Showing papers in "Planta Medica in 2001"

Effects of gum resin of Boswellia serrata in patients with chronic colitis.

Abstract: Patients studied here suffered from chronic colitis characterized by vague lower abdominal pain, bleeding per rectum with diarrhoea and palpable tender descending and sigmoid colon. The inflammatory process in colitis is associated with increased formation of leukotrienes causing chemotaxis, chemokinesis, synthesis of superoxide radicals and release of lysosomal enzymes by phagocytes. The key enzyme for leukotriene biosynthesis is 5-lipoxygenase. Boswellic acids were found to be non-redox, non-competitive specific inhibitors of the enzyme 5-lipoxygenase. We studied the gum resin of Boswellia serrata for the treatment of this disease. Thirty patients, 17 males and 13 females in the age range of 18 to 48 years with chronic colitis were included in this study. Twenty patients were given a preparation of the gum resin of Boswellia serrata (900 mg daily divided in three doses for 6 weeks) and ten patients were given sulfasalazine (3 gm daily divided in three doses for 6 weeks) and served as controls. Out of 20 patients treated with Boswellia gum resin 18 patients showed an improvement in one or more of the parameters: including stool properties, histopathology as well as scanning electron microscopy, besides haemoglobin, serum iron, calcium, phosphorus, proteins, total leukocytes and eosinophils. In the control group 6 out of 10 patients showed similar results with the same parameters. Out of 20 patients treated with Boswellia gum resin 14 went into remission while in case of sulfasalazine remission rate was 4 out of 10. In conclusion, this study shows that a gum resin preparation from Boswellia serrata could be effective in the treatment of chronic colitis with minimal side effects.

Antimycobacterial plant terpenoids.

Abstract: Tuberculosis (TB), mainly caused by Mycobacterium tuberculosis, is the leading killer among all infectious diseases worldwide and is responsible for more than two million deaths annually. For over thirty years no antitubercular agents with new mechanisms of action have been developed. The recent in­ crease in the number of multi-drug resistant clinical isolates of M. tuberculosis has created an urgent need for the discovery and development of new antituberculosis leads. This review covers recent reports on plant-derived terpenoids that have demonstrated moderate to high activity in in vitro bioassays against M. tuberculosis. In this review, mono-, sesqui-, di- and triterpenes, and sterols, their structural analogs and semisyn­ thetic derivatives will be discussed, with particular emphasis on the structural features essential for anti mycobacterial activity.

Isolation of three high molecular weight polysaccharide preparations with potent immunostimulatory activity from Spirulina platensis, aphanizomenon flos-aquae and Chlorella pyrenoidosa.

Abstract: This research describes the identification of three new high molecular weight polysaccharide preparations isolated from food-grade microalgae that are potent activators of human monocytes/macrophages: "Immulina" from Spirulina platensis, "Immunon" from Aphanizomenon flos-aquae, and "Immurella" from Chlorella pyrenoidosa. These polysaccharides are structurally complex and have estimated molecular weights above ten million daltons. All three polysaccharides are highly water soluble and comprise between 0.5 % and 2.0 % of microalgal dry weight. Immunostimulatory activity was measured using a transcription factor-based bioassay for nuclear factor kappa B (NF-kappa B) activation in THP-1 human monocytes/macrophages. Using this system the EC(50) values for these microalgal polysaccharides are between 20 and 110 ng/ml (about 10pM). THP-1 activation was confirmed by measuring immune cytokine mRNA induction using reverse transcriptase-polymerase chain reaction (RT-PCR). Each polysaccharide substantially increased mRNA levels of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). These polysaccharides are between one hundred and one thousand times more active for in vitro monocyte activation than polysaccharide preparations that are currently used clinically for cancer immunotherapy.

