次黄嘌呤对单胺氧化酶的抑制作用

实验证明给小鼠po次黄嘌呤25～500 mg/kg时,对肝和脑中单胺氧化酶B(MAOB)活性的抑制作用与剂量成明显的量—效关系,对MAO-A活性的抑制较弱,且无明显的量—效关系。给小鼠一次po次黄嘌呤500 mg/kg,于给药后16h,对MAO抑制作用最明显。sc时,对肝中MAO活性抑制也以给药后16 h最明显,但对脑中MAO活性抑制不明显。离体实验证明,次黄嘌呤对MAO-B的抑制为竞争性,对MAO-A则为混合型抑制。     

BCEF0083抗单胺氧化酶作用的研究

目的　研究一种白僵菌代谢产物提取物 (BCEF0 0 83)对单胺氧化酶 (MAO)的抑制作用。方法　提取动物脑组织重线粒体应用荧光分光光度计法检测MAO活性 ;采用大、小鼠体内外给药研究BCEF抗MAO作用的量效、时效关系 ,应用林 -贝氏法测定MAOKm值。结果　小鼠BCEF 50 0mg·kg- 1 ,ig给药后 0 5hMAO活性已有抑制 ,2～ 8h活性抑制明显 ,一次给药后 72h抑制作用基本消失 ;小鼠BCEF50 0、40 0、2 0 0、1 0 0、50、2 5mg·kg- 1 ,ig后 2h取脑组织测MAO活性 ,BCEF对MAO活性的抑制呈现一定的量效关系。BCEF体外给药对大鼠脑组织MAO活性的抑制随药物浓度增加而增强 ,BCEF体外给药对MAO A、MAO B抑制的IC50 (95 %可信限 )分别为 1 2 8 88(82 70～ 2 0 0 86)mg·L- 1 、1 84 1 4 (1 56 1 7～ 2 1 7 1 1 )mg·L- 1 ;BCEF对MAO A ,B抑制呈混合型抑制作用 ,Km值分别为 1 1 97、 8 1 3μmol·L- 1 。结论　BCEF0 0 83体内外给药对大、小鼠脑组织MAO活性具有抑制作用     

10—羟基癸烯酸对小鼠免疫功能的影响

观察蜂王浆的提取物10—羟基癸烯酸(10—HDA)对小鼠免疫功能的影响。选用雄性小鼠,ig及ip给药。结果表明,给药组小鼠的腹腔巨噬细胞对鸡红细胞的吞噬百分率和吞噬指数均较对照组为低。虽然10—HDA对小鼠外周血淋巴细胞计数无明显影响,但能抑制由PHA诱导的小鼠体内淋巴细胞转化。实验中还观察了10—HDA对小鼠肾上腺Vit C含量的影响。1次给药小鼠肾上腺的Vit C含变化不显著。给药7d的小鼠肾上腺VitC含量较对照组明显增加。该结果与ACTH给药后的效应一致。实验结果提示,10—HDA对小鼠免疫功能有一定的抑制作用,该抑制作用与其促进肾上腺皮质的功能有关。     

羟基红花黄色素A对脑缺血所致大鼠脑线粒体损伤的保护作用

目的研究羟基红花黄色素A对脑缺血所致大鼠脑线粒体损伤的保护作用。方法用栓线法制作大鼠大脑中动脉缺血(MCAO)模型，测定线粒体肿胀度、膜流动性、膜磷脂含量、呼吸功能、线粒体呼吸酶、超氧化物歧化酶(SOD)、丙二醛(MDA)、Ca²⁺等。结果羟基红花黄色素A(10，20 mg·kg^-1)能明显抑制缺血脑线粒体膜流动性的降低，膜磷脂降解，减少脑缺血引起的线粒体肿胀，抑制NADH脱氢酶、琥珀酸脱氢酶和细胞色素c氧化酶活性的降低，改善线粒体呼吸功能；同时羟基红花黄色素A能明显降低中风大鼠脑细胞线粒体MDA含量、升高SOD活性、抑制Ca²⁺过多摄入。结论羟基红花黄色素A对缺血脑细胞线粒体的损伤有明显的保护作用，该作用可能与清除氧自由基、抑制脂质过氧化、拮抗Ca²⁺有关。     

