We recently discovered that MeOH extract from
Brassica oleracea var. acephala (kale) (BO) promotes adipocyte differentiation
in vitro. Furthermore, we discovered that the CHCl
3 fraction, in particular, promotes adipocyte differentiation
in vitro and acts as an insulin sensitizer
in vivo. BO is widely taken as juice in Japan because of its vitamins and functional compounds that are beneficial to health and wellness. However, there are no studies evaluating the antihyperglycemic activity of BO in the literature. We examined the effect of the CHCl
3 fraction on plasma glucose concentrations in obese hyperglycemic
db/db mice. The CHCl
3 fraction reduced hyperglycemia in mouse models of type 2 diabetes and acted as an insulin sensitizer, as indicated by the lowered plasma glucose concentration after chronic oral administration of the CHCl
3 fraction. This fraction and thiazoridinedione antidiabetic agents, such as ciglitazone, share many biological activities: induction of adipocyte differentiation
in vitro, and reduction of hyperglycemia in animal models of type 2 diabetes. This finding demonstrates that BO may contain insulin-sensitizing constituents and could lead to the discovery of novel candidates for a new type of insulin-sensitizing drug.
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