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1.
Lantadene A (22 beta-angeloyloxy-3-oxo-olean-12-en-28-oic acid), a pentacyclic triterpenoid compound from lantana (Lantana camara) leaves has been obtained in two polymorphic forms I and II. Form I had white, fluffy, and rod-shaped uniform crystals. Form II particles were irregular, shining, and polyhedral. The two forms differed in melting behavior. The powder x-ray diffraction of form I showed sharp peaks whereas from II did not contain distinct peaks. From single-crystal three-dimensional x-ray structure determination, the molecular structure of form I has been established. A/B and B/C rings of the molecule are trans fused while D/E rings are cis fused. The packing of the molecule is stabilized by hydrogen bonding. Form I of lantadene A was non-toxic to guinea pigs on oral administration. Form II induced ictericity and toxicity associated with decrease in feed intake and fecal output, hepatomegaly, increase in plasma bilirubin, and acid phosphatase activity. 相似文献
2.
A bacterial strain capable of biotransformation oflantadene A(22-angeloyloxy-3-oxo-olean-12-en-28-oic acid),the pentacyclic hepatotoxin of lantana (Lantanacamara var. aculeata) has been isolated fromsoil using lantadene A as the sole carbon source. Theorganism is Gram negative, rod shaped, motile,catalase positive and has been identified as Alcaligenes faecalis. The isolate has been found tobe specific for lantadene A and did not utilizelantadene B. In studies using sucrose as an additionalcarbon source, A. faecalis elicitedbiotransformation of lantadene A to its trans isomer22-tigloyloxy-3-oxoolean-12-en-28-oic acid,designated as lantadene X and two other minormetabolites which could not be isolated in pure state. 相似文献
3.
Sabira Begum Anjum Ayub Bina Shaheen Siddiqui Shahina Fayyaz Firoza Kazi 《化学与生物多样性》2015,12(9):1435-1442
A new triterpene, lancamarolide ( 1 ), and seven known triterpenes, oleanonic acid ( 2 ), lantadene A ( 3 ), 11α‐hydroxy‐3‐oxours‐12‐en‐28‐oic acid ( 4 ), betulinic acid ( 5 ), lantadene B ( 6 ), and lantaninilic acid ( 7 ) were isolated from the aerial parts of Lantana camara in the course of bioassay‐guided isolation, and their nematicidal activities against Meloidogyne incognita, the root knot nematode, were carried out. Oleanonic acid was found to be the most active compound and exhibited 80% mortality after 72 h at 0.0625% concentration, which is comparable with that of the standard furadan. 相似文献
4.
Sabira Begum Anjum Ayub Syeda Qamar Zehra Bina Shaheen Siddiqui M. Iqbal Choudhary Samreen 《化学与生物多样性》2014,11(5):709-718
Two new natural triterpenes, lantaninilic acid and lantoic acid, along with the known triterpenes lantadene A, and oleanolic, ursolic, betulinic, lantanolic, and camaric acid, were obtained from the aerial parts of Lantana camara through bioassay‐guided isolation, monitoring the in vitro antileishmanial activity against promastigotes of Leishmania major. Oleanolic acid ( 3 ), ursolic acid ( 4 ), lantadene A ( 5 ), and lantanilic acid ( 7 ) showed significant leishmanicidal activities with IC50 values of 53.0, 12.4, 20.4, and 21.3 μM , respectively. The IC50 value of ursolic acid ( 4 ; 12.4 μM ) was found to be comparable with that of the standard drugs, pentamidine (IC50 15.0 μM ) and amphotericin B (IC50 0.31 μM ). The in vitro activities of L. camara and its constituents against promastigotes of Leishmania major are reported here for the first time. 相似文献
5.
Anita Singh Om P. Sharma Tej Krishan Bhat Surinder K. Vats Sudarshan Ojha 《International biodeterioration & biodegradation》2001,47(4)
Seven white-rot fungi, known to degrade complex biomolecules and xenobiotics were used for investigation on biodegradation of lantadene A (LA), the bioactive pentacyclic triterpenoid of Lantana camara. Pleurotus sajor-caju and Merulius tremellosus PRL-2845 did not degrade LA. Trametes versicolor MTCC-138, Heterobasidion annosum MTCC-146, Phellinus pini RAB-83-19, Pleurotus ostreatus MTCC-142 and Phlebia radiata 2 utilized LA to the extent of 11–15.7%. This is the first report on the fungal degradation of a pentacyclic triterpenoid. 相似文献
6.
