Nanoformulation of Leonotis leonurus to improve its bioavailability as a potential antidiabetic drug.

Nanostructured lipid carriers (NLCs) of Leonotis leonurus were successfully produced using high-pressure homogenisation (HPH) on a LAB 40 homogeniser. The particle size was determined for the formulation as well as short-term stability study. The formulation was exposed to Chang liver cells for a glucose uptake study and to INS-1 cells for a chronic insulin release study under normoglycaemic and hyperglycaemic conditions. The particle size of the extract NLC was 220 nm with a PdI of 0.08 after homogenisation at 800 bar. The formulation was stable at the tested temperatures. The extract NLC formulation at 1 µg/ml improved glucose uptake, relative to the control liver cells. Insulin release in INS-1 cells was also elevated under hyperglycaemic conditions when exposed to the NLCs, in comparison with the control untreated cells and the non-formulated extract. The plant extract encapsulated in NLC improved the uptake of glucose and enhanced the insulin sensitivity in vitro, compared to the extract.