Showing papers in "Planta Medica in 1997"

Anti-inflammatory actions of pentacyclic triterpenes.

Abstract: Pentacyclic triterpenes (PTs) as aglycones of saponins have a wide distribution in plants, and many of them have been used as anti-inflammatory remedies in folk medicine. This survey critically reviews the effects of PTs on proinflammatory mediator signalling pathways and data from experimental animal models and clinical trials. Because the knowledge of their actions is far from being satisfactory a critical summary of the partly promising but mostly scattered and preliminary data might promote productive research on chances and risks of PTs. Antiproliferative and anti-infectious actions and effects on intracellular cell signalling and hormone metabolism are beyond the scope of this short review, although such effects might also contribute to the understanding of the systemic anti-inflammatory actions of aglycones.

Studies on the anti-inflammatory activity of rhizomes of Nelumbo nucifera.

Abstract: The anti-inflammatory activity of the methanol extract of Nelumbo nucifera rhizome as well as of betulinic acid, a steroidal triterpenoid isolated from it, were evaluated on carrageenin and serotonin induced rat paw edema. Methanol extract at doses of 200 and 400 mg/kg and betulinic acid at doses of 50 mg/kg and 100 mg/kg p.o., showed significant anti-inflammatory activity in both the models of inflammation in rats. The effects produced were comparable to that of phenylbutazone and dexamethasone, two prototype anti-inflammatory drugs.

Antibacterial activity of extracts and constituents of Pelargonium sidoides and Pelargonium reniforme

Abstract: The antibacterial activity of extracts and isolated constituents (scopoletin, umckalin, 5,6,7-trimethoxycoumarin, 6,8-dihydroxy-5,7-dimethoxycoumarin, (+)-catechin, gallic acid and its methyl ester) of Pelargonium sidoides and Pelargonium reniforme (Geraniaceae), plant species used in folk medicine by the Southern African native population, was evaluated against 8 microorganisms, including 3 Gram-positive (Staphylococcus aureus, Streptococcus pneumoniae, and beta-hemolytic Streptococcus 1451) and 5 Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Haemophilus influenzae). Minimum inhibitory concentrations (MICs) varied with the preparation of the extracts and microorganisms tested, from about 0.6 mg/ml for aqueous phases to over 10 mg/ml for crude Pelargonium extracts. With the exception of the ineffective (+)-catechin, all the potentially active compounds exhibited antibacterial activities with MICs of 200-1000 micrograms/ml. The results provide for a rational basis of the traditional use of the titled Pelargonium species.

Role of human intestinal Prevotella oris in hydrolyzing ginseng saponins.

Abstract: The potential of intestinal bacteria to hydrolyze ginsenoside Rb1 to 20-O-beta-D-glucopyranosyl-20(S)-protopanaxadiol (I) was found in 79% of the fecal specimens from 58 human subjects whose age ranged from 1 to 64 years. Following a ginsenoside-Rb1-hydrolyzing activity assay, Prevotella oris strains were then isolated as a major bacterial species possessing the potential. All the intestinal isolates converted ginsenosides Rb1 and Rd to I, ginsenoside Rb2 to 20-O-[alpha-L-arabinopyranosyl(1-->6)-beta-D-glucopyranosyl]-20(S) -protopanaxadiol (II), and ginsenoside Rc to 20-O-[alpha-L-arabinofuranosyl(1-->6)-beta-D-glucopyranosyl]-20(S)- protopanaxadiol (III) like fecal microflora, but did not attack ginsenosides Re or Rg1 (protopanaxatriol-type). The isolates were susceptible to colimycin (MIC, 3.13 micrograms/ml) and then the treatment of specific pathogen free mice with colimycin (20 mg/kg/day) decreased intestinal bacterial Rb1-hydrolyzing potential from 22.1 +/- 1.2% to 4.7 +/- 2.7%, while the decreased potential was restored to 30.7 +/- 3.7% by the inoculation with P. oris isolates. These results suggest that the metabolism of protopanaxadiol saponins to metabolites I-III in the intestines seems most partly due to intestinal P.oris. In addition, the fact that neither intact ginsenoside Rb1 nor its middle metabolic derivatives but only the final metabolite I was detected at 1.0-7.3 micrograms/ml in blood after oral administration of mice with ginsenoside Rb1 (125 mg/kg) allows us to speculate that metabolites I-III are the most likely forms of protopanaxadiol saponins absorbed from the intestines.

