TCS-gold entered, and it could not be affected by pretreatment with Hepama-1 an hour. But, TCS-Hepama-1-gold particles bound to the microvilli of human liver carcinoma cells, and it can be inhibited competitively by pretreatment with Hepama-1 for an hour (see Table 3). These results indicated consistently that trichosanthin possesses a high affinity to the membrane of trophoblast cells and choriocarcinoma cells, and the internalization of this plant toxic protein into its target cells characterized by receptor-mediated endocytosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Localization of the potassium ion activation site in human liver fructose 1,6-bisphosphatase

Three mouse monoclonal antibodies of human liver fructose 1,6-bisphosphatase are shown to bind to the enzyme at different sites as determined by ELISA. The binding of one of the monoclonal antibodies, L2E1, mimics the effects of K+ ions, including increase in the enzyme activity and enhancement of the sensitivity of the enzyme to AMP inhibition. We tentatively suggest that human liver FruP2ase may have a specific K+ activation site, which at least partially overlaps with the L2E1 binding region. This site has been localized by analyzing the peptide fragments formed by cleavage with cyanogen bromide.

Constituents of the roots of Cynanchum bungei Decne. Isolation and structures of four new glucosides, bungeiside-A, -B, -C, and -D

Four new glucosides, bungeiside-A, -B, -C, and -D, were isolated from the roots of Cynanchum bungei Decne. The structures of the new compounds were determined by chemical and spectroscopic methods, including two-dimensional nuclear magnetic resonance (2D NMR) techniques, especially 1H-detected heteronuclear multiple-bond multiple-quantum coherence.

Isolation of novel lignans, heteroclitins F and G, from the stems of Kadsura heteroclita, and anti-lipid peroxidative actions of heteroclitins A-G and related compounds in the in vitro rat liver homogenate system

From the stems of Kadsura heteroclita, two new lignans named heteroclitins F and G were isolated and their structures were determined by various spectroscopic means including an X-ray diffraction method. Dibenzocyclooctadiene type lignans and related compounds isolated from the stems of K. heteroclita, potently inhibited the lipid peroxidation in the rat liver homogenate stimulated by Fe(2+)-ascorbic acid, CCl4-reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine 5'-diphosphate-NADPH.

Anti-lipid peroxidative effect of an extract of the stems of Kadsura heteroclita and its major constituent, kadsurin, in mice

Three-days successive p.o. administration of an EtOH extract of the stems of Kadsura heteroclita (Schizandraceae) or its major constituent, kadsurin, resulted in significant decreases of CCl4-induced lipid-peroxidation products, such as thiobarbituric acid reactive substances (TBA-RS), conjugated dienes and fluorescent products in the liver of mice. In contrast, a significant restoration of superoxide dismutase (SOD) activity reduced by CCl4-intoxication was observed in the administered groups, suggesting that the subchronic treatment of mice with the EtOH extract or kadsurin induce enzymes capable of scavenging oxygen radical species in the liver, though the extract and kadsurin themselves may have an anti-oxidant property.

Properties of chicken liver phosphofructokinase-2

Phosphofructokinase-2 was purified to homogeneity from chicken livers by homogenization, polyethylene glycol fractionation and column chromatography on DEAE-Sephadex A-50 and Blue-Sepharose 4B. Some properties of the enzyme were as follows: (i) The saturation curve of the enzyme for fructose 6-phosphate showed hyperbolic and the Km of fructose 6-phosphate was affected by inorganic phosphate while Vmax was not; (ii) the binding of ATP to the enzyme was of negative cooperativity with a Hill coefficient of 0.56; (iii) the activity of the enzyme was completely lost in the presence of EDTA. The enzyme was activated by Mg2+ at low concentrations, but inhibited by Mg2+ at high concentrations; (iv) the enzyme was stable below 30 degrees C and easily lost its activity when the temperature was above 40 degrees C; (v) the activity of the enzyme was stable at the range of pH 7-9, increased at pH 9.0-9.5 and decreased when pH was over 9.5; (vi) the enzyme was sensitive to trypsin and ATP protected the enzyme against the proteolysis of trypsin.

Chronotropic Effect of the Methanolic Extracts of the Plants of the Paris Species and Steroidal Glycosides Isolated from P. vietnamensis on Spontaneous Beating of Myocardial Cells1

Rhizomes of five identified plants of the PARIS species, Liliaceae, and Rhizoma Paridis which are sold as a crude drug named "Zao Xiu", "Qiyeyizhihua" or other names in nine different markets in China were tested for their effects on cultured cardiomyocytes. In the standard medium, eight methanol extracts out of sixteen at a concentration of 0.2 mg/ml stopped the spontaneous beating of myocardial cell sheets, but these extracts significantly increased the beating rate when the concentration was reduced to one half. In the culture medium with a low calcium concentration, 0.5 mM, the beating rate of the cells decreased to about 60% of that of the control in the standard medium. The addition of five of the extracts to the low calcium medium at a concentration of 0.1 mg/ml caused a stop of cell beating, but the other extracts increased beating rate at least by 10%. Three steroidal glycosides isolated from the rhizomes of P. VIETNAMENSIS (Takht.) H. Li also stimulated cell beating. Among them, diosgenin-3- O-alpha- L-rhamnopyranosyl-(1-->2) - (alpha- L-arabinofuranosyl-(1-->4))- D-glucopranoside (compound 1) was the most effective stimulant for cell beating as well as calcium uptake by the myocardial cells.

Purification and kinetics of mouse liver fructose 6-phosphate, 2-kinase

The mouse liver fructose 6-phosphate, 2-kinase was purified by ultracentrifugation, polyethylene glycol precipitation, and subsequently by chromatography on DEAE-Sephadex, Blue-Sepharose and phasphocellulose columns. Gel filtration and SDS polyacrylamide electrophoresis showed that the enzyme has a molecular weight of 110,000 with two identical subunits. Mg2+ is essential for its activity. The activation of the enzyme by Mg2+ showed a positive cooperativity. The substrate saturation curve for fructose 6-phosphate was sigmoidal and for ATP was hyperbolic. The Km's for ATP increased with decrease in concentrations of fructose 6-phosphate indicating that the sequence for the substrates binding was in an ordered mechanism with respect to fructose 6-phosphate prior to ATP. An ionizable residue at the active site with pKa 9.5 was essential for the ATP binding and the pKa shifted to 9.8 after the binding of ATP.

Synthesis of thymosin beta 4 by peritoneal macrophages and adherent spleen cells

Thymosin beta 4, previously identified as a component of thymosin fraction 5 isolated from calf thymus, is synthesized by peritoneal macrophages derived from rats or mice, including cells from nu/nu mice. Identification of thymosin beta 4 containing [35S]methionine was based on its retention time in reverse-phase HPLC and the recovery of radioactivity in peptides generated by mild acid hydrolysis or by digestion with trypsin. Thymosin beta 4 is also synthesized by rat and mouse spleen cells, and evidence is presented for its release from these cells.

Thymosin beta 4: a ubiquitous peptide in rat and mouse tissues

Thymosin beta 4, recently isolated from calf thymus, is present in a number of rat and mouse tissues, including spleen, thymus, brain, lung, liver, and heart muscle. High concentrations are found in peritoneal macrophages, suggesting that its occurrence in other tissues may be related to the presence of macrophages or macrophage-like cells in these tissues. The conclusion that "thymosin" beta 4 does not originate solely in the thymus gland is supported by the high concentrations found in tissues of athymic (nu/nu) mice.