In vivo effect of Piper sarmentosum methanolic extract on stress-induced gastric ulcers in rats.

INTRODUCTION: Piper sarmentosum (Piperaceae) is traditionally used by Asians to treat numerous common ailments including asthma, fever and gastritis. The aim of the research was to determine and compare the effects of Piper sarmentosum (PS) with omeprazole (OMZ) on gastric parameters in rats exposed to restraint stress. MATERIAL AND METHODS: The methanolic extract of PS was prepared in the dose of 500 mg/kg. Twenty-eight male Wistar rats were assigned to 4 equal sized groups: two control groups and two treated groups which were supplemented with either PS or OMZ orally at a dose of 500 mg/kg and 20 mg/kg body weight respectively. After 28 days of treatment, one control group, the PS and OMZ group were subjected to a single exposure of water-immersion restraint stress for 3.5 h. After the last exposure to stress, the stomach was excised for evaluation of the parameters. RESULTS: Oral supplementation of PS was as effective in preventing the formation of gastric lesion when compared with OMZ (p < 0.05). The increased gastric acidity and MDA due to stress was also reduced with supplementation of PS and OMZ. Only PS had the ability to reduce prostaglandin E2 loss (p = 0.0067) and have the ability to down regulate cyclooxygenase-2 (COX-2) mRNA expression (p = 0.01) with stress exposure. CONCLUSIONS: Piper sarmentosum possesses a similar protective effect against stress-induced gastric lesions as omeprazole. The protective effect was associated with decreased lipid peroxidation, increased prostaglandin E2, reduction in gastric acidity and reduction in COX-2 mRNA expression which was altered by stress.

Changes in blood pressure, vascular reactivity and inflammatory biomarkers following consumption of heated corn oil.

Consumption of corn oil for cooking purpose is gaining popularity. The present study examined the effect of heated corn oil on blood pressure and its possible mechanism in experimental rats. Thirty male Sprague-Dawley rats were randomly divided into 5 groups and were fed with the following diets, Group I was fed with basal diet only; whereas group II,III,IV and V were fed with basal diet fortified with 15% (w/w) either fresh, once-heated, five-times-heated or ten-times-heated corn oil, respectively for 16 weeks. Body weight, blood pressure were measured at baseline and weekly interval for 16 weeks. Inflammatory biomarkers which included soluble intracellular adhesion molecules (sICAM), soluble vascular adhesion molecules (sVCAM) and C reactive protein (CRP), were measured at baseline and the end of 16 weeks. The rats were sacrificed and thoracic aorta was taken for measurement of vascular reactivity. There was significant increase in the blood pressure in the groups fed with heated once, five-times (5HCO) and ten-times-heated corn oil (10-HCO) compared to the control. The increase in the blood pressure was associated with an increase in CRP, sICAM and sVCAM, reduction in vasodilatation response to acetylcholine and greater vasoconstriction response to phenylephrine. The results suggest that repeatedly heated corn oil causes elevation in blood pressure, vascular inflammation which impairs vascular reactivity thereby predisposing to hypertension. There is a need to educate people not to consume corn oil in a heated state.

Comparison between tocotrienol and omeprazole on gastric growth factors in stress-exposed rats.

AIM: To investigate and compare the effects of tocotrienol and omeprazole on gastric growth factors in rats exposed to water-immersion restraint stress (WIRS). METHODS: Twenty-eight male Wistar rats were randomly assigned to four groups of seven rats. The two control groups were administered vitamin-free palm oil (vehicle) and the two treatment groups were given omeprazole (20 mg/kg) or tocotrienol (60 mg/kg) by oral gavage. After 28 d of treatment, rats from one control group and both treated groups were subjected to WIRS one time for 3.5 h. Gastric lesions were measured and gastric tissues were obtained to measure vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and transforming growth factor-alpha (TGF-α) mRNA expression. RESULTS: Rats exposed to WIRS for 3.5 h demonstrated the presence of considerable ulcers in the form of gastric erosion. The lesion index in the stressed control (S) group was increased (P < 0.001) compared to the tocotrienol treated and omeprazole treated groups. Stress led to a decrease in gastric VEGF (P < 0.001), bFGF (P < 0.001) and TGF-α (P < 0.001) mRNA levels and caused an increase in EGF mRNA (P < 0.001) that was statistically significant compared to the non-stressed control group. Although both treatment agents exerted similar ulcer reducing ability, only treatment with tocotrienol led to increased expression of VEGF (P = 0.008), bFGF (P = 0.001) and TGF-α (P = 0.002) mRNA. CONCLUSION: Tocotrienol provides gastroprotective effects in WIRS-induced ulcers. Compared to omeprazole, tocotrienol exerts a similar protective effect, albeit through multiple mechanisms of protection, particularly through up-regulation of growth factors that assist in repair of gastric tissue injuries.