In vitro cytotoxicity of tanshinones from Salvia miltiorrhiza.

Abstract: The cytotoxicity-guided fractionation of the roots of Salvia miltiorrhiza B. (Labiatae) extracts led to the isolation of eighteen active principles 1 ∼ 18, responsible for the cytotoxicity against five cultured human tumor cell lines, i.e., A549 (non-small cell lung), SK-OV-3 (ovary), SK-MEL-2 (melanoma), XF498 (central nerve system) and HCT-15 (colon), using the SRB (sulfrhodamine-B) method in vitro. All active compounds 1 ∼ 18 including two novel components 5 and 11 were comprised of tanshinone pigments, unusual diterpenes exclusively found in this species. The proliferation of each examined tumor cell line was significantly inhibited (IC 50 values ranged from 0.2 to 8.1 μg/ml) during the continuous exposure of tumor cells to 1 ∼ 18 for 48 hours, respectively.

Antihyperglycemic effects of paeoniflorin and 8-debenzoylpaeoniflorin, glucosides from the root of Paeonia lactiflora.

Abstract: Paeoniflorin and 8-debenzoylpaeoniflorin were isolated from the dried root of Paeonia lactiflora Pall. (Ranunculaceae). They produced a significant blood sugar lowering effect in streptozotocin-treated rats and had a maximum effect at 25 min after treatment. This hypoglycemic action was also observed in normoglycemic rats only at 1 mg/kg. The antihyperglycemic activity of 8-debenzoylpaeoniflorin seems lower than that of paeoniflorin. Plasma insulin was not changed in paeoniflorin-treated normoglycemic rats indicating an insulin-independent action. Also, this glucoside reduced the elevation of blood sugar in glucose challenged rats. Increase of glucose utilization by paeoniflorin can thus be considered. There are no previous data showing the hypoglycemic activity of paeoniflorin and/or 8-debenzoylpaeoniflorin in rats.

Investigations on the gastroprotective and antidiarrhoeal properties of ternatin, a tetramethoxyflavone from Egletes viscosa.

Abstract: The study was designed to verify the gastroprotective and antidiarrhoeal effects of ternatin, a tetramethoxyflavone isolated from Egletes viscosa Less. The gastroprotective function of ternatin was evaluated in rats against gastric mucosal damage induced by hypothermic restraint stress, absolute ethanol, and indomethacin, whereas the antidiarrhoeal activity was investigated by studying its influence on gastrointestinal transit as measured by a charcoal marker and on castor oil-induced accumulation of intestinal fluid in mice and also on contractile responses evoked by acetylcholine, histamine, serotonin, and barium chloride in isolated guinea-pig ileum. The results demonstrate that pretreatment of animals with the plant flavonoid (25 and 50 mg/kg, i.p.) produces a significant inhibition of gastric lesions induced by ethanol but not those induced by restraint stress or indomethacin and suggest a probable involvement of a prostaglandins-independent mechanism of gastroprotection. At similar doses, both the intestinal transit as well as the accumulation of intestinal fluids induced by castor oil in mice were significantly inhibited by ternatin. Furthermore, the flavonoid antagonised the contractile responses evoked by different agonists on guinea-pig ileum in vitro and its inhibitory potential for the drugs are in the order of acetylcholine > histamine > serotonin > barium chloride. Taken together, these results point out a possible antidiarrhoeal effect of ternatin since inhibition of intestinal motility and secretion can greatly control clinical diarrhoea.

Anti-inflammatory activity of extracts from leaves of Phyllanthus emblica.

