Anti-diabetic effects of Cichorium intybus in streptozotocin-induced diabetic rats.

The present study was designed to investigate the hypoglycemic and hypolipidemic properties of an ethanolic extract of Cichorium intybus (CIE) which is widely used in India as a traditional treatment for diabetes mellitus. Male Sprague-Dawley rats aged 9 weeks (160-200 g) were administered with streptozotocin (STZ, 50mg/kg) intraperitoneally to induce experimental diabetes. The Cichorium intybus whole plant was exhaustively extracted with 80% ethanol, concentrated at 40 degrees C using a rotavapor and freeze dried to get powder. Hypoglycemic effects of CIE were observed in an oral glucose tolerance test (OGTT) in which, a dose of 125 mg of plant extract/kg body weight exhibited the most potent hypoglycemic effect. Moreover, daily administration of CIE (125 mg/kg) for 14 days to diabetic rats attenuated serum glucose by 20%, triglycerides by 91% and total cholesterol by 16%. However, there was no change in serum insulin levels, which ruled out the possibility that CIE induces insulin secretion from pancreatic beta-cells. In addition, hepatic glucose-6-phosphatase activity (Glc-6-Pase) was markedly reduced by CIE when compared to the control group. The reduction in the hepatic Glc-6-Pase activity could decrease hepatic glucose production, which in turn results in lower concentration of blood glucose in CIE-treated diabetic rats. In conclusion, our results support the traditional belief that Cichorium intybus could ameliorate diabetic state.

Antioxidants in Chinese herbal medicines: a biochemical perspective.

Recently, intense interest has focused on the antioxidant properties of natural products. In particular, Chinese herbal medicines (CHM) have become hot topics for life science researchers since many are reported to possess cardioprotective compounds, many of which remain to be identified. Indeed, the exact mechanisms by which CHM work remain unknown. Although many of these herbal remedies are undoubtedly efficacious, few have been scientifically investigated for their active chemical constituents and biological activities. We have previously reported higher activities of antioxidant defence enzymes such as superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferases in the liver of rats treated with the herb Salvia miltiorrhiza in a model of acute myocardial infarction. Using well established in vitro antioxidant assays employing 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and diphenyl-l-picrylhydrazyl (DPPH) we have shown that in addition to elevating endogenous antioxidant enzyme activity, Salvia miltiorrhiza and other CHM traditionally used for cardiovascular disorders (such as Rhizoma ligustici, Herba leonuri, Radix achyranthis bidentatae, and Camellia sinensis) contain potent antioxidant moieties in addition to their phenolic constituents. Furthermore, these novel non-phenolic components are effective inhibitors of oxidative reactions mediated by the inflammatory oxidants, peroxynitrite,hypochlorous acid and hydroxyl radical as well as iron-dependent lipid peroxidation. In this review, we discuss the various antioxidant properties of CHM in the context of their biochemical mechanisms.

Evaluation of the hypoglycemic and anti-oxidant activities of Morinda officinalis in streptozotocin-induced diabetic rats.

AIM OF STUDY: The aim was to investigate the hypoglycemic and anti-oxidant activities of the dried roots of Morinda officinalis in streptozotocin-induced diabetic rats. METHODOLOGY: An ethanolic extract of the dried roots of Morinda officinalis and its three fractions (ethyl acetate, n-butanol and water) were obtained. We evaluated the hypoglycemic effects of three different single doses of the crude extract and its fractions in normal and diabetic rats for three hours after administration. Administration of the extract at 150 mg/kg twice daily for 10 days to the diabetic rats was also carried out. The effects of the 10-day treatment on the fasting serum glucose, insulin, total cholesterol, triglycerides, body weight, food intake, fluid intake, hepatic superoxide dismutase (SOD), catalase (CAT) activities, reduced glutathione (GSH), thiobarbituric acid reactive substances (TBARS) and renal TBARS levels were monitored. RESULTS: In the three-hour dose response study, the crude ethanolic extract reduced the fasting serum glucose levels of the diabetic rats significantly at 150 mg/kg but increased those of the normal rats significantly at 600 mg/kg only. The water fraction demonstrated a dose dependent hypoglycemic effect in the diabetic rats whereas the n-butanol fraction increased the fasting serum glucose levels of the diabetic rats significantly at 50 mg/kg only within three hours after administration. The 10-day oral administration of the extract reduced the fasting serum glucose, hepatic and renal TBARS level and significantly increased the hepatic SOD and CAT activities as well as GSH levels. CONCLUSION: The results indicate that the dried roots of Morinda officinalis possess hypoglycemic, hyperglycemic and anti-oxidant properties.

