Showing papers in "Planta Medica in 1990"

Antimalarial activity of Tanzanian medicinal plants.

Abstract: Tanzanian medicinal plants were extracted and tested for in vitro antimalarial activity, using the multidrug resistant K1 strain of Plasmodium falciparum. Of 49 plants investigated, extracts of three plants were found to have an IC50 between 5-10 micrograms/ml, extracts of 18 other plants showed an IC50 between 10 and 50 micrograms/ml, all others were less active. The three most active extracts were obtained from the tubers of Cyperus rotundus L. (Cyperaceae), the rootbark of Hoslundia opposita Vahl. (Labiatae), and the rootbark of Lantana camara L. (Verbenaceae).

Hypoglycaemic effect of Momordica charantia extracts.

Abstract: The hypoglycaemic effect of orally administered extracts of fruits of cultivated Momordica charantia (karela) was examined in normal and streptozotocin diabetic mice. In normal mice, an aqueous extract (A) lowered the glycaemic response to both oral and intraperitoneal glucose, without altering the insulin response. This aqueous extract (A) and the residue after alkaline chloroform extraction (B) reduced the hyperglycaemia in diabetic mice at 1 hour. Material recovered by acid water wash of the chloroform extract remaining after an alkaline water wash (D) produced a more slowly generated hypoglycaemic effect. The results suggest that orally administered karela extracts lower glucose concentrations independently of intestinal glucose absorption and involve an extrapancreatic effect. Two types of hypoglycaemic substances with different time dependent effects are indicated.

Medicinal plant biotechnology.

Abstract: Biotechnology is described as methodology to enhance the formation and accumulation of desirable natural products and possible product modification in medicinal plants. Micropropagation, cell and hairy root culture as well as gene technology are being highlighted.

Analgesic and behavioural effects of Morinda citrifolia.

Abstract: The traditional therapeutic indications for the use of Morinda citrifolia L. (Rubiaceae) have been investigated. The lyophilised aqueous extract of roots of M. citrifolia was evaluated for analgesic and behavioural effects in mice. The extract did not exhibit any toxic effects but did show a significant, dose-related, central analgesic activity in the writhing and hotplate tests; this effect was confirmed by the antagonistic action of naloxone. Furthermore, administration of M. citrifolia extract at high dosages decreased all behavioural parameters in the two compartment test, the light/dark choice situation test, and the staircase test; together with the induced sleeping time, these results are suggestive of sedative properties.

Antiplatelet components in Panax ginseng.

Abstract: Panaxynol and ginsenosides Ro, Rg1, and Rg2 were found to be the main antiplatelet components in the diethyl ether and 1-butanol fractions, respectively, during the activity-guided fractionation of Panax ginseng, Panaxynol inhibited the aggregation, release reaction, and thromboxane formation in rabbit platelets while ginsenosides Ro, Rg1, and Rg2 suppressed the release reaction only.

Antimalarial compounds containing an alpha,beta-unsaturated carbonyl moiety from Tanzanian medicinal plants.

Abstract: Pure compounds were isolated from plant extracts with antimalarial activity. The extracts were obtained from the tubers of Cyperus rotundus L. (Cyperaceae), the rootbark of Zanthoxylum gilletii (De Wild) Waterm. (Rutaceae), and the rootbark of Margaritaria discoidea (Baill.) Webster (Euphorbiaceae). The most active compounds included (IC50 within brackets): alpha-cyperone (1) (5.5 micrograms/ml), N-isobutyldeca-2,4-dienamide (2) (5.4 micrograms/ml), and securinine (3) (5.4 micrograms/ml). A mixture of autoxidation products of beta-selinene was found to be the most active antimalarial substances obtained from C. rotundus (5.6 micrograms/ml.

[The Relative Configuration of Acetogenins Isolated from Annona squamosa: Annonin I (Squamocin) and Annonin VI].

