O
verwhelming evidence suggests that edible small and soft-fleshed berry fruits may have beneficial effects against several types of human cancers. 

A study published in Cancer Prevention Research, a journal of the American Association for Cancer Research, identifies components of black raspberries with chemopreventive potential.

Researchers at the Ohio State Comprehensive Cancer Center found that anthocyanins, a class of flavonoids in black raspberries, inhibited growth and stimulated apoptosis in the esophagus of rats with esophageal cancer.

"Our data provide strong evidence that anthocyanins are important for cancer prevention," said the study's lead author, Gary D. Stoner. Stoner and his team of researchers fed rats an anthocyanin-rich extract of black raspberries and found that the extract was nearly as effective in preventing esophageal cancer in rats as whole black raspberries containing the same concentration of anthocyanins.

This study demonstrates the importance of anthocyanins as preventive agents in black raspberries and validated similar in vitro findings. It is among the first to look at the correlation between anthocyanins and cancer prevention in vivo.

Stoner and his colleagues have conducted clinical trials using whole berry powder, which has yielded some promising results, but required patients to take up to 60 grams of powder a day. "Now that we know the anthocyanins in berries are almost as active as whole berries themselves, we hope to be able to prevent cancer in humans using a standardized mixture of anthocyanins," said Stoner.

"The goal is to potentially replace whole berry powder with its active components and then figure out better ways to deliver these components to tissues, to increase their uptake and effectiveness. Ultimately, we hope to test the anthocyanins for effectiveness in multiple organ sites in humans," said Stoner.

Other research has reported that dietary black raspberry powder inhibits tumor development in the rat esophagus by inhibiting the formation of DNA adducts and reducing the proliferation rate of preneoplastic cells (receding the formation of a benign or malignant tumor).
References:
1. Gary D. Stoner, et al. Chemopreventive Agents in Black Raspberries Identified. American Association for Cancer Research.
2. Seeram NP. Berry fruits for cancer prevention: current status and future prospects. J Agric Food Chem. 2008 Feb 13;56(3):630-5. PMID: 18211019.
3. Chen T, Rose ME, Hwang H, Nines RG, Stoner GD. Black raspberries inhibit N-nitrosomethylbenzylamine (NMBA)-induced angiogenesis in rat esophagus parallel to the suppression of COX-2 and iNOS. Carcinogenesis. 2006 Nov;27(11):2301-7. Carcinogenesis. 2006 Nov;27(11):2301-7.