Constituents and pharmacological effects of Eucommia and Siberian ginseng.

The bark and leaves of Eucommia ulmoides Oliv (Eucommiaceae) and "Siberian ginseng" (Ezoukogi in Japanese) prepared from the root bark or stem bark of Eleutherococcus senticosus Maxim (Acanthopanax senticosus Harms) have been used as tonic and anti-stress drug. The extracts of Eucommia showed anti-hypertensive, anti-complementary, anti-oxidative, and anti-gastric ulcer effects, and promoting collagen synthesis, accelating granuloma formation, and other pharmacological effects. The Siberian ginseng exhibited anti-fatigue, anti-stress, immuno-enhancing effect, CNS activity, and anti-depressive effect. By now, 40, 28, and 10 compounds have been isolated from Eucommia ulmoides bark, Eucommia ulmoides leaves, and Siberian ginseng, respectively, and their structures were elucidated. Their pharmacological activities were mainly due to lignans and iridoid glycosides.

In vitro metabolism of plant lignans: new precursors of mammalian lignans enterolactone and enterodiol.

The metabolism of the plant lignans matairesinol, secoisolariciresinol, pinoresinol, syringaresinol, arctigenin, 7-hydroxymatairesinol, isolariciresinol, and lariciresinol by human fecal microflora was investigated to study their properties as mammalian lignan precursors. The quantitative analyses of lignan precursors and the mammalian lignans enterolactone and enterodiol were performed by HPLC with coulometric electrode array detector. The metabolic products, including mammalian lignans, were characterized as trimethylsilyl derivatives by gas chromatography-mass spectrometry. Matairesinol, secoisolariciresinol, lariciresinol, and pinoresinol were converted to mammalian lignans only. Several metabolites were isolated and tentatively identified as for syringaresinol and arctigenin in addition to the mammalian lignans. Metabolites of 7-hydroxymatairesinol were characterized as enterolactone and 7-hydroxyenterolactone by comparison with authentic reference compounds. A metabolic scheme describing the conversion of the most abundant new mammalian lignan precursors, pinoresinol and lariciresinol, is presented.

MAPK upstream kinase (MUK)-binding inhibitory protein, a negative regulator of MUK/dual leucine zipper-bearing kinase/leucine zipper protein kinase.

Mitogen-activated protein kinase upstream kinase/dual leucine zipper-bearing kinase/leucine-zipper protein kinase (MUK/DLK/ZPK) is a MAPKKK class protein kinase that induces JNK/SAPK activation. We report here a protein named MBIP that binds to MUK/DLK/ZPK. MUK-binding inhibitory protein (MBIP) contains two tandemly orientated leucine-zipper-like motifs with a cluster of basic amino acids located between the two motifs. MBIP interacts with one of the two leucine-zipper-like motifs of MUK/DLK/ZPK and inhibits the activity of MUK/DLK/ZPK to induce JNK/SAPK activation. Notably, no similar effect was observed with another JNK/SAPK-inducing MAPKKK, COT/Tpl-2, showing the specificity of MBIP action. Furthermore, the overexpression of MBIP partially inhibits the activation of JNK by 0.3 m sorbitol in 293T cells. Taken together, these observations indicate that MBIP can function as a regulator of MUK/DLK/ZPK, a finding that may provide a clue to understanding the molecular mechanism of JNK/SAPK activation by hyperosmotic stress.

Pharmacologically active components of viticis fructus (Vitex rotundifolia). II. The components having analgesic effects.

