Supplementation of whole persimmon leaf improves lipid profiles and suppresses body weight gain in rats fed high-fat diet.

The objective of this study was to investigate the hypolipidemic effects of powdered whole persimmon leaf supplement in rats fed high-fat diet. Three groups of male Sprague-Dawley rats during 6 weeks were fed different diet: normal control (NC), high-fat (HF), and high-fat supplemented with powdered whole persimmon leaf (PL; 5%, wt/wt) groups. Body weight and relative weight of interscapular brown adipose tissue were significantly lower in the PL group than in the HF group, while plasma leptin concentration was higher. The supplementation of persimmon leaf significantly lowered the plasma total cholesterol and triglyceride concentrations, whereas elevated the ratio of HDL-C/total-C and improved the atherogenic index. Persimmon leaf supplementation led the hepatic cholesterol and triglyceride values to similar levels to the NC group. Accumulation of hepatic lipid droplets and the epididymal white adipocyte size of PL group were diminished comparing to the HF group. Hepatic HMG-CoA and ACAT activities were significantly higher in the PL group than in other groups. Contents of fecal triglyceride, cholesterol and acidic sterol were significantly higher in the PL group than in the HF group. Accordingly, we suggest that supplementation of the powdered whole persimmon leaf improves plasma and hepatic lipid levels profile partly via the increased fecal lipids in high-fat fed rats. These beneficial effects may be due to the properties of its phenolic compounds (1.15 g/100g) and high fiber (63.48 g/100g) content in the powdered persimmon leaf.

Naringin has an antiatherogenic effect with the inhibition of intercellular adhesion molecule-1 in hypercholesterolemic rabbits.

Naringin, a bioflavonoid found in citrus fruit peel, is known to have an antioxidative effect, but its effect on atherosclerosis has not been studied. This study evaluated the effect of naringin on blood lipid levels and aortic fatty streaks, and its action mechanism in hypercholesterolemic rabbits. Male New Zealand white rabbits were fed a 0.25% cholesterol diet and divided into an untreated group (n = 4), a naringin-treated group (n = 5; 500 mg/kg per day), and a lovastatin-treated group (n = 5; 20 mg/kg per day). After 8 weeks, blood was sampled and analyzed biochemically. Aorta and liver were harvested and examined histologically. Cholesterol level in rabbits fed the 0.25% cholesterol diet reached 17 times normal and decreased in the rabbits fed naringin and lovastatin, whose effects were not statistically significant (p > 0.05). However, both naringin and lovastatin effectively decreased the area of fatty streak in thoracic aorta on macroscopic analysis (p < 0.05) and significantly reduced subintimal foam cell infiltration on microscopic morphometry (p < 0.05). These foam cells were macrophages on immunohistochemical analysis. Naringin treatment inhibited hypercholesterolemia-induced intercellular adhesion molecule-1 (ICAM-1) expression on endothelial cells. Hypercholesterolemia caused fatty liver and elevation of liver enzymes, which was prevented by naringin but not by lovastatin. Naringin significantly reduced fatty streak formation and neointimal macrophage infiltration and also inhibited the expression of ICAM-1 in endothelial cells, suggesting that suppression of ICAM-1 contributed to the antiatherogenic effect. Naringin, unlike lovastatin, has a hepatoprotective action.

Dietary hematein ameliorates fatty streak lesions in the rabbit by the possible mechanism of reducing VCAM-1 and MCP-1 expression.

Hematein is a compound isolated from Caesalpinia sappan that has been used in oriental medicine as both an analgesic and an anti-inflammatory agent. In this study, we examined the anti-atherogenic potential of hematein using cholesterol-fed New Zealand White (NZW) rabbits. NZW rabbits were divided into a hematein-supplemented (0.05% in diet) group (n=6), a probucol-supplemented (0.25% in diet) group (n=6), and a control group (n=6). After 8 weeks of treatments, the extent of the atherosclerotic lesions was significantly reduced in the hematein-supplemented group and the probucol-supplemented group without changing plasma lipoprotein levels. Hematein and probucol prevented the up-regulation of the vascular cell adhesion molecule-1 (VCAM-1) expression on the descending aorta induced by cholesterol diet. In culture, hematein also significantly inhibited the secretion of soluble VCAM-1 and of monocyte chemotactic protein-1 (MCP-1) respectively induced by tumor necrotic factor alpha (TNF-alpha) and mildly oxidized low density lipoprotein in human umbilical vein endothelial cell (HUVEC) culture. Also, hematein inhibited monocyte adhesion to endothelial cell and the activation of NF-kappaB in HUVECs stimulated with TNF-alpha. The results of the present study suggest that the anti-atherogenic effect of hematein is not related to control of the plasma lipid profile but probably related to the inhibition of VCAM-1 and MCP-1 expression resulting in an amelioration of lesion development in the rabbit.

