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1.
The inhibitory effects of synthetic phenolic compounds on benzo(a)pyrene-induced neoplasia of the mouse forestomach have been measured by Wattenberg et al6 The efficiency of this inhibition has been estimated for each phenol, using R, the ratio of the number of tumors per mouse in the protected group over the number of tumours per mouse in the control group. We have observed a linear correlation between the chemoprotection efficiency R and the logarithm of the rate of quenching of singlet oxygen. k. by this family of phenols, log k being itself correlated with the one-electron oxidation potential of the phenols. These correlations suggest a charge transfer mechanism for the inhibition of neoplasia induced hy benzo(a)py-rene. The correlations described provide a theoretical basis for scaling the inhibitors of mutagenicity induced by polycyclic aromatic compounds in terms of their oxidation potentials 相似文献
2.
R V Bensasson M Rougée 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1988,307(18):807-810
Prooxidant states, characterised by an increase in the intracellular concentration of activated forms of oxygen, are able to promote tumors. The inhibitory effects of synthetic phenolic compounds added to the diet of mice on benzo(a)pyrene-induced neoplasia of the forestomach have been determined by Wattenberg et al. The efficiency of this inhibition has been estimated quantitatively for each phenol, using the ratio R of the number of tumors per mouse in the treated group over the number of tumors per mouse in the control group. We have observed a linear correlation between the antitumoral efficiency (1-R) and the logarithm of the rate of quenching of singlet oxygen, k, y, by this family of phenols, log k being itself correlated with the half-wave oxidation potential of the phenols. These correlations suggest a charge transfer mechanism for the inhibition of neoplasia induced by benzo(a)pyrene, B(a)P. It should be pointed out that singlet oxygen can be generated via enzymatic reactions in the dark and thus might play a role in the formation of the ultimate carcinogenic metabolite B(a)P-7, 8-dihydroxy-9, 10-epoxide. The correlations described emphasize the interest in scaling the inhibitors of mutagenicity induced by polycyclic aromatic hydrocarbons with respect to their oxidation potentials. Our result is a first step towards a better understanding of the molecular reactions involved in chemically-induced neoplasia and in its prevention. 相似文献
3.
Vandertol-Vanier HA Vazquez-Duhalt R Tinoco R Pickard MA 《Journal of industrial microbiology & biotechnology》2002,29(5):214-220
We are studying the enzymatic modification of polycyclic aromatic hydrocarbons (PAHs) by the laccase from Coriolopsis gallica UAMH 8260. The enzyme was produced during growth in a stirred tank reactor to 15 units ml−1, among the highest levels described for a wild-type fungus; the enzyme was the major protein produced under these conditions.
After purification, it exhibited characteristics typical of a white rot fungal laccase. Fifteen azo and phenolic compounds
at 1 mM concentration were tested as mediators in the laccase oxidation of anthracene. Higher anthracene oxidation was obtained
with the mediator combination of ABTS and HBT, showing a correlation between the oxidation rate and the mediator concentration.
Reactions with substituted phenols and anilines, conventional laccase substrates, and PAHs were compared using the native
laccase and enzyme preparations chemically modified with 5000 MW-poly(ethylene glycol). Chemically modified laccase oxidized
a similar range of substituted phenols as the native enzyme but with a higher catalytic efficiency. The k
cat increase by the chemical modification may be as great as 1300 times for syringaldazine oxidation. No effect was found of
chemical modification on mediated PAH oxidation. Both unmodified and PEG-modified laccases increased PAH oxidation up to 1000
times in the presence of radical mediators. Thus, a change of the protein surface improves the mediator oxidation efficiency,
but does not affect non-enzymatic PAH oxidation by oxidized mediators.
Received 10 December 2001/ Accepted in revised form 20 July 2002 相似文献
4.
Osamu Yamada Shuichi Ishida Fumio Futatsuya Kensaku Ito Hiroshi Yamamoto Katsura Munakata 《Bioscience, biotechnology, and biochemistry》2013,77(6):1235-1240
The discovery that anisomycin showed plant growth-regulating activity led to the investigation of compounds having p-methoxyphenyl group; the p-anisole derivatives. 4-Methoxydiphenylmethanes and related compounds inhibited the growth of both shoots and roots in test plants. Growth-inhibitory activity in the series of 4-methoxydiphenylmethanes was lowered by an increase in the electron donating or withdrawing ability of the substituent and was parabolically dependent on the Hammett’s σ. Selective actions of these compounds in their growth inhibition are discussed based on correlations between their activities against barnyard grass and other test plants.Some 4-methoxydiphenylmethanes induced chlorosis, a disturbance in phototropism or geotropism, and root hypertrophy. 相似文献
5.