三羟基异黄酮和17-β雌二醇对自由基缩血管效应的影响

目的 :研究自由基引发血管收缩的机制 ,并通过血管静息张力的变化探讨三羟基异黄酮和 17 β雌二醇对自由基缩血管效应的影响。方法 :制备猪冠状动脉血管环 ,固定于恒温肌槽内 ,待平衡后 ,加入各种药物观察血管张力的变化。结果 :内皮完整的血管环在O2· -作用下产生明显的收缩 ,去除内皮后无明显反应。 1μmol·L-1三羟基异黄酮对O2· -引发血管收缩有明显的抑制作用 (P <0 .0 1,n =16 ) ,1μmol·L-117 β雌二醇无明显作用。H2 O2 使去内皮血管环产生明显的收缩作用 ,对内皮完整的血管环缩血管效应不明显 ,30 μmol·L-1三羟基异黄酮可明显抑制H2 O2 的缩血管作用。结论 :三羟基异黄酮可明显抑制O2· -和H2 O2 的缩血管效应 ,其作用明显强于 17 β雌二醇。     

高效液相色谱法同时测定对羟基苯甲酸酯类及对羟基苯甲酸

目的 建立同时测定口服液体制剂中羟苯甲酯、羟苯丙酯及其降解产物对羟基苯甲酸的反相高效液相色谱系统,为口服制剂中防腐剂含量控制提供依据。方法 采用反相高效液相色谱法,色谱柱为Luna C18柱(250mm?4.6mm,5μm);以0.1%磷酸溶液为流动相A,以乙腈为流动相B,梯度洗脱;检测波长为254nm;流速为1.0ml/min。结果 羟苯甲酯在24.02~72.02μg/mL范围内,羟苯丙酯在3.04~9.04μg/mL范围内,对羟基苯甲酸在0.28~0.84μg/mL范围内浓度均与峰面积呈良好线性关系,线性方程分别为A=90569C 122945(r=0.9999)、A=86802C 15680(r=0.9999)和A=532.5C-498.6(r=0.9999);平均回收率分别为99.7%、99.8%和98.9%;对羟基苯甲酸检出限为0.10ng结论 该方法简便、准确,可用于口服液体制剂中防腐剂羟苯甲酯、羟苯丙酯及其降解产物对羟基苯甲酸含量测定。     

23-羟基桦木酸对B_(16)细胞系的诱导分化作用

目的评价 2 3 羟基桦木酸对黑色素瘤B16细胞的抑瘤作用。方法以MTT法测定细胞增殖的抑瘤率 ,并以B16细胞形态、黑色素含量、细胞周期变化及体内致瘤能力的测定作为观察指标。结果用 10～ 2 0 μg/ml的2 3 羟基桦木酸作用肿瘤细胞 ,见有不同程度的抑瘤作用 (P <0 .0 0 1)。表现为黑色素生成能力增加 ,细胞生长缓慢。可使B16细胞阻断在G1期 ,肿瘤体积明显缩小。结论 2 3 羟基桦木酸低剂量 (10～ 2 0 μg/ml)对B16细胞有明显的分化诱导作用 ,而对体内外黑色素瘤增殖有明显的抑制作用     

羟基脲对大鼠胚胎的肢芽和中脑细胞增殖和分化的影响

目的观察羟基脲(抗肿瘤药)对大鼠胚胎细胞增殖和分化的影响。方法用大鼠胚胎的中脑和肢芽细胞,用微团培养法观察不同浓度的羟基脲对其增殖和分化的影响。结果羟基脲对中脑细胞和肢芽细胞的半数增殖抑制浓度(IV50)分别为5.90、2.48μg·mL-1,半数分化抑制浓度(ID50)分别为2.01、0.67μg·mL-1。羟基脲对胚胎中脑和肢芽细胞增殖和分化具有明显的抑制作用,且呈剂量-反应关系。结论羟基脲对发育期神经母细胞和肢芽细胞的增殖和分化均具有抑制作用,可能是羟基脲导致中枢神经系统和四肢畸形的作用机制之一。     