Extraction, Isolation and Characterisation of Antitumor Principle, α-Hederin, from the Seeds of Nigella sativa

Abstract: We have previously reported the in vitro cytotoxic activity of column fraction 5 (CC-5) of an ethanolic extract of Nigella sativa seeds. In this study, the effect of CC-5 was evaluated for its in vivo antitumor activity against i.p. (intraperitoneally) implanted murine P388 leukemia and s.c. (subcutaneously) implanted LL/2 (Lewis lung carcinoma) cells in BDF1 mice (C57BL/6 x DBA/2 mice). CC-5 at doses of 200 and 400 mg/kg b.w. prolonged the life span of these mice by 153% compared to DMSO-treated control mice. The antitumor activity of a 21-day treatment of CC-5 against s.c. implanted LL/2 was tested in mice using four experimental protocols as described in the methods. In protocols C and D, CC-5 at a dose of 400 mg/kg b.w. produced significant tumor inhibition rate (TIR) values of 60% (P < 0.001) and 70% (P < 0.001) respectively. Alpha-hederin, a triterpene saponin isolated from CC-5, when given i.p. for 7 days at doses of 5 and 10 mg/kg b.w. to mice with formed tumors, produced significant dose-dependent TIR values of 48% (P < 0.05) and 65% (p < 0.01) respectively on day 8 and 50% (P < 0.01) and 71% (P < 0.001), respectively, on day 15, compared to 81% (P < 0.01) on day 8 and 42% (P < 0.01) on day 15 in the cyclophosphamide (CP)-treated group. The underlying mechanism(s) of antitumor activity of alpha-hederin remain to be established.

Capsaicin-like anti-obese activities of evodiamine from fruits of Evodia rutaecarpa, a vanilloid receptor agonist.

Abstract: Evodiamine, a major alkaloidal principle of Evodia fruits (Evodia rutaecarpa, Rutaceae), showed vanilloid receptor agonistic activities comparable to capsaicin. The Chinese literature refers to Evodia fruits as a "hot nature" herb. In spite of the similarities in the actions of evodiamine and capsaicin in vitro, evodiamine has no perceptible taste, including a peppery hot taste. Therefore, the effectiveness of evodiamine and the extract of Evodia fruits in preventing obesity on male C3H mice, or male SD rats were examined. When evodiamine was supplemented at 0.03% of the diet and fed to mice for 12 days, the perirenal fat weight became significantly lower than in the control group. The epididymal fat mass was also decreased in the evodiamine diet group. When evodiamine was supplemented at 0.02% in the form of ethanol extract of Evodia fruits to the high-fat diet and fed to rats for 21 days, the body weight, the perirenal fat weight, epididymal fat weight, the levels of serum free fatty acid, total lipids in the liver, triglyceride in the liver, and cholesterol level in the liver were significantly reduced as compared with the control diet group. Furthermore, both lipolytic activity in the perirenal fat tissue and specific GDP binding in brown adipose tissue mitochondria, as the biological index of enhanced heat production, were significantly increased in the evodiamine fed rats. Fasting mice subcutaneously administered 1-3 mg/kg evodiamine showed decreased core body temperature by 1-2 degrees C. This hypothermic effect was prevented by the pretreatment of intraperitoneally administered 10 mg/kg capsazepine, a vanilloid receptor antagonist. On the other hand, food-sated mice subcutaneously administered 1-3 mg/kg evodiamine showed unchanged core body temperature and increased tail skin temperature by more than 5 degrees C, suggesting the increased energy expenditure by enhanced heat dissipation. In conclusion, we have demonstrated that a novel non-pungent vanilloid receptor agonist, evodiamine, mimics the characteristic anti-obese effects induced by capsaicin. Evodiamine would induce heat loss and heat production at the same time and dissipate food energy, preventing the accumulation of perivisceral fat and the body weight increase.

Antibacterial activity of Hydrastis canadensis extract and its major isolated alkaloids.

Abstract: The antibacterial activity of extract and isolated major alkaloids (berberine, beta-hydrastine, canadine and canadaline) of Hydrastis canadensis L. (Ranunculaceae) was evaluated against 6 strains of microorganism: Staphylococcus aureus (ATCC 25 993 and ATCC 6538P), Streptococcus sanguis (ATCC 10 556), Escherichia coli (ATCC 25 922), Pseudomonas aeruginosa (ATCC 27 853). Bactericidal activity was evaluated by contact test by measuring the "killing time" on a low density bacterial inoculum, and bacteriostatic activity in liquid medium by M.I.C. values. The results provide a rational basis for the traditional antibacterial use of Hydrastis canadensis.

