Effect of medicinal plant extracts on the growth of microorganisms

Extracts obtained from sweatweed and licorice roots, flax seeds, milfoil, bur-marigold, plantain, coltsfoot, nettle, Indian corn stigmas, laminaria produced a stimulating effect on the growth of Candida albicans test strain and Streptococcus pyogenes test strain Dick 1. Sweatweed, licorice, Aerva lanata and violet extracts influenced the growth of Corynebacterium xerosis 1911, while sweatweed, violet, horse-tail, bur-marigold, camomile, plantain, and nettle extracts influenced the growth of shigellae. The stimulating effect could be supposedly produced by biologically active substances contained in medicinal plants (organic acids, alkaloids, carotinoids, vitamins, microelements). Further studies aimed at the identification of substances producing the stimulating effect are planned.     

Acaricidal activity of aqueous extracts of camomile flowers, Matricaria chamomilla, against the mite Psoroptes cuniculi

Arcaricidal properties of decoctions, infusions and macerates of dried flower heads of camomile, Matricaria chamomilla L. (Asterales: Asteraceae) were tested in vitro against the mite Psoroptes cuniculi Delafond (Parasitiformes: Psoroptidae). This mite species is responsible for otoacariasis in domestic animals. Mites were exposed to the extracts for 24, 48 or 72 h. All the extracts tested showed highly significant acaricidal activity when compared with controls. Among them, a decoction of 10% was the only formulation which gave 100% activity at all the three observations times.     

Investigation of camomile fermentation

Summary The content of apigenin is an important factor of camomile spasmolytic activity. The hydrolysis of apigenin-7-O--glucoside into free aglycone in camomile ligulate flowers was possible using -glucosidase from almonds. The transformation of apigenin glucosides into apigenin has been achieved by autofermentation of camomile ligulate flowers and camomile flower heads. There is a significant increase of apigenin content, whereas the composition of other active components in camomile practically were not changed by autofermentation.     

Regeneration of peppermint and orange mint from leaf disks

Leaf disks from peppermint, spearmint, orange mint, lavender mint and Scotch spearmint were cultured on various Murashige-Skoog-based media in order to regenerate shoots. A significantly larger average number of orange mint leaf disks regenerated shoots on basal medium containing 44.4 M benzyladenine (BA) and 250 ml l^-1 coconut water (CW). Shoots regenerated from peppermint leaf disks cultured on basal medium containing 44.4 M BA and 250 ml or 450 ml l^-1 CW. The most shoots regenerated from orange mint leaf disks cultured on medium containing 10 g l^-1 washed Difco Bacto-agar. Disks excised from the bases of the first expanding pair of orange mint leaves cultured under dark conditions regenerated a significantly larger average number of shoots. Histological studies suggested that shoots regenerated from the palisade parenchyma cells associated with vascular tissue.Abbreviations BA benzyladenine - NAA 1-naphthaleneacetic acid - TIBA 2,3,5-triiodobenzoic acid - CW coconut water     

Rab6 interacts with the mint3 adaptor protein

The Rab6 GTPase regulates a retrograde transport route connecting endosomes and the endoplasmic reticulum (ER) via the Golgi apparatus. Recently it was shown that active (GTP-loaded) Rab6A regulates intracellular processing of the amyloid precursor protein (APP). To characterize the role of Rab6A in APP trafficking and to identify effector proteins of the active Rab6A protein, we screened a human placenta cDNA library using the yeast two-hybrid system. We isolated an interacting cDNA clone encoding part of the adaptor protein mint3. The interaction between Rab6A and mint3 is GTP-dependent and requires the complete phosphotyrosine-binding (PTB) domain of the mint protein, which also mediates the association with APP. By confocal microscopy we show that Rab6A, mint3 and APP co-localize at Golgi membranes in HeLa cells. Density gradient centrifugation of cytosolic extracts confirms a common distribution of these three proteins. Our data suggest that mint3 links Rab6A to APP traffic.     

Derepressive Formation of l-Leucine-Pyruvate Transaminase under Nitrogen-Free Conditions in Gluconobacter suboxydans

l-Leucine-pyruvate transaminase activity increased 6- to 20-fold in 3 hr when Gluconobacter suboxydans cells grown on yeast extract-medium were transferred to and incubated in a nitrogen-free medium. The increase in enzyme activity was influenced remarkably by the age and concentration of cells used. The phenomenon depended upon de novo synthesis of enzyme protein.

