Subconscious olfactory influences of stimulant and relaxant odors on immune function

Nature Exposure and Its Effects on Immune System Functioning: A Systematic Review

Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a comprehensive overview of literature published on immunomodulatory effects of nature exposure by inhalation of natural substances. A systematic database search was performed in SCOPUS and PubMed. The quality and potential bias of included studies (n = 33) were assessed by applying the EPHPP (Effective Public Health Practice Project) tool for human studies and the ARRIVE (Animal Research: Reporting of In Vivo Experiments) and SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation) tools for animal studies. The synthesis of reviewed studies points to positive effects of nature exposure on immunological health parameters; such as anti-inflammatory, anti-allergic, anti-asthmatic effects or increased NK (natural killer) cell activity. Decreased expression of pro-inflammatory molecules, infiltration of leukocytes and release of cytotoxic mediators are outcomes that may serve as a baseline for further studies. However, partially weak study designs evoked uncertainties about outcome reproducibility and key questions remain open concerning effect sizes, duration of exposure and contributions of specific vegetation or ecosystem types.

Behavioral and Neurobiological Convergence of Odor, Mood and Emotion: A Review

The affective state is the combination of emotion and mood, with mood reflecting a running average of sequential emotional events together with an underlying internal affective state. There is now extensive evidence that odors can overtly or subliminally modulate mood and emotion. Relying primarily on neurobiological literature, here we review what is known about how odors can affect emotions/moods and how emotions/moods may affect odor perception. We take the approach that form can provide insight into function by reviewing major brain regions and neural circuits underlying emotion and mood, and then reviewing the olfactory pathway in the context of that emotion/mood network. We highlight the extensive neuroanatomical opportunities for odor-emotion/mood convergence, as well as functional data demonstrating reciprocal interactions between these processes. Finally, we explore how the odor- emotion/mood interplay is, or could be, used in medical and/or commercial applications.

Much More Than a Pleasant Scent: A Review on Essential Oils Supporting the Immune System

The augmenting acceptance and application of herbal medicine in prevention and treatment of diseases also involve the use of plant essential oils (EOs) through different routes of administration (aromatherapy). Scientific data supporting the efficacy of certain herbal products are continuously growing; however, the cumulative evidence is not always sufficient. The anti-inflammatory properties of EOs have been investigated more extensively and also reviewed in different settings, but so far, our review is the first to summarize the immune-supporting properties of EOs. Our aim here is to synthesize the currently available data on the immune function enhancing effects of EOs. An online search was conducted in the PubMed database, which was terminated at the end of July 2019. Other articles were found in the reference lists of the preselected papers. Studies that applied whole EOs with known components, or single EO constituents under in vitro or in vivo laboratory conditions, or in human studies, and de facto measured parameters related to immune function as outcome measures were included. Two specific fields, EO dietary supplementation for livestock and fish, and forest bathing are also explored. Some EOs, particularly eucalyptus and ginger, seem to have immune function enhancing properties in multiple studies.

Comparison of the therapeutic effect of the Persian Medicine Protocol with the common treatment of chronic rhinosinusitis: a randomized clinical trial

Background

Chronic rhinosinusitis is one of the most common diseases affecting the quality of life of patients. Patients suffer from high costs in the diagnosis and treatment of the disease. Frequent recurrence and failure of therapeutic protocols are among the most important issues in the management of this disease. In view of this, the use of traditional and complementary therapies to promote the treatment of this disease has been increasingly taken into account.

Objective

Comparison of the effectiveness of the Persian Medicine Protocol with the conventional therapy in the treatment of chronic rhinosinusitis.