Mary C. Allen Wesley W. Day 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1996,675(2):265
A simple and precise high-performance liquid chromatographic (HPLC) assay was developed and validated for the determination of a novel angiotensin II antagonist, 1-[5-(2-cyclopropyl-5,7-dimethyl-imidazo[4,5-b]pyridin-3-ylmethyl)thiopen-2-yl)cyclopent-3-enecarboxylic acid (CP-191,166, I), in dog and rat plasma. The internal standard (II, a saturated derivative of I) and analyte were extracted by liquid-liquid extraction using methyl tert.-butyl ether. Samples were analyzed by reversed-phase HPLC using a Zorbax C8 narrow-bore column with ultraviolet detection at 289 nm. The quantitation limit of I was 10 ng/ml and the calibration curve was linear over the range of 0.01–10.0 μg/ml (r2>0.99). In dog and rat plasma, intra- and inter-assay precision ranged from 0.00 to 3.36% and 0.00 to 4.95%, respectively. The average recoveries were similar (73%) for both I and II and the upper limit of quantification of I can be as high as 500 μg/ml. The method described has been successfully applied to the quantification of I in about 2000 dog and rat plasma samples over a nine-month period. 相似文献
7.
The liver is a target for toxic chemicals such as cadmium (Cd). When the liver is damaged, hepatic stellate cells (HSC) are activated and transformed into myofibroblast-like cells, which are responsible for liver fibrosis. Curcuma longa has been reported to exert a hepato-protective effect under various pathological conditions. We investigated the effects of C. longa administration on HSC activation in response to Cd induced hepatotoxicity. Forty adult male albino rats were divided into: group 1 (control), group 2 (Cd treated), group 3 (C. longa treated) and group 4 (Cd and C. longa treated). After 6 weeks, liver specimens were prepared for light and electron microscopy examination of histological changes and immunohistochemical localization of alpha smooth muscle actin (αSMA) as a specific marker for activated HSC. Activated HSC with a positive αSMA immune reaction were not detected in groups 1 and 3. Large numbers of activated HSC with αSMA immune reactions were observed in group 2 in addition to Cd induced hepatotoxic changes including excess collagen deposition in thickened portal triads, interlobular septa with hepatic lobulation, inflammatory cell infiltration, a significant increase in Kupffer cells and degenerated hepatocytes. In group 4, we observed a significant decrease in HSC that expressed αSMA with amelioration of the hepatotoxic changes. C. longa administration decreased HSC activation and ameliorated hepatotoxic changes caused by Cd in adult rats. 相似文献
8.
Peter Luger 《Carbohydrate research》1982,110(2)
X-Ray crystallographic analysis was performed on the compound to which had been assigned the structure of 1,2,3-tri-O-acetyl-4,5-dideoxy-4-C-[(R)-phenylphosphinyl]-α-
-lyxofuranose. The results showed that the compound has the proposed configuration, the five-membered ring is in the E3 conformation, with a tendency towards the 3T2 form, the substituents at P-5 and C-5 are linked bisectionally, the acetoxyl group at C-2 and the methyl group at C-4 are linked quasiequatorially, and the acetoxyl group at C-3 is linked axially. 相似文献
9.
S.A. Brooks D.R. Lachno B.D. Obermeyer 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,691(2):97
A rapid and sensitive high-performance liquid chromatographic method for the determination of the novel ergoline derivatives sergolexole (compound I), its acid metabolite (compound II) and cis-n-(2-hydroxycyclopentyl)-6-methyl-1-(1-methylethyl) ergoline-8-carboxamide (LY215840, compound III) in human plasma is reported. The compounds were extracted from plasma by automated solid-phase extraction and analysed on a reversed-phase C8 column with fluorescence detection. The limit of quantification for all compounds was 10 ng/ml and the response was linear over the range 10–1000 ng/ml. Validation studies showed the method to be both repeatable and reproducible with no interference from human plasma. The method has been used to support pharmacokinetic studies and has proved to be robust and effective. 相似文献
10.
