Chemical composition and in vitro anticholinesterase inhibitory activity of Citrus medica L. cv Diamante essential oil

The interest in medicinal plant research has increased in recent years, especially for the treatment of pathologies related to aging of the population such as Alzheimer’s disease (AD). Natural products such as rivastigmine and galantamine act as acetylcholinesterase inhibitors (AchE) and are actually the only effective treatment for AD. Plants of the genus Citrus are primarily valued for their edible fruit, but they also have traditional medicinal value. The peel of Citrus fruits has been used in traditional Asian medicine for centuries [1,2]. Citrus medica L. cv. Diamante (Diamante citron), known as Italian and Calabrese, is the cultivar more diffused in Italy and more sought by industry. Our previous study reported the chemical composition and the biological activity of Diamante citron peel n-hexane extract [3]. In this work the anticholinesterase activity by the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes of Citrus medica cv. Diamante peel essential oil assessed by the modified Ellman’s method was investigated to explore the beneficial effects of this Citrus cultivar [4]. The chemical composition of the essential oil of C. medica L. cv. Diamante peel obtained by hydrodistillation was determined by GC/MS analysis. A total of forty-two components, representing 95.3% of the total oil, were identified. Limonene and gamma-terpinene were the major components; the other most abundant were geranial, neral, alpha-pinene andbeta-pinene. The essential oil exerted an interesting inhibitory activity against BChE with an IC50 value of 154.6 microg/ml and AChE with an IC50 value of 171.3 microg/ml.