Impact of diets containing corn oil or olive/sunflower oil mixture on the human plasma and lipoprotein lipid metabolism

Summary Background The effects of monounsaturated fatty acids (MUFA) rich diets compared to those that are rich in polyunsaturated fatty acids (PUFA) as well as the effects of an intake of single oils compared to oil mixtures are controversially discussed and results are contradictory. Aim of this study To evaluate the effects of a plant oil-mixture (olive/sunflower oil; saturated/monounsaturated/polyunsaturated (S/M/P) = 14:69:17) high in oleic acid but also showing a moderate content of polyunsaturated fatty acids (PUFA) in comparison with a single, PUFA rich corn oil (S/M/P = 13:33:54) used in a normal, balanced diet on human plasma and lipoprotein metabolism. Methods The double-blind designed study comprised 28 healthy, non-smoking young men aged between 19 and 31 years. After two weeks of adjustment (mixed, balanced diet: 11.6 MJ average, average fat intake ∼105 g/d), the design included a two week test period in which a diet with 80 g corn oil/d vs a mixture of 68 g olive- and 12 g sunflower oil/d (total 80 g) as the main fat source was given, followed by a crossover after two weeks. Compliance and ingestion of diets were monitored by assessing the fatty acid pattern in LDL and by determination of α- and γ-tocopherol in plasma and LDL. Results Diets were well incorporated due to the significant changes in plasma- and LDL-tocopherol levels and the significant different average ratio of oleic acid to linoleic acid in LDL. The PUFA-rich corn oil diet was able to reduce low density lipoprotein (LDL) cholesterol from adjustment to T2 significantly (p < 0.01), which was also confirmed by a trend after cross over (p=0.15). Total cholesterol (only after cross over at T3), total triglycerides (TG) and very low density lipoprotein (VLDL)-TG were significantly lower at T2 after the corn oil diet than after the mixed oil diet. Total high density lipoproteins (HDL) and HDL cholesterol remained unchanged by both diets. Conclusions The results show that during the intervention of two weeks for each diet and the following cross over the corn oil diet had more influence on lipoprotein metabolism than the MUFA-rich diet. The hypocholesteremic effect of the PUFA-rich diet must also be connected with the high amount of unsaponifiable substances, mainly phytosterols in the corn oil. Received: 10 May 2001, Accepted: 17 September 2001     

Fumonisins and deoxynivalenol in corn-based food products in Portugal

A great diversity of crops is vulnerable to fungal attack and might be contaminated with mycotoxins. Currently it is estimated that 25% of the world's harvest production is contaminated to some level with these toxins. The presence of fumonisins and deoxynivalenol in corn-based foods, available in Portugal, was analyzed in order to produce some data that may be useful for hazard characterization. A total of 105 samples were screened, including, corn meal (41), sweet corn (49) and corn flakes (15). None of the 15 samples of corn flakes contained some detectable amount of fumonisins. However, fumonisin B1 (FB1) and fumonisin B2 (FB2) contamination was found in 100.0% and 70.7% of the corn meal samples, respectively. Sweet corn samples were positive in 73.4% for FB1, although no FB2 was detected. The highest levels of fumonisin were found in corn meal (maximum: 1300 microg FB1/kg and 450 microg FB2/kg). The presence of deoxynivalenol was not detected in any of the analyzed samples. Nevertheless these results indicate the need to establish, by corn products manufacturers, a continuous monitoring program to prevent and manage the occurrence of these contaminants.     