Abstract: Annonin I ( 1) and anonin VI ( 9) were isolated from the seeds of ANNONA SQUAMOSA L. (Annonaceae). The constitution of 1 is identical with that of squamocin, isolated by Fujimoto et al. (8). The relative configuration of 1 was elucidated by X-ray diffraction analysis of a derivative. The constitution and relative configuration of 9 was established by (13)C- and (1)H-NMR spectroscopy using data of derivatives.

Recent developments in the biosynthesis of the tropane alkaloids.

Abstract: Recent work on the biosynthesis of the tropane moiety of cocaine, hyoscamine, scopolamine, and related alkaloids is reviewed. Revision of the generally accepted biosynthetic pathway to these alkaloids is now proposed in the light of new discoveries. New information on the biosynthesis of some of the acid moieties (benzoic, tiglic and tropic acid) of the tropane ester alkaloids is also discussed.

Randomized, double-blind study of freeze-dried Urtica dioica in the treatment of allergic rhinitis.

Abstract: Ninety-eight individuals took part in a double-blind randomized study comparing the effects of a freeze-dried preparation of Urtica dioica (stinging nettles) with placebo on allergic rhinitis. Sixty-nine individuals completed the study. Assessment was based on daily symptom diaries, and global response recorded at the follow-up visit after one week of therapy. Urtica dioica was rated higher than placebo in the global assessments. Comparing the diary data Urtica dioica was rated only slightly higher.

Isoliquiritigenin: a new aldose reductase inhibitor from glycyrrhizae radix.

Abstract: Traditionally in Japan, some kampo medicines (traditional oriental herbal prescriptions) have long been used for the treatment of diabetic neuropathy. We have found that some aldose reductase inhibitors are included among these drugs. We further investigated the components of glycyrrhizae radix, a constituent of some kampo medicines, and isolated six compounds (GUs 9-17). Among these, GU-17, identified as isoliquiritigenin, had the most potent aldose reductase inhibiting activity. Isoliquiritigenin inhibited rat lens aldose reductase with an IC50 of 3.2 x 10(-7) M, using DL-glyceraldehyde as a substrate. It inhibited sorbitol accumulation in human red blood cells in vitro, with an IC50 of 2.0 x 10(-6) M. Isoliquiritigenin, when administered via an intragastric tube to diabetic rats, suppressed sorbitol accumulation in the red blood cells, the sciatic nerve, and the lens as effectively as ONO-2235. These results suggest that isoliquiritigenin may be effective in preventing diabetic complications.

tert-Butyl hydroperoxide-induced injury in isolated rat hepatocytes: a model for studying anti-hepatotoxic crude drugs.

Abstract: Tert-butyl hydroperoxide induces in freshly isolated rat hepatocytes malonaldehyde formation and lacticodehydrogenase and aspartate amino-transferase leakage This model, when adapted to crude extracts, permits the demonstration of both anti-lipoperoxidant and antihepatotoxic activity of reference products like quercetin and silymarin and plant extracts like Rosmarinus officinalis and Eschscholzia californica

Products of Allicin Transformation: Ajoenes and Dithiins, Characterization and their Determination by HPLC*.

Abstract: Constituents of crushed garlic bulbs ( ALLIUM SATIVUM L.), such as allicin, ( E/Z)-ajoene, and the vinyldithiins, were synthesized and purified by an LC method. Purity was proved by TLC, HPLC, and GC systems. Identity was confirmed by comparison with spectral data from the literature. In order to establish external standards, silica gel adsorbates of the respective substances were prepared. For quantitative determination of allicin and its transformation products, an isocratic HPLC method was developed. Calibration was performed by the use of these external standards, and by comparison to an internal standard. The influence of different media on allicin transformation, including the ( E/Z)-ratio of the ajoenes, has been elaborated.