The mechanism of hypoglycemic action of the semi-purified fractions of Averrhoa bilimbi in streptozotocin-diabetic rats.

In the present study, we have examined the possible mechanism of the hypoglycemic action of the semi-purified fractions of an ethanolic extract of Averrhoa bilimbi Linn (Oxalidaceae) leaves (ABe) in streptozotocin-diabetic male Sprague-Dawley (SD) rats. The ABe was partitioned with water and butanol to yield a butanol-soluble fraction (BuF) and a water-soluble fraction (AF). The AF was further partitioned with ethyl acetate and hexane to obtain ethyl acetate (EF) and hexane (HF) soluble fractions. The hypoglycemic property of each fraction was assessed by the oral glucose tolerance test (OGTT) at a dose of 125-mg/kg-body weight in streptozotocin (STZ)-diabetic rats (STZ 60 mg/kg i.p.). Fractions AF, BuF and the reference drug metformin (500 mg/kg body weight), produced significant blood glucose-lowering effect in the diabetic rats when compared to the vehicle (distilled water). In the long-term study, the diabetic rats were randomly divided into 4 groups and treated orally by gavage with vehicle, AF (125 mg/kg body weight), BuF (125 mg/kg body weight), and metformin (500 mg/kg body weight) respectively twice a day for 14 days. On day 7 and day 14, AF and BuF, like the reference drug, metformin, lowered the fasting blood glucose concentration significantly (P < 0.05) when compared with the vehicle. The serum insulin level was significantly increased in the AF-treated rats only on day 14 when compared to that in the vehicle-treated rats on day zero (P < 0.05). The serum insulin level in BuF-treated rats was also significantly higher (P < 0.05) on both day 7 and day 14 compared to that on day zero. Hepatic glucose-6-phosphatase activity was significantly lower (P<0.05) in AF- and metformin-treated groups, but not in BuF-treated groups, compared to that in vehicle-treated group. However, there was no change in hepatic glycogen content in AF-, BuF- and metformin-treated group compared to the vehicle-treated group. These results indicate that AF is more potent than BuF in the amelioration of hyperglycemia in STZ-diabetic rats and is a potential source for the isolation of new orally active agent(s) for anti-diabetic therapy.

Effects of Averrhoa bilimbi leaf extract on blood glucose and lipids in streptozotocin-diabetic rats.

The present study was designed to investigate the hypoglycemic and hypolipidemic activities of an ethanolic extract of Averrhoa bilimbi Linn. leaves (Oxalidaceae, Common name: Bilimbi) in streptozotocin (STZ)-diabetic rats. The optimal hypoglycemic dose (125 mg kg(-1)) was determined by performing the oral glucose tolerance test (OGTT) in both normal and STZ-diabetic rats. To investigate the effect of repeated administration of an ethanolic extract of Averrhoa bilimbi (ABe) leaves, diabetic rats were treated with vehicle (distilled water), ABe (125 mg kg(-1)) or metformin (500 mg kg(-1)) twice a day for 2 weeks. Like metformin, ABe significantly lowered blood glucose by 50% and blood triglyceride by 130% when compared with the vehicle. ABe also significantly increased the HDL-cholesterol concentrations by 60% compared with the vehicle. ABe thus significantly increased the anti-atherogenic index and HDL-cholesterol/total cholesterol ratio. However, like metformin, ABe did not affect total cholesterol and LDL-cholesterol concentrations, but significantly reduced the kidney lipid peroxidation level. These data show that ABe has hypoglycemic, hypotriglyceridemic, anti-lipid peroxidative and anti-atherogenic properties in STZ-diabetic rats.

Antihyperglycaemic and anti-oxidant properties of Andrographis paniculata in normal and diabetic rats.

