Patchouli

Pogostemon cablin (of the family Lamiaceae) is a herb commonly known as 'Pathcouli' and beyond its wide-spread usage as an aromatic and cosmetic it appears to have some medicinal usage in Japanese (Kampo) medicine with the name Kakko^[1] for the purposes of virology and some digestive aid usages.^[2] Moderan day usages is mostly as a substrate for cosmeceutical production of perfumes and fragrances.^[3]

There appears to be some evidence that it works as an insect repellant^[4] and may repel or kill mites,^[5][6] being comparatively effective on the former parameter.^[7]

Historical usage for mostly being a pleasant aroma and warding off insects, but also appears to have some anti-viral usage in traditional medicine

Compounds known to be in the volatile oil fragment include

• The sequesterpene known as Patchouli alcohol^[2][8] which is the main bioactive^[9] at around 30.65-33.3% of the essential oil^[10][11][12]
• δ-guaiene (2.03-14.5% essential oil) and α-guaiene (10.67-12.5% essential oil),^{[9][10][11][13]} with the study noting a low amount of δ-guaiene detected an appreciabile amount of β-guaiene (9.09%)^[10]
• α-patchoulene^[9] at 3.24-5% of the essential oil,^[10][11] β-patchouline at 1.58-2%,^[11] and γ-patchoulene at 2.4%^[11]
• Pogostol^[9] at 2.2% of the essential oil^[11]
• 2-(1,3-dihydroxy-but-2-enylidene)-6-methyl-3-oxo-heptanoic acid (DHEMH)^[5]
• Valencene, Elemol, and Farnesol^[2]
• Eicosene at 5.27%^[10]
• Caryophyllene at 3.5-8.64% of the essential oil,^[2][10][11] Aciphyllene at 3.1%,^[11] and Seychellene^[9] at 3.26-7.1%^[10][11]
• Napthoquinone at 2.45%^[10]
• Pachypodol^[14]
• Retusin^[14]
• Stigmast-4-en-3-one^[14]

Patchouli alcohol (a molecule within the essential oil portion) is by far the most prominent molecule consisting of about one third of the essential oil; other molecules in relatively higher levels in Patchouli are the Guainene class and the Patchouline class

Although Patchouli alcohol was named after Pogostemon cablin where it was first detected, it can be found in the rhizome of the plant Valeriana wallichii known as 'Indian Valerian' (not to be confused with Valerian officinalis), particularly in a Valeriana wallichii Patchouli Alcohol Chemotype.^[15] This plant has a highly variable content of Patchouli Alcohol at 13.4-66.7%.^[16]

Additionally, it should be noted that other herbs in the same family as Patchouli (Pogostemon) such as Pogostemon heyneanus have different phytochemical profiles in the essential oil;^[17] species may not be easily interchangeable.

Indian Valerian is also a good source of the bioactive thought to be unique to Patchouli

Patchouli oil (injections) has been found to not have a significant influence on a passive avoidance response in mice; this study also confirmed the inefficacy of Clary Sage while noting CNS stimulation from peppermint and chamomile.^[18]

In opposition of these results, inhalation of Patchouli oil (2% oil solution, with 20µL put on a cotton ball and inhaled for 3-7 minutes) in otherwise healthy females resulted in a reduction in CNS activity as assessed by systolic blood pressure amplitude (SBP-LF amplitude) over 5s intervals of measurement; the degree of CNS reduction relative to control was approximately 40%.^[19]

Some studies conducted in the Patchouli alcohol chemotype of Valeriana wallichii note that an extract of the essential oil (70% Patchouli alcohol) fed to rats at 40mg/kg acutely (10-20mg/kg being ineffective) noted a decrease in immonility time by 32.7% in a Forced Swim Test while the active control of Imipramine (10mg/kg) was not significantly different at 36.2% (after 14 days of treatment, Imipramine eventually reached 89.4%)^[15] This study noted that the extract increased norephedrine (20-23% at 20-40mg/kg) and Dopamine (15% at 40mg/kg) without influencing serotonin.^[15] These anti-depressant actions were later found to be inhibited with L-Arginine and Viagra (positive influencers of nitric oxide) and potentiated by both Methylene Blue and L-NAME^[20] suggesting that the nitric oxide pathway negatively regulates the observed anti-depressant effects.