Abstract: Leaves and fruits of Phyllanthus emblica L have been used for the anti-inflammatory and antipyretic treatment of rural populations in its growing areas in subtropical and tropical parts of China, India, Indonesia, and the Malay Peninsula In the present study, leaves of Ph emblica were extracted with ten different solvents (n-hexane, diethyl ether, methanol, tetrahydrofuran, acetic acid, dichloromethane, 1,4-dioxane, toluene, chloroform, and water) The inhibitory activity of the extracts against human polymorphonuclear leukocyte (PMN) and platelet functions was studied Methanol, tetrahydrofuran, and 1,4-dioxane extracts (50 micrograms/ml) inhibited leukotriene B4-induced migration of human PMNs by 90% and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced degranulation by 25-35% The inhibitory activity on receptor-mediated migration and degranulation of human PMNs was associated with a high proportion of polar compounds in the extracts as assessed by normal phase thin layer chromatography Diethyl ether extract (50 micrograms/ml) inhibited calcium ionophore A23187-induced leukotriene B4 release from human PMNs by 40%, thromboxane B2 production in platelets during blood clotting by 40% and adrenaline-induced platelet aggregation by 36% Ellagic acid, gallic acid and rutin, all compounds isolated earlier from Ph emblica, could not explain these inhibitory activities on PMNs or platelets by Ph emblica extracts These results show that the leaves of Ph emblica have inhibitory activity on PMNs and platelets, which confirm the anti-inflammatory and antipyretic properties of this plant as suggested by its use in traditional medicine The data suggest that the plant leaves contain as yet unidentified polar compound(s) with potent inhibitory activity on PMNs and chemically different apolar molecule(s) which inhibit both prostanoid and leukotriene synthesis

Betulinic Acid: Isolation from Triphyophyllum peltatum and Ancistrocladus heyneanus, Antimalarial Activity, and Crystal Structure of the Benzyl Ester*

Abstract: The known lupane-type triterpene betulinic acid (3) was isolated for the first time from Triphyophyllum peltatum and Ancistrocladus heyneanus. It was found to exhibit moderate to good in vitro antimalarial activity against asexual erythrocytic stages of the human malaria parasite Plasmodium falciparum. A first X-ray structure analysis succeeded after conversion into its benzyl ester 4.

Isolation and immunomodulatory effect of flavonol glycosides from Epimedium hunanense.

Abstract: The ethyl acetate and n-butanol fractions from aerial parts of E. hunanense were initially screened to find active fractions with immunomodulatory activity. Nine compounds, tricin (1), luteolin (2), thalictoside (3), icariin I (4), baohuoside I (5), quercitrin (6), icariin (7), epimedin C (8), and B (9) were isolated from this species for the first time, and 3 was isolated for the first time from flavonoid extracts of the genus. Their structures were established by chemical and spectroscopic methods. The immunomodulatory effects of the n-butanol fraction and epimedin C isolated from the fraction were investigated. Hydrocortisone acetate (HCA) was used as an immunosuppressant to inhibit the immune response of mice. The n-butanol fraction and epimedin C significantly enhanced the response of spleen antibody-forming cells (SAFC) to near normal in the mice treated with HCA. They also significantly enhanced lymphocyte proliferation and caused a significant recovery of interleukin-2 (IL-2) production in the mice inhibited with HCA. In conclusion, they are active principles with immunoenhancing effects.

In vitro antispasmodic compounds of the dry extract obtained from hedera helix

Abstract: Commercial dry extract of Hedera helix L. is used for the treatment of disorders of the respiratory tract; it is standardized towards papaverine (papaverine equivalent value, PE, activity of 1 g test substance equivalent to the activity of x mg papaverine) by in vitro antispasmodic activity on isolated guinea-pig ileum with acetylcholine as spasmogen. In order to determine the phytochemical basis for the antispasmodic activity, bioassay guided fractionation and subsequent isolation of phenolic compounds (flavonols, caffeoylquinic acids) and saponins (hederacoside C, alpha-hederin, hederagenin) was carried out. Fractions and isolates obtained were investigated for antispasmodic activity and their contribution to the activity of the extract was calculated. Significant activity was found for both saponins and phenolic compounds, the PE values being approx. 55 and 49 for alpha-hederin and hederagenin, 54 and 143 for quercetin and kaempferol, and 22 for 3,5-dicaffeoylquinic acid, respectively. In view of their relative high concentration the saponins contribute most to the anti-spasmodic activity, followed by dicaffeoylquinic acids and the flavonol derivatives. The results indicate that the summed PE value of the compounds mentioned is an acceptable agreement with the PE value of the whole extract determined biologically.

