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Finding a new type of cholinesterase inhibitor that would overcome the brain availability and pharmacokinetic parameters or hepatotoxic liability has been a focus of investigations dealing with the treatment of Alzheimer’s disease. Isothiocyanates have not been previously investigated as potential cholinesterase inhibitors. These compounds can be naturally produced from their glucosinolate precursors, secondary metabolites widely distributed in our daily Brassica vegetables. Among 11 tested compounds, phenyl isothiocyanate and its derivatives showed the most promising inhibitory activity. 2-Methoxyphenyl ITC showed best inhibition on acetylcholinesterase with IC50 of 0.57 mM, while 3-methoxyphenyl ITC showed the best inhibition on butyrylcholinesterase having 49.2% at 1.14 mM. Assessment of the antioxidant efficacy using different methods led to a similar conclusion. The anti-inflammatory activity was also tested using human COX-2 enzyme, ranking phenyl isothiocyanate, and 3-methoxyphenyl isothiocyanate as most active, with ∼99% inhibition at 50 μM.

Abstract:The purpose of this study was to compare the essential oil profiles of four Croatian Teucrium species (Lamiaceae), as determined by GC and GC/MS, with their antiphytoviral efficiency. A phytochemical analysis showed that T. polium, T. flavum, T. montanum and T. chamaedrys are characterized by similar essential oil compositions. The investigated oils are characterized by a high proportion of the sesquiterpene hydrocarbons β-caryophyllene (7.1-52.0%) and germacrene D (8.7-17.0%). Other important components were β-pinene from T. montanum and α-pinene from T. flavum. The investigated essential oils were proved to reduce lesion number in the local host Chenopodium quinoa Willd. infected with Cucumber Mosaic Virus (CMV), with reductions of 41. 4%, 22.9%, 44.3% and 25.7%, respectively.

Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen sulfur-containing compounds (thioesters, sulfides, isothiocyantes, nitriles, and others). Compounds that act as cholinesterase inhibitors still represent the only pharmacological treatment of Alzheimer´s disease. Numerous in vitro studies showed that some compounds, found in essential oils, have a promising cholinesterase inhibitory activity, such as α-pinene, δ-3-carene, 1,8-cineole, carvacrol, thymohydroquinone, α- and β-asarone, anethole, etc. This review summarizes the most relevant research published to date on essential oil constituents and their acetylcholinesterase/butyrylcholinesterase inhibitory potential as well as their structure related activity, synergistic and antagonistic effects.

Sea fennel, a rediscovered star of the coastal cuisine, has been investigated for its phytochemical profile and biological potential. Sea fennel flowers, stems and leaves were analyzed for essential oils (EOs) isolated by hydrodistillation, as well as non-volatiles obtained by ethanolic extraction. Limonene were found to be a dominant compound in EOs and ethanolic extracts; ranging from 57.5-74.2 % and 0.7-8.1 mg/g dry plant material, respectively. In addition total phenolic content was determined for ethanolic extracts. All samples and their main phytochemicals were tested for various methods. EO and extract obtained from flowers were tested for vasodilatory activity on rat aortic rings. Antioxidant activity of EOs was extremely low in comparison to extracts, on the contrary to cholinesterase inhibition where EOs showed better activity than extracts. Flower extract and chlorogenic acid showed stronger vasodilators in comparison to EO and limonene. The obtained results point out the potential impact of the dominant compounds from EO and extract on the biological properties of the sea fennel.