Essential oil composition and antimicrobial activity of three Zingiberaceae from S.Tomé e Príncipe.

Abstract: The essential oil composition of three Zingiberaceae widely used as medicinal aromatic plants from S. Tome and Principe: Aframomum danielli (Hook. f.) K. Schum., Curcuma longa L. and Zingiber officinale Rosc. was studied. Two samples of the essential oils from fruit of A. danielli and from rhizomes of the other two species, were obtained by hydrodistillation and analyzed by GC, GC-MS, and (13)C-NMR. The essential oil from fruits of A. danielli has been studied for the first time and was characterised by its high content of monoterpenes, with 1,8-cineole (25.5 - 34.4 %) the major constituent, followed by beta-pinene (14.1 - 15.2 %) and alpha-terpineol (9.9 - 12.1 %). Essential oils from the rhizomes of C. longa contained a lower content of ar-turmerone (4.0 - 12.8 %) than those reported in the literature for C. longa from other origins (24.7 - 31.4 %), whereas the results for Z. officinale essential oils were in accordance with the literature data. The essential oils of A. danielli and Z. officinale showed antimicrobial activity against all Gram-positive and Gram-negative bacteria tested, as well as against yeasts and filamentous fungi, using the agar diffusion method.

Polysaccharides from lichens : Structural characteristics and biological activity

Abstract: Lichens have been used for medicinal purposes throughout the ages, and beneficial claims have to some extent been correlated with their polysaccharide content. Of 13,500 lichen species growing worldwide, less than 100 species have been investigated for polysaccharide content. Lichen polysaccharides are mainly of three different structural types: beta-glucans, alpha-glucans, and galactomannans. In addition, a few complex heteroglycans have recently been described, such as thamnolan, a water-soluble, immunologically active heteroglycan with a novel rhamnopyranosylgalactofuranan type of structure. A number of investigations have been carried out on biological effects of lichen polysaccharides, most notably antitumour, immunomodulating, antiviral, and memory-enhancing effects. The current review summarizes present knowledge on the structural characteristics and biological activity of lichen polysaccrides.

Antithrombotic effect of geniposide and genipin in the mouse thrombosis model

Abstract: Geniposide is one of the constituents of Gardenia fruit (Gardenia jasminoides Ellis, Rubiaceae), which has been used in traditional medicine. Although its anti-inflammatory and antithrombotic effects have been reported, the way it acts is still unclear. We have investigated the effects of geniposide and its metabolite genipin on thrombogenesis and platelet aggregation. In an in vivo model, geniposide and genipin significantly (P < 0.05) prolonged the time required for thrombotic occlusion induced by photochemical reaction in the mouse femoral artery. In an in vitro study, both geniposide and genipin inhibited collagen-induced, but did not inhibit arachidonate-induced, mouse platelet aggregation. However aspirin, a cyclooxygenase inhibitor, inhibited arachidonate-induced platelet aggregation but only partially inhibited the collagen-induced one. We also showed, by measuring PLA 2 -catalyzed arachidonic acid release, that geniposide inhibited phospholipase A 2 (PLA 2 ) activity. We conclude that geniposide showed an antithrombotic effect in vivo due to the suppression of platelet aggregation. PLA 2 inhibition by geniposide is one possible anti-platelet mechanism.

Composition and antimicrobial activity of the essential oil of Salvia ringens.

Abstract: The essential oils of Salvia ringens (samples A and B), were analyzed by means of GC and GC/MS. From the seventy-five identified constituents representing 99.82 and 99.86% of the oils, 1,8-cineole and alpha-pinene were the major components. Furthermore, sample B exhibited a very interesting antimicrobial profile after it was tested against six gram (+/-) bacteria and three pathogenic fungi.

Inhibitory effect of stevioside on calcium influx to produce antihypertension.