The enzyme activity in cell-free extracts of cells incubated under a nitrogen-free condition decreased remarkably after heat treatment at 50°C (pH 6.0) or after freezing and thawing. The level of such enzyme inactivation was high in extracts of cells in the early stages of induction and low in later stages.     

Identification of the gene and characterization of the activity of the trans-aconitate methyltransferase from Saccharomyces cerevisiae.

We have identified the yeast open reading frame YER175c as the gene encoding the trans-aconitate methyltransferase of Saccharomyces cerevisiae. Extracts of a yeast strain with a disrupted YER175c gene demonstrate a complete loss of activity toward the methyl-accepting substrates trans-aconitate, cis-aconitate, DL-isocitrate, and citrate. Reintroduction of the YER175c gene on a plasmid results in an overexpression of the activity toward each of these methyl-accepting substrates. We now designate this gene TMT1 for trans-aconitate methyltransferase. We examined the methyl-accepting substrate specificity of this enzyme in extracts from overproducing cells. We found that trans-aconitate was the best substrate with a Km of 0.66 mM. Other substrates were recognized much more poorly, including cis-aconitate with a Km of 74 mM and the decarboxylation product itaconate with a Km of 44 mM. The ratio of the maximal velocity to the Km of these substrates was only 0.24% and 0.9% that of trans-aconitate; for other substrates including citrate and other tricarboxylate and dicarboxylate derivatives, this ratio ranged from 0.0003% to 0.062% that of trans-aconitate. We then asked if any of these compounds were present endogenously in yeast extracts. We were able to identify trans-aconitate 5-methyl ester as well as additional unidentified radiolabeled products when S-adenosyl-L-[methyl-3H]methionine was mixed with TMT1+ extracts (but not with tmt1- extracts), suggesting that there may be additional substrates for this enzyme. We showed that the product 5-methyl ester of trans-aconitate is not readily metabolized in yeast extracts. Finally, we demonstrated that the activity of the yeast trans-aconitate methyltransferase is localized in the cytosol and increases markedly as cells undergo the metabolic transition at the diauxic shift.     

Effect on cell surface hydrophobicity and susceptibility of Helicobacter pylori to medicinal plant extracts

Effects on aqueous extracts of medicinal plants on ten Helicobacter pylori strains were studied by the salt aggregation test to determine the possibility to modulate their cell surface hydrophobicity and by an agar diffusion assay for detection of antimicrobial activity. It was established that aqueous extracts of bearberry and cowberry leaves enhance cell aggregation of all H. pylori strains tested by the salt aggregation test, and the extract of bearberry possessed a remarkable bacteriostatic activity. Pure tannic acid showed a result similar to that of bearberry and cowberry extracts which contained a large amount of tannins. In contrast, extracts of wild camomile and pineapple-weed, which blocked aggregation of H. pylori, contained small amounts of tannins and did not reveal any antimicrobial activity. Tannic acid seems to be the component of bearberry and cowberry aqueous extracts with the highest activity to decrease cell surface hydrophobicity as well as in antibacterial activity against H. pylori.     

Anabolic and catabolic enzymes of urea metabolism in a carbohydrate-utilizing strain of Candida guilliermondii]

The yeast "H" of the genus Candida guilliermondii can grow on hydrocarbons as the only source for carbon. Urea can serve as a nitrogen source for this yeast which lacks detectable urease activity. During urea metabolism ammonia has never been accumulated in the culture medium. However, transferring the yeast from complete urea-medium into an urea containing phophate-buffer, the degradation of urea continues and ammonia is accumulated as well as CO2 evolved. In cell-free extracts of the yeast urea amidolyase activity was detected in the presence of ATP, biotin and specific cations. Obviously, the synthesis of urea amidolyase is induced by urea and arginine and repressed by the catabolite ammonia. Similarly the synthesis of arginase is regulated by arginine and ammonia. The analytical data of the arginase action differ significantly in relation to the carbon source of the culture medium. Both the level of arginase and ornithine carbamyl-transferase change in a characteristic way during the batch-culture. From the lower level of arginase in relation to ornithine carbamyltransferase it can be concluded that especially in alkane-metabolizing yeast the arginine catabolism is not very intensive.     

Insulin activity: stimulatory effects of cinnamon and brewer's yeast as influenced by albumin.

