Vanillin differentially affects azoxymethane-injected rat colon carcinogenesis and gene expression

Modulation of NADPH oxidase and Nrf2/HO-1 pathway by vanillin in cisplatin-induced nephrotoxicity in rats

OBJECTIVES

To investigate the protective effect of vanillin in cisplatin (CP)-induced nephrotoxicity in rats and elucidate the role of nrf-2 and its downstream antioxidant molecules.

METHODS

Rats received vanillin (100 mg/kg orally) for 10 constitutive days and CP (7.5 mg/kg, once, ip) on day 6 of vanillin administration.

KEY FINDINGS

Cisplatin suppressed body weight gain, increased serum urea and creatinine and renal malondialdehyde and nitric oxide while decreased renal total antioxidant capacity. Up-regulation of NADPH oxidase-4 (NOX-4) was marked in renal tissue of CP-treated rats along with down-regulation of the antioxidant genes (nuclear factor erythroid 2-related factor2 (NRF2) and haem oxygenase-1(HO-1)). Increased tumour necrosis factor-α and decreased interleukin-10 with increased myeloperoxidase activity were apparent in renal tissue of CP-treated rats along with marked tubular injury, neutrophil infiltration and increased apoptosis (caspase-3) and some degree of interstitial fibrosis. Vanillin prophylactic administration prevented the deterioration of kidney function, oxidative and nitrosative stress. It also suppressed NOX-4 and up-regulated NRF2 and HO-1 expression in renal tissue. Inflammation, apoptosis and tubular injury were also inhibited by vanillin.

CONCLUSIONS

The antioxidant mechanism by which vanillin protected against CP-induced nephrotoxicity involved the inhibition of NOX-4 along with the stimulation of Nrf2/HO-1 signalling pathway. These in turn inhibited inflammation and apoptosis.

Vanillin-Ameliorated Development of Azoxymethane/Dextran Sodium Sulfate-Induced Murine Colorectal Cancer: The Involvement of Proteasome/Nuclear Factor-κB/Mitogen-Activated Protein Kinase Pathways

Vanillin is a natural dietary flavoring widely used in the food industry. Colorectal cancer (CRC) is one of the common malignancies in the world. Chronic intestinal inflammation is a risk factor for the development of CRC. We have previously found that vanillin improves and prevents colitis in mice. Here we evaluated the inhibitory activities of vanillin on a mouse model of colitis-induced CRC. Mice were challenged intraperitoneally with azoxymethane (AOM) and orally with dextran sodium sulfate (DSS). Various dosages of vanillin were orally administered for 13 consecutive weeks. Vanillin alleviated the development of tumors in AOM/DSS-induced mice. The total number of tumors in 100 mg/kg vanillin group was significantly reduced by 57.14 ± 7.67%, compared with sham group. Gene expression analysis showed that vanillin downregulated the expression levels of proteasome genes in colon tissues. Moreover, vanillin at 10 mM significantly suppressed proteasome activities in HCT-116 cells by 41.27 ± 0.41%. Furthermore, vanillin diminished the phosphorylation of mitogen-activated protein kinases (MAPKs) and reduced the number of p65-positive cells, proliferating cells, and granulocytes in colon tissues with statistical significance. In conclusion, our data suggested that vanillin was a bioactive compound that ameliorated the development of AOM/DSS-induced colon cancer in mice. Moreover, the amelioration of vanillin might be associated with the downregulation of proteasome, nuclear factor-κB, and MAPK pathways.

Potential roles of chemical degradation in the biological activities of curcumin

Substantial pre-clinical and human studies have shown that curcumin, a dietary compound from turmeric, has a variety of health-promoting biological activities. A better understanding of the biochemical mechanisms for the health-promoting effects of curcumin could facilitate the development of effective strategies for disease prevention. Recent studies have shown that in aqueous buffer, curcumin rapidly degrades and leads to formation of various degradation products. In this review, we summarized and discussed the biological activities of chemical degradation products of curcumin, including alkaline hydrolysis products (such as ferulic acid, vanillin, ferulaldehyde, and feruloyl methane), and autoxidation products (such as bicyclopentadione). Though many of these degradation products are biologically active, they are substantially less-active compared to curcumin, supporting that chemical degradation has a limited contribution to the biological activities of curcumin.

Overview of the Role of Vanillin on Redox Status and Cancer Development

Bioactive natural products play critical roles in modern drug development, especially anticancer agents. It has been widely reported that various pharmacological activities of such compounds are related to their antioxidant properties. Vanillin is a natural substance widely found in many plant species and often used in beverages, foods, cosmetics, and pharmaceutical products. Antioxidant and anticancer potential have been described for this compound. Considering the importance of vanillin in the area of human health and food and pharmaceuticals sectors, in this review, we discuss the role of vanillin on redox status and its potential contribution to the prevention and the treatment of cancer.