The cytotoxic principles of Pseudolarix kaempferi : pseudolaric acid-A and -B and related derivatives

Abstract: Pseudolaric acid-A and -B, the novel diterpene acids isolated from Pseudolarix kaempferi, and their related derivatives have been tested for cytotoxicity against KB, A-549, HCT-8, P-388, and L-1210 tumor cells. The results showed that pseudolaric acid-A and -B demonstrated potent cytotoxicity. The selectivity of pseudolaric acid-A and -B which inhibit the growth of particular cell types within the disease-oriented human cancer cell line panels is discussed.

Anti-inflammatory activity and sub-acute toxicity of artemetin.

Abstract: The 5-hydroxy-3,6,7,3',4'-pentamethoxyflavone (artemetin) from Cordia verbenacea DC (Boraginaceae) showed marked anti-inflammatory activity using various experimental models in rats. Artemetin significantly inhibited carrageenin-induced paw edema following oral doses from 30.4 to 153.9 mg.kg-1. The doses of 102.6 and 153.9 mg.kg-1 showed an inhibitory effect similar to that of 50.0 mg.kg-1 of calcium phenylbutazone. The ED50 value of artemetin in rats was estimated to be 67.07 mg.kg-1. Repeated administration of artemetin at doses of 67.07 mg.kg-1 for a 6-day period reduced granuloma formation with a response comparable to that of 20.0 mg.kg-1 of calcium phenylbutazone. This same dose of artemetin also reduced the vascular permeability to intracutaneous histamine. Sub-acute toxicological experiments indicated a very low toxicity.

Anti-inflammatory activity of ginsenoside ro.

Abstract: Ginsenoside Ro, an oleanane-type saponin has been screened for activity in experimental models of inflammation. Ginsenoside Ro (10, 50, and 200 mg/kg, p.o.) inhibited an increase in vascular permeability in mice induced by acetic acid and reduced an acute paw edema in rats induced by compound 48/80 or carrageenin. Ginsenoside Ro did not suppress a developing adjuvant-induced edema in arthritic rats. However, ginsenoside Ro was found to be effective in hypercoagulable state, increase of connective tissue in the artery and calcium effluence from the bone in adjuvant-induced arthritic rats.

On the pharmacology of bromelain: an update with special regard to animal studies on dose-dependent effects.

Abstract: Bromelain, a standardized complex of proteases from the pineapple plant, is absorbed unchanged from the intestine of animals at a rate of 40%; in animal experiments it was found to have primarily anti-edema, antiinflammatory, and coagulation-inhibiting effects. These effects are due to an enhancement of the serum fibrinolytic activity and inhibition of the fibrinogen synthesis, as well as a direct degradation of fibrin and fibrinogen. Bromelain lowers kininogen and bradykinin serum and tissue levels and has an influence on prostaglandin synthesis, thus acting antiinflammatory. In in vitro and in animal studies, experimentally induced tumours could be inhibited by bromelain. Although many studies do not give extensive statistical data, the effects of bromelain in animal studies seem to be dose-dependent. Further investigations have to be carried out.

Pyrrolizidine Alkaloids from Ageratum conyzoides.

Abstract: Pyrrolizidine alkaloids (PAs) are widely distributed in many plant families. They mainly occur in the genus Senecio (Asteraceae) such as Heliotropium (Boraginaceae) and Crotalaria (Fabaceae). PAs are of great pharmaceutical interest because of their toxic activities and their associations with Lepidoptera. Some of these insects Sequester the PAs from the plants and use them as defense agents and as precursors for the pheromones danaidone, danaidal, and hydroxydanaidal (l, 2, 3). This insect-PA relationship has been studied with a number of Lepidoptera species, e.g. Daninae, Ithomiinae, and Arctiidae (4, 5) leading to the conclusion that this fact can be used as a "biological indicator" for PA content. In this way obvations in Kenya became of great interest, which showed u.ctt, apart from Crotalaria and Heliotropium species, the native occurring Ageratum conyzoides (Asteraceae) is attractive for Lepidoptera, too (6). This association prompted us to undertake a phytochemical investigation of A. conyzoides. Two PAs have been isolated, which were found by MS to be isomeric forms. On account of 2D-NMR studies the absolute configuration of both PAs were deduced as follows: 0-retronecine-(-)viridiflorine ester [lycopsamine (1)] and an 0-heliotridine-(-)viridiflorine ester [echinatine (2)]. This is the first report of the occurrence of PAs in Ageratum species.

