Effects of phytochemicals of Flemingia vestita (Fabaceae) on glucose 6-phosphate dehydrogenase and enzymes of gluconeogenesis in a cestode (Raillietina echinobothrida)

The crude root-peel extract of Flemingia vestita, containing genistein as the major isoflavone, has a vermifugal/vermicidal effect. It acts by causing flaccid paralysis accompanied by alterations in the activities of several tegumental enzymes and other metabolic activities in the fowl tapeworm, Raillietina echinobothrida. To elucidate the mode of action of the putative phytochemicals on energy metabolism, crude root-peel extract, pure genistein and praziquantel were tested on glucose 6-phosphate dehydrogenase (G6PDH) and enzymes of gluconeogenesis--pyruvate carboxylase (PC), phosphoenolpyruvate carboxykinase (PEPCK) and fructose 1,6-bisphosphatase (FBPase)--in R. echinobothrida. The activities of G6PDH, PEPCK and FBPase were largely restricted to the cytosolic fraction, while PC was confined to the mitochondrial fraction. Following treatments, the G6PDH activity was decreased by 23-31%, whereas the activities of PC and PEPCK were increased by 32-44% and 44-49%, respectively. There was no significant effect by any of the treatments on FBPase activity. We hypothesize that the phytochemicals from F. vestita, genistein in particular, influence the key enzymes of these pathways, which is perhaps a function of high energy demand of the parasite under anthelmintic stress.     

Anthelmintic efficacy of flemingia vestita (fabaceae): Genistein-induced alterations in the esterase activity in the cestode,raillietina echinobothrida

To ascertain the anthelmintic efficacy ofFlemingia vestita (an indigenous leguminous plant of Meghalaya, having putative anthelmintic usage), its crude root-tuber peel extract and active chemical principle, genistein, were testedin vitro with reference to esterase activity in the fowl tapeworm,Raillietina echinobothrida. With the localization of non-specific esterases (NSE) and cholinesterase (ChE), the organization of the cholinergic components of the nervous system in toto could be visualized in the cestodeo The specific ChE in the parasite is acetylcholinesterase (AChE). Both NSE and ChE were found in close association with the central and peripheral nervous components, besides being present in the tegument and muscular parts of the terminal male genitalia. The whole tissue homogenate of the parasite also showed a high AChE activity. After exposure to the crude peel extract (50 mg/ml of the incubation medium) and to genistein (0.5 mg/ml), a pronounced decline in the visible stain intensity in the cholinergic components of the nervous system and in the tegument was noticeable, indicating extremely reduced activity of NSE and ChE in these sites. The total AChE activity was also reduced to 4907% and 56–77%, following treatment with the peel extract and genistein, respectively. The reference drug, praziquantel (0.01 mg/ml) also caused reduction in the enzyme activity, somewhat at par with the genistein treatment. Genistein appears to have a transtegumental mode of action. Alteration in the AChE activity points towards acetylcholine, an inhibitory neurotransmitter in cestodes, as the potential target of action.     

Anthelmintic efficacy of Flemingia vestita: genistein-induced effect on the activity of nitric oxide synthase and nitric oxide in the trematode parasite,Fasciolopsis buski

The root-tuber peel of Flemingia vestita, an indigenous leguminous plant of Meghalaya (Northeast India), has usage in local traditional medicine as curative against worm infections. The peel and its active component, genistein, have been shown to cause flaccid paralysis, deformity of tegumental architecture and alterations in the activity of several enzymes in platyhelminth parasites. To investigate further the mode of action and anthelmintic efficacy of the plant-derived components, the crude peel extract of F. vestita and genistein were tested, hitherto for the first time, in respect of the unique neuronal messenger nitric oxide (NO) and the enzyme nitric oxide synthase (NOS) in Fasciolopsis buski, the large intestinal fluke of swine and human host. NADPH-diaphorase histochemical staining (a selective marker for NOS in neuronal tissues), which was demonstrable in the neuronal cell bodies in the cerebral ganglia, the brain commissure, the main nerve cords and in the innervation of the pharynx, ventral sucker, terminal genitalia and genital parenchyma of the parasite, showed a stronger activity in the treated worms. In biochemical analysis also, the NOS activity showed a significant increase in the parasites treated with the test materials and reference drug, compared to the untreated controls. The increase in NOS activity in the treated parasites can be attributed to an inducing effect of the plant-derived components.     

