Effects of Orally Administered Thymus Vulgaris Leaves on Memory, Anxiety, Depression, and Sleep Quality in University Students: A Randomized Controlled Trial
Condition: Memory Dysfunction; Anxiety; Depression; Sleep
MeSH terms: Depression; Depressive Disorder; Anxiety Disorders
Study type: Interventional

Summary: 
      Thymus vulgaris could potentially serve as a safer alternative to stimulant drugs for
      enhancing memory among university students. Furthermore, Thymus vulgaris may offer additional
      benefits in terms of reducing anxiety, depression, and improving sleep quality. However, it
      should be noted that the current research on the effects of orally administered Thymus
      vulgaris on the brain and nervous system is limited, and further studies are required to
      fully explore its potential advantages. Therefore, the purpose of this study is to
      investigate the effects of oral Thymus vulgaris on memory performance, anxiety, depression,
      and sleep quality in university students.
    

Detailed description: 
      Thymus vulgaris belongs to the Lamiaceae family and is a flowering plant. It can be found
      worldwide, although its origin is in southern Europe [1]. This plant is characterized by its
      compact, bushy nature and evergreen shrub structure. Its leaves are small, gray-green, highly
      aromatic, and it produces clusters of purple or pink flowers [2]. Thymus vulgaris is commonly
      used as a spice to enhance the flavor of food. It is also utilized in the form of dietary
      supplements; such as capsules or essential oils [3]. Throughout history, Thymus vulgaris has
      been employed in folk medicine due to its remarkable antimicrobial and anti-inflammatory
      properties [4]. In Jordanian traditional medicine, it is frequently utilized as an
      antiseptic, bronchial, sedative, and spasmolytic agent, as well as to improve cognitive
      function and memory [5-8]. Numerous studies have reported various health benefits associated
      with Thymus vulgaris leaves, including antioxidant [9], diuretic [10], anti-inflammatory
      [11], antiviral [12], anti-cancerous [13], cholesterol-lowering [14], glucose-lowering [15],
      anticonvulsant [16], anti-anxiety [17] and sedative-hypnotic activities [18].

      The primary constituents of Thymus vulgaris, notably thymol, p-cymene, γ-terpinene, linalool,
      and carvacrol, possess various neuropharmacological properties, including anti-anxiety,
      sedative, anticonvulsant, memory-enhancing, and anti-Alzheimer's disease effects [19].
      Asadbegi et al. conducted a study demonstrating that thymol exhibited neuroprotective
      properties by reducing memory impairment caused by intrahippocampal injection of the amyloid
      beta (Aβ) peptide in rats fed a high-fat diet [20]. Furthermore, Capibaride et al. confirmed
      the significant antidepressant-like effect of thymol by observing its ability to reverse
      behaviors associated with chronic corticosterone exposure and decrease in BDNF levels in
      female mice [21]. Azizi et al. demonstrated that carvacrol and thymol exerted neuroprotective
      effects against Aβ25-35-induced damage, potentially through the attenuation of oxidative
      stress and the modulation of PKC activity, a protein associated with memory function [22].
      Additionally, within the monoterpenes and sesquiterpenes, β-myrcene and caryophyllene have
      been identified as major compounds. β-myrcene is known for its analgesic, anxiolytic, and
      anti-inflammatory effects [23].

      Multiple studies have highlighted the positive impact of Thymus vulgaris on memory, anxiety,
      and depression. Akan et al. conducted research on rats using the Morris water maze and found
      that Thymus vulgaris L. exhibited beneficial effects against diabetes mellitus-induced
      neuropathy and cognitive impairment [24]. They attributed these effects to specific
      components like thymol, carvacrol, 8-terpinene, p-cymene, and α-pinene present in high
      amounts in the essential oil composition. Similarly, Rabiei et al. suggested that Thymus
      vulgaris extract demonstrated anti-amnesic properties in rats with Sco-induced memory
      deficits, as assessed by the Morris water maze and passive avoidance tests [25]. The authors
      proposed that this effect could be linked to the extract's antioxidant activity or its
      influence on the cholinergic system, with carvacrol and thymol playing significant roles
      based on their chemical composition. Additionally, an ethanol extract derived from Thymus
      vulgaris leaves displayed an anxiolytic profile in rats during the EPM test, unaffected by
      locomotor activity [17]. Finally, in the context of Alzheimer's disease, a neurodegenerative
      disorder involving cholinergic neuron loss, administration of thyme oil to Caenorhabditis
      elegans enhanced neurotransmission by regulating synaptic acetylcholine levels [26].

      The high prevalence of anxiety, depression, and sleep disorders among university students can
      significantly affect their memory function [27]. Consequently, an increasing number of
      university students have turned to using stimulant drugs to improve their memory performance
      and attention, despite the fact that such usage is unauthorized and not intended for
      therapeutic purposes [28]. However, the use of these drugs is associated with various side
      effects[29,30]. This has led neuroscience researchers to show a growing interest in
      identifying cognitive-enhancing drugs that can be safely used by healthy individuals without
      any detrimental effects.

      Based on the provided information, it is hypothesized that Thymus vulgaris could potentially
      serve as a safer alternative to stimulant drugs for enhancing memory among university
      students. Furthermore, Thymus vulgaris may offer additional benefits in terms of reducing
      anxiety, depression, and improving sleep quality. However, it should be noted that the
      current research on the effects of orally administered Thymus vulgaris on the brain and
      nervous system is limited, and further studies are required to fully explore its potential
      advantages. Therefore, the purpose of this study is to investigate the effects of oral Thymus
      vulgaris on memory performance, anxiety, depression, and sleep quality in university
      students.
    

Intervention name(s): Thymus vulgaris
Intervention type(s): Dietary Supplement
Intervention description(s): 500 mg of Thymus vulgaris (capsules) was given orally twice daily
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Supportive Care
Keywords: Thymus vulgaris leaves; Memory performance; Anxiety; Depression; Sleep