Is Valerian Root Good for Sleep?

Valerian (Valeriana officinalis L.) is a perennial herbaceous plant belonging to the Valerianaceae family and Valeriana genus, containing over 150 chemical components and exhibiting various pharmacological effects [1]. Valerian has sedative and sleep-inducing effects, effectively alleviating insomnia and improving sleep quality; it has anxiolytic properties, treating mild to moderate anxiety and helping severe patients reduce anxiety levels; it exhibits antitumor activity, reducing the risk of disease and inhibiting tumor proliferation; and it has antispasmodic effects, relaxing the gastrointestinal tract. Additionally, Valerian possesses multiple functions, such as antibacterial, anti-inflammatory, anti-fatigue, anti-depressant, anti-epileptic, and organ-protective effects. The following is a summary of its chemical components and pharmacological effects for reference.

1. Botanical characteristics and distribution of Valerian

Valerian, also known as “piercing heart grass,” “deer grass,” “small savior,” “sweet grass,” and “cat's food,” is a shade-loving perennial herbaceous plant [2]. It can grow up to 100 cm in height, with purple-red flowers, erect hollow stems, thick short rhizomes, and clustered fibrous roots [3]. The entire plant is medicinal, with the roots and rhizomes being the primary medicinal parts. Literature indicates that Valeriana has antispasmodic, analgesic, sedative, and calming effects. Valeriana species are predominantly distributed in temperate regions, with China's primary distribution areas in the northwest (Shaanxi, Qinghai), southwest (Sichuan, Guizhou), and northeast (Heilongjiang, Jilin) regions. Approximately 250 species are known worldwide [6]. Valerian prefers moist environments, tolerates waterlogging and drought, and thrives in neutral or slightly alkaline conditions, with sandy soil being optimal.

2 Active Components of Valerian Extracts

Valerian extracts are rich in various active components, including essential oils, flavonoids, alkaloids, cycloartenol, and lignans [7–10]. Chemical components are primarily distributed in the vegetative organs, with roots containing high levels of cycloartenol and essential oils, while flowers, stems, leaves, and fruits contain alkaloids and flavonoids [8].

2.1 Volatile Oils

The main components of volatile oils include borneol, valerian ketone, valerianic acid, and isovaleric acid esters, all of which possess biological activity [8, 11]. Valerian plants generally contain 0.5%–2% volatile oils, with some varieties as low as 0.03%. The content of volatile oils in Valeriana is influenced by factors such as soil type, variety, geographical environment, harvesting season, and storage time. For example: The volatile oil content of two-year-old Valeriana is higher than that of one-year-old plants; the volatile oil content decreases with increasing storage time; Valerian grown in fertile sandy soil has a higher oil content than that grown in other soils [8].

2.2 Flavonoids

Flavonoids primarily include quercetin, apigenin, acanthopanaxin, luteolin, genistein, and digitoxin [11, 12]. Flavonoids are primarily found in the flowers, fruits, stems, and leaves of Valeriana. Research has shown that flavonoid content in flowers and fruits is higher than in leaves [8].

2.3 Alkaloids

Alkaloids account for approximately 1% of Valeriana officinalis. After separation, 19 alkaloids were identified, including Actinonine, Valeriana A, Valeriana B, Valeriana, and Valeriana-like alkaloids, which are primarily classified into two categories: aliphatic alkaloids and monoterpenoid alkaloids [11, 13]. Alkaloids of the alphaphenyl type not only have extremely complex chemical structures but are also present in relatively large quantities [8]; monoterpenoid alkaloids include pyridine-type alkaloids and quaternary ammonium-type alkaloids, with pyridine-type alkaloids containing valerian alkaloid, kiwifruit alkaloid, and valerianine alkaloid, among others [14–16].

2.4 Cycloartenol terpenoids

In 1966, Thies et al. first isolated and identified valerianol (also known as valerian triester) from Valeriana plants and preliminarily demonstrated that valerian possesses sedative activity [17]. The main compound responsible for the sedative activity is valerianin in valerian. The main cycloether terpenoids include valerianin, valerianin acetate, dihydrovalerianin acetate, and isovalerianin acetate. According to reports, eight glycosides, 26 aglycones, and a total of 34 cycloartenolides have been isolated and identified from Valeriana [13]. Valerian plants contain various types of cycloether terpenoids, including diene ring-opening, monoene ring-opening, monoene ring-closing, and diene ring-closing types [18].

2.5 Lignans and others

Two lignans were isolated from Valeriana plants, namely prinsepiol-4-O-8-D-glucopyranoside and fraxiresinol-4'-O-B-D-glucopyranoside, with the former exhibiting stronger vasodilatory activity than the latter [11]. Lignans are primarily classified into two types: bicyclic epoxide and monocyclic epoxide [19]. Lignans contain trace amounts of substances with activity against AI adenosine receptors [12]. Additionally, Valeriana plants contain various organic acids (such as chlorogenic acid and caffeic acid) and 18 amino acids (such as arginine and tyrosine) [11].

