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PubMed1999

Insecticidal, anti-juvenile hormone, and fungicidal activities of organic extracts from different Penicillium species and their isolated active components.

Organic extracts from mycelium and culture broth of 21 Penicillium isolates have been tested for insecticidal, insect anti-juvenile hormone (anti-JH), and antifungal activities. Culture broth extracts were the most active, mainly against insects; nearly 25% of them have shown high entomotoxicity (100% mortality at 100 microg/cm(2)). A strong in vivo anti-JH activity against Oncopeltus fasciatus Dallas was detected in the culture broth extracts from P. brevicompactum P79 and P88 isolates. The two new natural products isolated from P79, N-(2-methyl-3-oxodec-8-enoyl)-2-pyrroline (1) and 2-hept-5-enyl-3-methyl-4-oxo-6,7,8,8a-tetrahydro-4H-pyrrolo[2,1-b]-1, 3-oxazine (2), possessed anti-JH and insecticidal activity, respectively, against O. fasciatus. Synthesized natural compound 1 has shown an ED(50) of 0.7 microg/nymph when assayed on newly molted fourth-instar nymphs of O. fasciatus. Promising biological activities have also been detected in the synthetic precursors.

Animals↗
PubMed1997

Properties of electrochemically active components in mammalian vitreous humor.

Antioxidants are considered to have important roles in protecting the eye against radiation, oxygen toxicity and other threats. Several water-soluble electrochemically-active compounds that might function as antioxidants in vitreous humor of rabbit, rat and bovine eyes were identified and quantitated. In that the rat is a nocturnal animal species and the other two are diurnal, the results allow a tentative evaluation on the comparative physiology of light-dark behavior patterns that influence this ocular fluid. All analyses were performed by HPLC with electrochemical detection. The utility of this approach is that components of vitreous humor can be identified by their retention time and by their characteristic response when the voltages of the two sensing electrodes are progressively brought together. Four compounds regarded as functional antioxidants in the animal kingdom were identified and quantitated. Other antioxidants known to be present in several biological fluids are not present at detectable or significant levels in vitreous humor; metabolites or precursors of these might be present in trace quantities.

Animals↗
PubMed2000

Electrophoretic behavior study and determination of some active components in Chinese medicinal preparations by capillary electrophoresis.

The determination of icariin (IC), rhein (RH), chrysophanol (CH), physcion (PHY), glycyrrhetic acid (GE), and glycyrrhizic acid (GI), in traditional Chinese preparations, Anshen Bunao oral liquid and Maren pill, has been investigated by micellar electrokinetic capillary electrophoresis. With borate buffer (10 mM), SDS (20 mM) and acetonitrile (10%) as background electrolyte (pH 9.55), 20 kV applied voltage and 254 nm UV detection, the six active compounds were completely separated within 10 min. The effects of buffer pH, concentration of borate, SDS and modifier on electrophoretic behavior and separation are discussed. Regression equations revealed linear relationships (correlation coefficients: 0.9960-0.9999) between the peak-area of each component and the content. In addition, the levels of the six active compounds in two kinds of traditional Chinese medicinal preparations were easily determined with recoveries of from 94.7% to 106.4%.

Chromatography, Micellar Electrokinetic Capillary↗
PubMed2000

Low levels of urokinase plasminogen activator components in basal cell carcinoma of the skin.

Basal cell carcinoma of the skin (BCC) is the most common cancer worldwide. Unlike most other human malignancies, BCCs rarely metastasise. In this investigation, we show that the serine protease urokinase plasminogen activator (u-PA), which is causally involved in metastasis, is expressed at lower levels in BCCs compared to other skin cancers, such as squamous-cell carcinomas (SCCs) or malignant melanomas. Similarly, the u-PA receptor as well as the inhibitor PAI-1 were present at lower levels in BCCs relative to both SCCs and melanomas. In contrast to u-PA, tissue-plasminogen activator, which is not thought to be involved in metastasis, was present at similar levels in the different types of skin lesion investigated. We conclude that the failure of BCCs to metastasise may at least be partially related to low expression of components of the u-PA system.

