Levomenthol

Gastric cancer (GC) represents one of the most lethal forms of cancer. When identified at an early stage, conventional treatment can be curative. The key to identifying GC at an early stage is high-quality esophagogastroduodenoscopy (EGD). This has led to an increased focus on quality standards in EGD to improve the detection rates of early GC and its premalignant lesions (PMLs), such as atrophic gastritis. In Asia, the routine use of antiperistaltic (antispasmodic) agents is advocated to improve the quality of mucosal visualization during diagnostic EGD. The rationale is that the cessation of peristalsis should yield a more stable intragastric visual field to enhance the detection of early GC. Hyoscine and glucagon are commonly used as antiperistaltic agents. Both, however, must be given either intravenously or via intramuscular injection. They both also have potentially serious systemic side effects, which can limit their routine use, particularly in the elderly or co-morbid patients. As a result of these side effects, there is growing interest in using peppermint oil or L-menthol topically as anti-peristaltic agents. As these agents are applied topically (either via direct spraying during the EGD or consumed as a premedication before the EGD), they are associated with fewer adverse events than systemically applied agents. This study aimed to synthesize, for the first time, the available data on the use of topically applied anti-peristaltic agents to decrease or stop peristalsis during diagnostic EGDs. This study is a systematic review and meta-analysis of published randomized controlled trials. Its reporting is per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. This study was registered prospectively with the PROSPERO register, registration number CRD42024601488. This systematic review and meta-analysis encompassed five high-quality randomized controlled trials with a low risk of bias. All included studies were conducted in Asian countries between 2011 and 2022. They comprised 538 patients, with a mean age of 62.7. Four of the included studies look at topically applied L-menthol at 160 mg, while one study looked at the role of 160 mg of phloroglucinol administered as a 20 mL oral premedication liquid 15 minutes before the EGD. All included trials involved diagnostic EGDs and reported their primary outcomes using the same scoring systems. The primary outcome of interest for this study was the efficacy of the antiperistaltic agents at stopping peristalsis for the duration of a diagnostic EGD. We found an odds ratio of 4.22 with a 95% confidence interval ranging from 2.47 to 7.21, favoring the antiperistaltic agents in terms of attaining a peristalsis score of 1 after administration.  This systematic review and meta-analysis represent the most up-to-date review on topical antiperistaltic agents during diagnostic EGD. We found that topical antiperistaltic agents effectively decrease or stop peristalsis during an EGD, and these effects persist for the duration of the EGD. Larger-scale studies will be required to determine whether their routine use translates into increased detection rates of early GC and its PMLs.

Glucose esters, heralded for their emulsifying and solubilizing properties, have found increasing application in food, pharmaceutical, and cosmetic sectors. However, the environmental impact of chemical synthesis and the problem of enzyme inactivation in enzymatic synthesis have hindered their application. To this end, deep eutectic solvents (DESs) with stabilized enzyme activity and better solubility properties are considered a promising solution. In the study, 12 kinds of hydrophilic DESs and 22 kinds of hydrophobic DESs were screened, and we examined their efficiency in the synthesis of glucose esters. The results indicated that d,l-menthol-based DESs have excellent performance, with the highest yield of 92.85%. The molecular dynamics simulations suggested that it can be attributed to DESs changing the size of substrate binding pocket, which in turn affects the substrate anchoring ability and the catalytic efficiency of lipase. To further evaluate the effects of the solvent on the substrate anchoring ability of enzymes, a novel strategy, namely, substrate anchoring index, which is based on the stability of the tetrahedral intermediate, was proposed and used for the designing of more efficient DESs. Fortunately, novel DESs based on cyclohexanone (menthol analogues) were successfully developed with a yield of 98.85%.