Thymol

The research was conducted to examine the neuroprotective effect of thymol and its precursor p-cymene on chronic immobility stress in adult male Wistar rats. The rats were subjected to 2.5 h of stress every day for 14 consecutive days by placing them inside a restrainer. Thymol (10 mg/kg) and p-cymene (50 mg/kg) were given to the rats during the same period. The results showed that thymol and p-cymene prevented the increase of MDA level, decline of GSH level, and decrease of SOD and GPx activity in the hippocampus of rats exposed to stress. These monoterpenes also prevented the increase in the expression of Tnfa, Il1b, Tlr4, and Nfkb, and the decrease in the expression of Nrf2, Ho1, and Bdnf. In addition, thymol and p-cymene inhibited the increase in the expression and activity of acetylcholinesterase in the hippocampus of animals exposed to immobility and enhanced the expression of A7nachr. They also reduced neuronal death in the CA1 region of stressed animals and improved their performance in the Morris water maze and elevated plus maze tests. Based on these findings, thymol and p-cymene may be effective in preventing neurodegenerative diseases as they reduce oxidative stress and neuroinflammation, strengthen ACh signaling, and stimulate Bdnf expression.

High amylose starch (HAMS) was employed as an effective carrier to incorporate thymol within pullulan nanofibers. Aqueous solutions with HAMS concentrations of 0 % - 5 % were investigated to study their effect on the incorporation of thymol during electrospinning. As a result, the loading capacity was significantly improved by the addition of HAMS, increasing from 2.38 % to 6.15 %. Thymol-starch mixture with an irregular structure was embedded within pullulan nanofiber according to SEM and TEM results. The HAMS-1, HAMS-3 and HAMS-5 were endowed with good anti-microbial inhibition against Escherichia coli and Bacillus cereus. Additionally, HAMS-5 exhibited sustained release of thymol, while the addition of HAMS improved the mechanical properties of HAMS-1. Further investigation into the interaction between HAMS, pullulan, and thymol in the nanofibers was conducted. HAMS proved effective in enhancing the bioavailability of thymol and provides a promising material for developing edible, sustainable polysaccharide antimicrobial nanofibrous films for the food industry.