对羟基苯甲酸钠的安全药理学研究

目的 观察对羟基苯甲酸钠对实验动物中枢神经系统和心血管系统的影响。方法 昆明小鼠单次灌胃给予20,50,100 mg·kg^-1对羟基苯甲酸钠溶液,通过小鼠甩尾试验、自主活动试验、爬杆试验、协调睡眠试验和Morris水迷宫试验,考察对羟基苯甲酸钠对中枢神经系统的影响。SD大鼠单次灌胃给予14,35,70 mg·kg^-1对羟基苯甲酸钠溶液,Beagle犬单次灌胃给予4.2,10.5,21 mg·kg^-1对羟基苯甲酸钠溶液,通过检测Beagle犬血压和体温以及SD大鼠的心电,考察对羟基苯甲酸钠对心血管系统和体温的影响。结果 对羟基苯甲酸钠对小鼠感觉-运动反射、自主活动行为、协调功能、戊巴比妥钠阈下睡眠剂量小鼠入睡率和学习记忆能力无明显影响;对Beagle犬血压、体温以及SD大鼠心电均无明显影响。结论 本实验条件下,单次灌胃给予对羟基苯甲酸钠溶液对实验动物中枢神经系统和心血管系统无明显影响。     

纳洛肼及14-羟基双氢吗啡肼与阿片受点结合的可逆性

用纳洛肼(NZI,1×10^-5M)或14-羟基双氢吗啡肼(HZI,1×10^-6)与大鼠脑匀浆P₂膜制备保温后,以Tris缓冲液反复洗涤,阿片受点可完全恢复与[³H]双氢吗啡([³H]DHM)的结合能力。在离体豚鼠回肠纵肌(GPI)试验中,HZI对电刺激收缩的抑制及NZI对吗啡(Mor)抑制作用的对抗亦皆可被洗掉,此外HZI对收缩的抑制还可被纳洛酮(Nal)所逆转,说明它们与阿片受点的结合都是可逆的。HZI镇痛作用ED₅₀为1.3 mg/kg(小鼠热板法SC),略强于Mor(3 mg/kg),持续时间与Mor相似。NZI对Mor镇痛的对抗可持续十余小时。     

Effect of centrophenoxine, piracetam and aniracetam on the monoamine oxidase activity in different brain structures of rats

In vitro studies of effects of some nootropic drugs (centrophenoxine, piracetam and aniracetam) on monoamine oxidase (MAO) activity in the rat striatum and hypothalamus, using tyramine, serotonin and beta-phenylethylamine as substrates, were carried out. At all concentrations used (5.10(-5)-1.10(-3) M) centrophenoxine inhibited total MAO, MAO A and MAO B in both brain structures. Piracetam activated striatal and hypothalamic total MAO, hypothalamic MAO A and MAO B but exerted a pronounced inhibitory effect on MAO A and MAO B activity in the striatum. Aniracetam inhibited total MAO and MAO A in both brain structures but activated striatal and hypothalamic MAO B. The different effects of centrophenoxine, piracetam and aniracetam on MAO activity in the brain structures support the view for the independent mode of action of nootropic drugs in spite of their similar molecular and metabolic activity.     

Selective acetylenic 'suicide' and reversible inhibitors of monoamine oxidase types A and B.

1 A number of aromatic-N-propargyl (acetylenic) compounds and indoleamines were tested for their inhibitory action on monoamine oxidase (MAO) type A and type B using the substrates 5-hydroxytryptamine (5-HT), beta-phenylethylamine (PEA) and dopamine. 2 Structure activity studies with aromatic-N-propragyl (acetylenic) derivatives have shown that MAO inhibitory potency is least dependent on the aromatic portion of the compounds. N-methylated propargyl derivatives are the most active and replacement of the methyl group with a higher alkyl or aromatic group results in significant reduction of activity. The triple bond in the N-propargyl portion is absolutely essential for activity and must be beta-to the nitrogen. It is the acetylenic group that gives these compounds their irreversible MAO inhibitory property. 3 The present study has indicated that since the acetylenic compounds resemble the enzyme substrates the distance between the aromatic ring and the N-propargyl terminal is crucial in designating the type A or type B MAO inhibitory property. For MAO type A inhibition, a distance equivalent to at least three carbon units is required, while for the inhibition of the B type enzyme this distance can be 1 or 2 carbon units. 4 The compounds AGN-1133 and AGN-1135 show most promise in Parkinson's disease or as anti-depressants because of their irreversible selective type B MAO inhibition in vitro and in vivo. 5 A number of indoleamine derivatives were found to be reversible selective type A inhibitors.     