The extract of Viticis Fructus appeared to have an analgesic effect, and was subjected to activity-guided separation using acetic acid-induced writhing in mice. The active fraction gave new compounds, vitexfolin A (1A), B and C, 10-O-vanilloylaucubin (3), dihydrodehydrodiconiferylalcohol-beta-D- (2'-O-p-hydroxybenzoyl)glucoside (4), and vanilloyl-beta-D-(2'O-p-hydroxybenzoyl)glucoside, together with agnuside (2) and erythro- and threoguaiacylglycerols. Compounds 1A and 2-4 showed significant writhing inhibition following oral administration at doses of 15, 50, 25, and 50 mg/kg, respectively. The effect on pressure pain threshold was tested using compounds 1A and 2 at a dose of 50 mg/kg, and only the former produced the analgesia. The analgesic effect of some related iridoid glucosides is also discussed.

Differential activation of two JNK activators, MKK7 and SEK1, by MKN28-derived nonreceptor serine/threonine kinase/mixed lineage kinase 2.

MKN28-derived nonreceptor type of serine/threonine kinase/mixed lineage kinase 2 (MST/MLK2) directly phosphorylates and activates SEK1/MKK4/JNKK1/SKK1 in vitro, thereby acting as a mitogen-activated protein (MAP) kinase kinase kinase in the JNK/SAPK pathway (Hirai, S. -i., Katoh, M., Terada, M., Kyriakis, J. M., Zon, L. I., Rana, A., Avruch, J., and Ohno, S. (1997) J. Biol. Chem. 272, 15167-15173). The in vitro reconstitution system for the kinase cascade allowed us now to identify JNK/SAPK activators involved in the MST/MLK2-dependent activation of JNK/SAPK in vivo. We show that at least two distinct MST/MLK2-dependent JNK/SAPK activators are present in the fractionated COS-1 cell lysate, and that they appear to be SEK1/MKK4/JNKK1/SKK1 and MKK7/JNKK2/SKK4 by Western blot analysis. Notably, a majority of the MST/MLK2-dependent JNK/SAPK-activating activity is found in MKK7-containing fractions, whereas the MEKK1-dependent activity is comparably distributed in SEK1- and MKK7-containing fractions. Moreover, MST/MLK2 activates recombinant MKK7 more effectively than recombinant SEK1, whereas MEKK1 activates both to a similar extent. In addition, the deletion analysis on MST/MLK2 showed that the kinase domain is responsible for the determination of substrate specificity. These results provide a molecular aspect to the differential regulation of the two JNK activators by a variety of cellular stimuli.

[Analysis of phenylethanoid glycosides of Herba cistanchis by RP-HPLC].

The Chinese drug "Rou Cong-rong" (Herba Cistanchis) is one of the commonly used drugs in Chinese traditional medicine. It is used to reinforce the vital function of kidney, especially that of the sexual organs and induce laxation, for the treatment of impotence, premature ejaculation in men, infertility, morbid leukorrhea, profuse metrorrhagia in women, and chronic constipation in the aged. This paper deals with the qualitative and quantitative analysis of phenylethanoid glycosides of four species and one variety of Genus Cistanche and 23 lots of commercial crude drugs of Herba Cistanchis by RP-HPLC. The results were as follows: the chemical constituents of Cistanche deserticola Ma, C. salsa (C. A. Mey) G. Beck, C. salsa var. albiflora P. F. Tu et Z. C. Lou and C. tubulosa were similar while those of C. sinensis were different from the others; the contents of echinacoside and acteoside of C. salsa, which were 2.13% and 1.51%, were the highest of the genus Cistanche. An ODS column (Alltima C18, 5 microns, 250 x 4.6 mm) was employed. Linear gradient elution of acetonitrile--1.5% acetic acid was used as mobile phase, and concentration of acetontrile was from 8% to 20% (0-60 min) in the qualitative analysis, and from 11.5 to 20% (0-35 min) in the quantitative analysis. The flow rate was 1.2 ml.min-1. The detection wavelength was set at 335 nm.

Anticomplementary activity of the constituents of Eucommia ulmoides bark.

A study was made on the anticomplementary activity of the lignoid and iridoid derivatives isolated from the bark of Eucommia ulmoides as well as the enzymatic hydrolysis products of the isolated iridoid glucosides.