Objective: To investigate the biological effects of carvacrol on rats with stomach-heat and stomach-cold and its regulation on transient receptor potential(TRP) channels in rats with stomach-heat, and to study the cold and heat properties of carvacrol and its possible mechanism. Methods: According to the random number method, 100 SD rats were divided into stomach-heat blank group, stomach-heat model group, Coptidis Rhizoma group, stomach-heat low-dose and high-dose carvacrol group, stomach-cold blank group, stomach-cold model group, Baked ginger group, stomach-cold low-dose group and high-dose carvacrol group, 10 rats in each group. The rat model of stomach-heat was established by intragastric administration of pepper aqueous solution (0.80 g/kg) and anhydrous ethanol, and the rat model of stomach-cold was established by intragastric administration of water extract of Anemarrhena asphodeloides and sodium hydroxide (10.40 g/kg). On the day of modeling, the rats in the Baked ginger group were given Baked ginger decoction (0.78 g/kg), and the rats in the Coptidis Rhizoma group were given Coptidis Rhizoma decoction (0.43 g/kg).The stomach-cold and stomach-heat low-dose group of carvacrol was given carvacrol emulsion (40 mg/kg), high-dose group was given carvacrol emulsion (80 mg/kg).All rats of the blank and model groups were given the equal volume of emulsion prepared by 5% dimethyl sulfoxide, 1% Tween 80, 1% polyethylene glycol 400, and 93% normal saline, once a day, for 7 days. The general condition of rats was observed and the body mass was recorded. The pathological morphology of gastric tissue was observed by hematoxylin-eosin staining. The changes of material and energy metabolism, cyclic nucleotide (cAMP), thyroid hormone and gastrointestinal hormone in each group were determined by enzyme-linked immunosorbent assay. The expression levels of transient receptor potential vanilloid subtype 1 (TRPV1), transient receptor potential channel M8 (TRPM8) and uncoupling protein-1 (UCP1) in rats with gastric fever were detected by Western blotting. Results: Compared with the stomach-heat blank group, the body mass of rats in the stomach-heat model group decreased at the fifth and seventh day (P<0.05). The contents (or ratio) of hepatic glycogen (HGlyc), total cholesterol (TC), triglyceride (TG), and vasoactive intestinal peptide (VIP) were decreased (P<0.05), and Na+ -K+ -ATPase, Ca2+ -Mg2+ -ATPase, cytochrome C oxidase (COX), NADH dehydrogenase (ND), cyclic adenosine phosphate (cAMP), cAMP/cyclic guanosine phosphate (cGMP), triiodothyronine (T3), thyroxine (T4), gastrin (GAS), motilin (MTL), and α-amylase (α-AMS) all increased (P<0.05). Compared with the stomach-heat model group, the body mass of rats in the Coptidis Rhizoma group decreased at the third, fifth, and seventh day, the contents (or ratio) of HGlyc, TC, TG, VIP and α-AMS were increased, and Na+ -K+ -ATPase, COX, ND, cAMP, cAMP/cGMP, T3, T4, and GAS all decreased (P<0.05). The body mass of rats in the stomach-heat low-dose carvacrol group decreased at the seventh day. The contents (or ratio) of HGlyc, TC, and VIP were increased, Na+ -K+ -ATPase, COX, ND, cAMP, cAMP/cGMP, T3, T4, and MTL all decreased, the expression of TRPV1 and UCP1 in gastric tissue decreased, while TRPM8 increased (P<0.05) in rats of the stomach-heat low-dose and high-dose carvacrol groups. Compared with the stomach-cold blank group, the body mass of rats in the stomach-cold model group decreased at the third, fifth, and seventh day, the contents (or ratio) of HGlyc, TC, TG, α-AMS, and VIP all increased, while Na+ -K+ -ATPase, Ca2+ -Mg2+ -ATPase, COX, ND, cAMP, cAMP/cGMP, T3, T4, GAS, and MTL all decreased (P<0.05). Compared with the stomach-cold model group, the body mass of rats in the Baked ginger group was increased at the seventh day, and the contents (or ratio) of HGlyc, VIP, and α-AMS all decreased, while Na+ -K+ -ATPase, COX, ND, cAMP/cGMP, T3, T4, GAS, and MTL all increased (P<0.05). The contents of HGlyc, cAMP, α-AMS, and VIP of rats in the stomach-cold low and high-dose carvacrol group all decreased (P<0.05). TG in the stomach-cold low-dose carvacrol group was increased. TC, Ca2+ -Mg2+ -ATPase, and cGMP all increased, while cAMP/cGMP decreased (P<0.05) in the high-dose carvacrol group. Conclusion In this study, the rat model of stomach-cold and stomach-heat were successfully established by using cold and heat factors. The result showed that carvacrol had a certain inhibitory effect on body mass, material energy metabolism, cyclic nucleotide level, thyroid hormone and gastrointestinal function in rats with stomach-heat, indicating that the drug was cold. Carvacrol′s cold medicinal property could be biologically explained by TRPV1 activation, UCP1 induction, and TRPM8 suppression.

The most common medications for the treatment of zoonotic toxoplasmosis are pyrimethamine and sulfadiazine, which may cause serious undesirable side effects. Thus, there is an urgent need to develop novel therapeutics. Baicalein (BAI, C₁₅H₁₀O₅) has been shown to perform well against protozoan parasites including Leishmania and Cryptosporidium. In this study, the inhibition efficacy of BAI on Toxoplasma gondii was evaluated using plaque, invasion, and intracellular proliferation assays. BAI effectively inhibited T. gondii (half-maximum inhibitory concentration (IC₅₀)=6.457×10^-5 mol/L), with a reduced invasion rate (33.56%) and intracellular proliferation, and exhibited low cytotoxicity (half-maximum toxicity concentration (TC₅₀)=5.929×10^-4 mol/L). Further investigation using a mouse model shed light on the inhibitory efficacy of BAI against T. gondii, as well as the potential mechanisms underlying its anti-parasitic effects. The survival time of T. gondii-infected ICR mice treated with BAI was remarkably extended, and their parasite burdens in the liver and spleen were greatly reduced compared with those of the negative control group. Histopathological examination of live sections revealed effective therapeutic outcomes in the treatment groups, with no notable pathological alterations observed. Furthermore, alterations in cytokine levels indicated that BAI not only effectively suppressed the growth of T. gondii but also prevented excessive inflammation in mice. Collectively, these findings underscore the significant inhibitory efficacy of BAI against T. gondii, positioning it as a promising alternative therapeutic agent for toxoplasmosis.
Animals ; Toxoplasma/drug effects* ; Flavanones/therapeutic use* ; Mice ; Antiparasitic Agents/therapeutic use* ; Mice, Inbred ICR ; Toxoplasmosis/drug therapy* ; Female