PHARMACOKINETIC STUDIES ON DRUG-HERB INTERACTION OF METFORMIN AND SYZYGIUM AROMATICUM AQUEOUS FLOWER EXTRACT IN SWISS ALBINO RATS.

Herb-drug interactions can be clinically relevant when conventional and herbal treatments are used together to treat and manage chronic conditions like diabetes mellitus. With its well-known erectile dysfunction and anti-diabetic qualities, Syzygium aromaticum is reported to be used in conjunction with orthodox medications like metformin. The aim of this study was to investigate the pharmacokinetics of drug-herb interaction involving metformin and S. aromaticum aqueous extract in Swiss albino rats received a single dose of metformin (5 mg/kg), then, after a washout period of two weeks, they received concurrently a single dosage of metformin (5 mg/kg) and extract of S. aromaticum (30 mg/kg). Whole blood samples (1 ml) were carefully drawn by tail bleeding for pharmacokinetics analysis at 0, 0.5, 1, 2-, 3-, 4- and 24-hours following administration. Co-administration of metformin and S. aromaticum affected all the pharmacokinetic parameters of metformin, significantly (P < 0.05). Co- administration of S. aromaticum extract significantly increased etformin's Cmax (21.46 ± 1.90 to 64.78 ± 4.23 µg/ml; P=0.021) and AUC (50.74 ± 5.74 to 86.27 ± 7.92 µg·h/ml; P=0.031), while Tmax decreased from 1.85 ± 0.14 to 1.20 ± 0.01 h (P=0.011), and Ka increased significantly (P=0.028). The elimination half-life (t1/2) was reduced (0.42 ± 0.04 to 0.18 ± 0.01 h; P=0.017), with a significant decrease in Vd (P=0.028). Clearance (Cl) showed a non-significant reduction. The findings show that the pharmacological effects of metformin may be enhanced by S. aromaticum extract, and patients should be informed of the potential implications of taking metformin and S. aromaticum at the same time. [ABSTRACT FROM AUTHOR]