The fatty acid-rich fraction of Eruca sativa (rocket salad) leaf extract exerts antidiabetic effects in cultured skeletal muscle, adipocytes and liver cells.

CONTEXT

Eruca sativa Mill. (Brassicaceae), commonly known as rocket salad, is a popular leafy-green vegetable with many health benefits.

OBJECTIVE

To evaluate the antidiabetic activities of this plant in major insulin-responsive tissues.

MATERIALS AND METHODS

Five E. sativa leaf extracts of varying polarity were prepared (aqueous extract, 70% and 95% ethanol extracts, the n-hexane-soluble fraction of the 95% ethanol extract (ES3) and the defatted 95% ethanol extract). Eruca sativa extracts were investigated through a variety of cell-based in vitro bioassays for antidiabetic activities in C2C12 skeletal muscle cells, H4IIE hepatocytes and 3T3-L1 adipocytes. Guided by the results of these bioassays, ES3 was fractionated into the saponifiable (SM) and the unspaonifiable (USM) fractions. Glucose uptake was measured using [H]-deoxy-glucose, while the effects on hepatic glucose-6-phosphatase (G6Pase) and adipogenesis were assessed using Wako AutoKit Glucose and AdipoRed assays, respectively.

RESULTS

ES3 and its SM fraction significantly stimulated glucose uptake with EC values of 8.0 and 5.8 μg/mL, respectively. Both extracts significantly inhibited G6Pase activity (IC values of 4.8 and 9.3 μg/mL, respectively). Moreover, ES3 and SM showed significant adipogenic activities with EC of 4.3 and 6.1 μg/mL, respectively. Fatty acid content of SM was identified by GC-MS. trans-Vaccenic and palmitoleic acids were the major unsaturated fatty acids, while palmitic and azelaic acids were the main saturated fatty acids.

DISCUSSION AND CONCLUSION

These findings indicate that ES3 and its fatty acid-rich fraction exhibit antidiabetic activities in insulin-responsive cell lines and may hence prove useful for the treatment of type 2 diabetes.