Lipid-lowering and antioxidative activities of 3,4-di(OH)-cinnamate and 3,4-di(OH)-hydrocinnamate in cholesterol-fed rats.

BACKGROUND: Polyphenols appear to have antioxidant activities and may mediate lipid lowering. METHODS: Four groups of rats, a high-cholesterol control (HC), HC+lovastatin, HC+3,4-di(OH)-cinnamate, and HC+3,4-di(OH)-hydrocinnamate, were given a semi-synthetic diet. The cinnamate derivative or lovastatin (0.1 g/100 g) supplements were given for 6 weeks. RESULTS: The plasma total cholesterol concentration was significantly lowered by the 3,4-di(OH)-cinnamate supplement compared to the control or lovastatin group. The 3,4-di(OH)-cinnamate and 3,4-di(OH)-hydrocinnamate supplements significantly lowered both the hepatic cholesterol and triglyceride levels, while lovastatin only lowered the hepatic cholesterol. The hepatic HMG-CoA reductase activities were significantly lower in the 3,4-di(OH)-cinnamate and 3,4-di(OH)-hydrocinnamate groups than in the control or lovastatin group. The ACAT activity was only significantly lower in the lovastatin group compared to the other groups. With regards the hepatic antioxidant enzyme system, the CAT activity was significantly higher in the 3,4-di(OH)-cinnamate and 3,4-di(OH)-hydrocinnamate groups compared to the control or lovastatin group. The two cinnamate derivatives resulted in an increased hepatic GSH-Px activity. Meanwhile, all the supplements significantly lowered the hepatic thiobarbituric acid reactive substances (TBARS) content. However, the 3,4-di(OH)-cinnamate and 3,4-di(OH)-hydrocinnamate supplements did not alter the neutral sterol and total fecal sterol. CONCLUSIONS: Both cinnamate derivatives were potent in lipid-lowering and altering the antioxidative enzyme. Furthermore, these results also suggest that 3,4-di(OH)-cinnamate is more effective than 3,4-di(OH)-hydrocinnamate in its lipid-lowering action.

Antioxidative activity of naringin and lovastatin in high cholesterol-fed rabbits.

The consumption of a cholesterol-enriched diet increases the degree of lipid peroxidation, which is one of the early processes of atherosclerosis. The aim of this trial was to determine the antioxidative effects of the citrus bioflavonoid, naringin, a potent cholesterol-lowering agent, compared to the cholesterol-lowering drug, lovastatin, in rabbits fed a high cholesterol diet. Male rabbits were served a high-cholesterol (0.5%, w/w) diet or high-cholesterol diet supplemented with either naringin (0.5% cholesterol, 0.05% naringin, w/w) or lovastatin (0.5% cholesterol, 0.03% lovastatin, w/w) for 8 weeks to determine the plasma and hepatic lipid peroxide, plasma vitamin A and E levels, and hepatic hydrogen peroxide levels, along with the hepatic antioxidant enzyme activities and gene expressions. Only the lovastatin group showed significantly lower plasma and hepatic lipid peroxide levels compared to the control group. The naringin supplementation significantly increased the activities of both hepatic SOD and catalase by 33% and 20%, respectively, whereas the lovastatin supplementation only increased the catalase activity by 23% compared to control group. There was no difference in the GSH-Px activities between the various groups. Content of H2O2 in hepatic mitochondria was significantly lower in groups supplemented with lovastatin and naringin than in control group. However, there was no difference in cytosolic H2O2 content in liver between groups. The concentration of plasma vitamin E was significantly increased by the naringin supplementation. When comparing the antioxidant enzyme gene expression, the mRNA expression of SOD, catalase and GSH-Px was significantly up-regulated in the naringin-supplemented group. Accordingly, these results would appear to indicate that naringin, a citrus bioflavonoid, plays an important role in regulating antioxidative capacities by increasing the SOD and catalase activities, up-regulating the gene expressions of SOD, catalase, and GSH-Px, and protecting the plasma vitamin E. In contrast, lovastatin exhibited an inhibitory effect on the plasma and hepatic lipid peroxidation and increased the hepatic catalase activity in high-cholesterol fed rabbits.