《Bioorganic & medicinal chemistry letters》2019,29(18):2604-2608
We have designed and synthesized twenty-six N-arylindazole-3-carboxamide (3a-p) and N-benzoylindazole (6a-j) derivatives to discover with excellent inhibition activities of α-MSH-stimulated melanogenesis. In the bio evaluation studies of these compounds, we discovered eighteen compounds, out of twenty-six exhibited more potent inhibition than the positive control arbutin. From the SAR studies, we identified 3k and 6g as lead compounds which displayed almost 5 and 9 times more potent inhibition of α-MSH-stimulated melanogenesis respectively than the reference arbutin. It is also evident the presence of electron withdrawing group at para position (R3) for the compounds (3a-p) and presence of +M group at ortho position (R5) for the compounds (6a-j) were crucial for their excellent inhibition activities of α-MSH-stimulated melanogenesis. 相似文献
6.
Nonexhaustive extraction (propanol, butanol, hydroxypropyl-β-cyclodextrin [HPCD]), persulfate oxidation and biodegradability assays were employed to determine the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in creosote-contaminated soil. After 16 weeks incubation, greater than 89% of three-ring compounds (acenaphthene, anthracene, fluorene, and phenanthrene) and 21% to 79% of four-ring compounds (benz[a]anthracene, chrysene, fluoranthene, and pyrene) were degraded by the indigenous microorganisms under biopile conditions. No significant decrease in five- (benzo[a]pyrene, benzo[b+k]fluoranthene) and six-ring compounds (benz[g,h,i]perylene, indeno[1,2,3-c,d]pyrene) was observed. Desorption of PAHs using propanol or butanol could not predict PAH biodegradability: low-molecular-weight PAH biodegradability was underestimated whereas high-molecular-weight PAH biodegradability was overestimated. Persulfate oxidation and HPCD extraction of creosote-contaminated soil was able to predict three- and four-ring PAH biodegradability; however, the biodegradability of five-ring PAHs was overestimated. These results demonstrate that persulfate oxidation and HPCD extraction are good predictors of PAH biodegradability for compounds with octanol-water partitioning coefficients of < 6. 相似文献
7.
Humayun Pervez Mohammad S. Iqbal Muhammad Younas Tahir Faiz-ul-Hassan Nasim Muhammad Iqbal Choudhary Khalid Mohammed Khan 《Journal of enzyme inhibition and medicinal chemistry》2013,28(6):848-854
A series of 15 previously reported N4-substituted isatin-3-thiosemicarbazones 3a-o has been screened for cytotoxic, antibacterial, antifungal and urease inhibitory activities. Compounds 3b, 3e and 3n proved to be active in cytotoxicity assay; 3e exhibited a high degree of cytotoxic activity (LD50 = 1.10 × 10? 5 M). Compound 3h exhibited significant antibacterial activity against B. subtilis, whereas compounds 3a, 3k and 3l displayed significant antifungal activity against one or more fungal strains i.e. T. longifusus, A. flavus and M. canis. In human urease enzyme inhibition assay, compounds 3g, 3k and 3m proved to be the most potent inhibitors, exhibiting relatively pronounced inhibition of the enzyme. These compounds, being non-toxic, could be potential candidates for orally effective therapeutic agents to treat certain clinical conditions induced by bacterial ureases like H. pylori urease. This study presents the first example of inhibition of urease by isatin-thiosemicarbazones and as such provides a solid basis for further research on such compounds to develop more potent inhibitors. 相似文献
8.