Abstract: Stevioside is a sweet-tasting glycoside occurring abundantly in the leaves of Stevia rebaudiana (Compositae). It has been used popularly in Japan and Brazil as a sugar substitute for decades. Previous study has shown that it lowered blood pressure in spontaneously hypertensive rats (SHRs) when administered intravenously. This study shows that intraperitoneal injection of stevioside 25 mg/kg also has antihypertensive effect in SHRs. In isolated aortic rings from normal rats, stevioside could dose-dependently relax the vasopressin-induced vasoconstriction in both the presence and absence of endothelium. However, stevioside had no effect on phenylephrine- and KCl-induced phasic vasoconstriction. In addition, stevioside lost its influence on vasopressin-induced vasoconstriction in Ca(2+)-free medium. The results indicate that stevioside caused vasorelaxation via an inhibition of Ca(2+) influx into the blood vessel. This phenomenon was further confirmed in cultured aortic smooth muscle cells (A7r5). Using 10(-5) M methylene blue for 15 min, stevioside could still relax 10(-8) M vasopressin-induced vasoconstriction in isolated rat aortic rings, showing that this vasorelaxation effect was not related to nitric oxide. The present data show that the vasorelexation effect of stevioside was mediated mainly through Ca(2+) influx inhibition.

Antioxidant activity of leaves of Salvia species in enzyme-dependent and enzyme-independent systems of lipid peroxidation and their phenolic constituents.

Abstract: The protective effects of eleven Salvia species native to Europe against enzyme-dependent and enzyme-independent lipid peroxidation were evaluated. The 50% aqueous methanolic extracts of the leaves of all tested plants were found to be more effective than the positive control alpha-tocopherol acid succinate. The extracts of S. candelabrum, S. ringens, S. tomentosa, S. nemorosa, and S. glutinosa displayed considerable concentration-dependent antioxidative effects that were comparable to those of the medicinal and aromatic plant S. officinalis. The concentrations of flavonoids, hydroxycinnamic acids and total phenolic compounds in each extract were quantified with the aim of clarifying the connection between activity and chemical composition.

Neurotrophic and Neuroprotective Actions of Ginsenosides Rb1 and Rg1

Abstract: The ginsenosides have many pharmacological actions, including various actions on the nervous system. Our previous studies have demonstrated that two ginsenosides, Rb(1) and Rg(1) improve performance in a passive avoidance-learning paradigm and enhance cholinergic metabolism. The present study was designed to examine the cellular neurotrophic and neuroprotective actions of two pure ginsenosides in two model systems. PC12 cells were grown in the absence or presence of nerve growth factor (NGF) as a positive control, and different concentrations of Rb(1) or Rg(1). To assess neurotrophic properties, neurite outgrowth was quantified for representative fields of cells. After 8 days in culture, both ginsenosides enhanced neurite outgrowth in the presence of a sub-optimal dose of (2 ng/ml) NGF, but did not significantly stimulate neurite outgrowth in the absence of NGF. However, after 18 days in culture, both ginsenosides increased neurite outgrowth in the absence of NGF. SN-K-SH cells were grown in the absence or presence of MPTP or beta-amyloid to assess neuroprotection. Rb(1) and Rg(1) both reversed MPTP-induced cell death. beta-Amyloid-induced cell death was not reversed by either ginsenoside, but Rg(1) produced a modest enhancement of cell death in this model. These results suggest that these two ginsenosides have neurotrophic and selective neuroprotective actions that may contribute to the purported enhancement of cognitive function.

Diarylheptanoids with free radical scavenging and hepatoprotective activity in vitro from Curcuma longa.

Abstract: Assay-guided fractionation of the EtOAc soluble fraction of the rhizomes of Curcuma longa furnished three DPPH free radical scavenging diarylheptanoids, curcumin (1), demethoxycurcumin (2), and bisdemethoxycurcumin (3). Compounds 1-3 showed the DPPH radical scavenging effects with IC(50) values of 2.8, 39.2, 308.7 microM, respectively. L-Ascorbic acid and resveratrol as positive controls exhibited IC(50) values of 22.5 and 25.0 microM, respectively. Compounds 1-3 showed significant hepatoprotective effects on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells. The EC(50) values of 1-3 are 86.9, 70.7, and 50.2 microM, respectively. Silybin (EC(50) = 69.0 microM) and silychristin (EC(50) = 82.7 microM) were used as positive controls.

