Effects of 1,8-Cineole and (-)-Linalool on Functional Brain Activation in a Working Memory Task

Recent updates on bioactive properties of linalool

Natural products, including essential oils and their components, have been used for their bioactivities. Linalool (2,6-dimethyl-2,7-octadien-6-ol) is an aromatic monoterpene alcohol that is widely found in essential oils and is broadly used in perfumes, cosmetics, household cleaners and food additives. This review covers the sources, physicochemical properties, application, synthesis and bioactivities of linalool. The present study focuses on the bioactive properties of linalool, including anticancer, antimicrobial, neuroprotective, anxiolytic, antidepressant, anti-stress, hepatoprotective, renal protective, and lung protective activity and the underlying mechanisms. Besides this, the therapeutic potential of linalool and the prospect of encapsulating linalool are also discussed. Linalool can induce apoptosis of cancer cells via oxidative stress, and at the same time protects normal cells. Linalool exerts antimicrobial effects through disruption of cell membranes. The protective effects of linalool to the liver, kidney and lung are owing to its anti-inflammatory activity. On account of its protective effects and low toxicity, linalool can be used as an adjuvant of anticancer drugs or antibiotics. Therefore, linalool has a great potential to be applied as a natural and safe alternative therapeutic.

Non-Cannabinoid Metabolites of Cannabis sativa L. with Therapeutic Potential

The cannabis plant (Cannabis sativa L.) produces an estimated 545 chemical compounds of different biogenetic classes. In addition to economic value, many of these phytochemicals have medicinal and physiological activity. The plant is most popularly known for its two most-prominent and most-studied secondary metabolites—Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and cannabidiol (CBD). Both Δ⁹-THC and CBD have a wide therapeutic window across many ailments and form part of a class of secondary metabolites called cannabinoids—of which approximately over 104 exist. This review will focus on non-cannabinoid metabolites of Cannabis sativa that also have therapeutic potential, some of which share medicinal properties similar to those of cannabinoids. The most notable of these non-cannabinoid phytochemicals are flavonoids and terpenes. We will also discuss future directions in cannabis research and development of cannabis-based pharmaceuticals. Caflanone, a flavonoid molecule with selective activity against the human viruses including the coronavirus OC43 (HCov-OC43) that is responsible for COVID-19, and certain cancers, is one of the most promising non-cannabinoid molecules that is being advanced into clinical trials. As validated by thousands of years of the use of cannabis for medicinal purposes, vast anecdotal evidence abounds on the medicinal benefits of the plant. These benefits are attributed to the many phytochemicals in this plant, including non-cannabinoids. The most promising non-cannabinoids with potential to alleviate global disease burdens are discussed.

Quantification of eucalyptol (1,8-cineole) in rat serum by gas chromatography-mass/mass spectrometry and its application to a rat pharmacokinetic study

Eucalyptol (1,8-cineole) is a biologically active cyclic monoterpenoid. In a preliminary study, we used gas chromatography-mass spectrometry to detect eucalyptol in the serum and brain tissue of rats after oral administration. However, the absorption characteristics in vivo and pharmacokinetic parameters of eucalyptol have not been published to date. The present study aims to develop and validate a simple, sensitive GC-MS/MS method with quadrupole mass analyzer type for the quantitative analysis of eucalyptol in rat serum and apply it to a pharmacokinetic study. The assay showed linearity of concentration range from 50 to 5,000 pg/ml with a limit of quantitation of 50 pg/ml. Intra- and inter-day precision for eucalyptol were 4.4-13.0 and <15.0%, respectively, and accuracy was within 10% for quality control samples. The recovery and stability results showed that the method was accurate and stable for quantitative analysis. The developed analytical method was successfully applied to a pharmacokinetic study after a single oral administration of eucalyptol in rat subjects. The serum concentration-time profiles indicate that the absorption characteristics of eucalyptol after oral administration are similar to those for intravenous administration.

