Table 1. Pharmacokinetic Parameters of Caffeine after Oral Administration as Alone (Group I) and Intravenous Administration of Pinocembrin Followed by Oral Administration of Caffeine (Group II) in Rats^a.

	caffeine
pharmacokinetic parameters	group I (alone)	group II (with pinocembrin)
Cmax (ng/mL)	1063 ± 102	1319 ± 140
Tmax (h)	0.7 ± 0.1	1.1 ± 0.2
AUC0–t (ng·h/mL)	2838 ± 141	4629 ± 409**
AUC0–∞ (ng·h/mL)	2851 ± 139	4864 ± 407**
T1/2 (h)	1.1 ± 0.1	0.8 ± 0.1
Vd/F (L/kg)	8.4 ± 1.2	4.1 ± 0.9*
Cl/F (L/h/kg)	5.3 ± 0.3	3.3 ± 0.3***

^aData are presented as the mean ± SEM (n = 5). *p < 0.05, ^**p < 0.01, and ^***p < 0.001 denote statistical significance when compared between group I versus group II. C_max, the highest plasma concentration; T_max, the time to reach C_max; AUC_0–t, the area under the curve for plasma concentrations from zero to the last measurable plasma sample time; AUC_0–∞, the area under the curve for plasma concentrations from zero to infinity; T_1/2, elimination half-life; V_d/F, the volume of distribution after oral administration; Cl/F, clearance after oral administration.