Phenylalanine is the predominant antisickling agent in Cajanus cajan seed extract.

Abstract: Amino acid analysis showed that solvent extracts of Cajanus cajan L. Millsp. (Fabaceae) seeds (white species) contain, as free amino acid, as much as 26.3% phenylalanine. Antisickling experiments based on the estimated amount of free phenylalanine in the methanol (water-soluble) extract of the seeds showed that the presence of this amino acid alone could account for about 70% of the antisickling potency of Cajanus cajan seed extract.

Hypoglycaemic activity of dioscoretine from tubers of Dioscorea dumetorum in normal and alloxan diabetic rabbits.

Abstract: Dioscoretine isolated from the aqueous fraction of the methanol extract of Dioscorea dumetorum tubers when administered intra-peritoneally to normal and alloxan diabetic rabbits produces significant hypoglycaemic effects at a dose of 20 mg/kg. The fasting blood sugar in normoglycaemic rabbits was reduced from 112 mg/100 ml to 55 mg/100 ml after 4 hours. In alloxan diabetic rabbits, the blood sugar was lowered from 520 mg/100 ml to 286 mg/100 ml at the same time interval. The aqueous fraction of the methanol extract produced comparable effects at 100 mg/kg. The chloroform fraction of the same extract raised the fasting blood sugar of normal rabbits to 196 mg/100 ml after 6 h. The acute toxicity studies gave LD50 values of 1.4 g/kg for the aqueous fraction and 0.58 g/kg for dioscoretine when tested on mice. The hypoglycaemic effects were compared to those of tolbutamide.

In vitro activity of protoanemonin, an antifungal agent.

Abstract: Protoanemonin, the lactone of gamma-hydroxy-vinylacrylic acid, isolated from Pulsatilla alpina has in vitro activity against fungi. The MIC is 15 micrograms/ml and RNA inhibition seems to be the first target of the drug. The LD50 of protoanemonin in male Swiss albino mice was 190 mg/kg.

Aromatic Constituents from Vladimiria souliei.

Abstract: The polar parts of the title plant gave several lignans including six new ones named vladinol A-F. The structures were elucidated by high field (1)H-NMR spectroscopy and a few chemical reactions. The stereochemistry was determined by the observed NOE's and by comparison of the (1)H-NMR data with those of related lignans.

Studies on insulin-like substances in Korean red ginseng

Abstract: Korean red ginseng powder was found to contain adenosine and an acidic substance which inhibited epinephrine-induced lipolysis and stimulated insulin-mediated lipogenesis from glucose (3, 4). In the present experiment, the chemical structure of this acidic substance is determined to be pyro-glutamic acid. Pyroglutamic acid exhibits selective modulations toward the opposite metabolic pathways in rat adipocytes; it inhibits the lipolysis but rather stimulates the lipogenesis. Based on these results, we suggest to call these substances (adenosine and pyro-glutamic acid) "selective modulators".

Antinarcotic effects of the standardized ginseng extract G115 on morphine.

Abstract: The study was undertaken to determine the antagonism of morphine analgesia by the standardized ginseng extract G115 from Panax ginseng, the inhibitory effects of orally administered G115 on the development of morphine-induced tolerance and physical dependence, the hepatic glutathione levels, the inhibitory effects of intraperitoneally administered G115 on the dopamine receptor supersensitivity, and the reverse tolerance to the locomotor accelerating effect of morphine. G115 significantly inhibits the development of morphine-induced tolerance and physical dependence, the hepatic glutathione level decrease induced by morphine multiple injections, the development of morphine-induced dopamine receptor supersensitivity, and reverse tolerance to the locomotor accelerating effect of morphine. It did not, however, antagonize morphine analgesia.