Cinnamon and Brewer's yeast extracts have been shown to potentiate the action of insulin in isolated adipocytes. In this study, isolated rat epididymal adipocytes were used to evaluate the influence of bovine serum albumin on insulin activity as affected by cinnamon and Brewer's yeast extracts. Albumin at 0.01-0.1% decreased the insulin stimulatory effects of cinnamon from 11.8- to 5.3-fold and 2% albumin decreased this effect to near control levels. Conversely, the insulin-enhancing properties of Brewer's yeast remained low in the presence of less than 0.25% albumin but subsequently increased 2.8-, 4.8- and 5.6-fold in the presence of 0.25, 0.50 and 1.0% albumin, respectively. In the absence of added insulin, increased activity of the insulin-stimulated utilization of glucose by both extracts was observed but only Brewer's yeast extract displayed additive effects when tested at higher insulin levels. Due to the inhibitory and enhancing effects of albumin on the insulin activity of cinnamon and Brewer's yeast, respectively, it is suggested that the effects of albumin be assessed when evaluating the insulin-enhancing effects of other substances using isolated adipocytes.     

Expression of the yeast galactokinase gene in Escherichia coli.

In Saccharomyces cerevisiae the genes for three of the enzymes involved in galactose metabolism are tightly linked near the centromere of chromosome II (Douglas and Hawthorne, 1964). However, the molecular mechanisms which control the expression of these genes are not well understood. A DNA fragment containing at least one of these yeast genes, the galactokinase gene (gal1), has been joined to the bacterial plasmid pBR322 and maintained in an Escherichia coli strain that carries a deletion in its own galactokinase gene, galK. The presence of the yeast gene was demonstrated by (i) complementation of the E. coli galactokinase deletion, (ii) by hybridization of the cloned DNA fragment to restriction enzyme digests of total yeast DNA and (iii) by assaying for yeast galactokinase activity in bacterial cell extracts. The yeast DNA fragment is 4700 base pairs long, and enables the host E. coli K-12 strain to grow in minimal medium containing galactose as the sole carbon source with a generation time of 14.3 h. The yeast galactokinase activity in the bacterial extracts is 0.7% of the bacterial galactokinase activity found in wild-type E. coli fully induced with fucose.     

Regulation of hydroxydocosanoic acid sophoroside production in Candida bogoriensis by the levels of glucose and yeast extract in the growth medium.

Cells of Candida bogoriensis produce as a major extracellular lipid 13-[(2'-O-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy]docosanoic acid 6',6'-diacetate (Ac2Glc2HDA), the diacetylated sophoroside of 13-hydroxydocosanoic acid (HDA), along with mono- and unacetylated derivatives. The HDA glycolipid production is greater than 2 g/liter when cells are grown on a "standard" medium of 3% glucose and 0.15% yeast extract. Either lowering the glucose concentration (0.5 to 2.0% glucose, at 0.2% yeast extract) or raising the yeast extract concentration (2 to 4% yeast extract at 3% glucose) greatly decreased the yield of this glycolipid, as well as its rate of synthesis measured by [14C]acetate incorporation. Total HDA production was also depressed on the low glucose medium, as was the activity of UDP-glucose:HDA glucosyltransferase, the first enzyme involved in the synthesis of Ac2Glc2HDA from HDA. Levels of acetyl-CoA:Glc2HDA acetyltransferase were not decreased by growth on a low glucose medium, however, even under conditions in which glycolipid production was less than 4% of that found in the standard medium. Low levels of the HDA glycolipids were monitored by high pressure liquid chromatography of their p-bromophenacyl esters, formed by the action of alpha,beta-dibromoacetophenone on the sodium salt of the lipid in the presence of a crown reagent catalyst. This regulation of extracellular Ac2Glc2HDA production by the nutrient composition of the growth medium may represent an important property in the adaptation of C. bogoriensis to its natural environment, the phyllosphere.     

Choline acetyltransferase in the nettle Urtica dioica L

Extracts of acetone-dried powders prepared from nettle leaves were shown to catalyse the synthesis of acetylcholine. The specific activity of the enzyme in these extracts is of the same order as that of extracts from mammalian sources, such as ox brain, and the effects of temperature and pH are similar to those reported for mammalian choline acetyltransferase. Synthesis is not restricted to the younger leaves but appears to be continuous up to senescence.     

Revealing the reviving secret of the white dead nettle (Lamium album L.)

