I wonder why they did the study with Spanish sage essential oil, considering it is quite hard to find and doesn't have a lot of the glowing positive reviews other essential oils have. Purity may be an issue concerning the latter.
I see it contains camphor, cineole, limonene, pamphene and pinene. I wonder which of these provides the uplifting effects, or if it's a combination of all of these?
I looked up limonene, which is also the main constituent in wild orange essential oil, and I came across a few studies (see below for the other ingredients):
Evaluation of acute toxicity of a natural compound (+)-limonene epoxide and its anxiolytic-like action.
Study Abstract:
The aim of the study is to determine the acute toxicity and anxiolytic-like effects of a mixture of cis and trans of (+)-limonene epoxide in animal models of anxiety. After acute treatment with (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg (i.p.) no mortality was noted during 14 days of observation. In general, behavior, food and water consumption showed no significant changes. In open field test, (+)-limonene epoxide at doses of 25, 50 and 75 mg/kg, after intraperitoneal administration, significantly decreased the number of crossings, grooming and rearing (p<0.001). All these effects were reversed by the pre-treatment with flumazenil (25 mg/kg, i.p.), similar to those observed with diazepam used as a positive standard. In the elevated-plus-maze test, (+)-limonene epoxide increased the time of permanence and the number of entrances in the open arms. All these effects were reversed by flumazenil, an antagonist of benzodiazepine receptors. In addition, (+)-limonene epoxide (75 mg/kg) also produced a significant inhibition of the motor coordination (p<0.01), that was reversed by flumazenil. In conclusion, the present work evidenced sedative and anxiolytic-like effects of (+)-limonene epoxide, which might involve an action on benzodiazepine-type receptors. These results indicate that the properties of (+)-limonene epoxide should be more thoroughly examined in order to achieve newer tools for management and/or treatment of central nervous system diseases and anxiolytic-like effects. The LD50 obtained for the acute toxicity studies using intraperitoneal route of administration was 4.0 g/kg. These findings suggest that acute administration of the (+)-limonene epoxide exerts an anxiolytic-like effect on mice, and it could serve as a new approach for the treatment anxiety, since it practically does not produce toxic effects.
Anxiolytic-like activity and GC-MS analysis of ®-(+)-limonene fragrance, a natural compound found in foods and plants.
Study Abstract:
The traditional use of essential oils in aromatherapy has offered numerous health benefits. However, few scientific studies have been conducted with these oils to confirm their therapeutic efficacy. (+)-Limonene is a chemical constituent of various bioactive essential oils. The present study reports on the anxiolytic-like effects of (+)-limonene in an elevated maze model of anxiety in mice. At concentrations of 0.5% and 1.0%, (+)-limonene, administered to mice by inhalation, significantly modified all the parameters evaluated in the elevated plus maze test. The pharmacological effect of inhaled (+)-limonene (1%) was not blocked by flumazenil. Analysis of (+)-limonene using gas chromatography-mass spectrometry (GC-MS) showed its volatility to be high. These data suggest possible connections between the volatility of (+)-limonene and its anxiolytic-like effect on the parameters evaluated in the elevated plus maze test. The data indicate that (+)-limonene could be used in aromatherapy as an antianxiety agent.
I didn't find much on camphor and anxiety/mood.
As for cineole, it appears to be an active constituent in rosemary oil, and is quite effective on cognition and mood:
Abstract
Objective
The mode of influence of the aromas of plant essential oils on human behaviour is largely unclear. This study was designed to assess the potential pharmacological relationships between absorbed 1,8-cineole following exposure to rosemary aroma, cognitive performance and mood.
Methods
Twenty healthy volunteers performed serial subtraction and visual information processing tasks in a cubicle diffused with the aroma of rosemary. Mood assessments were made pre and post testing, and venous blood was sampled at the end of the session. Pearson correlations were carried out between serum levels of 1,8-cineole, cognitive performance measures and change in mood scores.
Results
Here we show for the first time that performance on cognitive tasks is significantly related to concentration of absorbed 1,8-cineole following exposure to rosemary aroma, with improved performance at higher concentrations. Furthermore, these effects were found for speed and accuracy outcomes, indicating that the relationship is not describing a speed–accuracy trade off. The relationships between 1,8-cineole levels and mood were less pronounced, but did reveal a significant negative correlation between change in contentment and plasma 1,8-cineole levels.
Conclusion
These findings suggest that compounds absorbed from rosemary aroma affect cognition and subjective state independently through different neurochemical pathways.
The Effect of 1,8-Cineole Inhalation on Preoperative Anxiety: A Randomized Clinical Trial
Abstract
The aim of this study was to investigate the effect of inhalation of eucalyptus oil and its constituents on anxiety in patients before selective nerve root block (SNRB). This study was a randomized controlled trial carried out in 62 patients before SNRB. The patients were randomized to inhale limonene, 1,8-cineole, or eucalyptus oil, each at concentrations of 1% vol/vol in almond oil or almond oil (control). Anxiety-visual analog scale (A-VAS), state-trait anxiety inventory (STAI), profile of mood states (POMS), pain-visual analog scale (P-VAS), blood pressure, and pulse rate were measured before and after inhalation prior to SNRB. Measures of anxiety, including A-VAS (), STAI (), and POMS (), were significantly lower in 1,8-cineole than in the control group and significantly greater in 1,8-cineole than in the eucalyptus group in A-VAS. P-VAS was significantly lower after than before inhalation of limonene, 1,8-cineole, and eucalyptus, despite having no significant difference in the four groups compared with control group. 1,8-Cineole, a major constituent of eucalyptus, was effective in decreasing anxiety before SNRB. The present findings suggest that inhalation of 1,8-cineole may be used to relieve anxiety before, during, and after various operations, in addition to SNRB.
