Changes in lipid content and composition during the development of N-nitrosodiethylamine induced hepatocarcinoma

Volatile N-nitrosamines in processed meat products and salami from Turkey

N-nitrosamines are harmful components that can be formed in processed meat products. Due to its production technique, salami is an important meat product in terms of volatile N-nitrosamines. In this regard, the presence of volatile N-nitrosamines, which may pose a risk for human health, was investigated in salami. N-nitrosamines were extracted from the salami and determined with a validated GC-MS method. Accordingly, the analysed samples of salami contained 7.86-29.11 ppb total volatile N-nitrosamines. The salami brand affected the type and level of N-nitrosamines (P <,005).

Hypolipidemic Effect of Psidium guajava Leaf Extract Against Hepatotoxicity in Rats

BACKGROUND

Plant-based natural extracts cure several diseases in human. However, the extract of Psidium guajava leaf is not yet evaluated on changes of lipid profile in hepatic disease affected rats.

OBJECTIVE

The present study was aimed to evaluate the mitigation effect of the ethanolic extract of P. guajava leaf and its isolated quercetin fraction on hepatotoxic rats.

MATERIALS AND METHODS

Carbon tetrachloride (CCl4) was injected to rats for hepatic disease induction and silymarin drug was used as positive control to compare plant ethanolic extract. The lipid profiles were assessed in both plasma and liver tissue of diseased and control rats.

RESULTS

Levels of total cholesterol, triglycerides, free fatty acids, phospholipids, and low-density lipoprotein cholesterol were increased and the level of high-density lipoprotein cholesterol (HDL-C) was decreased in CCl4-induced hepatotoxic rats. The treatment of P. guajava (100, 200, and 300 mg/kg, bw) and isolated quercetin fraction (20 mg/kg, bw) doses decreased the elevated levels of all these parameters in diseased rats and restored the normal concentration of HDL-C.

CONCLUSION

The results of the present study concluded that the P. guajava leaf and its isolated quercetin fraction can significantly regulate lipid metabolism in CCl4-induced hepatotoxic rats and decrease the disease rate.

SUMMARY

Psidium guajava leaf extract reduces the hepatotoxicity and disease rate in ratsQuercetin fraction of leaf extract significantly regulates lipid profile in hepatic diseased rats. Abbreviations used: CCl4: Carbon tetrachloride; FFA: Free fatty acids; HDL-C: High-density lipoprotein cholesterol; LCAT: Lecithin cholesterol acyltransferase; LDL-C: Low-density lipoprotein cholesterol; PL: Phospholipids; TC: Total cholesterol; TG: Triglycerides; VLDL-C: Very low-density lipoprotein cholesterol.

Sphingolipid abnormalities in cancer multidrug resistance: Chicken or egg?

The cancer multidrug resistance (MDR) phenotype encompasses a myriad of molecular, genetic and cellular alterations resulting from progressive oncogenic transformation and selection. Drug efflux transporters, in particular the MDR P-glycoprotein ABCB1, play an important role in MDR but cannot confer the complete phenotype alone indicating parallel alterations are prerequisite. Sphingolipids are essential constituents of lipid raft domains and directly participate in functionalization of transmembrane proteins, including providing an optimal lipid microenvironment for multidrug transporters, and are also perturbed in cancer. Here we postulate that increased sphingomyelin content, developing early in some cancers, recruits and functionalizes plasma membrane ABCB1 conferring a state of partial MDR, which is completed by glycosphingolipid disturbance and the appearance of intracellular vesicular ABCB1. In this review, the independent and interdependent roles of sphingolipid alterations and ABCB1 upregulation during the transformation process and resultant conferment of partial and complete MDR phenotypes are discussed.

Cancer-preventive anti-oxidants that attenuate free radical generation by inflammatory cells

Active inflammatory leukocytes are a major endogenous source of reactive oxygen and nitrogen oxide species (RONS). We have recently established novel bioassay systems, in which either phorbol ester-stimulated, differentiated HL-60 human leukemia cells or lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages were co-cultured with AS52 Chinese hamster ovary cells. Extensive screening of extracts from Asian vegetables and fruits led to the identification of 1′-acetoxychavicol acetate (ACA), auraptene, nobiletin, and zerumbone, all of which were found to be highly anti-mutagenic in the above co-culture systems. Pretreatment of RAW264.7 macrophages with LPS led to the activation of mitogen-activated protein kinases (MAPKs) and Akt, together with the degradation of IκB-α protein, and the resultant activation of the AP-1, NF-κB, and CREB transcription factors. ACA abrogated ERK1/2 and JNK1/2, but not p38 activation, as well as the activation and transcriptional activation of NF-κB and CREB, whereas nobiletin allowed phosphorylation of these MAPKs, while it suppressed AP-1, NF-κB, and CREB activation. Interestingly, zerumbone did not have any effects on the latter transcription factors, although it did attenuate iNOS mRNA expression. In addition, auraptene suppressed iNOS protein production, but not mRNA expression, implying that it targets the translation step. Our model systems may be useful for identifying potentially anti-carcinogenic inhibitors of RONS generation.