Resveratrol and Malignancies

Nanoparticles Loaded with Docetaxel and Resveratrol as an Advanced Tool for Cancer Therapy

A growing interest in the use of a combination of chemosensitizers and cytostatics for overcoming cancer resistance to treatment and the development of their delivery systems has been observed. Resveratrol (Res) presents antioxidant, anti-inflammatory and chemopreventive properties but also limits multidrug resistance against docetaxel (Dtx), which is one of the main causes of failure in cancer therapy with this drug. However, the use of both drugs presents challenges, including poor bioavailability, the unfavourable pharmacokinetics and chemical instability of Res and the poor water solubility and dose-limiting toxicity of Dtx. In order to overcome these difficulties, attempts have been made to create different forms of delivery for both agents. This review is focused on the latest developments in nanoparticles for the delivery of Dtx, Res and for the combined delivery of those two drugs. The aim of this review was also to summarize the synergistic mechanism of action of Dtx and Res on cancer cells. According to recent reports, Dtx and Res loaded in a nano-delivery system exhibit better efficiency in cancer treatment compared to free drugs. Also, the co-delivery of Dtx and Res in one actively targeted delivery system providing the simultaneous release of both drugs in cancer cells has a chance to fulfil the requirements of effective anticancer therapy and reduce limitations in therapy caused by multidrug resistance (MDR).

Resveratrol modifies biliary secretion of cholephilic compounds in sham-operated and cholestatic rats

AIM

To investigate the effect of resveratrol on biliary secretion of cholephilic compounds in healthy and bile duct-obstructed rats.

METHODS

Resveratrol (RSV) or saline were administered to rats by daily oral gavage for 28 d after sham operation or reversible bile duct obstruction (BDO). Bile was collected 24 h after the last gavage during an intravenous bolus dose of the Mdr1/Mrp2 substrate azithromycin. Bile acids, glutathione and azithromycin were measured in bile to quantify their level of biliary secretion. Liver expression of enzymes and transporters relevant for bile production and biliary secretion of major bile constituents and drugs were analyzed at the mRNA and protein levels using qRT-PCR and Western blot analysis, respectively. The TR-FRET PXR Competitive Binding Assay kit was used to determine the agonism of RSV at the pregnane X receptor.

RESULTS

RSV increased bile flow in sham-operated rats due to increased biliary secretion of bile acids (BA) and glutathione. This effect was accompanied by the induction of the hepatic rate-limiting transporters for bile acids and glutathione, Bsep and Mrp2, respectively. RSV also induced Cyp7a1, an enzyme that is crucial for bile acid synthesis; Mrp4, a transporter important for BA secretion from hepatocytes to blood; and Mdr1, the major apical transporter for xenobiotics. The findings were supported by increased biliary secretion of azithromycin. The TR-FRET PXR competitive binding assay confirmed RSV as a weak agonist of the human nuclear receptor PXR, which is a transcriptional regulator of Mdr1/Mrp2. RSV demonstrated significant hepatoprotective properties against BDO-induced cirrhosis. RSV also reduced bile flow in BDO rats without any corresponding change in the levels of the transporters and enzymes involved in RSV-mediated hepatoprotection.

CONCLUSION

Resveratrol administration for 28 d has a distinct effect on bile flow and biliary secretion of cholephilic compounds in healthy and bile duct-obstructed rats.