影响玉米秸秆微生物降解制肥的因素浅析

试验以粉碎后的玉米秸杆为原料进行好氧微生物降解制造有机肥，通过比较不同含水率和通气条件对秸秆降解效率的影响，以及降解过程中温度，pH，微生物量的变化，总结出微生物降解玉米秸秆过程的变化规律。由试验可知，水分与通气条件均是影响发酵效果的重要因素，且制造堆肥的最佳含水率在60％－70％。     

玉米苞叶对动脉粥样硬化家兔平滑肌细胞凋亡及p53和Fas蛋白表达的影响

目的：探讨玉米苞叶防治动脉粥样硬化（AS）的机制。方法：选用大耳白家兔，复制家兔AS模型，随机分为动脉粥样硬化模型组，玉米苞叶组和正常对照组，成模后给予玉米苞叶煎剂治疗，8w后处死家兔，采用流氏细胞术检测平滑肌细胞的凋亡率以及凋亡相关基因p53和Fas蛋白表达。结果：模型组血管平滑肌细胞的凋亡率明显高于对照组（P＜0．05），p53和Fas蛋白的表达增强（P＜0．05），主动脉壁肉眼观测出现典型斑块。玉米苞叶组平滑肌细胞的凋亡率明显低于模型组（P＜0．05），p53和Fas蛋白表达下调（P＜0．05）；主动脉斑块面积较模型组明显减小，结论：玉米苞叶通过调节p53和Fas蛋白表达而调节AS家兔平滑肌细胞凋亡。     

Fish oil prevents colon cancer by modulation of structure and function of mitochondria

Cancer cells are more susceptible to metabolic perturbations due to impaired electron transport chain (ETC) that promote uncontrolled proliferation. Mitochondria play a pivotal role in bioenergetics and apoptosis, hence are considered as a promising target in tumor cell eradication. Therefore, the present study is designed to elucidate chemopreventive action of fish oil (FO) in combination with corn oil (CO) on mitochondria in colorectal cancer (CRC). Male Wistar rats were divided into groups depending on dietary regimen—Control group, FO + CO(1:1) and FO + CO(2.5:1). These groups were further subdivided depending on whether these received a weekly intraperitoneal injection of ethylenediamine tetra-acetic acid (EDTA) or N,N-dimethylhydrazine dihydrochloride (DMH) for a period of 4 weeks. The animals sacrificed 48 h and 16 weeks after EDTA/DMH treatment constituted initiation and post-initiation phase respectively. The structural and functional alterations in mitochondria were evaluated using transmission electron microscopy (TEM) and by assaying electron transport chain (ETC) enzymes. Mitochondrial lipid composition and cholesterol levels were also assessed. DMH treatment led to mitochondrial degeneration, disrupted cristae and a significant decrease in ETC complexes suggestive of metabolic reprogramming. Moreover, an increase in cholesterol and cardiolipin (CL) levels in post-initiation phase led to evasion of apoptosis. FO in both the ratios resulted in stabilization and increase in number of mitochondria, however, FO + CO(2.5:1) + DMH group also exhibited mitophagy and crystolysis alongwith altered dynamics in ETC which facilitated apoptosis. It also decreased cholesterol and CL levels to increase apoptosis. Fish oil targets mitochondria in a dose dependent manner that augments apoptosis and hence attenuates carcinogenesis.     

Corn oligopeptides protect against early alcoholic liver injury in rats

Background

The present study aimed to investigate the effects of corn oligopeptides (COPs) on early alcoholic liver injury in rats. A total of 70 Wistar rats were randomly assigned to 7 groups, including a normal control group, 3 alcohol control groups (2.0, 4.0 and 6.0 g/kg/BW ethanol), and 3 COP intervention groups (2.0, 4.0 and 6.0 g/kg/BW ethanol, with 900 mg/kg/BW COPs). The study duration lasted for 4 weeks. Serum markers were assayed, and a histopathological examination was conducted.

Results

We found that the COP treatment prevented the elevation of serum aminotransferase and alleviated the hepatic histological damage that was induced by alcohol. In addition, the COPs counteracted the changes in the SOD activity and the MDA content in serum. Furthermore, the COPs ameliorated the abnormal lipid metabolism.

Conclusion

These findings suggest that COPs have a significant protective effect on early alcoholic liver injury in rats.     