Summary Members of four homologous series of tetra-alkyl ammonium bromides (R
3N+(CH2)
n–1·CH3Br– whereR=H, CH3 or C2H5 andRN+H3Br– whereR represents the isomeric butyl series) have been synthesized and tested as sodium pump inhibitors, measured as ouabain-sensitive K+ influx, and as hemolytic agents on human red cells.Potency for both effects is presented graphically, plotting the logarithm of the concentration for half maximal effect against alkyl chain length. Both hemolysis and pump inhibition studies yielded a biphasic response consisting of two good straight lines, with effectiveness increasing up to C10–12 and then remaining constant up to C20.For hemolysis the alkyl ammonium series was most effective. The calculated free-energy change per methylene group was the same for three series of compounds, but the free-energy contribution from the headgroup was lower for the ammonium series.In contrast, although pump inhibition studies also yielded simple biphasic plots, inhibition occurred at 3- to 50-fold lower concentrations and there were significant differences between the three series, both in the free-energy changes per methylene group and in the headgroup contributions.We have analyzed these results thermodynamically to take account of hydrophobic interactions and the conformation of the alkyl chains. 相似文献
9.
Jiřina Relichová 《Biologia Plantarum》1981,23(2):104-109
In an embryo shoot apex more different mutations may be induced after the mutagenic treatment of seeds. These mutations may
be distributed among the apical initial cells in different ways. According to the proposed mathematical model it is possible
to estimate the proportion of initial cells with 0, 1, 2, …,x mutations in the apioes with a given number of initials,k, which is characteristic for each plant object, and under a certain number of induced mutations per apex,n, determined by the conditions of the mutagenio treatment. Owing to the disadvantage of multimutations in plant breeding it
is possible according to the formula P(X > 1) = 1 −e−n/k(l + n/k). to use, at a knownk, suchn’s which secure minimum multimutations. 相似文献
10.
Large inocula of Stenotrophomonas maltophilia VUN 10,003 were used to investigate bacterial degradation of benzo[a]pyrene and dibenz[a,h]anthracene. Although strain VUN 10,003 was capable of degrading 10–15 mg l−1 of the five-ring compounds in the presence of pyrene after 63 days, further addition of pyrene after degradation of the five-ring
polycyclic aromatic hydrocarbons (PAHs) ceased did not stimulate significant decreases in the concentration of benzo[a]pyrene or dibenz[a,h]anthracene. However, pyrene was degraded to undetectable levels 21 days after its addition. The amount of benzo[a]pyrene and dibenz[a,h]anthracene degraded by strain VUN 10,003 was not affected by the initial concentration of the compounds when tested at 25–100
mg l−1, by the accumulation of by-products from pyrene catabolism or a loss of ability by the cells to catabolise benzo[a]pyrene or dibenz[a,h]anthracene. Metabolite or by-product repression was suspected to be responsible for the inhibition: By-products from the
degradation of the five-ring compounds inhibited their further degradation. Journal of Industrial Microbiology & Biotechnology (2002) 28, 88–96 DOI: 10.1038/sj/jim/7000216
Received 30 January 2001/ Accepted in revised form 10 October 2001 相似文献
11.
Summary About 30 per cent of organic soil nitrogen can be hydrolized with HCl to amino acids; about 30 per cent is nonhydrolizable. In contrast to this high content of amino acid nitrogen is the small availability of the nitrogen to micro-organisms. In light of the theory proposing a reaction between the -amino group of amino acids or peptides and quinones formed during oxidation of lignin degradation products or other phenolic compound, different types of phenols were oxidized by phenolases in presence of amino acid compounds.It could be shown that the reaction of binding of nitrogen started at pH values higher than 6.5, and that only such phenols reacted which had no methoxylated hydroxyl groups. The reaction of some phenols during oxidation in presence of amino acids was accompanied by deamination and decarboxylation of the latter.The reaction products of phenols with amino acids were stable against hydrolysis. Using peptides it was found that all amino acids, except the N-terminal which is bound to oxidized phenols, could be hydrolyzed normally.With serum albumin it could be shown that there is a reaction with the amino group of the N-terminal amino acid and also with the -amino group of lysine residues with phenols during oxidation. The reacted protein seemed to be degraded normally with a protease ofBacillus subtilis.Guest Scientist as Fulbright Research Scholar from the Agronomy Department of the Iowa State University, Ames, Iowa, U.S.A. 相似文献
12.
Kinetics of Polycyclic Aromatic Hydrocarbon (PAH) Degradation in Long-term Polluted Soils during Bioremediation 总被引:1,自引:0,他引:1
Bioremediation experiments with ten different soil samples from former industrial sites which were long-term polluted with
polycyclic aromatic hydrocarbons (PAHs) were carried out using outdoor pot trials. The degradation of 15 PAHs according to
the US EPA was investigated for 168 weeks through repeated soil sampling and determination of the total PAH concentration.