Effect of naringin supplementation on cholesterol metabolism and antioxidant status in rats fed high cholesterol with different levels of vitamin E.

Some bioflavonoids are potent antioxidants and have pharmacological effects similar to those of vitamin E. The interactive effect of naringin and vitamin E was studied with respect to cholesterol metabolism and antioxidant status. Naringin supplementation (0.1%, wt/wt) with comparable levels of vitamin E was given to rats with a high-cholesterol (1%, wt/wt) diet for 5 weeks. The amount of vitamin E included in naringin-free and naringin diets was a low (low-E) and a normal (normal-E) level. The naringin supplementation significantly lowered the concentrations of plasma cholesterol and triglyceride compared to the naringin-free group in low vitamin E-fed rats. HMG-CoA reductase activity was significantly lowered by naringin supplementation within both the low-vitamin E group (794.64 +/- 9.87 vs. 432.18 +/- 12.33 pmol/min/mg protein, mean +/- SE; p < 0.05) and normal-vitamin E group (358.82 +/- 11.4 vs. 218.22 +/- 9.47 pmol/min/mg protein, mean +/- SE; p < 0.05) compared to each of the naringin-free group. The HMG-CoA reductase activity was also significantly lowered by increased dietary vitamin E when compared within the naringin and naringin-free group, respectively. Neither dietary naringin nor vitamin E did significantly change the activities of hepatic antioxidant enzymes and plasma thiobarbituric acid-reactive substance level. These data indicate that naringin lowers the plasma lipid concentrations when the dietary vitamin E level is low. The HMG-CoA reductase-inhibitory effect of naringin was more potent when dietary vitamin E was at a normal level. These data may contribute to understanding the interactive effect of naringin and vitamin E on cholesterol biosynthesis in high-cholesterol-fed rats.

Inhibitory activity for chitin synthase II from Saccharomyces cerevisiae by tannins and related compounds.

In the course of search for potent inhibitors of chitin synthase II from natural resources, seven tannins and related compounds were isolated from the aerial part of Euphorbia pekinensis and identified as gallic acid (1), methyl gallate (2), 3-O-galloyl-(-)-shikimic acid (3), corilagin (4), geraniin (5), quercetin-3-O-(2"-O-galloyl)-beta-D-glucoside (6), and kaempferol-3-O-(2"-O-galloyl)-beta-D-glucoside (7). These and nine related compounds, (-)-quinic acid (8), (-)-shikimic acid (9), ellagic acid (10), kaempferol (11), quercetin (12), quercitrin (13), rutin (14), quercetin-3-O-(2"-O-galloyl)-beta-D-rutinoside (15) and 1,3,4,6-tetra-O-galloyl-beta-D-glucose (16), were evaluated for the inhibitory activity against chitin synthase II and III. They inhibited chitin synthase II with IC(50) values of 18-206 microM, except for two organic acids, (-)-quinic acid (8) and (-)-shikimic acid (9). Among them, 3-O-galloyl-(-)-shikimic acid (3) was the most potent inhibitor against chitin synthase II of Saccharomyces cerevisiae with an IC(50) value of 18 microM. The inhibition appears to be selective for chitin synthase II, as they did not appreciably inhibit chitin synthase III.

Anti-atherogenic effect of citrus flavonoids, naringin and naringenin, associated with hepatic ACAT and aortic VCAM-1 and MCP-1 in high cholesterol-fed rabbits.

