In our previous studies, we found that both lyophilized strawberries and black raspberries exhibit significant and similar potential in prevention of esophageal squamous cell carcinoma (SCC). Berry phytochemicals are considered to be responsible, at least in part, for their health benefits that have been observed in other diseases. The current study was designed to provide leads for the development of specific phytochemicals or metabolites as chemopreventive agents using the principles of pharmacognosy. Lyophilized strawberries (Fragaria ananassa) were obtained from the California Strawberry Commission. Lyophilized black raspberries (Jewel variety) were obtained from the Stokes Raspberry Farm (Wilmington, OH). Sample (100 mg) of lyophilized berries was firstly extracted with acidified acetone. Berry phytochemicals were then identified with a combination of high performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS), accessible standards, UV-vis and reported mass. The identified compounds were classified into three main categories: anthocyanins (ACN), ellagitannin/ellagic acid/ellagic acid derivatives (EAs) and flavonols. By HPLC-MS/MS analysis, we found that ACN, EAs and flavonols account for 84.2%, 12.2% and 3.6% by dry weight in lyophilized black raspberries, respectively; and 58.4%, 32.8% and 8.8% by dry weight, respectively, in lyophilized strawberries. Cyanidin-3-rutinoside (58.2%) and cyaniding-3-xylorutinoside (18.2%) are the most and second abundant anthocyanins in black raspberries. While in strawberries, pelargonidin-3-glucoside accounts for 41.1%, most individual anthocyanin by dry weight. Pelargonidin-3-rutinoside is the only anthocyanin identified in both black raspberries and strawberries. There are more EAs in strawberries (32.8%) compared to them in black raspberries (12.2%). We also identified agrimoniin, a main ellagitannin, as the second most abundant phenolic by dry weight (16.2%) in strawberries. We treated esophageal SCC KYSE cell lines with cyanidin-3-rutinoside, pelargonidin-3-rutinoside and their metabolites including protocatechuic acid and 4-hydroxybenzoic acid. Our data showed that major berry anthocyanins and their metabolites can significantly inhibit esophageal SCC cell proliferation in vitro. Further research efforts are needed to test their abilities to modulate oncogenic signaling in esophageal SCC, many of which are currently underway.

Citation Format: Ni Shi, Kenneth M. Riedl, Steven J. Schwartz, Xiaoli Zhang, Zui Pan, Steven K. Clinton, Tong Chen. Experimental investigations on the effects of specific berry phytochemicals and metabolites in esophageal cancer prevention in vitro. [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 1902. doi:10.1158/1538-7445.AM2015-1902