Basal Cell Carcinoma↗
PubMed1986

Microheterogeneous forms of radioiodinated bovine thyrotropin: discrimination of different receptor-active components by gel permeation chromatography.

The products of the radioiodination and subsequent receptor adsorption of bovine TSH (bTSH) radiolabeled by the lactoperoxidase method have been further investigated. After receptor adsorption, [125I]bTSH was resolved by gel permeation chromatography on Sephadex G-100 (superfine) under low ionic strength conditions into three peaks of radioactivity (tracers 2a, 2b, and 2c, respectively). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions demonstrated that each tracer component was radiolabeled on both the alpha- and beta-subunits. Analysis of the three tracers by TSH radioreceptor assay (under different radioreceptor assay conditions) showed that tracers 2b and 2c exhibited saturable rebinding to crude thyroid membranes containing functional TSH receptors. However, tracer 2c exhibited a maximum binding 2-fold greater than tracer 2b. This difference has been attributed to the abundance of an apparently low affinity binding component in tracer 2c. Rechromatography of tracers 2b and 2c on Sephadex G-100 (superfine) under high ionic strength conditions yielded tracer profiles that were coincident, demonstrating that the initial separation under low ionic strength conditions was not based on differences in molecular volume. The data indicate that radioiodination of highly purified bTSH yields multiple tracer components. Further, receptor adsorption, commonly used to purify freshly iodinated bTSH before radioreceptor assay, purifies at least two species of receptor-active [125I] bTSH.

Animals↗
PubMed1989

Possible active components of tan-shen (Salvia miltiorrhiza) for protection of the myocardium against ischemia-induced derangements.

Extract of Tan-Shen (Salvia miltiorrhiza, Labiatae), a Chinese traditional crude drug, was reported to show beneficial activity for heart disease. Chemical examination on the extract was performed on the basis of screening for protective action on the ischemic myocardium. Isolated hearts were subjected to hypoxic perfusion for 20 min, followed by 45 min reoxygenation, and the recovery of cardiac contractile force and changes in UV absorbance of the perfusate were examined. Among the components isolated, tanshinone I, cryptotanshinone, and tanshinone VI elicited a significant enhanced recovery of the contractile force upon reoxygenation. This was associated with a decrease in the increase in UV absorbance of the perfusate, suggesting the preservation of ATP metabolites in the myocardium. This, in turn, may enhance the restoration of ATP upon oxygen-replenishment. The results suggest that tanshinone I, cryptotanshinone, and tanshinone VI can protect the myocardium against ischemia-induced derangements.

Animals↗
PubMed1999

Biologically active components against Drosophila melanogaster from Podophyllum hexandrum.

In the course of screening for novel naturally occurring insecticides from Chinese crude drugs, a dichloromethane extract of Podophyllum hexandrum was found to give an insecticidal activity against larvae of Drosophila melanogaster Meigen. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation. The compound was identified as podophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays for insecticidal activity, 1 showed a LC(50) value of 0.24 micromol/mL diet against larvae of D. melanogaster and a LD(50) value of 22 microg/adult against adults. Acetylpodophyllotoxin (1A), however showed slight insecticidal activity in both assays, indicating that the 4-hydroxyl group was an important function for enhanced activity of 1.

Animals↗
PubMed1979

Platelet-activating factor. Evidence for 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine as the active component (a new class of lipid chemical mediators).

A glyceryl ether containing phosphoglyceride, 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (Ac-GEPC), has been shown to have a biological activity indistinguishable from that of naturally generated (rabbit) platelet activating factor (PAF). Its biochemical and biological properties so closely parallel those of naturally occurring PAF that we propose they are one and the same compound. Both PAF and AcGEPC could be converted to an inactive form through base-catalyzed methanolysis and restored to 100% functional activity by reaction with acetic anhydride. The synthetic lipid, AcGEPC, elicited 50% secretion of serotonin from rabbit platelets at a level of 10(-10) M (based on phosphorus). A propionyl derivative had somewhat comparable activity towards platelets, whereas the butyryl homologue was some 7-fold less active and the stearoyl derivative was inactive. These short chain acylglyceryl ether phosphoglycerides represent an entirely new, potent and unique class of lipid chemical mediators. 1-Acyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (AcLL) also exhibited activity towards platelets but was some 200-fold less active than AcGepc. the propionyl lysolecithin behaved quite similarly to AcLL, but butyryl and stearoyl lysolecithins showed no activity.