Chemical constituents of Isatis indigotica.

Abstract: From the roots of Isatis indigotica, ten compounds (1-10) were isolated. Compound 1 is a new alkaloid whose structure was elucidated as (E)-3-(3',5'-dimethoxy-4'-hydroxy-benzylidene)-2-indolinone. Compounds 2-4 were discovered for the first time from a natural source and compounds 5-7 were originally isolated from this species. In a preliminary study, compounds 4-8 showed antiendotoxic activities in vitro.

Steroidal saponins from Asparagus officinalis and their cytotoxic activity.

Abstract: Two oligofurostanosides were isolated from the seeds of Asparagus officinalis L and their structures characterized as 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-(alpha-L-rhamnopyranosyl- (1-->4))-beta-D-glucopyranosyl]-26-O-[beta-D-glucopyranosyl]-(25R) -22 alpha-methoxyfurost-5-ene-3 beta,26-diol(methyl protodioscin) and its corresponding 22 alpha-hydroxy analogue (protodioscin). The structural identification was performed using detailed analysis of 1H- and 13C-NMR spectra including two-dimensional NMR spectroscopy (COSY, HMQC, NOESY and HMBC), and chemical conversions. These two compounds have been shown to inhibit the growth of human leukemia HL-60 cells in culture and macromolecular synthesis in a dose-dependent manner. The inhibitory effect on DNA synthesis was found to be irreversible.

Composition of essential oil of Zataria multiflora.

Abstract: The composition of the essential oil of Zataria multiflora Boiss. was studied by gas liquid chromatography (GLC), column chromatography (CC), NMR, and GLC/MS. The main constituents of the dry plant were thymol, carvacrol, while the main constituents of the fresh plant were thymol, carvacrol, p-cymene, linalool and gamma-terpinene. The structures of the major components were confirmed by IR and 1H-NMR.

Lignans from the roots of Urtica dioica and their metabolites bind to human sex hormone binding globulin (SHBG).

Abstract: Polar extracts of the stinging nettle (Urtica dioica L.) roots contain the lignans (+)-neoolivil, (-)-secoisolariciresinol, dehydrodiconiferyl alcohol, isolariciresinol, pinoresinol, and 3,4-divanillyltetrahydrofuran. These compounds were either isolated from Urtica roots, or obtained semisynthetically. Their affinity to human sex hormone binding globulin (SHBG) was tested in an in vitro assay. In addition, the main intestinal transformation products of plant lignans in humans, enterodiol and enterolactone, together with enterofuran were checked for their activity. All lignans except (-)-pinoresinol developed a binding affinity to SHBG in the in vitro assay. The affinity of (-)-3,4-divanillyltetrahydrofuran was outstandingly high. These findings are discussed with respect to potential beneficial effects of plant lignans on benign prostatic hyperplasia (BPH).

Taxol biosynthesis: an update.

Abstract: The novel diterpenoid taxol (paclitaxel) is now well-established as a potent chemotherapeutic agent. Total synthesis of the drug is not commercially feasible and, in the foreseeable future, the supply of taxol and its synthetically useful progenitors must rely on biological methods of production. The first three steps of taxol biosynthesis have been defined and the responsible enzymes described. These are the cyclization of the universal diterpenoid precursor geranylgeranyl diphosphate to taxa-4(5),11(12)-diene, the cytochrome P450-catalyzed hydroxylation of this olefin to taxa-4(20), 11(12)-dien-5 alpha-ol, and the acetyl CoA-dependent conversion of the alcohol to the corresponding acetate ester. Demonstration of these early steps of taxol biosynthesis suggests that the complete pathway can be defined by a systematic, stepwise approach at the cell-free enzyme level. When combined with in vivo studies to determine contribution to pathway flux, slow steps can be targeted for gene isolation and subsequent overexpression in Taxus to improve the yield of taxol and related compounds.

Rapid detection and subsequent isolation of bioactive constituents of crude plant extracts.