串果藤中甘草素和异甘草素对大鼠单胺氧化酶的体外抑制作用(英文)

目的:研究串果藤中甘草素和异甘草素体外对单胺氧化酶A型和B型的抑制作用.方法:根据不同的离心速度制备大鼠全脑粗线粒体作为单胺氧化酶的酶源;分别以5-羟基[侧链-2-~(14)C]色胺肌酸硫酸盐([~(14)C]5-HT)和2-苯基[1-~(14)C]乙基胺盐酸盐([~(14)C]β-PEA)为单胺氧化酶A型和B型放射性底物,用液体闪烁技术,研究甘草素和异甘草素酶抑制作用和抑制类型.结果:甘草素和异甘草素对单胺氧化酶A型和B型均具有抑制作用,呈良好的量效关系,对单胺氧化酶A型的IC_(50)(95％的可信限)分别为32(26-36)μmol/L和13.9(12.8-15.6)μmol/L,对单胺氧化酶B型的IC_(50)值分别为104.6(89.0-118.9)μmol/L和47.2(39.5-54.5)μmol/L.酶抑制特征曲线显示甘草素和异甘草素对单胺氧化酶A型呈非竞争性抑制,K_i值分别为31.5μmol/L和14.3μmol/L,而对单胺氧化酶B型呈混合竞争性抑制,K_i值分别为164.7μmol/L和62.2μmol/L,K_I值分别为15.2μmol/L和9.3μmol/L.结论:甘草素和异甘草素体外对单胺氧化酶A型呈非竞争性抑制作用,对单胺氧化酶B型呈混合竞争性抑制作用.     

Beyond Topoisomerase Inhibition: Antitumor 1,4‐Naphthoquinones as Potential Inhibitors of Human Monoamine Oxidase

Monoamine oxidase (MAO) action has been involved in the regulation of neurotransmitters levels, cell signaling, cellular growth, and differentiation as well as in the balance of the intracellular polyamine levels. Although so far obscure, MAO inhibitors are believed to have some effect on tumors progression. 1,4‐naphthoquinone (1,4‐NQ) has been pointed out as a potential pharmacophore for inhibition of both MAO and DNA topoisomerase activities, this latter associated with antitumor activity. Herein, we demonstrated that certain antitumor 1,4‐NQs, including spermidine‐1,4‐NQ, lapachol, and nor‐lapachol display inhibitory activity on human MAO‐A and MAO‐B. Kinetic studies indicated that these compounds are reversible and competitive MAO inhibitors, being the enzyme selectivity greatly affected by substitutions on 1,4‐NQ ring. Molecular docking studies suggested that the most potent MAO inhibitors are capable to bind to the MAO active site in close proximity of flavin moiety. Furthermore, ability to inhibit both MAO‐A and MAO‐B can be potentialized by the formation of hydrogen bonds between these compounds and FAD and/or the residues in the active site. Although spermidine‐1,4‐NQs exhibit antitumor action primarily by inhibiting topoisomerase via DNA intercalation, our findings suggest that their effect on MAO activity should be taken into account when their application in cancer therapy is considered.     

