Enhancement of Broccoli Indole Glucosinolates by Methyl Jasmonate Treatment and Effects on Prostate Carcinogenesis Ann G. Liu, 1 John A. Juvik, 2 Elizabeth H. Jeffery, 1 Lisa D. Berman-Booty, 3 Steven K. Clinton, 4 and John W. Erdman, Jr. 1 1 Division of Nutritional Sciences, Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. 2 Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA. 3 Department of Veterinary Biosciences and 4 Division of Medical Oncology, The Ohio State University, Columbus, Ohio, USA. ABSTRACT Broccoli is rich in bioactive components, such as sulforaphane and indole-3-carbinol, which may impact cancer risk. The glucosinolate profile of broccoli can be manipulated through treatment with the plant stress hormone methyl jasmonate (MeJA). Our objective was to produce broccoli with enhanced levels of indole glucosinolates and determine its impact on prostate carcinogenesis. Brassica oleracea var. Green Magic was treated with a 250 lM MeJA solution 4 days prior to harvest. MeJA-treated broccoli had significantly increased levels of glucobrassicin, neoglucobrassicin, and gluconasturtiin (P < .05). Male transgenic adenocarcinoma of mouse prostate (TRAMP) mice (n = 99) were randomized into three diet groups at 5–7 weeks of age: AIN-93G control, 10% standard broccoli powder, or 10% MeJA broccoli powder. Diets were fed throughout the study until termination at 20 weeks of age. Hepatic CYP1A was induced with MeJA broccoli powder feeding, indicating biological activity of the indole glucosinolates. Following * 15 weeks on diets, neither of the broccoli treatments significantly altered genitourinary tract weight, pathologic score, or metastasis incidence, indicating that broccoli powder at 10% of the diet was ineffective at reducing prostate carcinogenesis in the TRAMP model. Whereas broccoli powder feeding had no effect in this model of prostate cancer, our work demonstrates the feasibility of employing plant stress hormones exogenously to stimulate changes in phytochemical profiles, an approach that may be useful for optimizing bioactive component patterns in foods for chronic-disease-prevention studies. KEY WORDS:  Brassica oleracea  indole-3-carbinol  indole glucosinolates  neoglucobrassicin  sulforaphane INTRODUCTION E pidemiological studies provide moderate support for the hypothesis that consumption of cruciferous vegeta- bles reduces the risk of developing prostate cancer. 1 Broccoli is the most commonly consumed cruciferous vegetable in the United States with the average American eating 8.6 pounds (3.9 kg) of fresh broccoli and broccoli products each year. 2 Broccoli contains many glucosinolates including gluco- raphanin, which is hydrolyzed to sulforaphane and gluco- brassicin, which is hydrolyzed to indole-3-carbinol (I3C), which both demonstrate anticancer activity in rodent models and in vitro. 3,4 However, studying these compounds in iso- lation may obscure any inhibitory, additive, or synergistic actions or bioactive components that might take place when a whole vegetable is consumed. For example, neogluco- brassican, which is hydrolyzed to N-methoxy-I3C, has not previously been evaluated in an animal model of cancer and is reported to inhibit sulforaphane action in cell culture, but only when both compounds were at concentrations in excess of 5 lM. 5 Glucosinolates are divided into three classes based on the amino acid precursors from which they originate. Aliphatic glucosinolates are derived from methionine, indole gluco- sinolates are from tryptophan, and aromatic glucosinolates are from phenylalanine. These phytochemicals are consti- tutively present in cruciferous plant tissues, but they can also be rapidly induced by stresses, such as wounding, patho- gens, or herbivore attack. These stress conditions lead to the endogenous biosynthesis of jasmonates, which induce the synthesis of indole glucosinolates. 6 External applica- tion of methyl jasmonate (MeJA), a volatile methylester of jasmonic acid, has been shown to induce production of indole glucosinolates in Brassica species. 7–9 MeJA treat- ment offers a way of altering the phytochemical profile of broccoli to increase concentrations of potentially anticarci- nogenic bioactives. Manuscript received 10 September 2013. Revision accepted 28 May 2014. Address correspondence to: John W. Erdman, Jr., PhD, Division of Nutritional Sciences, Department of Food Science and Human Nutrition, University of Illinois at Urbana- Champaign, 905 S. Goodwin Ave., Urbana, IL 61801, USA, E-mail: jwerdman@illinois.edu JOURNAL OF MEDICINAL FOOD J Med Food 17 (11) 2014, 1177–1182 # Mary Ann Liebert, Inc., and Korean Society of Food Science and Nutrition DOI: 10.1089/jmf.2013.0145 1177