Abstract: Rapid detection of biologically active natural products plays a strategic role in the phytochemical investigation of crude plant extracts. In order to perform an efficient screening of the extracts, both biological assays and HPLC analysis with various detection methods are used. Combined techniques such as HPLC coupled to UV photodiode array detection (LC/UV) and to mass spectrometry (LC/MS or LC/MS/MS) provide useful structural information on the metabolites on-line prior to isolation. The recent introduction of HPLC coupled to nuclear magnetic resonance (LC/NMR) represents a powerful complement to the LC/UV/MS screening. Various plants belonging to the Gentianaceae and Leguminosae families have been analysed by LC/UV, LC/MS, LC/MS/MS, and LC/NMR. The use of all these coupled techniques allows the structural determination of known plant constituents rapidly and with only a minute amount of plant material. With such an approach, the time-consuming isolation of common natural products is avoided and an efficient targeted isolation of compounds presenting interesting chemical or biological features can be performed.

Activity of extracts and alkaloids of thai Alstonia species against human lung cancer cell lines.

Abstract: Methanol extracts of root barks of Alstonia macrophylla, A. glaucescens, and A. scholaris, collected from Thailand, have been assessed for cytotoxic activity against two human lung cancer cell lines, MOR-P (adenocarcinoma) and COR-L23 (large cell carcinoma), using the SRB assay. Significant cytotoxic activity was exhibited by the extract of A. macrophylla on both cell lines. Activity-directed fractionation led to the isolation of a novel indole alkaloid, O-methylmacralstonine, from the most active fraction of A. macrophylla along with four known alkaloids, talcarpine, villalstonine, pleiocarpamine, and macralstonine. Structure elucidation of the novel alkaloid was based on spectroscopic methods, especially 2D-NMR. The bisindole villalstonine was found to possess pronounced activity on both cell lines with an IC50 value less than 5 muM, but was about 10(3) times less potent than vinblastine sulphate. The monomeric alkaloid, talcarpine, was found to be inactive. Pleiocarpamine, O-methylmacralstonine and macralstonine were all considerably less active than villalstonine.

An analytical study, anti-inflammatory and analgesic effects of Harpagophytum procumbens and Harpagophytum zeyheri.

Abstract: The iridoids of Harpagophytum procumbens and Harpagophytum zeyheri were studied by CLHP. Harpagoside is the main iridoid for both drugs whereas 8-p-coumaroylharpagide is a representative iridoid of Harpagophytum zeyheri only. The ratio harpagoside/8-p-coumaroylharpagide can be used to distinguish chemically both species. For commercial dried aqueous extracts this ratio is intermediate because they are probably prepared from a mixture of H. procumbens and H. zeyheri drugs. The aqueous extracts of both drugs show similar analgesic and anti-inflammatory properties. Harpagophytum procumbens and Harpagophytum zeyheri should be accepted as sources for the drug Harpagophyti radix.

Inhibition of 5α-reductase and aromatase by the ellagitannins oenothein A and oenothein B from Epilobium species

Abstract: Species of the genus Epilobium (Onagraceae) have been investigated for their activity against 5 alpha-reductase and aromatase, two enzymes which are involved in the aetiology of benign prostatic hyperplasia (BPH). Activity-guided fractionation has led to the identification of two macrocyclic ellagitannins, oenothein A (1) and oenothein B (2), as the main constituents responsible for the inhibition of the two enzymes. Quantitation of oenothein B in 10 different species of Epilobium has shown that amounts of up to 14% in the crude plant extracts are possible.

Aged Garlic Extract and its Constituents Inhibit Cu2+-Induced Oxidative Modification of Low Density Lipoprotein

Abstract: Oxygen radical injury and lipid peroxidation have been suggested as major causes of atherosclerosis, cancer, liver disease, and the aging process More specifically, oxidative modification of low density lipoprotein (LDL) has been recognized as an important process of atherosclerosis In this study, we determined the effects of aged garlic extract (AGE), four of its constituents, and a metabolite on Cu 2+ -induced oxidative modification of LDL using an in vitro system All these compounds were shown to inhibit oxidative modification of LDL

Antinociceptive components of Ganoderma lucidum.

Abstract: The antinociceptive effects 134 extracts prepared from 45 species of mushrooms were examined by the acetic acid-induced writhing method. From the CH 2 Cl 2 extract of Ganoderma lucidum among the active extracts, ganoderic acids A, B, G and H and compound C6 were isolated as the antinociceptive components.

