Preventive Effects of Cinnamon Leaf Nanosuspension and Byproducts on Type II Diabetes and Parkinson’s Disease in Rat Models

Cinnamon leaves, an important source of cinnamaldehyde, have been shown to possess various pharmacological functions. A liposome-derived nanosuspension (CN), hydrosol (CH) and powder in water (CP) prepared from cinnamon leaves were explored for their preventive effects on type II diabetes (T2D) and Parkinson's disease (PD) in rat models. Fifteen compounds were determined by UPLC-MS/MS, with cinnamaldehyde being predominant. CN with a mean particle size at 22.6 nm was prepared by mixing extract, lecithin, Tween 80, soybean oil and water with an optimal ratio, while hydrosol was prepared by steam distillation. A high storage and gastrointestinal stability were observed for CN. Rats were pre-fed with CN, CH and CP separately for 4 weeks, followed by induction with T2D or PD, with all three groups showing better preventive effects on T2D given the number of injections for T2D induction. Additionally, the OGTT, HOMA-IR, TXB2 and aPTT levels were significantly higher in the induction group than in the CN, CH and CP groups, revealing an effective prevention of T2D and cardiovascular disease. For PD prevention, CN was the most effective in improving muscle stiffness based on the catalepsy test and elevation of dopamine, tyrosine hydroxylase, serotonin, mitochondrial DNA and antioxidant enzymes, accompanied by a decline in α-synuclein and malondialdehyde.