Renoprotective effect of virgin coconut oil in heated palm oil diet-induced hypertensive rats.

Virgin coconut oil, rich in antioxidants, was shown to attenuate hypertension. This study aimed to investigate the effects of virgin coconut oil on blood pressure and related parameters in kidneys in rats fed with 5-times-heated palm oil (5HPO). Thirty-two male Sprague-Dawley rats were divided into 4 groups. Two groups were fed 5HPO (15%) diet and the second group was also given virgin coconut oil (1.42 mL/kg, oral) daily for 16 weeks. The other 2 groups were given basal diet without (control) and with virgin coconut oil. Systolic blood pressure was measured pre- and post-treatment. After 16 weeks, the rats were sacrificed and kidneys were harvested. Dietary 5HPO increased blood pressure, renal thiobarbituric acid reactive substance (TBARS), and nitric oxide contents, but decreased heme oxygenase activity. Virgin coconut oil prevented increase in 5HPO-induced blood pressure and renal nitric oxide content as well as the decrease in renal heme oxygenase activity. The virgin coconut oil also reduced the elevation of renal TBARS induced by the heated oil. However, neither dietary 5HPO nor virgin coconut oil affected renal histomorphometry. In conclusion, virgin coconut oil has a potential to reduce the development of hypertension and renal injury induced by dietary heated oil, possibly via its antioxidant protective effects on the kidneys.

Preventive Effects of Tocotrienol on Stress-Induced Gastric Mucosal Lesions and Its Relation to Oxidative and Inflammatory Biomarkers.

This study aimed to investigate the possible gastroprotective effect of tocotrienol against water-immersion restraint stress (WIRS) induced gastric ulcers in rats by measuring its effect on gastric mucosal nitric oxide (NO), oxidative stress, and inflammatory biomarkers. Twenty-eight male Wistar rats were randomly assigned to four groups of seven rats. The two control groups were administered vitamin-free palm oil (vehicle) and the two treatment groups were given omeprazole (20 mg/kg) or tocotrienol (60 mg/kg) orally. After 28 days, rats from one control group and both treated groups were subjected to WIRS for 3.5 hours once. Malondialdehyde (MDA), NO content, and superoxide dismutase (SOD) activity were assayed in gastric tissue homogenates. Gastric tissue SOD, iNOS, TNF-α and IL1-ß expression were measured. WIRS increased the gastric MDA, NO, and pro-inflammatory cytokines levels significantly when compared to the non-stressed control group. Administration of tocotrienol and omeprazole displayed significant protection against gastric ulcers induced by exposure to WIRS by correction of both ulcer score and MDA content. Tissue content of TNF-α and SOD activity were markedly reduced by the treatment with tocotrienol but not omeprazole. Tocotrienol significantly corrected nitrite to near normal levels and attenuated iNOS gene expression, which was upregulated in this ulcer model. In conclusion, oral supplementation with tocotrienol provides a gastroprotective effect in WIRS-induced ulcers. Gastroprotection is mediated through 1) free radical scavenging activity, 2) the increase in gastric mucosal antioxidant enzyme activity, 3) normalisation of gastric mucosal NO through reduction of iNOS expression, and 4) attenuation of inflammatory cytokines. In comparison to omeprazole, it exerts similar effectiveness but has a more diverse mechanism of protection, particularly through its effect on NO, SOD activity, and TNF-α.