Lamium album, commonly known as white dead nettle or non-stinging nettle is a flowering herbaceous plant, native throughout Europe, Western Asia and North Africa. From ancient times this plant has been endowed with revival, curative and culinary virtues. In the past, in the traditional and folk medicine white dead nettle has been used mainly for its anti-inflammatory, astringent and anti-septic activity. Nowadays significant amount of knowledge on the efficacy of extracts and raw material of L. album is accumulated and a number of health-related beneficial activities have been scientifically proven. In vitro analyses conducted in various model systems have demonstrated antiviral, antimicrobial, antioxidant, anticancer, cytoprotective, wound healing and other important pharmacological effects. The present review summarizes the recent information on the phytochemical features of this pharmacologically important species. The findings on the chemical composition, biological activities and the pharmacological properties underlying the revival secret of white dead nettle are described and discussed in the view of potential applications for treatment of human diseases. Trends for further research are outlined.     

Biochemical and hemato-immunological parameters in juvenile beluga (Huso huso) following the diet supplemented with nettle (Urtica dioica)

The present study investigated the effects of different dietary nettle (Urtica dioica) levels on biochemical, hematological and immunological parameters in beluga (Huso huso). Fish were divided into 4 groups before being fed for 8 weeks with 0%, 3%, 6% and 12% of nettle. The blood samples were collected on week 4 and 8. The use of nettle did not significantly change the mean cell volume, mean cell haemoglobin, lymphocytes, eosinophils, albumin, glucose, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lysozyme activity on week 4 and 8. After 4 weeks, the total red blood cell (RBC) and hematocrit (Ht) showed a significant increase in 12% nettle group compared to the 3% nettle and control groups but haemoglobin (Hb) had a significant change in 12% nettle compared to the control. At the same time was not found a significant change in the mean cell haemoglobin concentration (MCHC), total white blood cell (WBC), neutrophils, respiratory burst activity (RB), total immunoglobulin (Ig) and total protein (TP), triglyceride (Tri) and cholesterol (Chol). After 8 weeks, the fish treated with nettle exhibited significantly increase in neutrophil and Hb levels compared to the control and between treatment groups, 12% nettle group shown the highest Hb while RBC and Hct values significantly rose in fish fed by 12% compared to the control. Supplementing 6% and 12% nettle increased the WBC and MCHC compared to the other groups. The group fed 12% showed a highly significant difference in RB, TP and Ig after 8 weeks. However, Tri and Chol were significantly decreased in the juvenile beluga fed by the 6% and 12% nettle diet compared to the other groups. The results suggest that by using this herb there will be an improvement in hemato-biochemical parameters and immune function of juvenile beluga.     

Partial purification and properties of a beta-glucosidase from Erwinia herbicola Y46.

A constitutive beta-glucosidase of Erwinia herbicola Y46 was studied as a prerequisite to an assessment of its significance in the release of bacteriotoxic aglycones from plant beta-glucosides, and the possible effects of the aglycones on the course of such plant diseases as "fire-blight". The enzyme was purified 86.5-fold from crude extracts of cells grown on yeast beef broth. Ammonium sulfate precipitation, DEAE-cellulose fractionation, and gel filtration through Sephadex G-100 resulted in a preparation having one peak of activity on isoelectrofocussing, on gel filtration through Sephadex G-200, and on polyacrylamide gel electrophoresis. The latter techniques demonstrated, in addition to the major protein band associated with activity, a single minor impurity. The enzyme was active against p-nitrophenyl-beta-glucoside (p-NPG) and phloridzin, but showed only very slight activity against salicin and arbutin, and no detectable activity against beta-methyl-D-glucoside, cellobiose, lactose, and esculin. The production of beta-glucosidase was maximum at the late log phase of growth on yeast beef broth medium and declined somewhat thereafter. The incorporation of inducers (carbohydrates) in defined basal medium resulted in only small variations in specific activity in the resulting cells; The activity (p-NPG substrate) was not inhibited by D-glucose, phloretin, esculin, salicin, arbutin, lactose, or cellobiose, but was slightly inhibited by 1.0 mM phloridzin. Slight inhibition was observed in the presence of sulfhydryl reagents (iodoacetamide, p-chloromercuribenzoate), but sodium azide, ethylene-diaminetetraacetic acid, Cu2+, and Zn2+ ions produced no effect. The activity was stable, in both crude and purified preparations, over the pH ranges 6.0-7.5 (100% activity) and 4.5-greater than 8.5 (50% activity). The enzyme retained 80% activity after 30 min at 50 degrees C, but only 25% after 30 min at 60 degrees C. The enzyme had a mean K-m value (phloridzin) of 1.35 times 10-4 M, an isoelectric point of 4.75, a molecular weight, determined by Sephadex G-200 gel filtration, of about 122 000, and an optimum pH for activity of 6.5-7.0.     