A systematic review of physiological responses to odours with a focus on current methods used in event-related study designs

OBJECTIVES

In odour research, there is still a lack of knowledge regarding the detailed understanding of the determinants and the magnitude of an odour's impact on human psychophysiology. Therefore, the present review aims to summarize current evidence on psychophysiological responses to olfactory events, to highlight diversity in research methods, and to provide recommendations for further research.

MATERIAL AND METHODS

Predefined search items were used for literature research in two databases, focussing on recent investigations of cardiac and electrodermal responses to short (<10 s) olfactory stimulations, combined with self-reports on odour experience, in a healthy population. The selected 27 publications were evaluated with regard to their methods and their findings on psychophysiological correlates of odour stimulation, following a conceptual scheme proposing mediating and moderating factors of physiological responses to odour stimuli.

RESULTS

The cardiac and electrodermal activity generally followed a discriminative pattern depending on the perceived pleasantness of an odour. Moreover, the trigeminal aspect of an odour stimulus became evident in electrodermal activity in several studies. Finally, for many of the here addressed potentially mediating and moderating variables, initial findings were obtained in some studies but these await corroboration by future research. With regard to the applied methodology, the reviewed studies were highly diverse, in terms of odour application, study design, and analysis of the time series data.

CONCLUSIONS

Future research is needed to advance our understanding of, and theoretical concepts beyond, psychophysiological responses to olfactory events, and to achieve experimentally validated methodological guidelines for psychophysiological measurements in olfaction research.

The Effect of Eucalyptol on Nursing Home Residents

Eucalyptol is one of the most popular volatile components. It is used in many essential oils for relieving sinus and lung congestion caused by a variety of conditions. This pilot study sought to analyze clinical evidence for the effect of the scent of eucalyptol on the cognitive function of elderly people. Seventy nursing-home residents with cognitive impairment were recruited. Three one-week experiments were performed: eucalyptol scent was diffused in bedrooms with a diffuser only at wake-up time in the first experiment, and at wake-up time and bedtime in the second and third experiments. Results showed that although an improvement was not seen when using Mini Mental State Examination (MMSE) and Cohen-Mansfild Agitation Inventory (CMAI) measures, Dementia Behavior Disturbance Scale (DBD) scores improved significantly, even though no subject reported perceiving the scent. The significant improvements of the behaviour were found not only among the subjects whose room had a diffuser but also among the subjects who were exposed to an unperceivable level of eucalyptol drifted in the living room.

Acute ingestion of rosemary water: Evidence of cognitive and cerebrovascular effects in healthy adults

BACKGROUND

The use of herbal extracts and supplements to enhance health and wellbeing is increasing in western society.

AIMS

This study investigated the impact of the acute ingestion of a commercially available water containing an extract and hydrolat of rosemary ( Rosmarinus officinalis L. syn. Salvia rosmarinus Schleid.). Aspects of cognitive functioning, mood and cerebrovascular response measured by near-infrared spectroscopy provided the dependent variables.

METHODS

Eighty healthy adults were randomly allocated to consume either 250 mL of rosemary water or plain mineral water. They then completed a series of computerised cognitive tasks, followed by subjective measures of alertness and fatigue. Near-infrared spectroscopy monitored levels of total, oxygenated and deoxygenated haemoglobin at baseline and throughout the cognitive testing procedure.

RESULTS

Analysis of the data revealed a number of statistically significant, small, beneficial effects of rosemary water on cognition, consistent with those found previously for the inhalation of the aroma of rosemary essential oil. Of particular interest here are the cerebrovascular effects noted for deoxygenated haemoglobin levels during cognitive task performance that were significantly higher in the rosemary water condition. This represents a novel finding in this area, and may indicate a facilitation of oxygen extraction at times of cognitive demand.

CONCLUSION

Taken together the data suggest potential beneficial properties of acute consumption of rosemary water. The findings are discussed in terms of putative metabolic and cholinergic mechanisms.