Didn't find much on pamphene, but I did find some interesting stuff related to pinene:
Daily Inhalation of α-Pinene in Mice: Effects on Behavior and Organ Accumulation
In phytotherapy, essential oils tend to be used daily for a period of days or weeks, rather than in a single application. However, the literature contains very little information on repeated use of essential oils. In this study, we investigated the effects on behavior and the accumulation in the brain and liver of α-pinene, an essential oil component, when inhaled by mice. Animals were individually housed in cages for 1 week. Mice inhaled α-pinene or water vapor (negative control) for 90 min/day for 1 day, 3 days, or 5 days, and they were then submitted to the elevated plus maze test for 10 min. We used gas chromatography with flame ionization detection to quantify concentrations of α-pinene in the brain and liver. There was significant anxiolytic-like activity, which remained constant for the 5 days' inhalation of α-pinene. On the other hand, the accumulation of α-pinene in the brain and liver peaked on the third day of inhalation. The existence of stress related to the new environment appears to have affected the change in the accumulation of α-pinene in the internal organs, keeping the anxiolytic-like action constant.
Expression of BDNF and TH mRNA in the Brain Following Inhaled Administration of α-Pinene
Essential oils are mainly administered by inhalation. Administration by inhalation is considered to occur through two pathways, neurological transfer and pharmacological transfer. However, the relationship between the two routes is not clear. To clarify this relationship, we administered α-pinene, which has an anxiolytic-like effect, to mice. Emotional behavior and accumulation and expression of relevant mRNAs in the brain (brain-derived neurotrophic factor (BDNF); tyrosine hydroxylase (TH)) were examined following inhaled administration of α-pinene (10 μL/L air for 60 or 90 min). To evaluate the anxiolytic-like effect, the elevated plus maze (EPM) test was used. Inhalation of α-pinene for 60 min produced a significant increase in the total distance traveled in the EPM test compared with control (water). The concentration of α-pinene in the brain after 60 min of inhalation was significantly increased compared with that after 90 min of inhalation. The expression of BDNF mRNA in the olfactory bulb and in the hippocampus was almost the same after 60 min of inhalation compared to that after 90 min of inhalation. The expression of TH mRNA in the midbrain after 60 min of inhalation was significantly increased compared with that of the control. Thus, an increase in α-pinene in the brain induces an increase in TH mRNA expression and increases locomotor activity. The anxiolytic-like effect may be related to both neurological transfer and pharmacological transfer.
So it appears that cineole, limonene, and pinene appear to be very promising along with possibly being antioxidants, though they can probably be found in combination in other essential oils.
Does anyone know how these affect serotonin receptors or dopamine receptors compared to linalool (found in lavender)?
From a previous post on another forum, I came across the following:
Valerian root oil affects GABA
Lemon oil affects serotonin 5ht1a
Rose oil affects dopamine
Rosemary oil affects norepinephrine
Oregano oil affects dopamine
Peppermint oil affects dopamine
Helichryshum oil affects dopamine
Out of curiosity, I pulled up info on carvacrol (found in oregano oil), and came up with this:
Antidepressant-like effect of carvacrol (5-Isopropyl-2-methylphenol) in mice: involvement of dopaminergic system.
Abstract
Carvacrol (5-isopropyl-2-methylphenol) is a monoterpenic phenol present in the essential oil of many plants. It is the major component of the essential oil fraction of oregano and thyme. In this study, the effect of carvacrol was investigated in two behavioral models, the forced swimming and tail suspension tests in mice, to investigate the possible antidepressant effect of this substance. Additionally, the mechanisms involved in the antidepressant-like effect of carvacrol in mice were also assessed. Carvacrol (cvc) was administered orally at single doses of 12.5, 25 and 50 mg/kg. The acute treatment of cvc decreased the immobility time in the forced swimming and tail suspension tests without accompanying changes in ambulation in the open-field test. The anti-immobility effect of carvacrol (25 mg/kg) was not prevented by pretreatment of mice with p-chlorophenylalanine, prazosin and yohimbine. On the other hand, the pretreatment of mice with SCH23390 or sulpiride completely blocked the antidepressant-like effect of carvacrol (25 mg/kg) in the forced swimming test. These results show that carvacrol presents antidepressant effects in the forced swimming and tail suspension tests; this effect seems to be dependent on its interaction with the dopaminergic system, but not with the serotonergic and noradrenergic systems.
I also found this post on another forum regarding oregano oil and obvious effects on dopamine:
I've been experimenting with low doses of oregano oil and I feel like it has helped my SA. I don't feel stimulated at all but I have been extremely motivated to get up and do stuff for the last couple of days. I usually sit around vegetation on my computer. I went to the gym and talked to people. I didn't feel the normal hesitation and paranoia I usually do. I also called up friends just to say hello. That's something I don't normally do, either. Took my dog for walk, cooked, you get the picture. Unlike other substances I've used before, I don't actually "feel it" working, I just act more normal and balanced in a social environment. It could be a placebo effect but I wasn't using it for my SA so this was a little unexpected. Anyways, it turns out that one of the essential oil in Oregano called carvacrol, actually has a dopaminergic effect. It's also interesting that I experience an improvement at significantly lower doses than that used in the study.
Any other experiences to share with essential oils?