Protective effects of red ginseng saponins against carbon tetrachloride-induced hepatotoxicity in Sprague Dawley rats.

Abstract: The protective effects of red ginseng saponins against carbon tetrachloride-induced hepatotoxicity were investigated in male Sprague Dawley rats. The total saponins of red ginseng standardized on ginsenosides-Rb1, -Rb2, -Rc, -Rd, -Re, and -Rg1 were used in the present study. The rats were administered the standardized saponins of red ginseng orally at 50, 100, and 200 mg/kg for 7 consecutive days, followed by an administration of carbon tetrachloride at 0.4 ml/kg in corn oil intraperitoneally for 24 h. The administration of saponin changed neither body and organ weights nor hematological and serum clinical parameters. The elevation of SGPT and SGOT activities induced by carbon tetrachloride was partially recovered by the administration of the saponin. The liver vacuolization and lymphoid cell aggregation by carbon tetrachloride were clearly recovered by the red ginseng saponins as examined histologically. The present results indicated that the standardized saponins of red ginseng used in these studies may partially recover the hepatotoxicity induced by carbon tetrachloride in male Sprague Dawley rats.

Protection of rat liver microsomes against carbon tetrachloride-induced lipid peroxidation by red ginseng saponin through cytochrome P450 inhibition.

Abstract: A possible role of cytochrome P450 (P450) inhibition by red ginseng saponins in carbon tetrachloride (CCl4)-induced lipid peroxidation was investigated in liver microsomes prepared from male Sprague Dawley rats. The total saponin of red ginseng standardized on ginsenosides-Rb1, -Rb2, -Rc, -Rd, -Re, and -Rg1 whose composition was studied in our previous report was used in the present study. The standardized saponin of red ginseng showed inhibitory effects on P450-associated monooxygenase activities in a dose-dependent manner, particularly p-nitrophenol hydroxylase activity which has been known to represent CCl4-activating P450 2E1 enzyme. Meanwhile, silymarin enhanced the activity of P450 2E1 enzyme in liver microsomes. When the lipid peroxidation was induced by incubating rat liver microsomes with CCl4 in the presence of NADPH, the standardized saponin significantly blocked the formation of thiobarbituric acid-reactive substances at the same concentrations showing P450 inhibition in liver microsomes. Silymarin revealed more potent protection against CCl4-induced lipid peroxidation. When the lipid peroxidation was induced by FeCl3, in which metabolic activation may not be required, only silymarin could protect the lipid peroxidation in liver microsomes. Taken together, our present results indicated that the inhibitory effects of red ginseng saponin on P450 enzymes may have a critical role in CCl4-induced lipid peroxidation in rat liver microsomes and that the mechanism of hepatoprotection by red ginseng saponin may be distinct from that of silymarin.

Antiplasmodial triterpene from Vernonia brasiliana.

Abstract: The hexane extract from leaves of Vernonia brasiliana (L.) Druce (Compositae) was active in vitro against Plasmodium falciparum and in vivo in mice infected with Plasmodium berghei. This extract was subjected to a bioassay-guided fractionation protocol based on the in vitro model. Lupeol was identified as a compound responsible for the activity, inhibiting the P.falciparum growth by 45% when tested at 25 micrograms/ml. However, this triterpene was inactive in vivo when 15 mg/kg were administered per os during four consecutive days to mice infected with P.berghei. beta-Amyrin and germanicol, isolated from the same fraction that yielded lupeol, were inactive in the in vitro assay.

In vitro antimutagenic effects of anthraquinone aglycones and naphthopyrone glycosides from Cassia tora.

Abstract: The antimutagenic activity of a methanol extract of Cassia tora seeds against aflatoxin B 1 (AFB 1 ) was demonstrated with the Salmonella typhimurium assay. The numbers of revertants per plate decreased significantly when this extract was added to the assay system using Salmonella typhimurium TA100 and/or TA98. The MeOH extract was then sequentially partitioned with CH 2 Cl 2 . n-BuOH and H 2 O. The CH 2 Cl 2 and n-BuOH fractions possessed antimutagenic activity but the H 2 O fraction was inactive. Neither the MeOH extract nor its fractions were capable of inhibiting the direct-acting mutagen N-methylN'-nitro-N-nitrosoguanidine suggesting that these fractions may prevent the metabolic activation of AFB 1 or scavenge the electrophilic intermediate capable of inducing mutations. Column chromatography using silica gel yielded pure chrysophanol, chryso-obtusin, and aurantio-obtusin from the CH 2 Cl 2 fraction and cassiaside and rubro-fusarin gentiobioside from the n-BuOH fraction. Each of these compounds demonstrated significant antimutagenic activity.