1. Oxidative stress is believed to be a pathogenetic factor in the development of diabetic complications. In the present study, we investigated the ethanolic extract of the aerial parts of Andrographis paniculata for antihyperglycaemic and anti-oxidant effects in normal and streptozotocin-induced type I diabetic rats. 2. Normal and diabetic rats were randomly divided into groups and treated orally by gavage with vehicle (distilled water), metformin (500 mg/kg bodyweight) or the extract (400 mg/kg bodyweight), twice a day for 14 days. 3. At the end of the 14 day period, the extract, like metformin, significantly increased bodyweight (P < 0.01) and reduced fasting serum glucose in diabetic rats (P < 0.001) when compared with vehicle, but had no effect on bodyweight and serum glucose in normal rats. Levels of liver and kidney thiobarbituric acid-reactive substances (TBARS) were significantly increased (P < 0.0001, P < 0.01, respectively), while liver glutathione (GSH) concentrations were significantly decreased (P < 0.005) in vehicle-treated diabetic rats. Liver and kidney TBARS levels were significantly lower (P < 0.0001, P < 0.005, respectively), whereas liver GSH concentrations were significantly higher (P < 0.05) in extract- and metformin-treated diabetic rats compared with vehicle-treated diabetic rats. Andrographis paniculata significantly decreased kidney TBARS level (P < 0.005) in normal rats. Hepatic superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were significantly lower in vehicle-treated diabetic rats compared with vehicle-treated normal rats. The extract, as well as metformin, significantly increased the activity of SOD and CAT, but had no significant effect on GSH-Px activity in diabetic rats. The extract and metformin did not produce significant changes in the activity of these anti-oxidant enzymes in normal rats. 4. Our results show that oxidative stress is evident in streptozotocin-diabetic rats and indicate that the ethanolic extract of A. paniculata not only possesses an antihyperglycaemic property, but may also reduce oxidative stress in diabetic rats.

Flavonol-cinnamate cycloadducts and diamide derivatives from Aglaia laxiflora.

Leaf extracts of the Malaysian plant Aglaia laxiflora provided two cytotoxic compounds, a new rocaglaol rhamnoside (1), a known rocaglaol (2), new (but inactive) flavonol-cinnamaminopyrrolidine adducts (3-6), and their probable biosynthetic precursors (7 and trimethoxyflavonol). All structures were elucidated primarily by 2D NMR spectroscopy. The structure and stereochemistry of aglaxiflorin A (3) were confirmed by single-crystal X-ray crystallography.

Effects of an ethanolic extract of Gynura procumbens on serum glucose, cholesterol and triglyceride levels in normal and streptozotocin-induced diabetic rats.

AIM OF STUDY: The aim was to demonstrate the effects of the leaves of Gynura procumbens (Lour.) Merr. on blood sugar and lipid levels in experimental animals. METHODOLOGY: We obtained an ethanolic extract of the leaves of G. procumbens and monitored the effects of an oral administration of (i) different single doses of the extract on oral glucose tolerance in streptozotocin-induced diabetic and normal rats and (ii) fourteen doses over 7 days on serum cholesterol and triglyceride levels in streptozotocin-induced diabetic rats. Metformin and glibenclamide were used as positive control drugs. RESULTS: The extract, at single doses of 50, 150 and 300 mg/kg orally, significantly suppressed the elevated serum glucose levels in diabetic rats; 150 mg/kg was found to be the optimum hypoglycaemic dose. The extract however did not significantly suppress the elevated serum glucose levels in normal rats, unlike glibenclamide. Metformin, but not glibenclamide, improved glucose tolerance in the diabetic rats. When the optimum dose was given to diabetic rats for 7 days, the extract significantly reduced serum cholesterol and triglyceride levels in these rats. CONCLUSION: These results indicate that the leaves of G. procumbens may have biguanide-like activity.

Cytotoxic and immunopotentiating effects of ethanolic extract of Nigella sativa L. seeds.

In-vitro cytotoxic screening of extracts of Nigella sativa L. seeds (Ranunculaceae) indicated cytotoxicity in the ethyl-acetate fraction (EAF) against different classes of cancer cell lines, P388, Molt4, Wehi 164, LL/2, Hep G2, SW620 and J82, as measured by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The ethyl-acetate column chromatographic fraction (CC-5) showed selectivity against Hep G2, Molt4, and LL/2. CC-5 was relatively non-toxic against human umbilical cord endothelial cells at 50 microg/ml. CC-5 had no stimulatory effect on mouse splenocytes as such. CC-5 and water fraction, however, enhanced the proliferative response in the presence of ConA (3 microg/ml), but not LPS (1 and 6 microg/ml). These data indicate that CC-5 possesses a potent cytotoxic effect as well as a potentiating effect on the cellular immune response. The mechanism whereby it produces this needs to be resolved.