In Vitro Effect of Alkaloids on Bloodstream Forms of Trypanosoma brucei and T. congolense

Abstract: The effect of 34 alkaloids of the piperidine, pyridine, tropane, isoquinoline, indole, quinolizidine, quinoline, purine, and steroidal types on the growth of Trypanosoma brucei, T. congolense, and human HL-60 cells was investigated in vitro. Berbamine, berberine, cinchonidine, cinchonine, emetine, ergotamine, quinidine, quinine, and sanguinarine showed trypanocidal activities with ED(50) (50% effective dose) values below 10 microM. Berberine, emetine, and quinidine were the most active compounds found; their ED(50) values and minimum inhibitory concentrations were comparable to those of the antitrypanosomal drugs suramin and diminazene aceturate. However, most of these compounds were also cytotoxic. In the case of emetine, the ratio of cytotoxic/trypanocidal activity was only 3 while for quinidine it was 300 indicating that this alkaloid could be a candidate for further drug development. DNA intercalation in combination with protein biosynthesis inhibition, which is the major mode of action of the active alkaloids, could be responsible for the observed trypanocidal and cytotoxic effects.

Osteoblastic proliferation stimulating activity of Psoralea corylifolia extracts and two of its flavonoids.

Abstract: Psoralea corylifolia L. fruit extracts exhibited osteoblastic proliferation stimulating activity in UMR106 cell line cultured in vitro. The flavonoids of corylin and bavachin were isolated and identified as active principles by activity-guided fractionation. The results suggested that Psoralea corylifolia L. fruit extracts and corylin and bavachin might stimulate bone formation or have potential activity against osteoporosis.

Antidiarrhoeal Activity of Piperine in Mice

Abstract: Peppers are common food ingredients used worldwide. They are also added in traditional antidiarrhoeal formulations of different herbs. Piperine (1) is an alkaloidal constituent of black and long peppers recently established as a bioavailability enhancer of drugs and other substances. As a part of efforts to study its effects on the gastrointestinal tract, the experiments were performed to determine the rationale, if any, for its use in traditional antidiarrhoeal formulations. Antidiarrhoeal activity of 1 against castor oil, MgSO4 and arachidonic acid was studied in mice. It significantly inhibited diarrhoea produced by these cathartics at 8 and 32 mg/kg p.o. dose. Inhibition of castor oil induced enteropooling by 1 suggests its inhibitory effect on prostaglandins. The results validate the rationale for its use in traditional antidiarrhoeal formulations.

Examination of lectins, polysaccharopeptide, polysaccharide, alkaloid, coumarin and trypsin inhibitors for inhibitory activity against human immunodeficiency virus reverse transcriptase and glycohydrolases.

Abstract: A variety of lectins were tested in vitro for inhibitory action against the activities of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase and the N-glycohydrolases (alpha-glucosidase, beta-glucosidase and beta-glucuronidase). Lectins from Phaseolus vulgaris, Momordica charantia, Ricinus communis and its constituent chains, and Agaricus bisporus were able to inhibit HIV-1 reverse transcriptase. P. vulgaris lectin and A. bisporus lectin were the most potent. The aforementioned lectins had only weak or no inhibitory effects on the glycohydrolases. The inhibitory effect of polysaccharopeptide from the mushroom Coriolus versicolor on HIV-1 reverse transcriptase and alpha-glucosidase was enhanced after chemical modification with chlorosulfonic acid. However, the inhibitory effect of the algal polysaccharide fucoidan on HIV-1 reverse transcriptase and alpha-glucosidase was not augmented by sulfation. Trypsin inhibitors from Phaseolus lunatus and Glycine max, gossypol and alkaloids from Corydalis yanhusuo were able to inhibit HIV-1 reverse transcriptase. Dicoumarol was capable of inhibiting HIV-1 reverse transcriptase, alpha-glucosidase, beta-glucosidase and beta-glucuronidase.

