Isoquercitrin inhibits the progression of pancreatic cancer in vivo and in vitro by regulating opioid receptors and the mitogen-activated protein kinase signalling pathway

Review of anticancer mechanisms of isoquercitin

This review was based on a literature search of PubMed and Scielo databases using the keywords “quercetin, rutin, isoquercitrin, isoquercitin (IQ), quercetin-3-glucoside, bioavailability, flavonols and favonoids, and cancer” and combinations of all the words. We collected relevant scientific publications from 1990 to 2015 about the absorption, bioavailability, chemoprevention activity, and treatment effects as well as the underlying anticancer mechanisms of isoquercitin. Flavonoids are a group of polyphenolic compounds widely distributed throughout the plant kingdom. The subclass of flavonols receives special attention owing to their health benefits. The main components of this class are quercetin, rutin, and IQ, which is a flavonoid and although mostly found as a glycoside, is an aglycone (lacks a glycoside side chain). This compound presents similar therapeutic profiles to quercetin but with superior bioavailability, resulting in increased efficacy compared to the aglycone form. IQ has therapeutic applications owing to its wide range of pharmacological effects including antioxidant, antiproliferative, anti-inflammatory, anti-hypertensive, and anti-diabetic. The protective effects of IQ in cancer may be due to actions on lipid peroxidation. In addition, the antitumor effect of IQ and its underlying mechanism are related to interactions with Wnt signaling pathway, mixed-lineage protein kinase 3, mitogen-activated protein kinase, apoptotic pathways, as well proinflammatory protein signaling. This review contributed to clarifying the mechanisms of absorption, metabolism, and actions of IQ and isoquercitrin in cancer.

Simultaneous determination and pharmacokinetic study of eight components in rat plasma by UHPLC-MS/MS after oral administration of Hypericum japonicum Thunb extract

A rapid and sensitive assay based on ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was established and validated for the simultaneous determination of gallic acid, protocatechuic acid, vanillic acid, caffeic acid, epicatechin, isoquercitrin, vincetoxicoside B and quercetin in rat plasma using catechin and daidzein as the internal standards (IS). Plasma samples added internal standards were acidified with formic acid then pretreated by direct protein precipitation with acetonitrile. The separation of eight constituents was achieved on a C18 column with gradient elution using methanol and 0.2% acetic acid aqueous solution as the mobile phase and detected by multiple reaction monitoring using electrospray ionization source in the positive-negative ionization mode. The method was validated for sufficient specificity, precision, accuracy, and sensitivity over the concentration range of 10-6000 ng mL(-1) for gallic acid, 1.5-3000 ng mL(-1) for protocatechuic acid, 10-15000 ng mL(-1) for vanillic acid, 2-3600 ng mL(-1) for caffeic acid, 1.5-3600 ng mL(-1) for epicatechin, 4-6000 ng mL(-1) for isoquercitrin, 2-9000 ng mL(-1) for vincetoxicoside B, and 20-18000 ng mL(-1) for quercetin. The overall intra‑run precision and the inter‑run precision were showed in the range of 1.0-14.2% and 2.8-12.9%, respectively, and the accuracy was no more than 12.8%. This analytical method was successfully applied to investigate the pharmacokinetics of eight ingredients in rats after oral administration of Hypericum japonicum Thunb extract.