Protective effect of selected flavonoids on in vitro daunorubicin-induced cardiotoxicity

Flavonoids are an ubiquitous group of polyphenolic substances with varied chemical structures present in foods of plant origin and act as free radical scavenging and chelating agents with a variety of biological activities. Using a model of spontaneously beating, cultured adult rat cardiomyocytes, this study examined the cardioprotective role of quercetin, naringenin, pycnogenol and a model antioxidant, trolox, against daunorubicin-induced toxicity. Cardiomyocyte protection was assessed by MTT test and extracellular lactate dehydrogenase detection. Protection of cardiomyocytes was concentration/dose dependent for quercetin > naringenin > pycnogenol > trolox. Quercetin (10(-4)-10(-6) mol/L) after 24 h of co-incubation with daunorubicin significantly increased the cardiomyocyte survival in all tested concentrations (p < 0.001). The cytoprotective effect of naringenin (10(-4)-10(-6) mol/L) was similar to those of quercetin (p < 0.001 and p < 0.01, respectively). Pycnogenol was the least effective of the flavonoids studied. On the other hand, all tested flavonoids had significantly better protective effects than trolox. The leakage of lactate dehydrogenase induced by daunorubicin was also prevented by the studied compounds and was in accordance with their cytoprotective activity.     

Chemoprotective effect of plant phenolics against anthracycline-induced toxicity on rat cardiomyocytes. Part II. caffeic, chlorogenic and rosmarinic acids

The chemoprotective effects of caffeic (CA), chlorogenic (CHA) and rosmarinic (RA) acids were tested against the toxicity of doxorubicin (DOX) in neonatal rat cardiomyocytes and the iron-dependent DOX induced lipid peroxidation of heart membranes, mitochondria and microsomes. The protectivity of these acids was compared with dexrazoxan, used as an adjuvant during DOX chemotherapy. The cytoprotective effects were assessed by enzyme (LDH and ASAT) and troponin I leakage, secondly by intracellular ATP content. All hydroxycinnamic acids proved non-cytotoxic, and they stabilized both membranes and the energetic status of cardiomyocytes. After preincubation of cardiomyocytes with the test compounds (100, 200 microm; 1 h) the cardiomyocytes were treated with the toxic agent, DOX (100 microm; 8 h). The test compounds protected cardiomyocytes against DOX induced oxidative stress (RA > CHA > or = CA) on all monitored parameters. Substantial preservation of monolayer integrity of the cardiomyocytes by test compounds was also found microscopically. All the acids were more effective in the assays used than dexrazoxan. RA showed the most effective cytoprotectivity. All the acids significantly reduced the iron-dependent DOX induced lipid peroxidation of heart membranes, although of the test compounds, CHA was found to be the most effective (IC(50) = 8.04 +/- 0.74/6.87 +/- 0.52 micro m for microsomes/mitochondria).     

高效液相色谱法同时测定金樱子中槲皮素、山萘酚、芹菜素的含量

目的建立金樱子中槲皮素、山萘酚、芹菜素含量测定方法。方法反相高效液相色谱法,色谱柱ZORBAXSB-C18(150mm×4.6mm,5μm);检测波长360nm;甲醇-0.2%磷酸(45:55)为流动相;柱温30℃;流速1.0mL/min。槲皮素、山萘酚、木犀草素、芹菜素理论板数分别大于5000、6000、6000、7000;四种化合物的分离度均大于1.5。结果槲皮素、山萘酚、木犀草素、芹菜素回归曲线分别为Y=1504.412X+9.9756,Y=1991.745X+8.6051,Y=567.591X+2.5397,Y=1811.803X+0.3074,在5.5216×10-2～19.3256×10-2μg/mL、4.608×10-2～16.128×10-2μg/mL、12.5504×10-2～43.9264×10-2μg/mL、6.0288×10-2～21.1008×10-2μg/mL范围内线性关系良好,相关系数r=0.99992～0.99998,槲皮素、山萘酚的加样回收率分别为100.5%、100.6%,RSD分别为3.7%、3.7%。样品分别含槲皮素、山萘酚、木犀草素、芹菜素0.28、0.25、0.0、0.04mg/g.结论本法为金樱子提供了分析黄酮化合物方法,该法简便可行,重复性好,数据及结果可靠。     