Cardioprotective effect of virgin coconut oil in heated palm oil diet-induced hypertensive rats.

CONTEXT: Virgin coconut oil (VCO) contains high antioxidant activity which may have protective effects on the heart in hypertensive rats. OBJECTIVES: The study investigated the effects of VCO on blood pressure and cardiac tissue by measuring angiotensin-converting enzyme (ACE) activity and its histomorphometry in rats fed with a heated palm oil (HPO) diet. MATERIALS AND METHODS: Thirty-two male Sprague-Dawley rats were randomly divided into four groups: (i) control, (ii) orally given VCO (1.42 ml/kg), (iii) fed with a HPO (15%) diet, and (iv) fed with a HPO diet and supplemented with VCO (1.42 ml/kg, po) (HPO+VCO) for 16 weeks. Blood pressure was measured monthly. After 16 weeks, rat hearts were dissected for lipid peroxidation (TBARS) and ACE activity measurement and histomorphometric study. RESULTS: Systolic blood pressure was significantly increased in the HPO group compared with the control starting at week eight (112.91 ± 1.32 versus 98.08 ± 3.61 mmHg, p < 0.05) which was prevented by VCO supplementation (91.73 ± 3.42 mmHg). The consumption of HPO increased TBARS and ACE activity in heart, which were inhibited by VCO supplementation. The increases in the myofiber width and area as well as nuclear size reduction in the HPO group were significantly prevented by VCO supplementation. CONCLUSION: These results suggested that VCO supplementation possesses a cardioprotective effect by preventing the increase in blood pressure via an antioxidant mechanism and remodeling in rats fed repeatedly with a HPO diet.

Tocotrienol Attenuates Stress-Induced Gastric Lesions via Activation of Prostaglandin and Upregulation of COX-1 mRNA.

The present study aims to distinguish the effect of tocotrienol on an important gastric protective factor, prostaglandin E2 (PGE2), in stress-induced gastric injury. Twenty-eight Wistar rats were divided into four groups of seven rats each. Two control groups were fed commercial rat diet, and two treatment groups were fed the same diet but with additional dose of omeprazole (20 mg/kg) or tocotrienol (60 mg/kg). After 28 days, rats from one control group and both treated groups were subjected to water-immersion restraint stress for 3.5 hours once. The rats were then sacrificed, their stomach isolated and gastric juice collected, lesions examined, and gastric PGE2 content and cyclooxygenase (COX) mRNA expression were determined. Both the regimes significantly attenuated the total lesion area in the stomach compared to the control. Gastric acidity, which was increased in stress, was significantly reduced in rats supplemented with omeprazole and tocotrienol. The PGE2 content was also significantly higher in the rats given tocotrienol supplementation compared to the control followed by an increase in COX-1 mRNA expression. We conclude that tocotrienol supplementation protected rat gastric mucosa against stress-induced lesions possibly by reducing gastric acidity and preserving gastric PGE2 by increasing COX-1 mRNA.

Parkia speciosa Hassk.: A Potential Phytomedicine.

Parkia speciosa Hassk., or stink bean, is a plant indigenous to Southeast Asia. It is consumed either raw or cooked. It has been used in folk medicine to treat diabetes, hypertension, and kidney problems. It contains minerals and vitamins. It displays many beneficial properties. Its extracts from the empty pods and seeds have a high content of total polyphenol, phytosterol, and flavonoids. It demonstrates a good antioxidant activity. Its hypoglycemic effect is reported to be attributable to the presence of ß -sitosterol, stigmasterol, and stigmast-4-en-3-one. The cyclic polysulfide compounds exhibit antibacterial activity, while thiazolidine-4-carboxylic acid possesses anticancer property. The pharmacological properties of the plant extract are described in this review. With ongoing research conducted on the plant extracts, Parkia speciosa has a potential to be developed as a phytomedicine.

Virgin coconut oil prevents blood pressure elevation and improves endothelial functions in rats fed with repeatedly heated palm oil.

