Antinociceptive activity of Thyme (Thymus vulgaris L.) and interactions with neurotropics and analgesics

The plant world represents an important source of potential therapeutic agents, but concomitant administration of herbal and conventional medications may result in interactions with subsequent beneficial or adverse effects. This study was designed to examine the analgesic effect of thyme tincture and thyme syrup, two commonly used thyme formulations, and their interactions with codeine, paracetamol, pentobarbital and diazepam in mice. The identification and quantification of thymol and carvacrol were carried out by GC/MS and GC/FID. The analgesic activity was studied using a hot plate method. Effects of thyme syrup on diazepam-induced motor coordination impairment in rotarod test and on pentobarbital-induced sleeping time were also determined. Thymol (175.3 µg/mL and 9.73 µg/mL) and carvacrol (10.54 µg/mL and 0.55 µg/mL) concentrations were measured in tincture and syrup, respectively. Thyme syrup and tincture exhibited effective analgesic activity in the hot plate pain model. Pretreatment with thyme formulations reduced analgesic activity of codeine, and potentiated the analgesic activity of paracetamol. Co-administration of thyme formulations has led to potentiation of diazepam and pentobarbital depressive central nervous system effects. Thyme formulations interacted with tested conventional drugs, probably through interference with their metabolic pathways and succeeding altered concentrations and pharmacological effects.

植物界是潜在治疗药物的重要来源，但草药与常规药物联合给药时，可能引发药物相互作用，进而产生有益或不良反应。本研究旨在考察两种常用百里香制剂——百里香酊剂（thyme tincture）与百里香糖浆（thyme syrup）的镇痛作用，以及它们与可待因（codeine）、对乙酰氨基酚（paracetamol）、戊巴比妥（pentobarbital）和地西泮（diazepam）在小鼠体内的相互作用。采用气相色谱-质谱联用法（GC/MS）与气相色谱-火焰离子化检测法（GC/FID），对百里香酚（thymol）与香芹酚（carvacrol）进行定性与定量分析。镇痛活性采用热板法（hot plate method）开展评价。此外，本研究还通过转棒实验（rotarod test）测定了百里香糖浆对地西泮诱导的小鼠运动协调能力损伤的影响，并检测了其对戊巴比妥诱导的睡眠时间的影响。分别在百里香酊剂与糖浆中检测到百里香酚（浓度依次为175.3 μg/mL与9.73 μg/mL）及香芹酚（浓度依次为10.54 μg/mL与0.55 μg/mL）。百里香糖浆与酊剂在热板疼痛模型中均表现出显著的镇痛活性。预先给予百里香制剂可减弱可待因的镇痛活性，却增强对乙酰氨基酚的镇痛作用。联合给予百里香制剂，可增强地西泮与戊巴比妥的中枢神经系统抑制效应。百里香制剂与受试常规药物存在相互作用，其机制可能为干扰药物代谢通路，继而改变药物浓度与药理效应。