On average, degradation was largest for acenaphthene (88%; 63 to 99%) and smallest for anthracene (22%; no significant degradation
to 89%). For most of the PAH single substances, degradation kinetics were characterised by a first initial phase of fast degradation.
In a subsequent second phase, degradation diminished and residual PAH concentrations were approached within 168 weeks, resulting
in a similar PAH pattern in the ten soil samples. Degradation kinetics was calculated through the selection of the appropriate
differential rate equation from a set of seven equations. Kinetics of PAH degradation was best fitted by single and two coupled
first order exponential equations with median R2 of 0.71 (0.01 to 1.00). Degradation rate constants of the rapid phase (k
1) ranged from 0.05×10−2 week−1 for benzo[k]fluoranthene to 18.3 week−1 for naphthalene and for the subsequent slow degradation phase (k
2) they ranged from 0.01×10−2 week−1 for benzo[a]anthracene to 2.3×10−2 week−1 for fluoranthene. Degradation was governed by desorption and diffusion processes of different rates, while microbial activity
did not influence the kinetics. Median disappearance times (DT50) ranged from 6.1 weeks for naphthalene to 522 weeks for benzo[k]fluoranthene. With the exception of the 6-ring PAHs dibenzo[ah]anthracene
and indeno[1,2,3-cd]pyrene, this sequence followed the PAHs’ degree of condensation. The total initial PAH concentration and
the residual concentration were correlated with R2 of 0.69, with larger initial PAH concentrations leading to larger residual concentrations and degradation rates. 相似文献
13.
Allyn H. Maeda Shinro Nishi Yuji Hatada Yasuhiro Ozeki Robert A. Kanaly 《Microbial biotechnology》2014,7(2):114-129
A pathway for the biotransformation of the environmental pollutant and high‐molecular weight polycyclic aromatic hydrocarbon (PAH) benzo[k]fluoranthene by a soil bacterium was constructed through analyses of results from liquid chromatography negative electrospray ionization tandem mass spectrometry (LC/ESI(–)‐MS/MS). Exposure of Sphingobium sp. strain KK22 to benzo[k]fluoranthene resulted in transformation to four‐, three‐ and two‐aromatic ring products. The structurally similar four‐ and three‐ring non‐alternant PAHs fluoranthene and acenaphthylene were also biotransformed by strain KK22, and LC/ESI(–)‐MS/MS analyses of these products confirmed the lower biotransformation pathway proposed for benzo[k]fluoranthene. In all, seven products from benzo[k]fluoranthene and seven products from fluoranthene were revealed and included previously unreported products from both PAHs. Benzo[k]fluoranthene biotransformation proceeded through ortho‐cleavage of 8,9‐dihydroxy‐benzo[k]fluoranthene to 8‐carboxyfluoranthenyl‐9‐propenic acid and 9‐hydroxy‐fluoranthene‐8‐carboxylic acid, and was followed by meta‐cleavage to produce 3‐(2‐formylacenaphthylen‐1‐yl)‐2‐hydroxy‐prop‐2‐enoic acid. The fluoranthene pathway converged with the benzo[k]fluoranthene pathway through detection of the three‐ring product, 2‐formylacenaphthylene‐1‐carboxylic acid. Production of key downstream metabolites, 1,8‐naphthalic anhydride and 1‐naphthoic acid from benzo[k]fluoranthene, fluoranthene and acenaphthylene biotransformations provided evidence for a common pathway by strain KK22 for all three PAHs through acenaphthoquinone. Quantitative analysis of benzo[k]fluoranthene biotransformation by strain KK22 confirmed biodegradation. This is the first pathway proposed for the biotransformation of benzo[k]fluoranthene by a bacterium. 相似文献
14.
