[Chemical constituents of Actinidia kolomikta (Rupr. et Maxim.) Planch]

Two crystalline components I and II were isolated from the roots of Actinidia kolomikta. I was identified as delta 7-stigmasterol and II was named alpha-kolomiktriose and elucidated as 2, 3-di-0-beta-D-galactopyranosyl-alpha-D-galactopyranose on the basis of spectral data (13C NMR, 1H NMR, IR and EI-MS).

[Studies on the anticomplementary activity of Jozann. Anticomplementary activity of steroid derivatives]

Methanol extracts of 53 crude drugs were tested on the anticomplementary activity. Of these, 12 samples showed the potent activity. Of these 12 samples, the extract of Jozann (Dichrome Radix) was studied on the isolation and structural elucidation of the anticomplementary constituents. As active constituents, 3 beta-hydroxystigmast-5-en-7-one was isolated and its structure was confirmed by deriving this compound from beta-sitosterol. The activity of such steroid derivatives as stigmastane, cholestane, androstane and pregnane type steroids were further studied. Of these, several kinds of steroids showed the potent activity. From these experiments, the structure and activity relationship was discussed.

[Constituents of the root of Berneuxia thibetica Decne]

Three crystals have been isolated from the root of Berneuxia thibetica. On the basis of spectral data, crystals A and B have been identified as chrysosplenetin B and 22,23-dihydrospinasterone respectively, while crystal C is a mix of spinasterol and 22,23-dihydrospinasterol.

Antimutagens from Momordica charantia

The antimutagenic principle of the green fruits of Momordica charantia was shown by the micronucleus test to be an intractable mixture of novel acylglucosylsterols. The antimutagens were extracted from the green fruits with ethanol and isolated from the bioactive petroleum ether and carbon tetrachloride extracts by repeated and sequential flash column chromatography. The major component of the mixture is 3-O-[6'-O-palmitoyl-beta-D-glucosyl-stigmasta-5,25(27)-dien and the minor component is the stearyl derivative (Guevara, 1989). At a dosage range in mice of 50-12.5 micrograms extract/g, the mixture reduced by about 80% the number of micronucleated polychromatic erythrocytes induced by the well-known mutagen mitomycin C. Structure-activity correlation studies suggested that the antimutagenic activity may reside in the peculiar lipid-like structure of the acylglucosylsterols. Ingestion of these compounds may result in their absorption in the plasma membrane lipid bilayer which could adversely affect the membrane permeability towards mitomycin C and disrupt the cellular activity of the latter.

[Studies on the chemical constituents of Ardisia crenata Sims]

A new bergenin derivative isolated from the root of Ardisia crenata was determined to be 11-o-syringylbergenin by spectral methods. Other compounds were identified as spinasterol, series fatty acids, beta-sitosterol-beta-D-glucoside, norbergenin and sucrose respectively. The last three were obtained for the first time from the genus of Ardisia.

[Sterols from Gynostemma pentafillum]

The sterol fraction of Gynostemma pentafillum contains beta-sito sterol and isofucosterol. The identification of these compounds has been carried out through NMR and MS data.

Chonemorphine, stigmasterol, and ecdysterone: steroids isolated through bioassay-directed plant screening programs

In a bioassay-directed screening programme of plants for the identification of active constituents the following steroids were isolated. Chonemorphine was identified as the antiamoebic and antitrichomonad principle of Chonemorpha fragrans. Stigmasterol from Coleus forskohlii and ecdysterone from Diploclisia glaucescens were inactive constituents isolated during the process of purifying the active principles of the plants. D. glaucescens roots are a high-yielding source (0.5% of the dry root weight) of ecdysterone.

Isolation of two new C30 sterols, (24E)-24-N-propylidenecholesterol and 24 epsilon-N-propylcholesterol, from a cultured marine Chrysophyte

Two new sterols, (24E)-24-n-propylidenecholesterol and 24 epsilon-n-propylcholesterol, were isolated from a cultured marine Chrysophyte. Since most of the steroids found in marine invertebrates are unchanged or modified sterols of algal or symbiotic origin, the discovery of these two unusual sterols in a unicellular alga grown under well-defined conditions contributes to our knowledge of sterols in marine food chains and offers a potential substrate for biosynthetic labeling experiments.

Chromatography on lipophilic dextran gels for fractionation of low molecular weight compounds I: steroid digitonides

A method for the separation of 3beta-hydroxysterols from other sterols is presented. The method involves precipitating 3beta-hydroxysterols as the digitonides. The digitonide is then decomposed and separated into components using chromatography on highly cross-linked lipophilic polysaccharide gels. The digitonin in the mother liquor is separated from other sterols using the same chromatographic procedure.