Subchronic toxicity study of corn silk with rats

Aim of this study

Corn silk is a traditional herbal medicine in China, which has been used in many parts of the world for the treatment of edema as well as for cystitis, gout, kidney stones, nephritis, prostatitis and similar ailments. However, there is little scientific evidence about its safety. As a part of its safety assessment, a subchronic toxicity was performed in this paper.

Methods

The subchronic toxicity was investigated in male and female Wistar rats by dietary administration at concentrations of 0.5%, 2.0% and 8.0% (w/w) for 90 days. Overall health, body weight, food consumption, hematology, blood chemistry, organ weights, gross and microscopic appearance of tissues were compared between test and control groups.

Results

A number of significant differences were seen between groups, but none of them was considered to be adverse. Based on the present study, the no-observed-adverse-effect level (NOAEL) of corn silk is at least 8.0% which corresponds to a mean daily corn silk intake of approximately 9.354 and 10.308 g/day/kg body weight for males and females, respectively.

Conclusion

The results obtained in the present study suggest that consumption of corn silk has no adverse effects and support the safety of corn silk for humans.     

Effect of corn gluten and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet

This study examined the effects of corn gluten (CG) and its hydrolysate consumptions on weight reduction in rats fed a high-fat diet. Eight-month-old male Sprague-Dawley rats (n=40) were fed a high-fat diet (40% calorie as fat) for 4 weeks. They were then randomly divided into four groups and fed the isocaloric diets with different protein sources for 8 weeks. The protein sources were casein (control group), intact CG (CG group), CG hydrolysate A (CGHA group, 30% of protein as peptides and 70% as free amino acids) and CG hydrolysate P (CGHP group, 93% of protein as peptides and 7% as free amino acids). Body weight gain, adipose tissue weights, nitrogen balance, absorptions of energy, protein and fat, lipid profiles in plasma, liver and feces and hepatic activities of carnitine palmitoyl transferase (CPT), fatty acid synthase (FAS), malic enzyme (ME) and glucose-6-phosphate dehydrogenase (G6PDH) were assessed. The CGHA diet had the highest amount of BCAAs, especially leucine, and most of them existed as free amino acid forms. The CGHA group showed significant weight reduction and negative nitrogen balance. Protein absorption and apparent protein digestibility in the CGHA group were significantly lower than those in other groups. Adipose tissue weights were the lowest in the CGHA group. Activity of CPT tended to be higher in the CGHA group than in other groups and those of FAS, ME and G6PDH were significantly lower in the CGHA group than in other groups. In conclusion, the CGHA diet which had relatively high amounts of free amino acids and BCAAs, especially leucine, had a weight reduction effect by lowering adipose tissue weight and the activities of FAS, ME and G6PDH in experimental animals, but it seemed to be a negative result induced by lowering protein absorption, increasing urinary nitrogen excretion and protein catabolism.     

益气活血复方与复方丹参制剂治疗心绞痛疗效的系统评价

目的系统评价益气活血复方与复方丹参制剂治疗冠心病心绞痛的疗效和安全性。方法两名作者独立收集资料和评价纳入文献质量,采用RevMan4.2.2软件对资料进行Meta分析。结果①对20项研究的临床疗效有效率合并效应量的检验：OR合并=3.74,其95%CI为[2.58,5.43],P〈0.01;②对18项研究的心电图疗效有效率合并效应量的检验：OR合并=2.29,95%CI为[1.85,2.83],P〈0.01。结论益气活血复方治疗冠心病心绞痛的疗效优于复方丹参制剂,且不良反应少。     

玉米须在肝胆系统疾病的应用

玉米须(Corn Silkor Stigma Maydis)是一种物美价廉的药物,其"味甘、淡,性微温",玉米须含有多种有效化学成分,具有降糖、降压、降脂,抗菌,利胆、排石,止血,抗肿瘤,提高免疫力等药理作用,目前应用于临床治疗多种疾病。现仅就玉米须在肝胆疾病方面应用作综合讨论。