Animals↗
PubMed1953

Tissue culture studies; isolation of the active components in the ultrafilterable portion of the chick embryo extract.

A fraction of the ultrafilterable portion of chick embryo extract was isolated by alcohol extraction of a lyophilized powder of the ultrafiltrate followed by ion exchange removal of many of the inert components of the alcohol extract. This fraction contained 3 per cent of the ultrafilterable nitrogen but was capable of completely restoring the growth-promoting activity of dialyzed embryo extract, when tested with chick heart fibroblasts in roller tube cultures. The low nitrogen content, shape of the ultraviolet absorption spectrum, and presence of few free amino acids, suggest that non-dialyzable compounds serve as the chief source of nutrition for this system.

Animals↗
PubMed2003

Antifungal effects of different organic extracts from Melia azedarach L. on phytopathogenic fungi and their isolated active components.

Extracts from different parts of Melia azedarach L. were studied as potential antifungal agents for selected phytopathogenic fungi. In a serial agar dilution method, hexanic and ethanolic extracts from fruit, seed kernels, and senescent leaves exhibited fungistatic activity against Aspergillus flavus,Diaporthe phaseolorum var. meridionales, Fusarium oxysporum, Fusarium solani, Fusarium verticillioides, and Sclerotinia sclerotiorum. Both hexanic extract from senescent leaves and ethanolic extract from seed kernel were highly effective on all tested fungi, with minimum inhibitory concentration (MIC) values ranging from 0.5 to 25 mg/mL and 0.5 to 5 mg/mL, respectively. In addition, all of the above-mentioned extracts showed fungicidal activity on these fungi, with ethanolic seed kernel extract being the most active. Three compounds displaying activity against F. verticillioides were isolated from the ethanolic seed kernel extract and were characterized as vanillin (1), 4-hydroxy-3-methoxycinnamaldehyde (2), and (+/-)-pinoresinol (3), with MICs of 0.6, 0.4, and 1.0 mg/mL, respectively. These compounds also showed a synergistic effect when combined in different concentrations, needing four times less concentration to reach complete inhibition in the growth of F. verticillioides.

Antifungal Agents↗
PubMed1966

The effect of high ionic strength on the sedimentation properties of the biologically active component of bacterial ribonucleic acid.

1. The sedimentation properties of the fraction of bacterial RNA which stimulates the incorporation of amino acids into acid-insoluble material in vitro depend on the ionic strength of the sedimentation medium. 2. The different distributions of stimulatory activity found in centrifuged linear sucrose gradients loaded with bacterial RNA and containing 0.1m- or 0.6m-sodium chloride resemble closely the different sedimentation profiles of rapidly labelled RNA observed under the same conditions. 3. These findings agree with those of previous work of a similar nature (Willson & Gros, 1964) and demonstrate that the component of bacterial RNA preparations which stimulates the incorporation of amino acids into acid-insoluble peptides in vitro is contained in their rapidly labelled fraction.

Carbon Isotopes↗
PubMed2002

Ultraviolet-B activates components of the systemin signaling pathway in Lycopersicon peruvianum suspension-cultured cells.

