Herbal remedies historically represent the first pharmacological compounds used in
the treatment of many diseases. Despite being considered safer than synthetic drugs,
food and drug interactions must be extensively evaluated in terms of their absorption,
excretion, distribution and metabolism. Plants containing thymol have been used in
traditional medicine for the treatment of various diseases, such as cardiovascular
diseases, cancer and diabetes. To understand the bioavailability of thymol in animal
organisms and to establish the suitable concentration for beneficial effects on animal
health, its metabolic path needs to be understood at the molecular level. Oral bioavailability
represents the fraction of administered thymol reaching the systemic circulation and
is a key parameter that affects its efficacy. Therefore, to propose an appropriate
dose, the study of thymol oral bioavailability has received significant attention.
Information concerning the bioactivity of thymol and its metabolites in animal organisms
could also be applied to human medicine and may help in the utilization of herbal
medicine in humans and in veterinary healthcare. However, relatively few studies on
the bioavailability and pharmacokinetics of thymol are available to date. According
to our knowledge from the current literature, thymol metabolites, mostly thymol sulphate
and glucuronide, were detected in the plasma and urine of humans and in the plasma,
intestinal content, faeces and tissues in rats, pigs, chickens, horses and rabbits.
To precisely understand the metabolic processes and biological activity of thymol
and its metabolites within organisms, more clinical studies are necessary, with preclinical
comprehensive research on animal models.
Funding VEGA 2/0009/20