3 Pharmacological effects of Valeriana

3.1 Sedative and Sleep-Promoting Effects

Based on research over the past 20 years, Valerian root extracts have been found to possess sedative and sleep-promoting effects. Xu Hong et al. [20] conducted experiments using mice to investigate the pharmacological effects of Valerian essential oil on the central nervous system. The results indicated that Valerian essential oil significantly inhibited the mice's spontaneous behavioral activity and reduced the frequency of such activities, demonstrating good sedative and inhibitory effects. Tao Tao et al. [21] conducted experiments on Kunming strain mice using Valerian alcohol extracts, observing their behavioral activities. The results indicated that Valerian alcohol extracts could effectively reduce the behavioral activities of mice, increase the number of times mice fell asleep, and prolong sleep duration. Huang Baokang et al. [22] conducted a comparative study on four medicinal plants of the Valeriana genus. The results indicated that Valeriana can shorten the activity time of mice, inhibit the frequency of their activities, and prolong their sleep duration.

Chen Shuaijia et al. [23] conducted experiments on mice using the petroleum ether extract of black water valerian (roots and rhizomes). The results indicated that the petroleum ether extract of black water valerian improved sleep quality in mice, increased the number of times mice fell asleep, shortened the time to fall asleep, and prolonged sleep duration. According to other literature reports, valerian has sedative and sleep-inducing effects, with its main components being valerian lactone and valerenic acid, both of which have good sedative effects [8]. This sedative and sleep-inducing effect can help improve sleep quality, with its mechanism similar to that of pentobarbital. The sedative and sleep-inducing effects of valerian have been recognized by European countries for many years and are included in multiple pharmacopoeias, making it a popular herbal medication for treating mild to moderate insomnia [24, 25]. Other compounds in valerian root extract that exert sedative and hypnotic effects include flavonoids, valerenone, valerian triol, valerenic acid, valerian alkaloids, and dihydrovalerenone. These compounds shorten the sleep preparation phase and prolong sleep duration, thereby effectively improving sleep quality.

3.2 Anxiolytic effects

In studies on Valerian root, double-blind trials in adults showed a reduction in subjective anxiety, indicating that Valerian root extract can reduce anxiety levels [11]. Wang Yanli et al. [26] investigated the anti-anxiety effects and mechanisms of valerian using a high-cross maze game experiment in mice. The results showed that valerian reduced anxiety levels in mice, demonstrating its anti-anxiety effects. Medical research indicates that the hypothalamic-pituitary-adrenal axis system plays a role in the mechanism of anxiolytic effects [6]. Hattesohl M et al. [27] conducted studies on Valeriana plants using a mouse swimming test, and found that within the dosage range of 100–500 mg/kg of methanol extract and ethanol extract, the 45% methanol and 35% ethanol extracts showed the most significant effects, indicating that Valeriana plants possess notable anxiolytic effects.

3.3 Antitumor Effects

Zhang Shuqin et al. [28] observed human leukemia HL-60 and leukemia K-562 cell lines under a microscope, measured absorbance values, recorded cell growth status and morphology, and calculated the tumor inhibition rate, concluding that valerian ring-ether terpenoids exhibit significant antitumor effects. Related experiments found that Valeriana contains dihydrovaleriana, and the extracted dihydrovaleriana has inhibitory effects on liver cancer cells [8]. Valeriana can inhibit T2 lymphocytes and liver cancer cells, and can also kill dangerous cancer cells, with dihydrovaleriana rapidly reacting with corresponding sites in liver cells [6].

3.4 Antispasmodic effects

Valerian essential oil not only has sedative and sleep-inducing effects but also exhibits excellent antispasmodic and analgesic properties [6]. Wagner H et al. [29] found that ethanol extracts of Valeriana plants exhibit significant antispasmodic and analgesic effects. In a guinea pig ileum experiment, Valeriana demonstrated stronger antispasmodic effects than papaverine. Parvaneh Mirabi et al. [30] conducted a double-blind study involving 100 female students to investigate the effects of Valeriana. During the baseline and intervention periods, pain severity was recorded through visual analog scoring and multidimensional assessment, and overall behavioral observations were made. The results indicated that Valeriana effectively alleviated pain severity and treated dysmenorrhea.

3.5 Other effects

Related studies indicate that Valerian root also possesses antidepressant [7]; antibacterial (Gram-positive bacteria), anti-inflammatory [31]; anti-fatigue, antioxidant, antiepileptic, and antiarrhythmic [32]; and therapeutic effects for gallbladder stones, liver and kidney protection, and neuroprotection [6].

4 Development and Application Prospects

In summary, Valerian root extract has sedative, anxiolytic, antitumor, antispasmodic, analgesic, and hepatoprotective effects. Currently, there are few Valerian-based products available in the domestic market, and further development is needed. The Valerian essential oil products currently available are expensive due to complex extraction processes and low oil yield. Based on Valerian's sedative and sleep-inducing effects, various affordable, safe, and effective products without side effects, such as Valerian sleep-aid sachets and Valerian sleep-aid mosquito coils, can be developed to address insomnia issues. Additionally, various pharmaceuticals can be developed based on the other benefits of Valerian root. In the future medical field, valerian's anti-tumor properties can be applied to cancer treatment, its antibacterial and anti-inflammatory properties to wound care, and its antidepressant effects to alleviate mild or moderate depression. Additionally, valerian root extracts can be developed into health supplements for liver and kidney protection. In summary, valerian possesses significant medicinal value. Its full development and utilization will not only contribute to the advancement of pharmaceutical science but also yield substantial economic benefits.

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