Tsutomu Higashijima Yasuyuki Shimohigashi Tetsuo Kato Nobuo Izumiya Tamio Ueno Tatsuo Miyazawa 《Biopolymers》1983,22(4):1167-1187
Cyclic tetradepsipeptides, AM-toxin I and II, are the host-specific phytotoxins of Alternaria mali. In order to elucidate conformation-toxicity relationships, we analyzed the 270-MHz proton nmr spectra of AM-toxins and hydrogenated analogs, (D -Ala2)AM-toxin I (toxic) and (L -Ala2)AM-toxin I (not toxic), in (C2H3)2SO. These cyclic tetradepsipeptides do not contain N-substituted amino acid residues, and all the peptide and ester groups have been found to be transoid. Two conformers with very unequal populations have been found for AM-toxin I and II; the Cβ?Cα? C?O conformations of the Dha2 residues are nonplanar S-trans in the major conformer and nonplanar S-cis in the minor conformer. Only one ring conformation has been found for each of (L -Ala2) and (D -Ala2)AM-toxin I. (L -Ala2)AM-toxin I takes a C4-type ring conformation; all the C?O groups and Cα-H bonds are oriented to the same side of the ring. (D -Ala2)AM-toxin I takes a new ring conformation; the side chain and C?O group of the L -Amp1 residue are oriented to the same side of the ring. This new conformation is also found for the major conformers of AM-toxin I and II and thus appears to be required for the toxicity. The ring conformations of Tyr(OCH3)1-bearing analog tetradepsipeptides have been found to be much the same as those of Amp1-bearing depsipeptides. Furthermore, on the basis of the two distinct conformations of (D -Ala2) and (L -Ala2)AM-toxin I, an empirical rule is proposed for the stable ring conformations of cyclic tetra-D ,L -peptides, not containing N-substituted amino acid residues. 相似文献
11.
The helix-coil transformation for tropocollagen solutions and its relationship to transformations involving the crystalline form of the protein 总被引:1,自引:0,他引:1
Collagen molecules can exist, in the aggregate crystalline state (C) and in solutions, as tropocollagen helices (H) or random coils (RC). We have compared the role of temperature, salt type, and salt concentration, C8, on the transformations: C → RC (I), H → RC (II), and H → C (III) under near-isoelectric conditions. Processes I and II occur in the direction from ordered to disordered form on increasing temperature, while process III occurs in the direction crystal → dissolved helices on lowering temperature. The order of both anions and cations for increasing the stability of the dissolved random coiled form is similar for processes I and II, but the order of the anions for increasing the stability of the dissolved helices, according to process III, is reversed with respect to the Hofmeister series. TI and TII are greatly and continuously depressed by some salts on increasing C8 while, for other salts, they are at first slightly depressed and then raised. TIII, instead, is at first raised and then lowered on increasing C8. For a given salt the field of stability of each form is determined, on a pseudo-phase diagram, by the relative positions of the TI versus C8, the TII versus C8, and the TIII versus C8, curves. The similarity of the effect of temperature, salt type, and concentration on processes I and II supports the contention that both processes are controlled by the interaction of the random coiled form with the salt solution. The phenomenon of crystallization by increasing temperature is complicated by large time effects and, often by lack of reversibility. Assuming, nevertheless, that there is an underlying equilibrium process, two possible interpretations are proposed. The peculiar trend of the TIII versus C8 curve is justified on the basis that it reflects the usual change from salting in to salting out on increasing C8, allowing for the fact that the dissolved phase is stable in the low-temperature range. The reversal of the order of anions for process III can be most simply justified in terms of the slight cat ionic character of the tropocollagen units. Accordingly, the dissolved helices will be more; stable of the crystalline form depending upon the occurrence of a net charge different from zero on the protein, as well as upon low ionic strength and low temperature. Minute alterations of KCl concentrations are able to cause isothermal precipitation of fibers and probably constitute a controlling factor for the fibrogenesis in vivo. 相似文献
12.
The synthesis of four chiral NAD+ models 1 and their 1,4-dihydro analogs 2 is described. From the temperature dependence of the 1H-nmr spectra it is concluded that for these compounds two preferred conformations I and II, differing slightly in energy, exist. Both conformations are “folded” with the more or less parallel p-anisyl and pyridine groups mutually gauche, but in I the pyridine group is rotated by about 180° as compared with II, thus leading to a conspicuous difference in orientation of the substituent Z (NH2CO, C6H5NHSO2, (CH2)4NSO2, or (C4H8ON)SO2) in the pyridine ring toward the anisyl group. The most stable conformation (I) has Z closest to the center of the p-anisyl group. In 360-MHz spectra of the dihydropyridines at low temperature (−10°C), slow interconversion of I and II leads to the observation of an XY pattern for the C-4 methylene protons of the 1,4-dihydropyridine system. The anisochronity in this methylene group is caused mainly by the anisotropy of the neighboring p-anisyl group. 相似文献
13.