The mechanism underlying the hypocholesterolaemic activity of aqueous celery extract, its butanol and aqueous fractions in genetically hypercholesterolaemic RICO rats.

Drinking aqueous celery extract for 8 weeks caused a significant reduction in serum total cholesterol (TC) level in growing genetically hypercholesterolaemic (RICO) rats. In addition, administration of butanol fraction (Fbu) and aqueous fraction (Faq) of celery extract for 7 days by intraperitoneal (i.p.) infusion effectively decreased the serum TC and high-density lipoprotein cholesterol (HDL-C) levels of adult RICO rats. The 8-week study showed that oral intake of celery extract could enhance the 14C-cholesterol/metabolites excretion. The liver and small intestinal sterol synthesis were not affected. Also, long term drinking of aqueous celery extract did not lead to any undesirable side effects on liver functions. The Fbu and Faq lowered serum TC level mainly through increased bile acid excretion but not by modulating the activity of the rate-limiting enzyme for cholesterol biosynthesis, HMG-CoA reductase. Hence, the mechanism elucidated supports that suggested by the 8-week study. A preliminary chemical characterisation of Fbu and Faq fractions by thin layer chromatography (TLC) showed the presence of sugars and amino acids. There is a possibility that polar compounds with sugar or amino acid side chains(s) could contribute to the hypocholesterolaemic action of celery extract.

Salvia miltiorrhiza and ischemic diseases.

The demonstration of beneficial effects of salvia miltiorrhiza (DanShen) on ischemic diseases has revolutionized the management of angina pectoris, myocardial infarction (MI) or stroke in Chinese society. Experimental studies have shown that DanShen dilated coronary arteries, increased coronary blood flow, and scavenged free radicals in ischemic diseases, so that it reduced the cellular damage from ischemia and improved heart functions. Clinical trials also indicated that DanShen was an effective medicine for angina pectoris, MI, and stroke. This review will focus on DanShen's effects in angina pectoris, MI and stroke.

Anti-diabetic property of ethanolic extract of Andrographis paniculata in streptozotocin-diabetic rats.

AIM: To investigate the anti-diabetic effect of a crude ethanolic extract of Andrographis paniculata in normal and streptozotocin (STZ)-induced diabetic rats. METHODS & RESULTS: Oral administration of the extract at different doses (0.1, 0.2, and 0.4 g/body weight) significantly reduced the fasting serum glucose level in STZ-diabetic rats compared to the vehicle (distilled water), but not in normal rats. This effect was dose-dependent. A similar result was seen with metformin (0.5 g/body weight). In the glucose tolerance test, an oral administration of the extract at the same doses suppressed the elevated glucose level in normal and diabetic rats, as did metformin. The effects were also dose-respondent. In the long-term experiment, the extract (0.4 g/body weight), metformin (0.5 g/body weight), and vehicle were given twice daily to diabetic rats for 14 d. On d 15, fasting serum glucose levels were found to be significantly lower in the extract- and metformin-treated groups (P < 0.001) than in the vehicle-treated group. The mean food and water intakes over 14 days were significantly lower in the extract-treated group (P < 0.05, P < 0.01, respectively) and also in the metformin-treated group (both P < 0.001) when compared to the vehicle-treated group. No significant change in insulin level was observed among the 3 groups of diabetic rats. The extract, like metformin, maintained the leptin levels after 14-d treatment, whereas this level was significantly decreased (P < 0.05) in the vehicle-treated group. The activity of hepatic glucose-6-phosphatase (G-6-Pase) was significantly reduced by the extract as well as by metformin (both P < 0.05). No significant difference in hepatic glycogen stores was noted among the 3 groups. The extract caused 49.8% reduction of fasting serum triglyceride levels, compared to 27.7% with metformin. However, neither the extract nor metformin significantly affected serum cholesterol level. CONCLUSION: The ethanolic extract of A paniculata possesses antidiabetic property. Its antidiabetic effect may be attributed at least in part to increased glucose metabolism. Its hypotriglyceridemic effect is also beneficial in the diabetic state.

Effects of 14-deoxyandrographolide and 14-deoxy-11,12-didehydroandrographolide on nitric oxide production in cultured human endothelial cells.