Methods

A randomized clinical trial was conducted at Imam Reza Hospital in Mashhad, Iran from July 2016 to March 2017. For patients with chronic rhinosinusitis symptoms, endoscopy of the sinuses was performed by an ENT specialist and in the case of negative endoscopy, paranasal sinus CT scan was requested. A total of 42 patients with chronic rhinosinusitis were randomly assigned to two groups. The first group (classical) received systemic and intranasal cortisone, and the second group (traditional) received a therapeutic Persian medicine protocol including intranasal lavender oil, and Liquorice Marjoram Tea (L. M. tea) for six weeks. The symptoms of the patients were evaluated using the SNOT-22 questionnaire at the beginning of the study and at the sixth week. If no improvement occurs, treatment continued for 12 weeks. Data were analyzed by SPSS version 16, using ANOVA, independent-samples and paired-samples t-test, Wilcoxon signed-rank test, and simple linear regression.

Results

In 20 patients in the traditional group, the decrease in SNOT score was observed as 56% after 6 weeks treatment (p=0.001), which is similar to the effect of the first group (classical). Although there was no statically significant difference between the two groups, in clinical terms, the difference in mean systemic symptoms such as confusion with 1.05 (p=0.5) and fatigue with 1.63 (p=0.01) had more improvement in the traditional group, and the difference in mean local symptoms such as nasal congestion with 2.37 (p=0.78) and runny nose with 1.95 (p=0.14) had a more decrease in the classical group.

Conclusion

The results of this trial indicate the effectiveness of the Persian Medicine Protocol (including Lavender oil and L.M tea) in the treatment of chronic rhinosinusitis, especially on improving systemic symptoms. Nevertheless more clinical studies are necessary to support the acquired results.

Trial registration

This trial was registered at the Iranian Center for Clinical Trials (ID: IRCT2015112425217N1).

Funding

This research is part of a PhD thesis and is funded by the Vice-Chancellor for Research at Mashhad University of Medical Sciences, Grant No. 931673.

Effects of the hydroalcoholic extract of Rosa damascena on learning and memory in male rats consuming a high-fat diet

CONTEXT

High-fat diet (HFD) can cause deficits in learning and memory through oxidative stress and increase Alzheimer disease risk. Rosa damascena Mill. (Rosaceae) extract possesses potent antioxidant properties.

OBJECTIVE

This study investigated the effects of the hydroalcoholic extracts of petals of R. damascena on learning and memory in male rats consuming an HFD.

MATERIALS AND METHODS

Forty male Wistar rats (200-250 g) were randomly assigned to four groups: control, R. damascena extract, HFD and HFD + extract. The extract (1 g/kg bw daily) was administered by oral gavage for 1 month. Animals were allowed free access to high-fat chow for 3 months. The Morris water maze and the passive avoidance learning tests were used to assess learning and memory.

RESULTS

In the passive avoidance learning test, the step-through latencies in the retention test (STLr) of the extract (147.4 ± 23.3) and HFD (150.3 ± 25.2) groups were significantly lower than those of the control group (270.4 ± 10.5) (respectively, p < 0.001 and p < 0.01). STLr was significantly higher in the HFD + extract group (265.3 ± 10.6) than in the HFD group (150.3 ± 25.2) (p < 0.01). Time spent in the dark compartment (TDC) in the HFD + extract group (5.3 ± 2.6) was significantly lower than that in the HFD group (85.8 ± 19.1) (p < 0.05).

DISCUSSION AND CONCLUSION

Our results indicate that, while HFD or R. damascena extract alone leads to memory deficits, R. damascena extract exerted a positive effect on HFD-induced memory deficits. We hypothesize that the observed effects of R. damascena extract are likely due to its strong antioxidant properties.

New insights on food intake control by olfactory processes: the emerging role of the endocannabinoid system

The internal state of the organism is an important modulator of perception and behavior. The link between hunger, olfaction and feeding behavior is one of the clearest examples of these connections. At the neurobiological level, olfactory circuits are the targets of several signals (i.e. hormones and nutrients) involved in energy balance. This indicates that olfactory areas are potential sensors of the internal state of the organism. Thus, the aim of this manuscript is to review the literature showing the interplay between metabolic signals in olfactory circuits and its impact on food intake.