Effect of isoflavone from Flemingia vestita (Fabaceae) on the Ca2+ homeostasis in Raillietina echinobothrida, the cestode of domestic fowl

The alcoholic crude root-peel extract of Flemingia vestita and its major isoflavone, genistein, have been shown to have a vermifugal/vermicidal effect by causing a flaccid paralysis accompanied by alterations in the structural architecture of the tegumental interface and metabolic activity in Raillietina echinobothrida, the cestode of domestic fowl. In the present study, the crude root-peel extract and pure genistein were tested in vitro with respect to Ca2+ homeostasis and the occurrence of some metal ions was detected in the parasite. Live cestodes were incubated in pre-defined concentrations of the crude root-peel extract, genistein and praziquantel (as reference drug), till the paralysis time with simultaneous maintenance of respective controls. In the parasite tissue, a significant amount of Ca2+ (approximately 400 microg/g dry tissue wt) was found to be present besides magnesium, iron, zinc, lead and chromium, whilst manganese, cadmium and nickel were below the level of detection. The Ca2+ concentration was decreased significantly by 39%-49%, in the parasite tissue exposed to the test materials in comparison to the respective controls. There was also an increase in Ca2+ efflux by 91%-160% into the culture medium under similar treatments. The changes in Ca2+ homeostasis may be related to the rapid muscular contraction and consequent paralysis in the parasite due to the anthelmintic stress caused by the phytochemicals of F. vestita.     

Anthelmintic efficacy of genistein, the active principle of Flemingia vestita (Fabaceae): alterations in the free amino acid pool and ammonia levels in the fluke, Fasciolopsis buski

The crude root-peel extract of Flemingia vestita, its active principle genistein and the reference flukicide oxyclozanide were tested against Fasciolopsis buski, the giant intestinal trematode. The amino acid composition of F. buski was demonstrated using HPLC and it was observed that the free amino acid (FAA) pool of the control worm consisted of aspartate, threonine, serine, glutamic acid, glutamine, proline, glycine, alanine, valine, methionine, isoleucine, leucine, tyrosine, lysine, histidine, arginine, phosphoserine, taurine, citrulline, ornithine, β-alanine, and γ-amino butyric acid (GABA). Of the amino acids detected valine was found to be the maximum in quantitative analysis. In qualitative analysis the FAA pool of the parasites under various treatments remained same as that of the control; however, quantitatively the level of various FAAs in the parasite was significantly affected. The treated parasites showed a marked decrease in the levels of arginine, ornithine, tyrosine, leucine, isoleucine, valine, alanine, glycine, proline, serine, threonine, and taurine following treatment with 20 mg/ml of crude peel extract, 0.5 mg/ml of genistein and 20 mg/ml of the reference drug, though an increase in the levels of glutamic acid, glutamine, phosphoserine, citrulline and GABA was noticeable. Enhanced levels of GABA and citrulline under the influence of genistein may be implicated in alterations of nitric oxide release and consequent neurological change (e.g. paralysis) in the parasite. Ammonia in the tissue homogenate as well as in the incubation medium showed a quantitative increase compared to the controls after treatment with the various test materials. The ammonia level increased by 40.7%, 66.4% and 18.16% in treatments with F. vestita, genistein and oxyclozanide, respectively, at the mentioned dosages. The changes in the levels of the amino acids and nitrogen components post treatment suggest that the amino acid metabolism in the parasite may have been altered under the influence of the test materials.     