Structural characterization and antitumor activity of a pectic polysaccharide from the roots of Angelica acutiloba.

Abstract: The polysaccharide fraction from the root of Angelica acutiloba Kitagawa showed a potent antitumor activity against ascitic form of Sarcoma-180, IMC carcinoma, and Meth A fibrosarcoma as well as the solid form of MM-46 tumor. An active polysaccharide, AR-4E-2, was purified by precipitation with cetyl-trimethylammonium bromide, anion-exchange chromatography on DEAE-Sepharose, and gel filtration on Sepharose CL-4B from the polysaccharide fraction. An active polysaccharide fraction showed a weak anti-complementary activity. AR-4E-2 was composed of arabinose, galactose, and rhamnose in the molar ratios of 3.3:1.0:0.7, and also contained 14.5% galacturonic acid and 3.2% protein. Methylation analysis and base-catalysed beta-elimination studies suggested that AR-4E-2 contained a rhamnogalacturonan moiety in which 2,4-di-substituted rhamnose residues were attached to 4-substituted galacturonic acid through position 2 of rhamnose. AR-4E-2 also contained highly branched 3,5-arabinan and (1----4)-galactan.

Molluscicidal and antischistosomal activities of Zingiber officinale.

Abstract: Experiments were conducted to study the major constituents of Zingiber officinale responsible for its molluscicidal activity and the effect of the active component on different stages of Schistosoma mansoni. Gingerol and shogaol exhibited potent molluscicidal activity on Biomphalaria glabrata. Gingerol (5.0 ppm) completely abolished the infectivity of Schistosoma mansoni miracidia and cercariae in B. glabrata and mice, respectively, indicating that the molluscicide is capable of interrupting schistosome transmission at a concentration lower than its molluscicidal concentrations.

Sarothralin G: a new antimicrobial compound from Hypericum japonicum.

Abstract: A new antibiotic compound, sarothralin G from Hypericum japonicum Thunb. (Sarothra japonica) has been isolated and its structure was elucidated on the basis of spectroscopic data. The compound contains phloroglucinol and filicinic acid moieties.

Cytostatic and antibacterial activity of some compounds isolated from several lamiaceae species from the canary islands.

Abstract: A chemotherapeutic study has been carried out on thirteen products Eeleven diterpenes, one lignan, (+)-sesamin, and a coumarin, siderin] isolated from SALVIA and SIDERITIS species considered endemic to the Canarian flora. The data obtained suggest that some diterpenoid compounds show an interesting cytostatic activity, specially galdosol ( 6) with an ID (50) value of 0.5 microg/ml. These compounds also evidence a moderate antibacterial activity against Gram positive bacteria.

Fractionation and characterization of mitogenic and anti-complementary active fractions from kampo (Japanese Herbal) medicine "juzen-taiho-to".

Abstract: "Juzen-Taiho-To" (TJ-48), which is a kampo (Japanese herbal) medicine prepared by decocting a prescription of ten kinds of herbs, has several immunostimulating activities. In order to characterize the active substances for anti-complementary and mitogenic activities, TJ-48 was fractionated. Anti-complementary activity was observed in the water- and methanol-insoluble fraction (F-2) and the crude polysaccharide fraction (F-5), whereas mitogenic activity was only found in F-5. However, other low molecular mass fractions did not show both activities. Methylation analysis indicated that F-2 mainly contained amylopectin-like polysaccharides. Both Pronase digestion and periodate oxidation decreased the anti-complementary activity of F-2, and the beta-amylase-resistant fraction of F-2 still retained the potent anti-complementary activity. When F-5, which has the most potent of both activities, was further fractionated, only the major acidic polysaccharide fraction, F-5-2, showed potent mitogenic activity. Endo-alpha-(1----4)-polygalacturonase digestion showed that F-5-2 mainly contained pectic polysaccharides, and the endo-polygalacturonase treatment of F-5-2 reduced the mitogenic activity but not the anti-complementary activity. F-2 and F-5 each activated the complement system by a different mode of action.