Biomarkers of dietary intake are prominent tools in nutritional research. The alkylresorcinol metabolites 3,5-dihydroxybenzoic acid (3,5-DHBA) and 3-(3,5-dihydroxyphenyl)propanoic acid (3,5-DHPPA) have been proposed as exposure biomarkers of whole-grain (WG) wheat and rye intake. However, the profile of alkylresorcinol metabolites is not fully understood. The aim of this study was to investigate the metabolism of alkylresorcinols in mice and in humans, while further determining urinary pharmacokinetics of the novel alkylresorcinol metabolites to explore their potential as biomarkers of WG wheat intake. Utilization of the liquid chromatography-mass spectrometry approach resulted in 10 alkylresorcinol metabolites identified in mice and in humans, including 3 phenolic acids and 7 of their phase II conjugates. Among them, 2 novel metabolites were discovered: 5-(3,5-dihydroxyphenyl)pentanoic acid (3,5-DHPPTA) and 2-(3,5-dihydroxybenzamido)acetic acid (3,5-DHBA glycine). The structures of these 2 metabolites were confirmed by comparing with authentic standards synthesized in-house. In the pharmacokinetic study, a group of 12 volunteers consumed a polyphenolic-restricted diet for 4 d before ingesting WG wheat bread containing 61 mg of alkylresorcinols. Urine samples were collected for 32 h, and alkylresorcinol metabolites were quantified with HPLC-coulometric electrode array detection. The mean urinary excretion rates and mean apparent half-life of 3,5-DHPPTA, 3,5-DHBA glycine, 3,5-DHBA, and 3,5-DHPPA at each time point were determined. Our results suggest that 3,5-DHPPTA and 3,5-DHBA glycine may be used in combination with 3,5-DHBA and 3,5-DHPPA as potential biomarkers to increase the accuracy of recording WG wheat and rye intake in epidemiologic studies. Further validation of 3,5-DHPPTA and 3,5-DHBA glycine as potential biomarkers is warranted.

Regular aspirin use has been convincingly shown to reduce the risk of colorectal cancer. However, long-term use of aspirin leads to gastrotoxicity. Herein, we designed and synthesized a novel class of resveratrol-based aspirin prodrugs to simultaneously release aspirin and resveratrol to attenuate the side effects caused by aspirin. Prodrug RAH exerted enhanced anticancer activities which are better than a physical mixture of aspirin and resveratrol as well as each individually. Metabolism of RAH in mice showed that the majority of RAH is decomposed to release resveratrol and aspirin or salicylic acid either in the intestine or after absorption. Mechanistic studies demonstrate RAH inhibits cell cycle arrest through downregulation of cyclins and induces apoptosis by activation of caspase-3 in cancer cells. These findings highlighted the improved anticancer properties of resveratrol-based aspirin prodrugs. RAH may represent novel and safe alternatives of aspirin for the purpose of daily use in the future.

Black tea contains two major pigments, theaflavins and thearubigins. These polyphenols have been associated with certain health benefits including prevention of heart disease and cancer. Elucidating and characterizing the structural aspects of thearubigins, the most abundant pigment in black tea, has been a challenge for many years. Therefore further studies of black tea polyphenols must be conducted in effort to solve this thearubigin dispute. In the present study, black tea extract was found to possess theaflavin trigallate and tetragallate by means of liquid chromatography/electrospray ionization mass spectrometry. These structures were confirmed by analysis of the MS(n) (n = 1-4) spectra and comparison of the MS/MS spectra of the product ions to the MS/MS spectra of authentic (-)-epigallocatechin-3-gallate, (-)-epicatechin-3-gallate and theaflavin-3,3'-digallate. To our knowledge, this is the first report to confirm the presence of theaflavin trigallate and tetragallate in black tea.

Biomarkers of dietary intake are prominent tools in nutritional research. Alkylresorcinol (AR) metabolites, 3,5‐dihydroxybenzoic acid (3,5‐DHBA) and 3‐(3,5‐dihydroxyphenyl)propanoic acid (3,5‐DHPPA), have been proposed as exposure biomarkers of whole grain (WG) wheat and rye intake. However, the profile of AR metabolites is not fully understood. The aim of this study was to investigate the metabolism of ARs in mice and in humans, while further determining urinary pharmacokinetics of the novel AR metabolites to explore their potential as biomarkers of WG wheat intake. Utilization of LC‐MS approach resulted in ten AR metabolites (1‐10) identified in mice and in humans, including three phenolic acids and seven of their phase II conjugates. Among them, two novel metabolites were discovered, 5‐(3,5‐dihydroxyphenyl)pentanoic acid (3,5‐DHPPTA) and 2‐(3,5‐dihydroxybenzamido)acetic acid (3,5‐DHBA glycine). The structures of these two metabolites were confirmed by comparing with authentic standards synthesized in house. In the pharmacokinetic study, a group of twelve volunteers followed a polyphenolic restricted diet for 4 d before ingesting WG wheat bread containing 61mg ARs. Urine samples were collected for 32 h, and AR metabolites were quantified with HPLC‐CEAD. The mean urinary excretion rates and mean t1/2 of 3,5‐DHPPTA, 3,5‐DHBA glycine, 3,5‐DHBA and 3,5‐DHPPA at each time point were determined. Our results suggest that 3,5‐DHPPTA and 3,5‐DHBA glycine may be utilized in combination with 3,5‐DHBA and 3,5‐DHPPA as potential biomarkers to increase the accuracy of recording WG wheat and rye intake in epidemiologic studies. Further validation of 3,5‐DHPPTA and 3,5‐DHBA glycine as potential biomarkers is warranted. Grant Funding Source: 1This work was partially supported by funding from USDA‐NIFA grant 2012‐38821‐20012 to S. Sang.

In more than a century of use, the benefits of aspirin have been exploited in different therapeutic areas, from inflammation to cardiovascular diseases and cancer prevention. However, the major limitation to the use of aspirin is its side effect to cause ulceration and bleeding in the gastrointestinal tract. The present study found that resveratrol, a natural chemopreventive agent from grapes and berries, and its methylated derivatives can react with acetylsalicyloyl chloride to form resveratrol aspirinate (RAS) and related derivatives. Among all the synthesized derivatives, we found that RAS is the most active component and have much stronger growth inhibitory effect on human colon cancer cells (HCT-116 and HT-29) than resveratrol and aspirin along, as well as the combination of resveratrol and aspirin. In addition, we found that RAS can be hydrolyzed to regenerate resveratrol and aspirin in mice and in human colon cancer cells. Therefore they serve as prodrugs of aspirin and resveratrol and its derivatives. Compared to simply combining aspirin and resveratrol, RAS has not only greater growth inhibitory effects on human colon cancer cells, but also can prevent the damage of gastric epithelial cells caused by direct contact between aspirin and gastric mucosa. Further mechanistic studies found that RAS inhibited cell growth through regulating cell cycle arrest via down-regulation of cyclins D1 and E, and inducing cancer cell apoptosis via mitochondrial pathway. In addition, two stable RAS analogues, for the first time, were successfully synthesized to demonstrate the importance of the scaffold composed of resveratrol and aspirin in the anti-cancer activity of RAS. Our results demonstrated for the first time that resveratrol based aspirin derivatives represent a brand-new, safer and improved alternative to aspirin in anti-cancer and anti-inflammatory therapies. Note: This abstract was not presented at the meeting. Citation Format: Shengmin Sang, Yingdong Zhu, Junsheng Fu, Kelly Shurlknight. Resveratrol aspirinate derivatives as novel chemopreventive agents for colon cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4658. doi:10.1158/1538-7445.AM2015-4658