The anti-atherogenic effects of the citrus flavonoids, naringin and naringenin, were evaluated in high cholesterol-fed rabbits. At 3 months of age, 30 male New Zealand White (NZW) rabbits were divided into three groups (n = 10 per group). The rabbits were fed a 1% cholesterol diet alone (control group) or a diet supplemented with either 0.1% naringin or 0.05% naringenin for 8 weeks. The plasma lipoprotein levels, total cholesterol, triglyceride, and high-density lipoprotein showed no significant differences in the control and experimental groups. Hepatic acyl-CoA:cholesterol acyltransferase (ACAT) activity was slightly low in naringin (5.0%)- and naringenin (15.0%)-fed rabbits, compared to control group. The aortic fatty streak areas were significantly lower in both the naringin (19.2 +/- 5.6%)- and naringenin (18.1 +/- 6.5%)-supplemented groups than in the control group (60.4 +/- 14.0%). The expression levels of vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemotactic protein-1 (MCP-1), by semiquantitative RT-PCR analysis of the thoracic aorta, were significantly lower in the flavonoids supplemented groups than in the control group. These results suggest that the anti-atherogenic effect of the citrus flavonoids, naringin and naringenin, is involved with a decreased hepatic ACAT activity and with the downregulation of VCAM-1 and MCP-1 gene expression.

Interactive effect of hesperidin and vitamin E supplements on cholesterol metabolism in high cholesterol-fed rats.

Certain bioflavonoids are potent antioxidants and have pharmacologic effects similar to those of vitamin E. Accordingly, the interactive effect of hesperidin and vitamin E was studied with respect to cholesterol metabolism and the antioxidant status. Hesperidin supplement (0.1%, wt/wt) with comparable levels of vitamin E was provided with a high-cholesterol (1%, wt/wt) diet to rats for 5 weeks. The amount of vitamin E included in the hesperidin-free and hesperidin diets was either a low (low-E) or a normal (normal-E) level. The hesperidin supplement and different levels of dietary vitamin E did not significantly alter the concentrations of plasma triglycerides. However, the inclusion of hesperidin significantly lowered the concentration of plasma cholesterol in both the low-vitamin E group and the normal-vitamin E group compared to the hesperidin-free groups (p < 0.05). The hepatic triglyceride content was significantly lowered by the hesperidin supplement, as opposed to the plasma triglyceride content, regardless of the vitamin E level in the diet. The hepatic HMG-CoA reductase activity was significantly lowered by the hesperidin supplement with both the low-vitamin E and the normal-vitamin E compared to the hesperidin-free groups (p < 0.05). The hepatic HMG-CoA reductase activity was also significantly lowered with an increase in the dietary vitamin E within the hesperidin and hesperidin-free groups. The excretion of fecal neutral sterol and acidic sterols tended to be lower with the hesperidin supplement. Neither dietary hesperidin nor vitamin E significantly changed the hepatic antioxidant enzyme activity. This data indicates that hesperidin lowers the concentration of plasma cholesterol and the hepatic triglyceride content regardless of the dietary vitamin E level. However, the concentration of plasma cholesterol in the hesperidin-free groups was dependent on the dietary vitamin E level. This information may contribute to understanding the interactive effect of hesperidin and vitamin E on cholesterol biosynthesis in high cholesterol-fed rats.

Low-density lipoprotein-antioxidant constituents of Saururus chinensis.

A new diarylbutane lignan, saururin A (1), and a known 8-O-4'-type neolignan, machilin D (2), were isolated from a total methanol extract of the underground parts of Saururus chinensis. The structures of 1 and 2 were elucidated by spectroscopic data analysis. Compounds 1, 2, and virolin (3) (the methyl ether of 2) exhibited significant low-density lipoprotein (LDL)-antioxidant activity in the thiobarbituric acid-reactive substance (TBARS) assay with IC(50) values of 8.5, 2.9, and 4.3 microM, respectively.

Hypocholesterolemic effect of naringin associated with hepatic cholesterol regulating enzyme changes in rats.