Identification and isolation of the cyclooxygenase-2 inhibitory principle in Isatis tinctoria.

Abstract: Various extracts prepared from the traditional dye and medicinal plant Isatis tinctoria L. were submitted to a broad in vitro screening against 16 anti-inflammatory targets. Dichloromethane (DCM) extracts from dried leaves showed a marked cyclooxygenase (COX) inhibitory activity with a preferential effect on COX-2 catalysed prostaglandin synthesis. A supercritical fluid extraction (SFE) procedure employing CO2-modifier mixtures was developed by which the bioactivity profile and chromatographic fingerprint of the DCM extract could be reproduced. High-resolution activity directed on-line identification of the COX-2 inhibitory principle, using a combination of LC-DAD-MS with a microtitre-based bioassay, led to the identification of tryptanthrin (1) as the constituent responsible for essentially all COX-2 inhibitory activity in the crude extract. Following on-line identification, 1 was isolated at preparative scale and its structure confirmed by comparison with synthetic tryptanthrin. In an assay with lipopolysaccharide stimulated Mono Mac 6 cells, tryptanthrin (1) was of comparable potency (IC50 = 64 nM) than the preferential COX-2 inhibitors nimesulide (IC50 = 39 nM) and NS 398 (IC50 = 2 nM). The SFE extract and 1 showed no cytotoxicity in Mono Mac 6 and RAW 264.7 cells when tested at 100 microg/ml and 10 microM, respectively.

Investigations of the mechanism of membrane activity of selected triterpenoid saponins.

Abstract: The experiments with different triterpenoid saponins showed a significant difference in the microphysiometric activity between acylated and non-acylated compounds. Only acylated saponins in low concentrations were able to activate the metabolism of endothelial cells after short-time incubation in a transient manner lasting approximately 2 hours. The strongest effect was produced by virgaureasaponin b, an incubation with 4 microg/ml over 6 min induced a stimulation of the metabolic activity of 190% maximum after 30 min. This treatment did not induce non-reversible toxic effects, and could be repeated in the same way after a recovery period. The saponins without acylation in the glycosidic part did not induce metabolic stimulation, even in concentrations higher than observed for the acylated compounds. The current interpretation of the results is connected with the suggestion that especially acylated saponins are able to integrate into the cellular membrane transiently. This integration might induce pore-like structures which change the membrane permeability associated with alterations in the ionic homeostasis between intracellular and extracellular compartments.

Inhibition of prostaglandin E2 production by platycodin D isolated from the root of Platycodon grandiflorum.

Abstract: Platycodin D, isolated from the root of Platycodon grandiflorum A. DC. (Campanulaceae) suppressed prostaglandin E2 production at 10 and 30 microM in rat peritoneal macrophages stimulated by the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA). Platycodin D3 and oleanolic acid showed no effect at these concentrations. Western blot analysis revealed that the induction of COX-2 protein by TPA was inhibited by platycodin D in parallel with the inhibition of prostaglandin E2 production. Platycodin D showed no direct effect on COX-1 and COX-2 activities. TPA-induced release of [3H]arachidonic acid from pre-labeled macrophages was also not inhibited by platycodin D.

A Sesquiterpene Lactone, Costunolide, from Magnolia grandiflora Inhibits NF-κB by Targeting IκB Phosphorylation

Abstract: A sesquiterpene lactone, costunolide (CTN), was identified from Magnolia grandiflora together with parthenolide (PTN) by its strong inhibition of LPS-induced NF-kappa B activation. CTN, which showed more potent inhibition than PTN in the NF-kappa B activation, strongly suppressed nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. RT-PCR and Western blot analyses demonstrated that CTN suppressed the expression of iNOS mRNA and protein in a dose-dependent manner. CTN also significantly inhibited LPS-induced DNA-binding activity of NF-kappa B as well as the LPS-induced degradation of I kappa B-alpha and -beta. Furthermore, CTN inhibited LPS-induced phosphorylation of I kappa B-alpha. These findings support that CTN inhibits NO production by down-regulating iNOS expression, at least, in part through the inhibition of I kappa Bs' phosphorylation and degradation, which are essential for the activation of NF-kappa B.

