Identification and quantification of glucosinolates in sprouts derived from seeds of wild Eruca sativa L. (salad rocket) and Diplotaxis tenuifolia L. (wild rocket) from diverse geographical locations

The Brassicaceae rocket species Eruca sativa L. (salad rocket) and Diplotaxis tenuifolia L. (wild rocket) are consumed throughout the world in salads, predominantly the leaves but also the flowers and more recently the sprouts (seedlings). Ontogenic profiling of glucosinolates and flavonoids in plants derived from commercial seed of these species has previously been done, but no studies have been conducted to determine how geographical origin affects glucosinolate composition in rocket species. Seeds from wild E. sativa L. and D. tenuifolia L. from diverse regions of the world were obtained from gene banks and grown under controlled conditions. Sprouts were harvested when they would normally be harvested for consumption, and glucosinolates were extracted and profiled in these accessions. All of the sprouts from Italian E. sativa L. had consistently high total glucosinolate content, with only a few exceptions, and also the highest percentage contents of 4-mercaptobutylglucosinolate. In contrast, sprouts produced from Central and Eastern European seeds had a much higher percentage of 4-methylthiobutylglucosinolate. With a single exception, Tunisia, all sprouts produced from North African seeds had very high 4-methylthiobutylglucosinolate contents. The single sample from China had a high total glucosinolate content and glucosinolate profile that was very similar to the accessions from Uzbekistan and Pakistan. All of the D. tenuifolia L. sprouts had consistently high total glucosinolate contents, and a high percentage of this was 4-mercaptobutylglucosinolate. This glucosinolate variation in levels and profiles of the rockets can be used for genetic studies, selected breeding, and human intervention studies.