Pharmacological Properties and Molecular Mechanisms of Thymol: Prospects for Its Therapeutic Potential and Pharmaceutical Development

Abstract

Thymol, chemically known as 2-isopropyl-5-methylphenol is a colorless crystalline monoterpene phenol. It is one of the most important dietary constituents in thyme species. For centuries, it has been used in traditional medicine and has been shown to possess various pharmacological properties including antioxidant, free radical scavenging, anti-inflammatory, analgesic, antispasmodic, antibacterial, antifungal, antiseptic and antitumor activities. The present article presents a detailed review of the scientific literature which reveals the pharmacological properties of thymol and its multiple therapeutic actions against various cardiovascular, neurological, rheumatological, gastrointestinal, metabolic and malignant diseases at both biochemical and molecular levels. The noteworthy effects of thymol are largely attributed to its anti-inflammatory (via inhibiting recruitment of cytokines and chemokines), antioxidant (via scavenging of free radicals, enhancing the endogenous enzymatic and non-enzymatic antioxidants and chelation of metal ions), antihyperlipidemic (via increasing the levels of high density lipoprotein cholesterol and decreasing the levels of low density lipoprotein cholesterol and low density lipoprotein cholesterol in the circulation and membrane stabilization) (via maintaining ionic homeostasis) effects. This review presents an overview of the current in vitro and in vivo data supporting thymol’s therapeutic activity and the challenges concerning its use for prevention and its therapeutic value as a dietary supplement or as a pharmacological agent or as an adjuvant along with current therapeutic agents for the treatment of various diseases. It is one of the potential candidates of natural origin that has shown promising therapeutic potential, pharmacological properties and molecular mechanisms as well as pharmacokinetic properties for the pharmaceutical development of thymol.

Synthesis of thymyl esters and their insecticidal activity against Spodoptera litura (Lepidoptera: Noctuidae)

“…These chemicals can interact with neuromodulator octopamine, a neurotransmitter unique to insects, and also induce neurotoxicity via effects on gated chloride channels GABA. 12,33 Concerning the stability, thymol has antioxidant property and can be susceptible to degradation by temperature, light and oxygen to generate phenoxide radicals that further proceed to oxidative and polymerization reactions, 34,35 which may result in a loss of insecticidal efficacy. This phenomenon is consistent with the results obtained by Pavela that post-application temperature affected to the insecticidal activity of thymol and Thymus vulgaris oil against Spodoptera littoralis and Culex quinquefasciatus larvae.…”

Thymol, thyme, and other plant sources: Health and potential uses

“…The antioxidant properties may be related to its phenolic structure, which may adsorb and neutralize free radicals and exhibit redox properties (Yu et al, 2016). This compound scavenges hydroxyl free radicals and produces phenoxyl radicals, major transient species (Nagoor Meeran et al, 2017), being more active than the synthetic antioxidant terc-butylated hydroxytoluene in vitro (Gavaric, Smole Mozina, Kladar, & Bozin, 2015). As an example, Gavaric et al (2015) reported the following values for the IC 50 of thyme essential oil (41.6% of thymol) and thymol: 0.2 and 28.82 μg/ml, respectively.…”

“…It was obtained in its pure form some 134 years later by Lallemand (1853). Nevertheless, thymol extract from the thyme plant was used thousands of years ago by the ancient Egyptians as a preparation to help preserving mummies (Nagoor Meeran, Javed, Al Taee, Azimullah, & Ojha, ).…”

Efficient extraction of black cumin ( Nigella sativa L.) seed oil containing thymol, using liquefied dimethyl ether (DME)

“…This is especially noteworthy as thymol is one of the most potent phytochemicals present in black seed. Various studies have described its antioxidant, antitumor, antimicrobial, and anti-inflammatory activities (Meeran, Javed, Al Taee, Azimullah, & Ojha, 2017). Its ability to act as an anti-cancer agent is proposed to be via pathways, such as antiproliferation, cell cycle arrest, and apoptosis (Li et al, 2017).…”