Decompositions of amorphous cellulose induced by cellulases of Trichoderma reesei were evaluated from gradients at zero time of exponential functions which were fitted to nephelometrically measured values of turbidty of incubated solutions of cellulose [turbidity = A × exp (B × t)+ C [A, B, C = constants, t = time]]. Synergistic enhancements of decomposition of amorphous cellulose resulted in the range of 300 p.c. whenever of the two isoenzymes of cellobiohydrolase I of Trichoderma reesei (CBH I, being an exo-glucanase) one was incubated together with one of the isoenzymes of CBH II (being really an endo-glucanase). Accessibility of amorphous cellulose to enzymatic decomposition being calculated from the fitted function by the term (A/(A + C)) × 100 [p.c.] resulted for the CBH I isoenzymes and for the CBH II/1 in the range of 27 to 38 p.c. of the total substrate. Incubations of CBH II/1 in with CBH I/1 and CBH I/2 were followed by increases of accessibility to 85 and 87 p.c., respectively. CBH II/2 by itself caused a substrate accessibility in the range of 80 p.c., which increased to 96 p.c. when it was incubated together with CBH I/1 or CBH I/2. Amorphous cellulose dispersing activity (ACD activity) being evaluated from the fitted function by the term (A + C)/(Ac + Cc) × 100 [p.c.] (Ac + Cc × control turbidity at zero time) was not increased when a CBH I isoenzyme was incubated together with a CBH II isoenzyme. EG I, a convetional endo-glucanase from Tr. reesei proved not to act synergistically in any case when incubated together with one of the CBH isoenzymes. On the contrary, EG I turned out to act antagonistically to CBH II/1 and CBH II/2. Results can be interpreted as an exo-endo-synergism taking place between C1-specific exo- and endo-glucanases. 相似文献
14.
Acetylene-reducing activities (ARA) of strains ofEnterobacter agglomerans, Azospirillum brasilense, Azotobacter chroococcum, and Bacillus, isolated from temperate or tropical soils, were compared at different temperatures to study temperature adaptability.
All Enterobacter strains and Bacillus strain C-11-25 reduced C2H2 at temperatures as low as 5°C. ARA by Enterobacter strains declined sharply above 30°C but ARA by Bacillus strain C-11-25
continued to increase with an increase in temperature.A. brasilense strain sp 245, isolated from wheat roots in Brazil, reduced more C2H2 at lower temperatures than strain Cd, isolated from a Californian soil. Similarly, the temperate strain ofA. chroococcum was a better N2 fixer than the tropicalA. chroococcum strain at lower temperatures. Tropical strains ofA. brasilense andA. chroococcum reduced more C2H2 than temperate strains at higher temperatures. Therefore, it appears that temperate and tropical N2-fixing organisms adapt themselves to their particular environment and should have more potential to benefit crops grown at
the particular temperatures favorable to them.
Only Bacillus strain C-11-25 has potential to benefit both temperate and tropical crops because it reduced significant acetylene
over a wide temperature range. 相似文献
15.
Larson MR Rajashankar KR Crowley PJ Kelly C Mitchell TJ Brady LJ Deivanayagam C 《The Journal of biological chemistry》2011,286(24):21657-21666
The Streptococcus mutans antigen I/II (AgI/II) is a cell surface-localized protein that adheres to salivary components and extracellular matrix molecules. Here we report the 2.5 Å resolution crystal structure of the complete C-terminal region of AgI/II. The C-terminal region is comprised of three major domains: C1, C2, and C3. Each domain adopts a DE-variant IgG fold, with two β-sheets whose A and F strands are linked through an intramolecular isopeptide bond. The adherence of the C-terminal AgI/II fragments to the putative tooth surface receptor salivary agglutinin (SAG), as monitored by surface plasmon resonance, indicated that the minimal region of binding was contained within the first and second DE-variant-IgG domains (C1 and C2) of the C terminus. The minimal C-terminal region that could inhibit S. mutans adherence to SAG was also confirmed to be within the C1 and C2 domains. Competition experiments demonstrated that the C- and N-terminal regions of AgI/II adhere to distinct sites on SAG. A cleft formed at the intersection between these C1 and C2 domains bound glucose molecules from the cryo-protectant solution, revealing a putative binding site for its highly glycosylated receptor SAG. Finally, electron microscopy images confirmed the elongated structure of AgI/II and enabled building a composite tertiary model that encompasses its two distinct binding regions. 相似文献
16.