Anthelmintic efficacy of Flemingia vestita (Fabaceae): alterations in glucose metabolism of the cestode, Raillietina echinobothrida

The root-tuber peel of Flemingia vestita and its active component, genistein, were tested in respect of glucose metabolism in the cestode, Raillietina echinobothrida. Live R. echinobothrida, collected from the intestine of freshly slaughtered domestic fowl, were incubated at 39±1 °C in defined concentrations of the root-peel crude extract (5 mg/ml), genistein (0.2 mg/ml) and praziquantel (1 μg/ml) in phosphate buffered saline with 1% of dimethyl sulphoxide with simultaneous maintenance of controls. In the treated worms, there was a significant decrease in the glycogen concentration accompanied with the decrease of glucose by 14–32%, whereas the malate concentration increased by 49–134% as compared to controls. Both in controls and treated parasites, however, the pyruvate content was not measurable. While alanine and lactate contents showed a decline by 7–25% in the parasites exposed to all test materials, the lactate efflux into the incubation medium showed 37–71% increase in treatments indicating an overall increase of lactate production in comparison to controls. The results showing a decline in the glycogen and glucose contents and a significant rise in the malate content and lactate efflux under treatment conditions suggest that the energy demand in the parasites possibly got enhanced under stress, though it did not influence a switch over towards aerobic degradation of glucose in the parasites.     

Phytochemicals from Flemingia vestita (Fabaceae) and Stephania glabra (Menispermeaceae) alter cGMP concentration in the cestode Raillietina echinobothrida

Cyclic GMP (cGMP) mediates various physiological functions of nitric oxide (NO) synthesized by nitric oxide synthase (NOS). A crude peel extract and purified fraction of Flemingia vestita, as well as a crude rhizome extract of Stephania glabra and fractions were tested with respect to the activity of NOS, NO efflux and cGMP concentration in the cestode Raillietina echinobothrida in order to find out the possible mode of anthelmintic action of these plant-derived components. For comparison purposes, the parasites were also treated with pure genistein, sodium nitroprusside (SNP-a known NO donor), and the reference drug, praziquantel (PZQ). At the time of onset of paralysis in the parasites, a significant increase (32%-87%) in the NOS activity and a two to three fold increase of NO efflux into the incubation medium were observed in the treated parasites in comparison to their respective controls. The cGMP concentration in the treated parasites' tissue was also increased by 44%-103%. However, in the presence of NG-nitro-L-arginine methyl ester, a potent inhibitor of NOS, there was no increase in the cGMP concentration in the parasite tissue. This study indicates that the phytochemicals, in particular genistein and tetrahydropalmatine, from F. vestita and S. glabra, respectively, disturb the downstream signalling pathway of NO, as indicated by the change in cGMP concentration in the parasite tissue.     

Biological effects of extracts obtained from Stryphnodendron adstringens on Herpetomonas samuelpessoai

We report the effect of Stryphnodendron adstringens on the trypanosomatid Herpetomonas samuelpessoai. The parasites were grown at 28 degrees C in a chemically defined medium containing crude extract and fractions at concentrations from 100 to 5000 microg/ml obtained from S. adstringens. Concentrations of 500, 1000, 2500, and 5000 microg/ml both crude extract and semi-purified fraction progressively inhibited the protozoans' growth. At a concentration of 100 microg/ml, crude extract or a semi-purified (F3) fraction did not affect the growth of the protozoans. The F3-9 - F3-12 sub-fractions, at a concentration of 1000 microg/ml, also showed increased inhibitory activity on H. samuelpessoai. The IC50 of the crude extract and the F3 fraction were 538 and 634 microg/ml, respectively. Ultrastructural and enzymatic alterations in the trypanosomatids were also evaluated. H. samuelpessoai cultivated in the presence of IC50 crude extract showed considerable ultrastructural alterations, such as marked mitochondrial swelling with a large number of cristae and evident Golgi complex vesiculation, as observed by transmission electron microscopy. Cells exposed to 538 microg/ml of crude extract at 28 degrees C for 72 h, showed decreased activity of the enzyme succinate cytochrome c reductase, a typical mitochondrion marker, as compared to untreated cells.     