14-deoxyandrographolide (DA) and 14-deoxy-11,12-didehydroandrographolide (DDA) are two diterpenoids isolated from A. paniculata, a popular folk medicine used as an antihypertensive drug in Malaysia. We have previously reported that DDA exhibited a greater hypotensive effect in anaesthetized rats and a vasorelaxant activity in isolated rat aorta, compared with DA. Their vasorelaxant activities were mediated through the activation of the enzymes, nitric oxide synthase (NOS) and guanylyl cyclase. The present study demonstrated that both DA and DDA stimulated nitric oxide (NO) release from human endothelial cells. DDA compared with DA caused a greater production of NO; this is in line with the finding of the earlier study that the vasorelaxant effect of DDA was more dependent on endothelium than DA.

Lipid peroxidative stress and antioxidative enzymes in brains of milk-supplemented rats.

Skim milk cultured with lactic acid bacteria has been previously reported to reduce lipid peroxidation in rat livers. In this study, the effects of skim milk and cultured milk supplementation on peroxidative stress in brains of weanling rats were investigated. We observed a reduction of brain thiobarbituric acid reacting substances (TBARS) concentration in milk-supplemented animals as compared with controls. In brains of control rats, the superoxide dismutase (SOD) enzyme levels were significantly higher than those from the milk-supplemented animals. In addition, SOD activity in control animal brains had a positive correlation with the TBARS concentration. There was no significant differences in the brain glutathione-S-transferase (GST) levels of all the three groups of animals. The results suggest that milk supplementation may be beneficial in reducing peroxidative stress in the developing rat brain.

Mechanisms of cardiovascular activity of Andrographis paniculata in the anaesthetized rat.

The cardiovascular activities of crude water extract (WE) of Andrographis paniculata (Burm. f.) Nees (Acanthaceae), its three semi-purified ethyl acetate (FA), n-butanol (FB) and aqueous (FC) fractions, as well as andrographolide, a major plant constituent, were elucidated in anaesthetized Sprague-Dawley (SD) rats for the very first time. FA and andrographolide, which possesses multiple pharmacological activities, elicited no drop in mean arterial blood pressure (MAP), while WE, FB and FC produced a significant fall in MAP in a dose-dependent manner without significant decrease in heart rate. The ED50 values for WE, FB and FC were 11.4, 5.0 and 8.6 mg/kg-respectively. These suggested that the hypotensive substance(s) of the crude water extract was concentrated in FB. Pharmacological antagonist studies were consequently only tested in FB (5 mg/kg). The hypotensive action of FB was not mediated through effects on the beta-adrenoceptor, muscarinic cholinergic receptor and angiotensin-converting enzyme, for it was not affected by propranolol, atropine and captapril, respectively. However, it seems to work via alpha-adrenoceptors, autonomic ganglion and histaminergic receptors, since the hypotensive effect of FB was negated or attenuated in the presence of phentolamine, hexamethonium as well as pyrilamine and cimetidine.

Hypotensive activity of aqueous extract of Andrographis paniculata in rats.

1. The hypotensive activity of an aqueous extract of Andrographis paniculata was studied using chronic intraperitoneal (i.p.) infusions by osmotic pumps. The extract exhibited a dose-dependent hypotensive effect on the systolic blood pressure (SBP) of spontaneously hypertensive rats (SHR). 2. The optimum hypotensive dose determined was repeated in a study in SHR and their normotensive controls, Wistar-Kyoto (WKY) rats, to demonstrate its comparative effects on the SBP, plasma and lung angiotensin-converting enzyme (ACE) activities, as well as on lipid peroxidation in the kidneys, as measured by the thiobarbituric acid (TBA) assay. 3. The extract significantly lowered the SBP of both SHR and WKY rats. 4. Plasma, but not lung, ACE activity and kidney TBA level were significantly lower in extract-treated SHR when compared with vehicle-treated SHR controls. 5. Plasma and lung ACE activities as well as kidney TBA levels were not significantly different between extract- and vehicle-treated WKY rats. 6. This study indicates that the aqueous extract of A. paniculata lowers SBP in the SHR possibly by reducing circulating ACE in the plasma as well as by reducing free radical levels in the kidneys. The mechanism(s) of hypotensive action seems to be different in WKY rats.

In vitro cytotoxicity and immunomodulating property of Rhaphidophora korthalsii.