Chitinases I and II were purified from the culture supernatant of Aeromonas sp. 10S-24 by ammonium sulfate precipitation, SP-Sephadex C-50 chromatography, Sephacryl S-200 gel filtration, and chromatofocusing. Both enzymes were most active at pH 4.0 and the optimum temperature for I and II were 50°C and 60°C. Chitinase I was stable at pHs between 4 and 9 and at temperatures below 50°C and chitinase II was stable at pHs between 5 and 7 and at temperatures below 45°C. The molecular weights were estimated by 8D8 polyacrylamide gel electrophoresis to be 112,000 and 115,000 for I and II respectively, while gel filtration showed the molecular weight to be 114,000 for both types of the enzyme. The pIs for I and II were 7.9 and 8.1, respectively. The activities of both enzymes were inhibited by Ag+ and iodoacetic acid. 相似文献
17.
《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1995,665(1):193-199
A sensitive gradient high-performance liquid chromatographic (HPLC) method for the simultaneous quantitation of a dopamine autoreceptor agonist CI-1007 (I) and its metabolite PD 147693 (II) is described. Monkey plasma samples were purified by liquid-liquid extraction using hexane. Liquid chromatographic separation was achieved on two C18 analytical columns (installed in series) using gradient elution. Column effluent was monitored using a fluorescence detector programmed to change wavelengths at specified times. Minimum quantitation limits of I and II were 3.0 and 5.0 ng/ml, respectively, for a plasma sample volume of 0.100 ml. Linearity was demonstrated up to 300 ng/ml. The assay has been applied to the analysis of I and II in plasma from monkeys following intravenous and oral doses of I. 相似文献
18.
The formation of a blue chromogen between sodium borohydride-treated lantadene A (22β-angeloyloxy-3-oxoolean-12-en-28-oic acid) and acetic anhydride-sulfuric acid (9:1) formed the basis of a spectrophotometric method for its quantitation. The chromogen had a broad absorption maximum (λmax) at 630–645 nm. The optimum amount of sodium borohydride for lantadene A reduction was 1 mg/mg lantadene A in methanolic solution. The chromogen was stable for 5, 7, and 26 min after reaction at 25, 18, and 0°C, respectively. The method is convenient, sensitive, and reproducible. The amount of lantadene A in the leaves of Lantana camara collected in the month of May quantitated by the present method was found to be 13.6 mg/g dry weight of the leaves. 相似文献
19.
Robert Messner Eva M. Kubicek-Pranz Andrea Gsur Christian P. Kubicek 《Archives of microbiology》1991,155(6):601-606
Monoclonal antibodies have been used to determine the presence of cellobiohydrolases I and II (CBH I and II), and endoglucanase I (EG I) on the surface of conidia from Trichoderma reesei QM 9414 and RUT C-30, and 8 other Trichoderma species. For this purpose, proteins were released from the conidial surface by treatment with a non-ionic detergent (Triton X-100 and -octylglucoside), followed by SDS-PAGE/Western blotting and immunostaining. Both CBH I and II were clearly present, but — unlike in extracellular culture fluids from Trichoderma — CBH II was the predominant cellulase. In T. reesei EG I could not be detected. The higher producer strain T. reesei RUT C-30 exhibited a higher conidial level of CBH II than T. reesei QM 9414. In order to assess the importance of the conidial CBH II level for cellulase induction by cellulose, multiple copies of the chb2 gene were introduced into the T. reesei genome by cotransformation using PyrG as a marker. Stable multicopy transformants secreted the 2- to 4-fold level of CBH II into the culture medium when grown on lactose as a carbon source, but their CBH I secretion was unaltered. Upon growth on cellulose, both CBH I and CBH II secretion was enhanced. Those strain showing highest cellulase activity on cellulose also appeared to contain the highest level of conidial bound CBH II. CBH II was also the predominant conidial cellulase in various other Trichoderma sp. However, roughly the same amount of conidial bound CBH II was detected in all strains, although their cellulase production differed considerably. 相似文献
20.
N. Ammigan U. J. Nair A. J. Amonkar S. V. Bhide 《Journal of biochemical and molecular toxicology》1989,4(1):7-13
The modulation of the phase I and phase II biotransformation enzymes upon treatment with tobacco extract (TE) and N'-nitrosonornicotine (NNN) was investigated using male Sprague-Dawley rats fed differential protein diets. It was observed that the animals fed a low protein diet showed an overall decrease in the basal levels of hepatic and pulmonary phase I and II enzymes. TE and NNN significantly decreased the detoxifying system in the low-proteinfed animals. Animals fed 20% protein, however, showed significant increases in glutathione and glutathione S-transferase upon treatment. Furthermore, TE and NNN treatment brought about a significant depletion in the hepatic pool of vitamin A with a concomitant increase in the vitamin C levels. 相似文献