In vitro and in vivo leishmanicidal activity of Dysoxylum binectariferum and its fractions against Leishmania donovani

The leishmanicidal effect of crude ethanolic extract of stem bark of Dysoxylum binectariferum and its fractions has been investigated against Leishmania donovani, the causative agent of visceral leishmaniasis. Ethanolic extract was lethal to promastigotes as well as amastigote forms in macrophage system at the concentration of 100 microg/ml. Chloroform fraction significantly inhibited promastigote multiplication and was also active against amastigotes in infected J774A.1 macrophages at 100 microg/ml. Hexane fraction was moderately active and the other fractions were inactive against both the forms. When tested in vivo in hamsters, ethanolic extract was toxic at 500 mg/kg whereas exhibited marginal activity (67.7+/-5.3%) at 250 mg/kg x 5, p.o. on day 7 post treatment (p.t.) which increases slightly (69+/-4.7) by day 30 p.t. Chloroform and n-hexane fractions exhibited 64.3+/-4% and 47.8+/-4.6% parasite inhibition at the dose of 100 mg/kg x 5 p.o., respectively. The pure compound, rohitukine, obtained from chloroform fraction showed weaker in vitro activity and was ineffective in infected hamsters. The lead potential of this plant need further investigations.     

Molecular docking and enzyme kinetic studies of dihydrotanshinone on metabolism of a model CYP2D6 probe substrate in human liver microsomes

The effects of Danshen and its active components (tanshinone I, tanshinone IIA, dihydrotanshinone and cryptotanshinone) on CYP2D6 activity was investigated by measuring the metabolism of a model CYP2D6 probe substrate, dextromethorphan to dextrorphan in human pooled liver microsomes. The ethanolic extract of crude Danshen (6.25-100 μg/ml) decreased dextromethorphan O-demethylation in vitro (IC(50)=23.3 μg/ml) and the water extract of crude Danshen (0.0625-1 mg/ml) showed no inhibition. A commercially available Danshen pill (31.25-500 μg/ml) also decreased CYP2D6 activity (IC(50)=265.8 μg/ml). Among the tanshinones, only dihydrotanshinone significantly inhibited CYP2D6 activity (IC(50)=35.4 μM), compared to quinidine, a specific CYP2D6 inhibitor (IC(50)=0.9 μM). Crytotanshinone, tanshinone I and tanshinone IIA produced weak inhibition, with IC(20) of 40.8 μM, 16.5 μM and 61.4 μM, respectively. Water soluble components such as salvianolic acid B and danshensu did not affect CYP2D6-mediated metabolism. Enzyme kinetics studies showed that inhibition of CYP2D6 activity by the ethanolic extract of crude Danshen and dihydrotanshinone was concentration-dependent, with K(i) values of 4.23 μg/ml and 2.53 μM, respectively, compared to quinidine, K(i)=0.41 μM. Molecular docking study confirmed that dihydrotanshinone and tanshinone I interacted with the Phe120 amino acid residue in the active cavity of CYP2D6 through Pi-Pi interaction, but did not interact with Glu216 and Asp301, the key residues for substrate binding. The logarithm of free binding energy of dihydrotanshinone (-7.6 kcal/mol) to Phe120 was comparable to quinidine (-7.0 kcal/mol) but greater than tanshinone I (-5.4 kcal/mol), indicating dihydrotanshinone has similar affinity to quinidine in binding to the catalytic site on CYP2D6.     

Fasciola gigantica: Anthelmintic effect of the aqueous extract of Artocarpus lakoocha

The effect of the crude extract of Artocarpus lakoocha (70% composition is 2,4,3′,5′- tetrahydroxystilbene -THS) on adult Fasciola gigantica was evaluated after incubating the parasites in M-199 medium containing 250, 500, 750 and 1000 μg/ml of the crude extract, or triclabendazole (TCZ) at the concentrations of 80 and 175 μg/ml as the positive control, for 3, 6, 12 and 24 h, using relative motility (RM) assay and observation by scanning electron microscope (SEM). Decreased contraction and motility were first observed after 3 h incubation with TCZ at the concentration 80 and 175 μg/ml. TCZ markedly reduced the parasite’s motility at the concentration of 175 μg/ml at 6 h, and killed the worms after 12 h exposure. The crude extract of A. lakoocha at all concentrations reduced the parasite’s motility similar to TCZ at 3 h incubation. In 250 and 500 μg/ml of the crude extract, the values were decreased from 3 to 12 h, then they were stable between 12 and 24 h and reduced to the level approximately 30-40% of the control. At 750 and 1000 μg/ml concentrations the crude extract rapidly reduced the RM values from the start to 12 h and killed the parasites between 12 and 24 h incubation. The crude extract also inhibited the larval migration by 75% and 100% at the concentrations of 250-500 and 750-1000 μg/ml, respectively. TCZ and the crude extract caused sequentially changes in the tegument including swelling, followed by blebbings that later ruptured, leading to the erosion and desquamation of the tegument syncytium. As the result, lesion was formed which exposed the basal lamina. The damage appeared more severe on the dorsal than the ventral surface, and earlier on the anterior part and lateral margins when compared to the posterior part. The severity and rapidity of the damages were enhanced with increasing concentration of the crude extract. Hence, the crude extract of A. lakoocha, may exert its fasciolicidal effect against adult F. gigantica by initially causing the tegumental damage.     

