Effects of an Australian native plant, Emu bush extracts on cellular glucose metabolism under basal and hyperglycaemic conditions 'in vitro'

Traditional medicine can form the basis for the development of new drugs and our laboratory is currently screening a wide range of these to identify novel anti-diabetic molecules. Emu bush, an Australian native plant is utilized by indigenous people of Australia as a treatment for various illnesses. Although there was no evidence of emu bush being used as a diabetes treatment, this study investigated the effects of crude extracts of emu bush on glucose uptake by muscle tissues under basal and hyperglycaemic conditions 'in vitro'. The various parts of the emu bush including leaves, fruits, bark and wood were extracted by soaking 1 g in 10 ml of solvents such as hexane, chloroform, ethylacetate, butanol, methanol and water separately. These extracts were dried and dissolved in 10 ml of water, filtered through 0.22 μm filters and stored at -20°C prior to use. Muscle pieces (3–5) approximately 2 mm cubed from 4-week-old mice were added to 24 well culture plates in 1 ml of DMEM culture media supplemented with 0.1%BSA and with 5 mM (basal) or 12 mM (hyperglycemic) glucose. The plates were incubated in 5% CO2 at 37°C and all treatments; including the controls were tested in triplicate. The results indicate that the glucose uptake in response to treatment was not significantly different from control under basal conditions except for inhibitory activity of methanolic and aqueous extracts of leaves, fruits and bark. Experiments under hyperglycemic conditions suggest that the hexane and butanol extracts of the leaves and aqueous extracts of the bark significantly increased the glucose uptake (32.08 ± 0.6; 28.78 ± 0.31; 26.83 ± 0.52 % respectively) when compared with control (19.42 ± 0.23%). These results suggest that the leaves and bark of the emu bush are a potential source of anti-diabetic molecules, and further research is required in order to characterize the biological phenomena and to identify those anti-diabetic molecules.