Apoptosis induced by isoliquiritigenin in human gastric cancer MGC-803 cells.

Abstract: Isoliquiritigenin, which is possibly a principal anti-tumor constituent of licorice, a traditional Chinese herb, was examined for apoptosis-inducing activity in human gastric cancer MGC-803 cells. Typical morphological and biochemical features of apoptosis including cell shrinkage, chromatin condensation, DNA ladder formation, and appearance of apoptotic peaks (subG(1)) were observed in MGC-803 cells with isoliquiritigenin treatment. Using Fluo-3 and Rh123 as fluorescent probes, respectively, it was found that the intracellular free calcium concentration increased and the mitochondrial transmembrane potential (Deltapsi(m)) decreased in a dose-dependent manner in apoptotic cells. These results suggest that isoliquiritigenin induced apoptosis of MGC-803 cells through calcium- and Deltapsi(m)-dependent pathways, indicating that it is potentially useful as a natural anti-cancer agent.

Monoamine oxidase inhibitors from rhizoma of Coptis chinensis.

Abstract: Three protoberberine alkaloids jatrorrhizine, berberine and palmatine were isolated from the monoamine oxidase (MAO) inhibitory fraction of the methanol extract of Coptis chinensis rhizoma. Jatrorrhizine was shown to inhibit non-competitively both MAO-A and -B from rat brain mitochondria with the IC50 values of 4 and 62 microM, respectively. Berberine only competitively inhibited MAO-A with an IC50 values of 126 microM whereas palmatine exhibited, up to 200 microM, no inhibition on any type of the enzyme. The structure-activity relationship was briefly discussed.

Lignan and phenylpropanoid glycosides from Phillyrea latifolia and their in vitro anti-inflammatory activity.

Abstract: Three phenylpropanoid glycosides (salidroside, syringin and coniferin) and one lignan (phillyrin) isolated from the leaves of Phillyrea latifolia L. (Oleaceae) were tested for interactions with the cyclo-oxygenase and 5-lipoxygenase pathways of arachidonate metabolism in calcium-stimulated mouse peritoneal macrophages and human platelets, and for their effects on cell viability. These compounds are capable of exerting inhibitory actions on enzymes of the arachidonate cascade. Phillyrin, salidroside and syringin exert a preferential effect on the cyclo-oxygenase pathway, inhibiting release of the cyclo-oxygenase metabolites prostaglandin E2 (IC50 values 45.6 microM, 72.1 microM and 35.5 microM, respectively) and to a lesser extent reducing thromboxane B2 levels (IC50 values 168 microM, 154 microM and 29.3 microM, respectively). In contrast, coniferin can be classified as a "dual inhibitor", since it produces reduction in generation of both cyclo-oxygenase (IC50 values 75.2 microM for prostaglandin E2 and 619 microM for thromboxane B2) and 5-lipoxygenase metabolites, but the effects are greater against leukotriene C4 (IC50 value 63.6 microM). Structure-activity relationships of the three phenylpropanoid glycosides are discussed. Thus, like some other compounds found in medicinal herbs, our molecules possess an array of potentially beneficial anti-eicosanoid properties which may, alongside other constituents, contribute to the claimed therapeutic properties of the plant from which they are derived.

Kalopanaxsaponin A is a basic saponin structure for the anti-tumor activity of hederagenin monodesmosides.