Partial purification of new milk-clotting enzyme produced by Nocardiopsis sp

Numerous attempts have been made to replace calf rennet with other milk clotting proteases because of limited supply and increasingly high prices. The aim of this work was to investigate the characteristic of the milk-clotting enzyme from Nocardiopsis sp. The partial purification extract was obtained by fractional precipitation with ammonium sulphate. Of the fractions obtained by precipitation, 40-60% possessed the milk-clotting activity (156.25 U/mg). The chromatography of 40-100% ammonium sulphate fraction in DEAE-cellulose yielded four fractions (F4, F5, F6, F7) with milk-clotting activity. The F5 yielded the best milk-clotting activity (20 U/ml). Both crude and partially purified extract were active at the range pH 4.5-11.0, however, optimum activity was displayed at pH 11.0 and pH 7.5, respectively. The milk-clotting activity was highest at 55 degrees C for both crude and partially purified extract. The crude and partial purification extract were inactivated at 65 and 75 degrees C after 30 min.     

Adaptations of glycogen metabolism in rat epididymal adipose tissue during fasting and refeeding.

It is well documented that adipose tissue glycogen content decreases during fasting and increases above control during refeeding. We now present evidence that these fluctuations result from adaptations intrinsic to adipose tissue glycogen metabolism that persist in vitro: in response to insulin (1 milliunit/ml), [3H]glucose incorporation into rat fat pad glycogen was reduced to 10% of control after a 3-day fast; incorporation increased 6-fold over fed control on the 4th day of refeeding following a 3-day fast. We have characterized this adaptation with regard to alterations in glycogen synthase and phosphorylase activity. In addition, we found that incubation of fat pads from fasted rats with insulin (1 milliunit/ml) increased glucose-6-P content, indicating that glucose transport was not the rate-limiting step for glucose incorporation into glycogen in the presence of insulin. In contrast, feeding a fat-free diet resulted in dramatic increases in glycogen content of fat pads without a concomitant increase in glucose incorporation into glycogen in response to insulin (1 milliunit/ml). Thus, fasting and refeeding appeared to alter insulin action on adipose tissue glycogen metabolism more than this dietary manipulation.     

Genistein differentially inhibits postreceptor effects of insulin in rat adipocytes without inhibiting the insulin receptor kinase.

Genistein, an isoflavone putative tyrosine kinase inhibitor, was used to investigate the coupling of insulin receptor tyrosine kinase activation to four metabolic effects of insulin in the isolated rat adipocyte. Genistein inhibited insulin-stimulated glucose oxidation in a concentration-dependent manner with an ID50 of 25 micrograms/ml and complete inhibition at 100 micrograms/ml. Genistein also prevented insulin's (10(-9) M) inhibition of isoproterenol-stimulated lipolysis with an ID50 of 15 micrograms/ml and a complete effect at 50 micrograms/ml. The effect of genistein (25 micrograms/ml) was not reversed by supraphysiological (10(-7) M) insulin levels. In contrast, genistein up to 100 micrograms/ml had no effect on insulin's (10(-9) M) stimulation of either pyruvate dehydrogenase or glycogen synthase activity. We determined whether genistein influenced insulin receptor beta-subunit autophosphorylation or tyrosine kinase substrate phosphorylation either in vivo or in vitro by anti-phosphotyrosine immunoblotting. Genistein at 100 micrograms/ml did not inhibit insulin's (10(-7) M) stimulation of insulin receptor tyrosine autophosphorylation or tyrosine phosphorylation of the cellular substrates pp185 and pp60. Also, genistein did not prevent insulin-stimulated autophosphorylation of partially purified human insulin receptors from NIH 3T3/HIR 3.5 cells or the phosphorylation of histones by the activated receptor tyrosine kinase. In control experiments using either NIH 3T3 fibroblasts or partially purified membranes from these cells, genistein did inhibit platelet-derived growth factor's stimulation of its receptor autophosphorylation. These findings indicate the following: (a) Genistein can inhibit certain responses to insulin without blocking insulin's stimulation of its receptor tyrosine autophosphorylation or of the receptor kinase substrate tyrosine phosphorylation. (b) In adipocytes genistein must block the stimulation of glucose oxidation and the antilipolytic effects of insulin at site(s) downstream from the insulin receptor tyrosine kinase. (c) The inhibitory effects of genistein on hormonal signal transduction cannot necessarily be attributed to inhibition of tyrosine kinase activity, unless specifically demonstrated.     