Composition and antimalarial activity in vitro of the essential oil of Tetradenia riparia.

Abstract: The essential oil from the leaves and stems of Tetradenia riparia was analysed by GC and GC/MS and 35 components were identified. The main constituents were alpha-terpineol (22.6%), fenchone (13.6%), beta-fenchyl alcohol (10.7%), beta-caryophyllene (7.9%), and perillyl alcohol (6.0%). Moderate antimalarial activities were recorded against two strains of Plasmodium falciparum.

Alkamide levels in Echinacea purpurea: a rapid analytical method revealing differences among roots, rhizomes, stems, leaves and flowers.

Abstract: A rapid extraction, clean-up, and RPLC procedure suitable for routine quantitative analyses of alkamide levels in Echinacea purpurea extracts is described. The 13 C-NMR spectra of the main diene-diyne alkamides in E. purpurea are reported. Alkamide levels differed significantly among roots, rhizomes, stems, leaves, and flowers of E. purpurea. Roots were distinguished from other plant parts by higher levels of the C 12 diene-diyne alkamides, whereas levels of the C 12 tetraene alkamides and C 11 diene-diynes were highest in vegetative stems. The ratio of the two stereoisomeric C 12 tetraene alkamides differed between flowers and all other E. purpurea parts. These results are important for standardisation of medicinal preparations of E. purpurea.

Antineoplastic agents. II. Four furostanol glycosides from rhizomes of Dioscorea collettii var. hypoglauca.

Abstract: During activity-guided fractionations to screen for antineoplastic agents, further studies by means of preparative HPLC led to the isolation of four known furostanol saponins: protoneodioscin, protodioscin, protoneogracillin, protogracillin, along with their corresponding artifacts: methyl protoneodioscin, methyl protodioscin, methyl protoneogracillin, and methyl protogracillin, from the rhizomes of Dioscorea collettii var. hypoglauca. Among them, protoneodioscin, protodioscin, and protoneogracillin are first reported from the title plant. The structures of the compounds were established on the basis of chemical evidence and spectral analysis (1H-NMR, 13C-IMMR, 1H-1H COSY, HMQC, HMBC, and FAB-MS). These eight compounds all caused morphological abnormality of Pyricularia oryzae mycelia. They also showed cytotoxic activities against the cancer cell line of K562 in vitro as antineoplastic agents.

Isolation and Characterization of the Glycoprotein Fraction with a Proliferation-Promoting Activity on Human and Hamster Cells in Vitro from Aloe vera Gel

Abstract: Fractions of leaf gel from Aloe barbadensis Mill. were prepared by gel permeation using DEAE Sephadex A-25, Sepharose 6B, and Sephadex G-50 columns. These were then tested by in vitro assays for proliferation of human normal dermal and baby hamster kidney cells. The glycoprotein fraction promoted cell growth, while the neutral polysaccharide fraction did not show any growth stimulation. Moreover, the polar-colored glycoprotein fraction strongly inhibited the in vitro assays. An active glycoprotein fraction (protein 82%, carbohydrate 11%) examined on polyacrylamide gel electrophoresis (PAGE) and SDS-PAGE showed a single band. Its molecular weight was 29 kD on a Sephadex G-50 column and its isoelectric point was pH 6.8. Immunoblotting after SDS-PAGE showed that the glycoprotein was composed of two subunits (14 kD). Deglycosylation of glycoprotein (Pg21-2b fraction) by trifluoromethanesulphonic acid provided a protein band with a molecular weight of 13 kD on SDS-PAGE. The colored glycoprotein fraction was shown on SDS-PAGE to be a mixture with a molecular weight of 18 kD-15 kD. It was later hydrolyzed with 10% H2SO4 to produce phenolic substances.