An in vitro cytotoxic screening of extracts of Rhaphidophora korthalsii indicated cytotoxicity in the ether fraction. ED50 values of the extract against P388, Molt 4, KB and SW 620 were 12, 14, 8 and 13 micrograms/ml, respectively. The extract was relatively more toxic on P388 and Molt 4 cell lines at concentrations of 50 micrograms/ml and 100 micrograms/ml. Screening with mouse splenocytes showed that the hot water extract had splenocytes stimulating activity.

Effects of celery extract and 3-N-butylphthalide on lipid levels in genetically hypercholesterolaemic (RICO) rats.

1. Aqueous celery extract was administered intraperitoneally to genetically hypercholesterolaemic (RICO) and normocholesterolaemic (RAIF) rats via Alzet osmotic pumps over a 13 day period. 2. The serum cholesterol concentration of the celery extract-treated RICO rats was found to be significantly lower (P < 0.05) than the control rats. Aqueous celery extract was effective in preventing the rise of cholesterol level in the RICO rats. However, no such observation was seen in the RAIF rats. The serum triglyceride level was unchanged in both strains of rats. 3. When 3-n-butylphthalide (BuPh), a unique component in celery, was administered in the same manner to the RICO and RAIF rats, it did not produce significant changes in the serum and liver lipid profiles of these rats. The activities of hepatic 3-hydroxy-3-methylglutaryl CoA reductase in both strains of rats were also not significantly different from their respective controls. 4. Together with our recently reported thin-layer chromatography findings that BuPh was not detected in the aqueous celery extract, this study suggests that the effect of celery extract on serum cholesterol levels in the RICO rats could be attributed to chemical constituents other than BuPh.

Effects of aqueous celery (Apium graveolens) extract on lipid parameters of rats fed a high fat diet.

The antihyperlipidemic property of aqueous celery extract was studied in rats. Two groups of Wistar rats were fed a high fat diet for eight weeks to induce hyperlipidemia. One group was supplemented with aqueous celery extract in the diet while the other group served as control. At the end of the experiment, a significant reduction was found in the serum total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), and triglyceride (TG) concentrations in the celery-treated rats. However, the concentration of hepatic TG was significantly higher in the celery-treated group than in the control group. Hepatic triacylglycerol lipase (HL) activity was found to be significantly lower in the celery-treated rats while the reverse was observed for the hepatic microsomal P450 content. Analysis of an ethereal extract of the aqueous extract of celery by thin layer chromatography (TLC) with two different solvent systems showed that the extract did not contain 3-n-butylphthalide (BuPh), a unique compound in celery that has previously been reported to have lipid-lowering action. Our study indicates that other active principle(s) could be responsible for the observed effects of aqueous celery extract on serum and hepatic lipid levels.

The effects of tannic acid on serum lipid parameters and tissue lipid peroxides in the spontaneously hypertensive and Wistar Kyoto rats.

The effects of tannic acid or its vehicle (normal saline) on blood pressure, blood lipid parameters, liver and kidney malonaldehyde (MDA) levels were investigated in the spontaneously hypertensive rats (SHR) and the normotensive Wistar Kyoto rats (WKY). When tannic acid dissolved in normal saline, was injected intraperitoneally (i.p.) twice a week at a single dose of 15 mg/rat/injection (30 mg/week) for a period of 10 weeks to the SHR, the serum total cholesterol (TC), low density lipoprotein cholesterol (LDLC), and triglycerides (TG) were significantly lower compared to the vehicle-treated SHR. However, there was no significant difference in the high density lipoprotein cholesterol (HDLC) concentration. Administration (i.p.) of tannic acid to the WKY did not cause any significant effects on the serum TC, LDLC, and TG levels. The HDLC concentration of the tannic acid-treated WKY was significantly higher than in the vehicle-treated WKY. The LDLC/HDLC ratio was significantly lowered compared to their respective controls for both strains of rats. When tannic acid was administered (i.p.) by osmotic pumps over a 13 day period (30 mg tannic acid/week), the kidney MDA level in the SHR was found to be significantly lower than in the vehicle-treated SHR. The liver MDA level was not significantly different between the treated and control rats. In the WKY, MDA was detected in trace amounts in the kidneys of both the control and treated rats. There were appreciable amounts of MDA detected in the liver of the control and treated rats but these were not significantly different from one another.(ABSTRACT TRUNCATED AT 250 WORDS)