Valeriana wallichii Patchouli alcohol chemotype has limited evidence for anti-depressive effects, which may apply to Patchouli if the main bioactive underlying these effects is Patchouli alcohol (insofar not estaglished)

Patchouli alcohol has shown anti-inflammatory activity in activated macrophages by suppressing the translocation of NF-kB, thought to be secondary to reducing ERK1/2 (one of three MAPKs) phosphorylation.^[21] Antiinflammatory effects have been noted with Patchouli alcohol elsewhere in LPS-activated macrophages where 10-40μM noted that iNOS induction, COX-2 mRNA, and PGE₂ content were concentration-dependently inhibited.^[22] Cytokines such as IL-1β, IL-6, and TNF-α were all similarly reduced to the same degree, although no parameter exceeding 50% reduction (between LPS control and non-activated control)

Has general anti-inflammatory effects in vitro, although it does not appear to be that potent overall in the classical macrophage activation assay

Combination therapy with Curcuma wenyujin, Crysthanthemum, and Patchouli oil (named CPZ from Traditional Chinese Medicine; 1:3:3 ratio) at 85-170mg/kg in mice noted that the reduction of DMB-induced ear vasodilation (indicative of inflammation) was reduced to a comparable level as the active control of 25mg/kg Indomethacin while the lower doses (42.5-85mg/kg) were comparable to Indomethacin in reducing carrageenan-induced paw edema; the higher doses were comparable for only 1-2 hours before losing efficacy.^[23]

Combination therapy involving Patchouli has been noted to have anti-inflammatory properties

In regards to the flu (Influenza viral strain A/PR/8/34; H1N1), a methanolic extract appears to have potent anti-viral activity by inhibiting neuraminidase by 99.8% at 10μg/mL and preserving 97.5% of infected cells without direct cytotoxicity unto the cells at the tested concentration.^[2] This was attributed to Patchouli alcohol (molecule), which reduced viral plaque formation by 75% at 2μg/mL, and was determined to have an IC₅₀ of 2.635-2.875μM (535-639ng/mL).^[2] This study later noted that the application of Patchouli alcohol on two viral H3N2 strains and failed to replicate the nanomolar potency, with no detectable activity up to 10μg/mL on A/Guizhou/54/89 and an IC₅₀ of 40.82μM on B/Ibaraki/2/85.^[2]

Pathcouli alcohol itself failed to inhibit neuraminidase on these two tested strains^[2] while interfering with neuraminidase function in another study assessing H2N2 strains with an IC₅₀ of 4.03+/-0.23, significantly weaker than the active control of Oseltamivir (Tamiflu).^[24]

Appears to have efficacy in vitro for inhibiting viral replication of the flu (Influenza) with quite a fair bit of potency on H1N1 but only moderate levels of potency on other viral strains

One study has been conducted in mice injected with the H1N1 virus, where 20-80mg/kg of isolated Patchouli oil was able as effective as 70mg/kg Ribavirin in preserving the life of mice given a lethal dose and with 80mg/kg reducing the viral load in lung tissue to a similar level as Ribavirin.^[25]

The amount of detectable Immunoglobulins specific for influenza (A, G, and M) and the cytokines IL-10 and IFN-γ in the serum of mice fed Pathouli alcohol was also significantly enhanced in a dose-dependent manner, with lung concentrations for Immunoglobulin G (but not A nor M) and both cytokines increasing at 40-80mg/kg of Pathouli Oil.^[25] This was met with significant enhancement of the percentage of T-cells expressing CD3+ or CD4+ receptors, with a suppression of CD8+ receptors (no dose dependence) and TNF-α appeared to be suppressed.^[25]

At least one mouse study has confirmed in vivo anti-influenza effects with Patchouli Alcohol with 80mg/kg (human estimated equivalent of 6.4mg/kg) being slightly lesser or equally effective as Ribavirin

One study that used Patchouli as a 'relaxing' aroma (as well as both Lavender and Rose Oil) noted that participants blinded the the purpose of the study and exposured to the aroma of the three aforementioned herbs failed to significantly influence the immune system when measure white blood cell parameters and count.^[11]

TNF-α was significantly reduced in females only (no significant effect on the whole group) as was Plasminogen activator inhibitor 1 (PAI-1).^[11]

The aroma of Pathcouli has only been tested once, but failed to significantly influence immunity