山柰酚和槲皮素对乳鼠心肌缺氧复氧及过氧化损伤的保护作用

目的:观察山柰酚和槲皮素对乳鼠心肌细胞缺氧复氧损伤的干预作用并探讨其作用机理。方法:取大鼠新生乳鼠心肌细胞做原代培养,MTT法检测细胞活力,确定药物作用安全范围;考察药物对心肌细胞缺氧复氧损伤模型LDH漏出的改变;复制心肌细胞过氧化氢损伤模型,观察药物对细胞活力及上清液中LDH含量的影响。结果:山柰酚和槲皮素125μg/ml以下对心肌细胞活力无明显影响。山柰酚或槲皮素100、50、25、12.5μg/ml均可以降低缺氧复氧损伤后心肌细胞的LDH漏出率(P<0.01或P<0.05),其中山柰酚100、50、25μg/ml浓度,槲皮素以50、25、12.5μg/ml浓度作用较佳。山柰酚、槲皮素对心肌细胞过氧化氢损伤均有显著的抑制作用,均呈浓度依赖性,并可显著降低过氧化氢损伤所致的LDH释放。结论:山柰酚和槲皮素具有显著的抗心肌细胞缺氧损伤的能力,与其抗氧化的药理作用有关。     

Effects of flavonoids on cytochrome P-450 from rat liver microsomes: Inhibition of enzyme activities and protection against peroxidative damage

A series of flavonoids, able to inhibit non-enzymic and enzymic lipid peroxidation, were investigated as inhibitors of cytochrome P-450 mediated reactions (aminopyrine N-demethylation and aniline hydroxylation) in rat liver microsomes. The most potent compounds were chrysin, luteolin, amentoflavone and eriodictyol (aminopyrine N-demethylation) and apigenin, kaempferol and quercetin (aniline hydroxylation). Some structure-activity relationships were established for inhibition of aminopyrine N-demethylation and it was observed that the resorcinol configuration of the ring A is a determinant feature, whereas O-glycosylation abolished the activity. Most of the compounds showed lower activity on aniline hydroxylation. The presence of these flavonoids during incubation of microsomes in a medium containing NADPH did not modify the cytochrome P-450 concentration and protected against lipid peroxidation induced degradation of this cytochrome.     

Hepatoprotective and free radical scavenging activities of phenolic petrosins and flavonoids isolated from Equisetum arvense

Hepatoprotective activity-guided fractionation of the MeOH extract of Equisetum arvense L. (Equisetaceae) resulted in the isolation of two phenolic petrosins, onitin (1) and onitin-9-O-glucoside (2), along with four flavonoids, apigenin (3), luteolin (4), kaempferol-3-O-glucoside (5), and quercetin-3-O-glucoside (6). Among these, compounds 1 and 4 exhibited hepatoprotective activities on tacrine-induced cytotoxicity in human liver-derived Hep G2 cells, displaying EC(50) values of 85.8 +/ -9.3 microM and 20.2 +/- 1.4 microM, respectively. Silybin, used as a positive control, showed the EC(50) value of 69.0 +/- 3.3 microM. Compounds 1 and 4 also showed superoxide scavenging effects (IC(50) = 35.3 +/- 0.2 microM and 5.9 +/- 0.3 microM, respectively) and DPPH free radical scavenging effect (IC(50) of 35.8 +/- 0.4 microM and 22.7 +/- 2.8 microM, respectively). These results support the use of this plant for the treatment of hepatitis in oriental traditional medicine.     