N.C. Elliott F.L. Tao R. Fuentes-Granados K.L. Giles D.T. Elliott M.H. Greenstone K.A. Shufran T.A. Royer 《Biological Control》2006,38(3):325-330
We evaluated the D-vac suction machine for sampling predatory arthropods in Oklahoma winter wheat fields. The efficiency of D-vac sampling was low for adult Coccinellidae and Carabidae. Sampling efficiency was greater for coccinellid larvae. Sampling efficiency was high for adult and immature Nabidae and Chrysopidae, for Araneae, and for adult Staphylinidae. For most predators, there were significant correlations between the number of individuals in D-vac samples and the number of individuals per m2 in the field. The highest correlation was 0.82 for adult Staphylinidae. Correlations for most predators were <0.60. Significant partial correlations between D-vac sample estimates and ancillary abiotic and biotic variables occurred for most predators, indicating that D-vac sampling efficiency was affected environmental variables. Multiple regression models were constructed to relate population estimates from D-vac sampling to absolute density by adjusting estimates for influential abiotic and biotic environmental variables. Significant regression models were not achieved for adult Coccinellidae or adult Carabidae, and the coefficient of determination was low (0.18) for the model for adult Nabidae. Higher values of R2 were achieved for larval Coccinellidae, Chrysopidae adults and larvae, Nabidae nymphs, Araneae, and adult Staphylinidae. Among abiotic variables, air temperature and wind velocity most frequently entered into step-wise regression models. Among biotic variables, wheat plant growth stage and wheat tiller density frequently entered into models. 相似文献
15.
The rheological attributes of polymers as wheat dough are strongly related to its microstructure. To quantify dough protein microstructure confocal laser scanning microscopy combined with image analysis was used. The effect of three experimental factors pH (addition of lactic acid and sodium hydroxide), water addition, and sodium chloride (NaCl) addition on empirical and fundamental rheological properties as well as microstructural protein properties were studied and modeled by applying a response surface methodology. The obtained models revealed high correlations between the experimental factors and the complex shear modulus (R 2?=?0.97), dough resistance (Rmax k; R 2?=?0.91) and stickiness (R 2?=?0.93). Furthermore it was possible to determine microstructural attributes as the area fraction (R 2?=?0.88) and Feret??s diameter (R 2?=?0.86) as a function of pH, water and NaCl addition. Especially measures of Rk max revealed highly significant correlations with the protein microstructure as the branching index (r?=?0.79). 相似文献
16.
Twelve naturally-occurring organosulfur compounds were investigated as inhibitors of cytochrome P450 1 (CYP450 1)-mediated activation of benzo[a]pyrene (B[a]P) in human hepatoma (HepG2) cells. Inhibition depended on the presence of a diallyl group and the number of S atoms. Diallyl trisulfide (DATS), with a diallyl group and three S atoms, had the highest activity with an IC50 of 0.4 mM, and 1.5-fold higher potency than diallyl disulfide (DADS) containing a diallyl group and two S atoms. Organosulfur compounds containing an alkyl group were less effective, or even ineffective, inhibitors of both CYP450 1 and B[a]P-induced cytotoxicity than DADS and DATS. Alliin and S-allyl cysteine containing the S-cysteinyl group had no inhibition. 相似文献
17.
《Chronobiology international》2013,30(1):77-93
The change of an indirect pharmacological response R(t) can be described by a periodic time-dependent production rate kin (t) and a first-order loss constant kout. If kin(t) follows some biological rhythm (e.g., circadian), then the response R(t) also displays a periodic behavior. A new approach for describing the input function in indirect response models with biorhythmic baselines of physiologic substances is introduced. The present approach uses the baseline (placebo) response Rb(t) to recover the equation for kin(t). Fourier analysis provides an approximate equation for Rb(t) that consists of terms (usually two or three) of the Fourier series (harmonics) that contribute most to the overall sum. The model differential equation is solved backward for kin(t), yielding the equation involving Rb(t). A computer program was developed to perform the square L2-norm approximation technique. Fourier analysis was also performed based on nonlinear regression. Cortisol suppression after inhalation of fluticasone propionate (FP) was modeled based on the inhibition of the secretion rate kin(t) using ADAPT II. The pharmacodynamic parameters kout and IC50 were estimated from the model equation with kin(t) derived by the new approach. The proposed method of describing the input function needs no assumption about the behavior of kin(t), is as efficient as methods used previously, and is more flexible in describing the baseline data than the nonlinear regression method. (Chronobiology International, 17(1), 77–93, 2000) 相似文献
18.
Induced resistance of the mountain birch against its main defoliator Epirrita autumnata is a well-characterized phenomenon. The causal mechanism for this induced deterioration, however, has not been unequivocally
explained, and no individual compound or group of traditional defensive compounds has been shown to explain the phenomenon.