Abstract: Hederagenin, delta-hederin [hederagenin alpha-L-arabinoside], kalopanax-saponin A [hederagenin 3-O-alpha-L-rhamnosyl(1-->2)-alpha-L- arabinoside], kalopanaxsaponin I [hederagenin 3-O-beta-D-xylosyl(1-->3)-alpha-L- rhamnosyl(1-->2)-alpha-L-arabinoside], and sapindoside C [hederagenin 3-O-beta-D-glucosyl(1-->4)-beta-D-xylsyl (1-->3)-alpha-L-rhamnosyl(1-->2)-alpha-L-arabinoside] were isolated from stem bark of Kalopanax pictus Nakai (Araliaceae). Among glycosides of hederagenin, disaccharide (kalopanaxsaponin A, commonly also called alpha-hederin), trisaccharide (kalopanaxsaponin I), and tetrasaccharide (sapindoside C) showed significant cytotoxicity on several types of tumor cells, while hederagenin itself exhibited only weak cytotoxicity and its monosaccharide (delta-hederin) was non-cytotoxic. From these results, it suggests that the arabinosyl moiety at C-3 blocks the activity of hederagenin and the position of the second sugar for glycoside linkage is also important for cytotoxicity. In the in vivo experiments, kalopanaxsaponin A (15 mg/kg, i.p.) apparently increased the life span of mice bearing Colon 26 and 3LL Lewis lung carcinoma, as well as cisplatin (3 mg/kg, i.p.). These results indicated that kalopanaxsaponin A has potential anti-tumor applications.

Steroidal saponins from Tribulus terrestris

Abstract: Three new steroidal saponins were isolated from the fruits of Tribulus terrestris, and their structures were elucidated as (25R,S)-5 alpha-spirostane-12-one-3 beta-ol-3-O-beta-xylopyranosyl(1-->2)- [beta-xylopyranosyl(1-->3)]-beta-glucopyranosyl(1-->4)-[alpha-rhamno- pyranosyl(1-->2)]-beta-galactopyranoside; 26-O-beta-glucopyranosyl-(25S)-5 alpha-furostane-12-one-3 beta,22 alpha,26-triol-3-O-beta-glucopyranosyl(1-->2)-beta-galactopyranoside; 26-O-beta-glucopyranosyl-(25S)-5 alpha-furostane-12-one-3 beta,22 alpha,26-triol-3-O-beta-glucopyranosyl(1-->4)-[alpha- rhamnopyranosyl(1-->2)]-beta-galactopyranoside, respectively, by spectroscopic analysis and color reaction.

Cytotoxicity and lipid peroxidation-inhibiting activity of flavonoids.

Abstract: Thirty-five flavonoids of seven different types, namely isoflavonoids, chalcones, dihydroflavonols, flavanols, flavanones, flavones, and flavonols were investigated for their ability to inhibit ascorbate-induced microsomal lipid peroxidation and their cytotoxicity. For each activity a structure-activity relationship was established. Subsequently, an antioxidant selectivity index, i. e., the maximal non-toxic dose divided by the IC(50) value for lipid peroxidation, was introduced. Kaempferol showed the highest antioxidant selectivity index of all flavonoids tested.

Piperine inhibits gastric emptying and gastrointestinal transit in rats and mice

Abstract: Piperine (1), an alkaloid of black and long peppers, inhibited gastric emptying (GE) of solids/liquids in rats and gastrointestinal transit (GT) in mice in a dose and time dependent manner. Compound 1 significantly inhibited GE of solids and GT at the doses extrapolated from humans (1 mg/kg and 1.3 mg/kg p.o. in rats and mice, respectively). However, at the same dose the effect was insignificant for GE of liquids. One week oral treatment of 1 mg/kg and 1.3 mg/kg in rats and mice, respectively, did not produce a significant change in activity as compared to single dose administration. GE inhibitory activity of 1 is independent of gastric acid and pepsin secretion.

Authentication of medicinal Dendrobium species by the internal transcribed spacer of ribosomal DNA.

Abstract: Herba Dendrobii (Shihu) is a commonly used Chinese medicine derived from the stem of several orchid species belonging to the genus Dendrobium. It is rather expensive and adulteration is frequent. Proper authentication of the medicinal species is necessary to protect consumers and support conservation measures. DNA sequences of the internal transcribed spacer 2 (ITS 2) of 16 Dendrobium species were shown to be significantly different from one another by an average of 12.4% and from non-orchids and Pholidota (an adulterant of Shihu) by 29.8% and 18.8%, respectively. The intra-specific variation among the Dendrobium species studied was only about 1%. Therefore, ITS 2 regions could be adopted as a molecular marker for differentiating medicinal Dendrobium species from one another and also from non-orchids and adulterants.