Among the early responses of Lycopersicon peruvianum suspension-cultured cells to the polypeptide wound signal systemin are the alkalinization of the culture medium and the activation of a 48-kDa mitogen-activated protein kinase (MAPK). Here, we report that both responses are induced in the cells by exposure to ultraviolet-B (UV-B) radiation. Suramin, an inhibitor of systemin receptor function, strongly inhibited the UV-B-induced medium alkalinization and MAPK activity. The UV-B response was also reduced when cells were initially treated with systemin or the systemin antagonist Ala-17-systemin, which competitively inhibits binding of systemin to the systemin receptor. Cells that were initially treated with either UV-B or systemin exhibited a strongly reduced response to a subsequent elicitation with systemin. The desensitization was transient, reaching a maximum at 30-60 min after the initial treatment. Several hours later, depending on the initial UV-B dose or systemin concentration, the cells regained their initial responsiveness. When cells were irradiated with low doses of UV-B and subsequently treated with systemin, the UV-B response reached levels higher than the response without UV-B treatment. The data provide evidence for an involvement of the systemin receptor and/or systemin-responsive signaling elements in the UV-B response.

Adenosine Triphosphatases↗
PubMed2000

Alpha-thujone (the active component of absinthe): gamma-aminobutyric acid type A receptor modulation and metabolic detoxification.

Alpha-thujone is the toxic agent in absinthe, a liqueur popular in the 19th and early 20th centuries that has adverse health effects. It is also the active ingredient of wormwood oil and some other herbal medicines and is reported to have antinociceptive, insecticidal, and anthelmintic activity. This study elucidates the mechanism of alpha-thujone neurotoxicity and identifies its major metabolites and their role in the poisoning process. Four observations establish that alpha-thujone is a modulator of the gamma-aminobutyric acid (GABA) type A receptor. First, the poisoning signs (and their alleviation by diazepam and phenobarbital) in mice are similar to those of the classical antagonist picrotoxinin. Second, a strain of Drosophila specifically resistant to chloride channel blockers is also tolerant to alpha-thujone. Third, alpha-thujone is a competitive inhibitor of [(3)H]ethynylbicycloorthobenzoate binding to mouse brain membranes. Most definitively, GABA-induced peak currents in rat dorsal root ganglion neurons are suppressed by alpha-thujone with complete reversal after washout. alpha-Thujone is quickly metabolized in vitro by mouse liver microsomes with NADPH (cytochrome P450) forming 7-hydroxy-alpha-thujone as the major product plus five minor ones (4-hydroxy-alpha-thujone, 4-hydroxy-beta-thujone, two other hydroxythujones, and 7,8-dehydro-alpha-thujone), several of which also are detected in the brain of mice treated i.p. with alpha-thujone. The major 7-hydroxy metabolite attains much higher brain levels than alpha-thujone but is less toxic to mice and Drosophila and less potent in the binding assay. The other metabolites assayed are also detoxification products. Thus, alpha-thujone in absinthe and herbal medicines is a rapid-acting and readily detoxified modulator of the GABA-gated chloride channel.

Absinthe↗
PubMed1975

Biologically active components from mycobacterial cell walls. III. Production of experimental allergic encephalomyelitis in guinea-pigs.

The efficacy of various fractions of mycobacterial cell walls in producing experimental ahlergic encephalomyelitis (EAE) has been evaluated. BCG (Bacillus-Calmette-Buérin) cell walls were effective in producing EAE in all animals at dose levels as low as 40 mug. Study of subfractions of these cell walls revealed the following: (1) wax D was active, but required larger doses than BCG cell walls; (2) the chloroform-methanol-soluble (CMS) portion of wax D and P3 (a mycolic acid-trehalose ester contained therein) were inactive; (3) the chloroform-methanol-insoluble (CMI) portion of wax D was active; (4) exhaustively delipidated cell wass skeletons of BCG, Nocardia asteroides, Mycobacterium smegmatis, Corynebacterium diphtheriae and M. kansaii were active; (5) two water-soluble adjuvants prepared from mycobacteria were active. These results suggest that the mycobacterial structure responsible for EAE adjuvanticity is present in the organic solvent-insoluble cell wall skeleton framework. The activity of wax D may be due to the presence of cell-wall skeleton constituents which are found in varying quanity in most wax D preparations. Wax D components soluble in a solution of chloroform:methanol (diluted 2:1 v/v) do not produce EAE.

Adjuvants, Immunologic↗