Exploring the potential biological activities and chiral composition of Lippia origanoides Kunth essential oil: inhibition of enzymes linked to Alzheimer’s disease and Type 2 diabetes

Diabetes mellitus and Alzheimer’s disease (AD) are increasingly common in ageing population. Type 2 diabetes is an important risk factor for AD due to shared phenotypes, including mitochondrial dysfunction. The insulin resistance characteristic of diabetes alters the AD pathology by affecting amyloid precursor protein (APP) metabolism, contributing to plaque formation. Impaired glucose and lipid metabolism, which is often associated with obesity, further exacerbate AD progression. In addition, there is new evidence of a link between the composition of the gut microbiota and the risk of obesity-related diseases. Inhibition of enzymes such as acetylcholinesterase (AChE), butyrylcholinesterase (BChE), alpha-glucosidase and lipase offers potential therapeutic opportunities for both AD and diabetes. Essential oils (EOs), complex mixtures of volatile compounds obtained from individual plant species by hydrodistillation and steam distillation or mechanical processes have diverse applications in perfumery, cosmetics, and pharmaceuticals [4], with recent focus on their potential in inhibiting disease-associated enzymes. This study therefore focused on a remarkable Brazilian native essential oil, Lippia origanoides Kunth EO, which has been investigated for some biological activities such as its antimicrobial, insecticidal, acaricidal and larvicidal properties, but not for its promising enzyme inhibitory activity with the exception of a paper dealing with AChE inhibition. Lippia origanoides EO was chemically characterised, subjected to chiral analysis, and tested for its inhibitory effect on AChE, BChE, alpha-glucosidase and lipase. The results showed significant activity against all four enzymes, suggesting that the role of this EO as an adjuvant treatment with a broad spectrum of activity could be further investigated in addition to conventional therapies.