Giardia lamblia: the effects of extracts and fractions from Mentha x piperita Lin. (Lamiaceae) on trophozoites

Giardia lamblia is a parasite that causes giardiasis in humans and other mammals. The common treatment includes different classes of drugs, which were described to produce unpleasant side effects. Mentha x piperita, popularly known as peppermint, is a plant that is frequently used in the popular medicine to treat gastrointestinal symptoms. We examined the effects of crude extracts and fractions from peppermint against G. lamblia (ATCC 30888) on the basis of trophozoite growth, morphology and adherence studies. The methanolic, dichloromethane and hexanic extracts presented IC(50) values of 0.8, 2.5 and 9.0microg/ml after 48h of incubation, respectively. The aqueous extract showed no effect against the trophozoites with an IC(50)>100microg/ml. The aqueous fraction presented a moderate activity with an IC(50) of 45.5microg/ml. The dichloromethane fraction showed the best antigiardial activity, with an IC(50) of 0.75microg/ml after 48h of incubation. The morphological and adhesion assays showed that this fraction caused several alterations on plasma membrane surface of the parasite and inhibited the adhesion of G. lamblia trophozoites. Cytotoxic assays showed that Mentha x piperita presented no toxic effects on the intestinal cell line IEC-6. Our results demonstrated antigiardial activity of Mentha x piperita, indicating its potential value as therapeutic agent against G. lamblia infections.     

Trypanosoma cruzi: antiprotozoal activity of parthenolide obtained from Tanacetum parthenium (L.) Schultz Bip. (Asteraceae, Compositae) against epimastigote and amastigote forms

This study reports the activity of crude extracts, fractions and parthenolide (pure compound) obtained from Tanacetum parthenium against two forms of the parasite Trypanosoma cruzi. Feverfew is a traditional herbal medicine that has been used for the treatment of migraine, fever and arthritis. Activity against epimastigote forms was observed for crude extracts, fractions and parthenolide, and a progressive increase in the antitrypanosomal effect was observed in the course of the purification process. The pure compound showed IC50/96h and IC90/96h of 0.5 microg/ml and 1.25 microg/ml, respectively. The cytotoxic effect of parthenolide in LLMCK2 cells was 3.2 microg/ml (CC50/96h) and the selectivity index was 6.4. No hemolysis was detected for the pure compound. The internalization index of T. cruzi in LLMCK2 cells was reduced almost 51% at the concentration of 2 microg/ml of parthenolide, and 96.6% at 4 microg/ml. Scanning and transmission electron microscopy permitted observation of morphological modifications and ultrastructural alterations.     