This study was performed to explore the effects of virgin coconut oil (VCO) in male rats that were fed with repeatedly heated palm oil on blood pressure, plasma nitric oxide level, and vascular reactivity. Thirty-two male Sprague-Dawley rats were divided into four groups: (i) control (basal diet), (ii) VCO (1.42 mL/kg, oral), (iii) five-times-heated palm oil (15%) (5HPO), and (iv) five-times-heated palm oil (15%) and VCO (1.42 mL/kg, oral) (5HPO + VCO). Blood pressure was significantly increased in the group that was given the 5HPO diet compared to the control group. Blood pressure in the 5HPO + VCO group was significantly lower than the 5HPO group. Plasma nitric oxide (NO) level in the 5HPO group was significantly lower compared to the control group, whereas in the 5HPO + VCO group, the plasma NO level was significantly higher compared to the 5HPO group. Aortic rings from the 5HPO group exhibited attenuated relaxation in response to acetylcholine and sodium nitroprusside as well as increased vasoconstriction to phenylephrine compared to the control group. Aortic rings from the 5HPO + VCO group showed only attenuated vasoconstriction to phenylephrine compared to the 5HPO group. In conclusion, VCO prevents blood pressure elevation and improves endothelial functions in rats fed with repeatedly heated palm oil.

Involvement of inflammation and adverse vascular remodelling in the blood pressure raising effect of repeatedly heated palm oil in rats.

Oil thermoxidation during deep frying generates harmful oxidative free radicals that induce inflammation and increase the risk of hypertension. This study aimed to investigate the effect of repeatedly heated palm oil on blood pressure, aortic morphometry, and vascular cell adhesion molecule-1 (VCAM-1) expression in rats. Male Sprague-Dawley rats were divided into five groups: control, fresh palm oil (FPO), one-time-heated palm oil (1HPO), five-time-heated palm oil (5HPO), or ten-time-heated palm oil (10HPO). Feeding duration was six months. Blood pressure was measured at baseline and monthly using tail-cuff method. After six months, the rats were sacrificed and the aortic arches were dissected for morphometric and immunohistochemical analyses. FPO group showed significantly lower blood pressure than all other groups. Blood pressure was increased significantly in 5HPO and 10HPO groups. The aortae of 5HPO and 10HPO groups showed significantly increased thickness and area of intima-media, circumferential wall tension, and VCAM-1 than other groups. Elastic lamellae were disorganised and fragmented in 5HPO- and 10HPO-treated rats. VCAM-1 expression showed a significant positive correlation with blood pressure. In conclusion, prolonged consumption of repeatedly heated palm oil causes blood pressure elevation, adverse remodelling, and increased VCAM-1, which suggests a possible involvement of inflammation.

Deep-fried keropok lekors Increase Oxidative Instability in Cooking Oils.

BACKGROUND: This study was performed to compare the oxidative quality of repeatedly heated palm and soybean oils, which were used to fry keropok lekors and potato chips. METHODS: A kilogramme of keropok lekors or potato chips was fried in 2.5 L of palm or soybean oil at 180 °C for 10 minutes. The frying process was repeated once and four times to obtain twice-heated and five-times-heated oils. The peroxide value and fatty acid composition of the oils were measured. RESULTS: Frequent heating significantly increased the peroxide values in both oils, with the five-times-heated oils having the highest peroxide values [five-times-heated palm: 14.26 ± 0.41 and 11.29 ± 0.58 meq/kg vs fresh: 2.13 ± 0.00, F (3,12) = 346.80, P < 0.001; five-times-heated soybean: 16.95 ± 0.39 and 12.90 ± 0.21 meq/kg vs fresh: 2.53 ± 0.00 oils, F (3,12) = 1755, P < 0.001, when used to fry keropok lekors and potato chips, respectively]. Overall, both oils showed significantly higher peroxide values when keropok lekors were fried in them compared with when potato chips were fried. In general, the heated soybean oil had significantly higher peroxide values than the heated palm oil. Fatty acid composition in the oils remained mostly unaltered by the heating frequency. CONCLUSION: keropok lekors, when used as the frying material, increased the peroxide values of the palm and soybean oils. Fatty acid composition was not much affected by the frequency of frying or the fried item used.