Studies on cyclic adenosine 3' ,5'-monophosphate levels, Adenylate cyclase and phosphodiesterase activities in the dimorphic fungus Mucor rouxii.

The germination of spores of Mucor rouxii into hyphae was inhibited by 2 mm dibutyryl cyclic adenosine 3′,5′-monophosphate or 7 mm cyclic adenosine 3′,5′-monophosphate; under these conditions spores developed into budding spherical cells instead of filaments, provided that glucose was present in the culture medium. Removal of the cyclic nucleotides resulted in the conversion of yeast cells into hyphae. Dibutyryl cyclic adenosine 3′,5′-monophosphate (2 mm) also inhibited the transformation of yeast to mycelia after exposure of yeast culture to air.Since in all living systems so far studied adenylate cyclase and cyclic adenosine 3′,5′-monophosphate phosphodiesterase are involved in maintaining the intracellular cyclic adenosine monophosphate level, the activity of both enzymes and the intracellular concentration of cyclic adenosine monophosphate were investigated in yeast and mycelium extracts. Cyclic adenosine monophosphate phosphodiesterase and adenylate cyclase activities could be demonstrated in extracts of M. rouxii. The specific activity of adenylate cyclase did not vary appreciably with the fungus morphology. On the contrary, cyclic adenosine monophosphate phosphodiesterase activity was four- to sixfold higher in mycelial extracts than in yeast extracts and reflected quite accurately the observed changes in intracellular cyclic adenosine monophosphate levels; these were three to four times higher in yeast cells than in mycelium.     

Ribonuclease activity during Gl arrest of the yeast Saccharomyces cerevisiae

When cells of the yeast, Saccharomyces cerevisiae, were deprived of nitrogen, a condition leading to Gl arrest, there was an immediate increase in the levels of total ribonuclease (RNase) activity within these cells. During starvation, only the cells arrested in Gl showed increased RNase activity. Although the RNase activities of extracts of starved and actively growing cells were similarly influenced by pH, the activities of starved cells were less stable on both storage and heating. Differences were also noted in substrate specificity. The results of this study suggest that arrest within Gl may increase RNase activity. However, all RNases did not appear to be influenced equally, since the total pool of RNase activity from log phase and Gl arrested cells showed differences in stability and substrate specificity.Non-standard abbreviations YNB, MIN liquid synthetic media (Johnston et al., 1977a) - YNB-N nitrogen-free medium - MIN-S sulfate-free medium - TCA trichloroacetic acid     

Studies on the decomposition of lignosulfonates by the fungi Pleurotus ostreatus and Trametes pubescens.

The fungi Pleurotus ostreatus and Trametes pubescens were grown in a mineral medium containing 1% of glucose and 0.9% of lignosulfonates introduced into the culture medium in the form of yeast waste liquor. Chromatography of extracts of the medium and determinations of sulphur and lignosulfonates have revealed that the fungi studied utilized the constituents of the yeast waste liquor (lignosulfonates) as carbon source. This was manifested in an increase of dry mass of the mycelium and protein as compared with the control. The constituents of the yeast waste liquor were also found to have a stimulating effect on the formation of both exo-and endoenzymes, laccase and peroxidase. This may indicate that these oxidases take part in the decomposition of lignosulfonates.     

Synergism between plant extract and antimicrobial drugs used on Staphylococcus aureus diseases

Searches for substances with antimicrobial activity are frequent, and medicinal plants have been considered interesting by some researchers since they are frequently used in popular medicine as remedies for many infectious diseases. The aim of this study was to verify the synergism between 13 antimicrobial drugs and 8 plant extracts--"guaco" (Mikania glomerata), guava (Psidium guajava), clove (Syzygium aromaticum), garlic (Allium sativum), lemongrass (Cymbopogon citratus), ginger (Zingiber officinale), "carqueja" (Baccharis trimera), and mint (Mentha piperita)--against Staphylococcus aureus strains, and for this purpose, the disk method was the antimicrobial susceptibility test performed. Petri dishes were prepared with or without dilution of plant extracts at sub-inhibitory concentrations in Mueller-Hinton Agar (MHA), and the inhibitory zones were recorded in millimeters. In vitro anti-Staphylococcus aureus activities of the extracts were confirmed, and synergism was verified for all the extracts; clove, guava, and lemongrass presented the highest synergism rate with antimicrobial drugs, while ginger and garlic showed limited synergistic capacity.