Valerenic acid is a

sesquiterpenoid Sesquiterpenes are a class of terpenes that consist of three isoprene units and often have the molecular formula C15H24. Like monoterpenes, sesquiterpenes may be cyclic or contain rings, including many unique combinations. Biochemical modificatio ...

constituent of the essential oil of the valerian plant. Valerian is used as a herbal sedative which may be helpful in the treatment of

insomnia Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

. Valerenic acid may be at least partly responsible for valerian's sedative effects, in addition to the other valerenic acids hydroxyvalerenic acid and acetoxyvalerenic acid. Valerian supplements are often standardized to contain a particular amount of valerenic acid by weight (often 0.8%). Valerenic acid acts as a subtype-selective GABA_A receptor

positive allosteric modulator In pharmacology and biochemistry, allosteric modulators are a group of substances that bind to a receptor to change that receptor's response to stimulus. Some of them, like benzodiazepines, are drugs. The site that an allosteric modulator binds to ...

via a

binding site In biochemistry and molecular biology, a binding site is a region on a macromolecule such as a protein that binds to another molecule with specificity. The binding partner of the macromolecule is often referred to as a ligand. Ligands may includ ...

in the

transmembrane domain A transmembrane domain (TMD) is a membrane-spanning protein domain. TMDs generally adopt an alpha helix topological conformation, although some TMDs such as those in porins can adopt a different conformation. Because the interior of the lipid bi ...

at the β⁺α⁻ interface. At receptors expressed in

Xenopus ''Xenopus'' () (Gk., ξενος, ''xenos''=strange, πους, ''pous''=foot, commonly known as the clawed frog) is a genus of highly aquatic frogs native to sub-Saharan Africa. Twenty species are currently described within it. The two best-know ...

oocytes An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female g ...

(frog eggs) it was shown that only assemblies incorporating β2 or β3 subunits were stimulated by valerenic acid. A study in mice demonstrated that a single amino acid substitution (N265M) in the β3 subunit severely decreases the anxiolytic effect. Modulation of ion channel action was not significantly dependent on incorporation of α1, α2, α3 or α5 subunits. At the 5-HT_5A receptor valerenic acid acts as a

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist. They may also be considered ligands which display both agonistic and antagonis ...

. This serotonin receptor subtype is distributed in the suprachiasmatic nucleus, a tiny brain region implicated in the

sleep-wake cycle A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., endogenous) and responds to ...

. A study in 2006 found valerian extract as well as valerenic acid to inhibit

NF-κB Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellular ...

, a protein complex that controls the

transcription Transcription refers to the process of converting sounds (voice, music etc.) into letters or musical notes, or producing a copy of something in another medium, including: Genetics * Transcription (biology), the copying of DNA into RNA, the fir ...

of DNA, in

HeLa HeLa (; also Hela or hela) is an immortalized cell line used in scientific research. It is the oldest and most commonly used human cell line. The line is derived from cervical cancer cells taken on February 8, 1951, named after Henrietta ...

(cultured human cancer) cells. This was measured with the IL-6 / Luc (

Interleukin-6 Interleukin 6 (IL-6) is an interleukin that acts as both a pro-inflammatory cytokine and an anti-inflammatory myokine. In humans, it is encoded by the ''IL6'' gene. In addition, osteoblasts secrete IL-6 to stimulate osteoclast formation. Smoo ...

luciferase) assay as a measurement tool. The study mentioned that such inhibition may be connected to the reported

anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as o ...

action of the valerian plant. A small study with six human subjects found that valerenic acid peaked in concentration after about an hour and had an average half-life of 1.1 +/- 0.6 hours after oral ingestion of a commercially available valerian root supplement. A later study from the same lab done with sixteen older women found similar values.

References

5-HT5A agonists GABAA receptor positive allosteric modulators Sedatives {{sedative-stub