The extraction of coconut oil has been performed using supercritical carbon dioxide (SC-CO2). The extractions were performed at pressure and temperature ranges of 20.7-34.5 MPa and 40-80 °C, respectively. It was observed that almost all (more than 99%) of the total oil could be extracted. Response surface methodology (RSM) was applied to evaluate the effects of the parameters (pressure, temperature and CO2 consumption) on the extraction yield and medium-chain triglycerides (MCTs), in terms of the fatty acid content in the extracted oil. A correlation was established with p-values for both responses significant at the 95% confidence level.

Oxidative stress-mediated lipid peroxidation is a known cause of endothelial injury or dysfunction. Deprivation of rapid eye movement (REM) sleep is associated with oxidative stress. To date, the pathogenesis of increased blood pressure after sleep deprivation remains poorly understood, particularly in the REM sleep phase. Our aim was to investigate the effects of REM sleep deprivation on blood vessels in the REM sleep-deprived rat model. Twenty-eight male Sprague-Dawley rats were divided into four equal groups: free-moving control rats, rats deprived of REM sleep for 72 h (REMsd), tank control rats and 72 h sleep-recovered rats after 72 h of REM sleep deprivation. The rats were deprived of REM sleep using the inverted flowerpot technique. Food consumption, body weight gain and systolic blood pressure were monitored. At the end of the experiment, the descending thoracic aorta was isolated for the measurement of oxidative stress markers. Despite a significant increase in food consumption in the REMsd group compared with the other groups, there was a significant reduction in body weight gain. Systolic blood pressure also showed a significant increase in the REMsd group compared with the other groups. Superoxide dismutase activity was significantly lower and malondialdehyde concentrations significantly higher in the REMsd group compared with the other groups. Increased levels of malondialdehyde are suggestive of lipid peroxidation in the blood vessels, and oxidative stress may be attributed to the initiation of the process. The changes after REM sleep deprivation revert during sleep recovery. In conclusion, the findings of the present study provide convincing evidence that REM sleep deprivation induced lipid peroxidation, leading to endothelial damage.

INTRODUCTION: Rapid eye movement (REM) sleep deprivation causes oxidative stress, leading to endothelial dysfunction, a predictor of cardiovascular disease. It is still unclear what causes endothelial dysfunction in patients with sleep disorder. This study evaluates the effects of REM sleep deprivation on the endothelium in the rat model of REM sleep deprivation. MATERIALS AND METHODS: Sprague-Dawley male rats (N=28) were divided into four groups (n=7); (1) free-moving control (FMC), (2) REM sleep deprivation (REMsd), (3) tank control (TC), and (4) sleep recovery (SR). The inverted flowerpot technique was utilised to develop REM sleep deprivation. Bodyweight gain (BWg), food consumption (Fc), and systolic blood pressure (SBP) were evaluated. The descending thoracic aorta was isolated to assess oxidative stress markers, in vitro functional study, and histomorphological examination. RESULTS: REM sleep deprivation showed a decrease in BWg significantly despite a significant increase in Fc, increased SBP, increased oxidative stress markers, caused endothelial dysfunction and endothelial cell damage. In REM sleep-deprived rats, there was a significant reduction in antioxidant markers, including total antioxidant capacity (TAC), superoxide dismutase (SOD) activity, catalase (CAT), and glutathione (GSH), while the levels of malondialdehyde (MDA) were significantly increased. The REM sleep-deprived rats displayed altered vascular function, including impaired vasorelaxation and hypercontractility. Histomorphology of the endothelium in REM sleep-deprived rats revealed features of endothelial damage. CONCLUSION: REM sleep deprivation is suggested to be linked to endothelial dysfunction due to endothelial damage. These changes are proposed to result from increased oxidative stress. Sleep recovery reduced the harmful effects following REM sleep deprivation.