Tilianin

Depressant effects of Agastache mexicana methanol extract and one of major metabolites tilianin.[Pubmed:25902158]

Asian Pac J Trop Med. 2015 Mar;8(3):185-90.

OBJECTIVE: To determine the depressant-like effects and the possible mechanism of action of Tilianin isolated from active methanol extract of Agastache mexicana (A. mexicana). Also, to establish the pharmacophoric requirements of Tilianin, as a possible ligand of GABAA/BZD receptor, by the alignment of diazepam, CGS-9896 and diindole, using a previously described pharmacophoric model. METHODS: Tilianin (30 to 300 mg/kg, ip. and 300 mg/kg, po.) and methanol crude extract (10 to 300 mg/kg, ip. and 300 mg/kg po.) from A. mexicana were evaluated for potential sedative and anxiolytic-like response drugs by using open-field, hole-board, cylinder of exploration, plus-maze and sodium pentobarbital-induced hypnosis mice methods. RESULTS: Methanol extract and Tilianin showed anxiolytic-like activity from a dosage of 30 mg/kg, ip. or 300 mg/kg, po. and were less potent than diazepam 0.1 mg/kg, a reference anxiolytic drug used. Moreover, depressant activity of both potentiates sodium pentobarbital (SP)-induced sleeping time. The anxiolytic-like effect of 30 mg/kg ip. observed for the extract and Tilianin, by using the plus-maze model, was partially prevented in the presence of flumazenil (a GABAA/BZD antagonist, 5 mg/kg ip.) but not in the presence of WAY 100635 (a selective 5-HT1A receptor antagonist, 0.32 mg/kg, ip.). Pharmacophoric modeling alignments of three agonist of GABAA/BZD allow identify seven chemical features. Tilianin contains six of the seven features previously determined. CONCLUSIONS: Results indicate that Tilianin is one of the bioactive metabolites in the anxiolytic-like activity of A. mexicana, reinforcing its central nervous system uses, where GABAA/BZD, but not 5-HT1A, receptors are partially involved.

Cardioprotective effects of tilianin in rat myocardial ischemia-reperfusion injury.[Pubmed:25405380]

Mol Med Rep. 2015 Mar;11(3):2227-33.

Tilianin, the main effective flavonoid monomer enriched from Dracocephalum moldavuca L., has been shown to have cardioprotective effects. However, the mechanism of Tilianin cardioprotection remains largely unknown. The present study aimed to investigate the effects of Tilianin preconditioning on myocardial ischemia/reperfusion injury and to analyze the possible mechanism of action. A total of 48 male Sprague Dawley rats were randomized into sham, model myocardial ischemia/reperfusion injury (MI/RI), propranolol hydrochloride positive control, and high, medium and lowdose Tilianin groups (n=8 each). The rats in the Tilianin groups were perfused with either 1.5, 2.5 or 5.0 mg/kg/d Tilianin a week prior to surgery. The positive control group were perfused with 25 mg/kg/d propranolol. Saline was administered to the sham surgery and the MI/RI groups. The MI/RI model was established by ligating the left anterior descending coronary artery for 30 min, which was subsequently removed and the mice were observed for 120 min prior to sacrifice. Na+K+ATPase, Ca2+ATPase, nitric oxide (NO), nitric oxide synthase (NOS) and endothelial systemrelated factors were analyzed using the respective detection kits. Immunohistochemistry was used to determine the expression levels of Bcl2 and Bax. Caspase3 activity was measured by quantitative polymerase chain reaction. The results showed that Tilianin preconditioning significantly increased ATPase activity (P<0.01 and P<0.05) as compared with the model group. With regards to the regulation of endothelial function, significant decreases (P<0.01 and P<0.05) were detected in the serum NO levels and myocardial NOS activity when Tilianin was administered to MI/RI rats, as compared with the model group, . In addition, the Tilianin drug groups exhibited dosedependent reductions in the serum levels of endothelin 1 and thromboxane B2, and increases in the serum levels of calcitonin generelated peptide and 6keto prostaglandin F1a as compared with the model group (P<0.01 and P<0.05). Notably, the administration of Tilianin significantly inhibited apoptosis, as evidenced by an increase in Bcl2 expression, and reductions in Bax and caspase3 mRNA expression levels (P<0.01 and P<0.05). These data indicate that pretreatment with Tilianin exerts potent cardioprotective effects in rats with MI/RI. The antiMI/RI effects comprised relieving calcium overload, correction of energy metabolism, improvement of endothelial function and inhibiting cell apoptosis.

Antihypertensive and vasorelaxant effects of tilianin isolated from Agastache mexicana are mediated by NO/cGMP pathway and potassium channel opening.[Pubmed:19447223]

Biochem Pharmacol. 2009 Jul 1;78(1):54-61.

Current investigation was undertaken to elucidate the mode of action of Tilianin, isolated from Agastache mexicana, as a vasorelaxant agent on in vitro functional rat thoracic aorta test and to investigate the in vivo antihypertensive effect on spontaneously hypertensive rats (SHR). Tilianin (0.002-933 microM) induced significant relaxation in a concentration- and endothelium-dependent and -independent manners in aortic rings pre-contracted with noradrenaline (NA, 0.1 microM), and serotonin (5-HT, 100 microM). Effect was more significant (p < 0.05) in endothelium-intact (+E) aorta rings than when endothelium was removed(E). Pre-treatment with N-nitro-L-arginine methyl ester (L-NAME; 10 microM) or 1-H-[1,2,4]-oxadiazolo-[4,3a]-quinoxalin-1-one (ODQ, 1 microM) produced a significant change of the relaxant response and activity was markedly inhibited, but not by indomethacin (10 microM) or atropine (1 microM). Furthermore, Tilianin (130 microM) provoked a significant displacement to the left in the relaxation curve induced by sodium nitroprusside (SNP; 0.32 nM to 0.1 microM). Moreover, Tilianin induced significant in vitro NO overproduction (1.49 +/- 0.86 microM of nitrites/g of tissue) in rat aorta compared with vehicle (p < 0.05). In addition, pre-treatment with tetraethylammonium (TEA, 5 mM) and 2-aminopyridine (2-AP, 0.1 microM) shifted to the right the relaxant curve induced by Tilianin (p < 0.05). Finally, a single oral administration of Tilianin (50 mg/kg) exhibited a significant decrease in systolic and diastolic blood pressures (p < 0.05) in SHR model. Results indicate that Tilianin mediates relaxation mainly by an endothelium-dependent manner,probably due to NO release, and also through an endothelium-independent pathway by opening K+ channels, both causing the antihypertensive effect.