The effects of the citrus bioflavonoid naringin were tested by using it as a supplement in a high-cholesterol diet. Male rats were fed for 42 days with a 1% (wt/wt) high cholesterol diet either with or without naringin-supplementation (0.1%, wt/wt) to study the effect on plasma lipid levels, hepatic lipid contents, hepatic enzyme activity, and the excretion of fecal neutral sterols. Naringin did not significantly alter the levels of plasma triglycerides, however, the levels of plasma cholesterol (3.80 +/- 0.31 mmol/L vs. 2.61 +/- 0.30 mmol/L, mean +/- SE; p < 0.05) and hepatic cholesterol (70.3 +/- 4.3 mg/g vs. 54.3 +/- 3.8 mg/g, mean +/- SD; p < 0.05) were significantly lowered compared to those of the control. HMG-CoA reductase (2487.0 +/- 210.0 pmole/min/mg vs. 1879.0 +/- 236.0 pmole/min/mg, mean +/- SE; p < 0.05) and ACAT (806.0 +/- 105.0 pmole/min/mg vs. 643.0 +/- 80.0 pmole/min/mg, mean +/- SE; p < 0.05) activities were both substantially lower in the naringin-supplemented group than in the control. The naringin supplementation markedly decreased the excretion of fecal neutral sterols (204.7 +/- 28.5 mg/day) compared to the control (521.9 +/- 53.9 mg/day). The combination of the inhibited HMG-CoA reductase (-24.4%) and ACAT (-20.2%) activities as a result of naringin supplementation could account for the decrease of fecal neutral sterols.

Plasma and hepatic cholesterol and hepatic activities of 3-hydroxy-3-methyl-glutaryl-CoA reductase and acyl CoA: cholesterol transferase are lower in rats fed citrus peel extract or a mixture of citrus bioflavonoids.

The cholesterol-lowering effects of tangerine peel extract and a mixture of two citrus flavonoids were tested. Male rats were fed a 1 g/100 g high-cholesterol diet for 42 d with supplements of either tangerine-peel extract or a mixture of naringin and hesperidin (0.5 g/100 g) to study the effects of plasma and hepatic lipids, hepatic enzyme activities, and the excretion of fecal neutral sterols. Both the tangerine-peel extract and mixture of two flavonoids significantly lowered the levels (mean +/- SE) of plasma (2.44 +/- 0. 59 and 2.42 +/- 0.31 mmol/L, vs. 3.80 +/- 0.28 mmol/L, P < 0.05), hepatic cholesterol (0.143 +/- 0.017 and 0.131 +/- 0.010 mmol/g vs. 0.181 +/- 0.003 mmol/g, P < 0.05), and hepatic triglycerides (0.069 +/- 0.007 and 0.075 +/- 0.006 mmol/g vs. 0.095 +/- 0.002 mmol/g, P < 0.05) compared to those of the control. The 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase (1565.0 +/- 106. 0 pmol. min-1. mg protein-1 and 1783.0 +/- 282 pmol. min-1. mg protein-1 vs. 2487.0 +/- 210.0 pmol. min-1. mg protein-1, P < 0.05) and acyl CoA: cholesterol O-acyltransferase (ACAT) activities (548.0 +/- 65.0 and 615.0 +/- 80.0 pmol. min-1. mg protein-1 vs. 806.0 +/- 105.0 pmol. min-1. mg protein-1, P < 0.05) were significantly lower in the experimental groups than in the control. These supplements also substantially reduced the excretion of fecal neutral sterols compared to the control (211.1 +/- 26.7 and 208.2 +/- 31.6 mg/d vs. 521.9 +/- 53.9 mg/d). The inhibition of HMG-CoA reductase and ACAT activities resulting from the supplementation of either tangerine-peel extract or a combination of its bioflavonoids could account for the decrease in fecal neutral sterol that appears to compensate for the decreased cholesterol biosynthesis in the liver.

Inhibitory effect of triterpenes from Crataegus pinatifida on HIV-I protease.

The methanol extracts of the leaves of Crataegus pinnatifida showed potent inhibitory activities against HIV-1 protease at a concentration of 100 micrograms/ml. The subsequent fractionation and isolation of the extract gave two active compounds. Their structures were identified as uvaol (1) and ursolic acid (2) by spectral data. These active compounds inhibit HIV-1 protease with IC50 values of 5.5 and 8.0 microM, respectively.

Chitin synthase II inhibitory activity of ursolic acid, isolated from Crataegus pinnatifida.

