Protective Effects of Natural Antioxidants on Inflammatory Bowel Disease: Thymol and Its Pharmacological Properties

Abstract

Inflammatory bowel disease (IBD) is a gastrointestinal disease that involves chronic mucosal or submucosal lesions that affect tissue integrity. Although IBD is not life-threatening, it sometimes causes severe complications, such as colon cancer. The exact etiology of IBD remains unclear, but several risk factors, such as pathogen infection, stress, diet, age, and genetics, have been involved in the occurrence and aggravation of IBD. Immune system malfunction with the over-production of inflammatory cytokines and associated oxidative stress are the hallmarks of IBD. Dietary intervention and medical treatment suppressing abnormal inflammation and oxidative stress are recommended as potential therapies. Thymol, a natural monoterpene phenol that is mostly found in thyme, exhibits multiple biological functions as a potential adjuvant for IBD. The purpose of this review is to summarize current findings on the protective effect of thymol on intestinal health in the context of specific animal models of IBD, describe the role of thymol in the modulation of inflammation, oxidative stress, and gut microbiota against gastrointestinal disease, and discuss the potential mechanism for its pharmacological activity.

Thymol targeting interleukin 4 induced 1 expression reshapes the immune microenvironment to sensitize the immunotherapy in lung adenocarcinoma

“…Thyme is widely used in traditional medicine in China for its antitussive, expectorant, and acesodyne properties. The pharmacokinetic properties of thymol have been revealed in several previous studies 27,28 . Thymol exhibits a diverse array of biological and therapeutic activities, including antifungal, antileishmanial, and antiviral properties 29–31 .…”

Oxidative Stress, Inflammation, Gut Dysbiosis: What Can Polyphenols Do in Inflammatory Bowel Disease?

“…However, limitations such as poor response, systemic side effects, high recurrence rate, and high cost still need to be addressed [ 31 , 32 ]. Recently, an increasing number of studies have applied antioxidants to alleviate oxidative stress and inflammation in the intestinal tract and have received some favorable feedback for the treatment of IBD [ 33 ]. Therefore, exploiting pathogenesis-based therapeutics remains attractive for new drug discovery and development.…”

Thymol as a Potential Neuroprotective Agent: Mechanisms, Efficacy, and Future Prospects

“…Thymol has demonstrated potent antioxidant properties in numerous in vivo and in vitro studies. ,,− These studies have shown that thymol can scavenge ROS effectively, as evidenced by its ability to reduce the levels of oxidative stress markers. Jamali et al demonstrated the extracellular antioxidant capacity of thymol using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, two most common radical scavenging assays, the results showed that the half-maximal inhibitory concentration (IC 50 ) is about 61.6, and 98.3 μg/mL, respectively .…”

“…12 Many studies from in vitro and animal experiments have demonstrated that thymol possesses potent antioxidant, anti-inflammatory, antimicrobial, and immune-regulation functions. 13,14 On the basis of these pharmacological properties, thymol has been widely used in the pharmaceutical field for treating various diseases, including, chronic fibrosis, cancer, immune and inflammatory diseases, cardiovascular disease, infectious disease, and metabolic disease. 15−20 Recently, some studies showed that thymol exhibited potential therapeutic effects for several neurological diseases, such as Parkinson's disease, Alzheimer's disease, neuro-depression, aging-related learning, and memory impairment.…”

“…Thymol (2-isopropyl-5-methylphenol, Figure ), a naturally occurring monocyclic phenolic compound, is the major active component of the essential oils extracted from several thyme species, including Origanum vulgare , Coridothymus capitatus , and Thymus vulgaris . Many studies from in vitro and animal experiments have demonstrated that thymol possesses potent antioxidant, anti-inflammatory, antimicrobial, and immune-regulation functions. , On the basis of these pharmacological properties, thymol has been widely used in the pharmaceutical field for treating various diseases, including, chronic fibrosis, cancer, immune and inflammatory diseases, cardiovascular disease, infectious disease, and metabolic disease. − Recently, some studies showed that thymol exhibited potential therapeutic effects for several neurological diseases, such as Parkinson’s disease, Alzheimer’s disease, neuro-depression, aging-related learning, and memory impairment. − For example, Javed and colleagues reported that oral thymol supplementation (i.e., 50 mg/kg/day for 28 days) could significantly decrease the biomarkers of oxidative stress, inflammatory response in the brain tissues of rats, following to effectively attenuate neurotoxicity and neurodegeneration caused by rotenone, an inducer of Parkinson’s disease . Similarly, Abu-Elfotuh et al found that oral thymol administration at the final dose of 15 mg/kg/day for 5 weeks (i.e., 35 days) could effectively improve neuronal degeneration and behavioral impairments in rats via the inhibition of oxidative stress, apoptotic cell death, and neuroinflammatory response in the brain tissues of rats with Parkinson’s Disease .…”