Applications of bromelain from pineapple waste towards acne

Bromelain is a proteolytic mixture obtained from pineapple (Ananas comosus (L. Merr)). It has diversified clinical properties and is used in alleviation of cancer, inflammation and oxidative stress. The current study focuses on extraction of bromelain from different parts of pineapple such as core, crown, fruit, peel and stem. The extracted enzyme was precipitated using ammonium sulphate at 40% saturation followed by dialysis. The fold of purification obtained for peel, crown, core, fruit and stem were found to be 1.948, 1.536, 1,027, 1.989, and 1.232 respectively. Bromelain activity was estimated using Azocasein assay, the highest activity was seen in peel at 3.417 U/μg. Antimicrobial activity and MIC of the bromelain purified and crude fractions was studied against the test organisms. Peel crude and purified extract exhibited highest inhibitory effect towards S. aureus followed by P. acne. The antioxidant activity was evaluated using DPPH antioxidant assay. IC50 values peel, fruit, stem and crown are found to be 13.158 μg/ml, 24.13 μg/ml and 23.33 μg/ml and 113.79 μg/ml respectively. The purified bromelain from peel, stem and crown was used to create a facewash formulation towards pathogens frequently associated with skin infections. Common skin pathogens like S. aureus and P. acne were found highly sensitive to its action. The aim of this study was to evaluate the potential of bromelain isolated from waste parts of pineapple in alleviation of acne due to its diverse antimicrobial properties.     

Antileishmanial activity of indole alkaloids from Aspidosperma ramiflorum

The present study was designated to evaluate the antileishmanial activity of acid and basic fractions that were obtained after acid-basic extraction, from ethanolic 70% crude extract and pure compounds from the stem bark of Aspidosperma ramiflorum. The basic alkaloidal fraction presented a good activity against the extracellular form (promastigotes) of Leishmania (L.) amazonensis (LD(50) value<47 microg/ml). Based on these findings, the basic fraction was fractionated on silica gel column chromatography in a bioassay-guided fractionation affording individual purified ramiflorines A and B. Both ramiflorines A and B showed significant activity against Leishmania (L.) amazonensis (LD(50) values of 16.3+/-1.6 microg/ml and 4.9+/-0.9 microg/ml, respectively). Our results are promising, showing that these compounds are biologically active against Gram-positive bacteria.     

小桐子提取物除草活性的生物测定

为全面了解小桐子(Jatropha curcas L. )提取物的除草活性,以萝卜(Raphanus sativus L. )、苋(Amaranthus tricolor L. )、苏丹草[Sorghum sudanense (Piper) Stapf]和黑麦草(Lolium perenne L. )为实验材料,对小桐子果壳和枝叶的水、乙醇(体积分数95%)、正丁醇、乙酸乙酯、氯仿和石油醚粗提物的除草活性进行了生物测定,并从中筛选出抑制作用最强的水粗提物进行进一步的活性组分分离及其除草活性的生物测定.测定结果显示,小桐子果壳和枝叶的6种溶剂提取物(10 g·L~(-1))对供试的4种植物幼苗的根长和茎高均有不同程度的抑制作用,其中水粗提物和乙醇(体积分数95%)粗提物的抑制作用较强,且水粗提物对供试的4种植物幼苗的根长和茎高的抑制作用均在75%以上,显著高于其他溶剂粗提物(P<0.05);石油醚粗提物的抑制作用最小,均在10%以下.小桐子果壳和枝叶水粗提物的石油醚、氯仿、乙酸乙酯、正丁醇和水萃取物(10 g·L~(-1))对萝卜和苏丹草幼苗的根长和茎高均有不同程度的抑制作用,其中水、正丁醇和乙酸乙酯萃取物的抑制作用显著高于氯仿和石油醚萃取物,抑制率均在70%以上;水萃取物的抑制作用最强,抑制率均在80%以上;石油醚萃取物的抑制作用最小,抑制率均在10%以下.研究结果表明,小桐子果壳和枝叶的水粗提物具有一定的除草活性,其有效成分为极性较大的组分.     

青蒿提取物抗单纯疱疹病毒活性研究

用细胞病变效应(CPE)法证明了青蒿水提物具有抗单纯疱疹病毒Ⅱ型(HSV—2)活性,通过初步分离纯化得到抗HSV—2活性的有效成分。用MTT法研究了青蒿水提物和有效成分的细胞毒性和抗HSV—2活性,CC50分别为5．29mg／ml和4,94mg／ml,IC50分别为1．45mg／ml和0．128mg／ml,TI分别为3．65和38．6。以0．5mg／ml的无环鸟苷(ACV)作为阳性对照,结果显示有效成分在体外可以明显抑制HSV—2的致细胞病变作用,效果与ACV相当。