Two triterpenoid compounds, ursolic acid and uvaol, were isolated from Crataegus pinnatifida Bunge leaves. Ursolic acid inhibits chitin synthase II from S. cerevisiae with an IC50 value of 0.84 microgram/ml and the inhibition appears to be selective for chitin synthase II, whereas uvaol has no inhibitory activity up to 280 micrograms/ml. Oleanolic acid, alpha-hederin hydrate, and betulic acid inhibited the chitin synthase II activity under the same conditions with an IC50 of 5.6, 64.3, and 98.7 micrograms/ml, respectively.

Inhibition of chitin synthase II by catechins from stem bark of Taxus cuspidata.

Two flavonoids, (+/-)-catechin and (-)-epicatechin, were isolated from the stem bark of Taxus cuspidata by monitoring chitin synthase II inhibitory activity. The compounds inhibit chitin synthase II with an IC50 of 15 and 29 micrograms/ml, respectively and appear to be selective for chitin synthase II. They did not inhibit chitin synthase III.

Acyl-CoA:Cholesterol Acyltransferase Inhibitory Activity of Lignans Isolated from Schizandra, Machilus and Magnolia Species.

Fifteen lignans were isolated from the fruits of SCHIZANDRA CHINENSIS, the leaves of MACHILUS THUNBERGII, and the flower buds of MAGNOLIA DENUDATA. They were identified as gomisins, schizandrin, wuweizisu, schizantherin, licarins, and machilin, which inhibited rat liver ACAT with IC (50) values of 25-200 microM. Comisin N is the most potent inhibitor with IC (50) value of 25 microM in these lignans.

A glycine-rich RNA-binding protein gene is differentially expressed during acute hypersensitive response following Tobacco Mosaic Virus infection in tobacco.

During efforts for cloning disease resistance-responsive genes, a cDNA encoding a putative Nicotiana glutinosa glycine-rich RNA binding protein (ngRBP) was isolated from TMV induced cDNA library. Northern blot hybridization revealed that ngRBP gene is negatively regulated during early hours of TMV induced acute hypersensitive response (HR). Under greenhouse conditions induced expression of ngRBP gene was observed after 24 h following TMV infection. Salicylic acid and copper also induced ngRBP mRNA expression. Our findings are suggestive of some possible role for ngRBP in plant-pathogen interaction.

Acyl-CoA : cholesterol acyltransferase inhibitors from Magnolia obovata.

In the course of a search for acyl-CoA : cholesterol acyltransferase (ACAT) inhibitors from natural sources, new types of ACAT inhibitors were isolated from the extract of Magnolia obovata leaves, and identified as obovatol, honokiol, and magnolol. The active compounds inhibit rat liver ACAT with IC50 values of 42, 71, and 86 microM, respectively.

Polyacetylene analogs, isolated from hairy roots of Panax ginseng, inhibit Acyl-CoA : cholesterol acyltransferase.

In the course of our screening program for acyl-CoA : cholesterol acyltransferase (ACAT) inhibitors from Korean herbal medicines, ACAT inhibitors were isolated from the hairy roots of Panax ginseng (Araliaceae) and identified as panaxynol, panaxydol, panaxydiol, and panaxytriol. These active compounds inhibit rat liver ACAT with IC50 values of 94, 80, 45 and 79 microM, respectively.

Molecular cloning of a metallothionein-like gene from Nicotiana glutinosa L. and its induction by wounding and tobacco mosaic virus infection.

The cloning and characterization of genes expressed in plant disease resistance could be an initial step toward understanding the molecular mechanisms of disease resistance. A metallothionein-like gene that is inducible by tobacco mosaic virus and by wounding was cloned in the process of subtractive cloning of disease resistance-response genes in Nicotiana glutinosa. One 530-bp cDNA clone (KC9-10) containing an open reading frame of 81 amino acids was characterized. Genomic Southern blot hybridization with the cDNA probe revealed that tobacco metallothionein-like genes are present in few or in one copy per diploid genome. Northern blot hybridization detected strong induction of a 0.5-kb mRNA by wounding and tobacco mosaic virus infection, but only mild induction was detected when copper was tested as an inducer. Methyl jasmonate, salicylic acid, and ethylene were also tested as possible inducers of this gene, but they had no effect on its expression. The possible role of this gene in wounded and pathogen-stressed plants is discussed.