Phenolic compounds are the main secondary metabolites in mountain birch leaves, and the biological activity of phenolics usually
depends on their oxidation. In this study, we found that the activity of polyphenoloxidases (PPOs), enzymes that oxidize o-diphenols to o-diquinones, was induced in trees with introduced larvae, and bioassays showed that both growth and consumption rates of larvae
were reduced in damaged trees. PPO activity was negatively associated with both larval growth and consumption rates in trees
with bagged larvae, but not in control trees. Our results suggest that the oxidation of phenolics by PPOs may be a causal
explanation for the rapidly induced resistance of mountain birch against E. autumnata. This finding also helps to explain why correlations between insect performance and phenolics (without measuring indices
explaining their oxidation) may not produce consistent results. 相似文献
19.
M. Wolter F. Zadrazil R. Martens M. Bahadir 《Applied microbiology and biotechnology》1997,48(3):398-404
The degradation of eight unlabeled highly condensed polycyclic aromatic hydrocarbons (PAH) and the mineralization of three
14C-labeled PAH by the white-rot fungus Pleurotus sp. Florida was investigated. Three concentrations containing 50, 250 or 1250 μg each unlabeled PAH/5 g straw were added
to sterile sea sand. Selected treatments were added subsequently with 14C-labeled pyrene, benzo[a]anthracene or benzo[a]pyrene. The PAH-loaded sea sand was then mixed into straw substrate and incubated. The disappearance of the unlabeled four-to
six-ring PAH: pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenz[a,h]anthracene and benzo[ghi]perylene, was determined by high-performance liquid chromatography. After 15 weeks of incubation, the recoveries were less
than 25% for initial amounts of 50 μg (controls above 85%). The recoveries of unlabeled PAH increased in the inoculated samples
with increasing concentrations applied. No correlation could be determined between the number of condensed rings of the PAH
and the recoveries of added PAH. Pleurotus sp. Florida mineralized 53% [14C]pyrene, 25% [14C]benzo[a]anthracene and 39% [14C]benzo[a]pyrene to 14CO2 in the presence of eight unlabeled PAH (50 μg applied) within 15 weeks. During the course of cultivation, Pleurotus sp. Florida degraded more than 40% of the wheat straw substrate. Variation of the initial concentration of PAH did not influence
the extent of degradation of the organic matter.
Received: 16 December 1996 / Received revision: 17 March 1997 / Accepted: 22 March 1997 相似文献
20.
Triterpenoids and Flavonoids from the Leaves of Astragalus membranaceus and Their Inhibitory Effects on Nitric Oxide Production
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Zhi‐Bin Wang Ya‐Dong Zhai Zhen‐Ping Ma Chun‐Juan Yang Rong Pan Jia‐Li Yu Qiu‐Hong Wang Bing‐You Yang Hai‐Xue Kuang 《化学与生物多样性》2015,12(10):1575-1584
Four new cycloartane triterpenes, named huangqiyegenins V and VI and huangqiyenins K and L ( 1 – 4 , resp.), together with nine known triterpenoids, 5 – 13 , and eight flavonoids, 14 – 21 , were isolated from a 70%‐EtOH extract of Astragalus membranaceus leaves. The structures of the new compounds were elucidated by detailed spectroscopic analyses, and the compounds were identified as (9β,11α,16β,20R,24S)‐11,16,25‐trihydroxy‐20,24‐epoxy‐9,19‐cyclolanostane‐3,6‐dione ( 1 ), (9β,16β,24S)‐16,24,25‐trihydroxy‐9,19‐cyclolanostane‐3,6‐dione ( 2 ), (3β,6α,9β,16β,20R,24R)‐16,25‐dihydroxy‐3‐(β‐D ‐xylopyranosyloxy)‐20,24‐epoxy‐9,19‐cyclolanostan‐6‐yl acetate ( 3 ), and (3β,6α,9β,16β,24E)‐26‐(β‐D ‐glucopyranosyloxy)‐16‐hydroxy‐3‐(β‐D ‐xylopyranosyloxy)‐9,19‐cyclolanost‐24‐en‐6‐yl acetate ( 4 ). All isolated compounds were evaluated for their inhibitory activities against LPS‐induced NO production in RAW264.7 macrophage cells. Compounds 1 – 3, 14, 15 , and 18 exhibited strong inhibition on LPS‐induced NO release by macrophages with IC50 values of 14.4–27.1 μM . 相似文献