马鞭草黄酮类化学成分的研究

从马鞭草Verbena officinalsL.中分离得到5个化合物,经理化鉴定和光谱分析确定其结构,结果均为黄酮类化合物,分别为:木犀草素(1)、山柰酚(2)、槲皮素(3)、芹菜素(4)和4′-羟基汉黄芩素。其中化合物1,2和3为首次从该植物中分离得到。     

Prostaglandin inhibitory and antioxidant components of Cistus laurifolius, a Turkish medicinal plant

As Cistus laurifolius has been used traditionally to treat inflammatory and rheumatic disorders, its leaves were tested for prostaglandin (PG) inhibitory and antioxidant activities. The leaf extract showed both activities, i.e., inhibitory effect at 300 microg/ml on PGE1- and E2-induced contractions in guinea pig ileum and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect. The separation guided by the activities shown by these dual assays provided sixteen compounds, 1-16. Known compounds 1-12 and 15 were identified as 3-O-methyl quercetin (1), 3,7-O-dimethyl quercetin (2), genkwanin (3), 3,7-O-dimethyl kaempferol (4), 3,4'-O-dimethyl quercetin (5), apigenin (6), 3,4'-O-dimethyl kaempferol (7), ellagic acid (8), beta-sitosterol-3-O-beta-glucoside (9), quercetin 3-O-alpha-rhamnoside (10), 5-O-p-coumaroyl quinic acid methyl ester (11), 1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-alpha-l-rhamnopyranoxypropyl)-2-methoxyphenoxy]-1,3-propanediol (12) and 2,3-dihydro-2-(4'-alpha-l-rhamnopyranosyloxy-3'-methoxyphenyl)-3-hydroxymethyl-7-methoxy-5-benzofuranpropanol (15). New lignan glycosides 13 and 14 were determined to be olivil 9-O-beta-D-xyloside and berchemol 9-O-rhamnoside, respectively. Compound 16 was isolated as a 2:1 mixture of two diastereomers, the major one of which was determined to be (7S,8R)-dihydrodehydrodiconiferyl alcohol 9'-O-alpha-L-rhamnoside. The structures were determined by detailed 2D NMR analysis together with NOEDF and CD. PG inhibitory effect was observed in 1, 5, 10, 12 and 16 at 30 microg/ml and antioxidant activity, in 1, 2, 8, 10, 12-14 and 16.     

Inhibitory effects of several flavonoids on E-selectin expression on human umbilical vein endothelial cells stimulated by tumor necrosis factor-alpha

The present study investigates the suppressive effect of flavonoids on TNF-alpha-stimulated E-selectin expression on HUVECs by carrying out a comparative examination of the 37 flavonoids. Several flavonoids: fisetin, luteolin and apigenin (subclass of flavone), kaempferol and quercetin (flavonols), eriodictyol (flavanones), genistein (isoflavones) and butein (chalcone) exhibit the inhibitory effects. Considerations to the structure of flavonoids, the C2-C3 double bond of C-ring and 4-oxo functional group are essential for their inhibition activities. These results help to explain the pharmacological efficacy of flavonoids as anti-inflammatory compounds.     

Influence of silymarin and its flavonolignans on doxorubicin-iron induced lipid peroxidation in rat heart microsomes and mitochondria in comparison with quercetin

Silymarin, an extract of Silybum marianum seeds, and the constituent flavonolignans silybin, silydianin and silychristin, as well as the flavonol quercetin, protected rat heart microsomes and mitochondria against iron-dependent doxorubicin induced lipid peroxidation. Quercetin was found to be more potent than either silymarin or its three constituents, whose cytoprotectivity was comparable. The radical scavenging activity of the compounds was investigated using a DPPH colour reduction assay and cyclic voltametry to assess their antioxidant activities. In contrast to quercetin, silybin, silydianin and silychristin did not chelate iron in aqueous solution. The results suggest that silymarin may prevent doxorubicin-mediated damage to rat heart membrane primarily through a free radical scavenging mechanism.