Contribution of Monoamine Oxidase (MAO) to the Binding of Tertiary Basic Drugs in Lung Mitochondria

The effects of tertiary amine-containing basic drugs on the enzymes located in the mitochondria and the effect of monoamine oxidase inhibitors (MAOIs) on drug accumulation in lung mitochondria have been studied. Various basic drugs inhibited MAO activity but not other mitochondrial marker enzymes. The potency of MAO inhibition correlated well with their lipid solubility, and the basic drugs inhibited MAO activity dose dependency and competitively. Further, MAO inhibition correlated well with binding affinity to lung mitochondria, and the binding of tertiary amine drugs to lung mitochondria was decreased by treatment with MAOIs. A good correlation was observed between the potency of MAOIs to inhibit the binding of the basic drug to the high-affinity site in mitochondria and the MAO inhibitory activity in mitochondria. These results indicate that mitochondrial MAO is one of the binding sites for tertiary basic drugs in the lung. We think that the action and/or adverse reaction of some drugs may result from inhibition of mitochondrial MAO to metabolize various biogenic amines and that mitochondrial MAO may function as a reservoir for basic drugs.     

Inhibitory potency of some isatin analogues on human monoamine oxidase A and B.

Isatin is an endogenous compound which acts as a selective inhibitor of monoamine oxidase (MAO) B. In this study a range of isatin analogues were tested for their in vitro inhibition of human MAO A and B. Most of the analogues were less potent than isatin. Hydroxylation of the aromatic ring changed the inhibitory potency in favour of MAO A, with 5-hydroxyisatin being a potent and selective MAO A inhibitor (IC50 8 microM). Isatinic acid, which is formed reversibly from isatin at alkaline pH, showed no inhibition.     

Effect of a non-steroidal anti-inflammatory agent, tolmetin sodium on exudative inflammation in experimental animals (author's transl)

Effect of tolmetin sodium(Tol) on acute and subacute exudative inflammation was tested in experimental animals. Tol had a potent inhibitory activity (ED50 = 0.75 mg/kg, p.o.) on the increased vascular permeability induced by acetic acid in mice, and the potency was about 0.4 times that of indomethacin (Ind), and 6-93 times that of ibuprofen (Ibu), phenylbutazone(Phe) and aspirin(Asp). The inhibitory activity of Tol(ED50 = 18.2 mg/kg, p.o.) on UV-induced erythema in guinea pigs was about 0.3 times that of Ind. A recovery of the hind paw edema of rats, produced by a mixture of kaolin and carrageenin, was promoted by oral administration of Tol(2.5 approximately 20 mg/kg x 5/2 days). Tol(80 mg/kg/day, p.o.) showed a significant activity in inhibiting the exudation caused by croton oil in rats, and the activity was about 0.025 times that of Ind and greater than that of Ibu, Phe and Asp. Tol(100-800 microgram/ml) inhibited in a dose-dependent manner the phytohemagglutinin-induced blast transformation of cultured lymphocytes from rat thymus, as did salicylic acid. In vitro, Tol showed a potent activity similar to that of Ibu and Phe in preventing the denaturation of bovine serum albumin and the lysis of rat erythrocytes. From these results, it is suggested that Tol has a particularly potent inhibitory activity on acute exudative inflammation, and the mode of action may be attributed to a mechanism similar to that seen with other acidic non-steroidal anti-inflammatory drugs.     

Effect of the antidepressant minaprine on both forms of monoamine oxidase in the rat

The antidepressant minaprine (3-(2-morpholino-ethylamino) 4-methyl 6-phenyl pyridazine, dihydrochloride) and its main metabolites were examined for their monoamine oxidase (MAO) inhibitory effects in the rat. In our experimental conditions, minaprine displayed in vitro a very weak affinity for brain MAO A and B with IC50S close to 1 mM. However, ex vivo, after intraperitoneal administration, this drug behaved as a specific and short-acting type A MAO inhibitor (MAOI) of mild potency (ED50 = 12.8 mg/kg). In comparison, the reversible type A MAOIs, moclobemide and cimoxatone, were respectively 14 and 15 times more potent. When administered orally, minaprine proved to be considerably less active. The results presented in this study suggest that minaprine inhibits MAO A mainly after being converted into active metabolites. However, the chloroform extractable metabolites were found inactive in vitro towards this enzyme, suggesting that MAO inhibitory activity is mediated by one or more other non-identified metabolites.