Pharmacokinetics of Cymbopogon citratus Infusion in Rats after Single Oral Dose Administration

Cymbopogon citratus, commonly known as lemongrass, is a tropical herb used in worldwide traditional medicine for centuries. Studies previously conducted by our team demonstrated its antioxidant and anti-inflammatory effects, and recently, the antiinflammatory potential was also observed in vivo. However, little is known about its pharmacokinetics. The current study aimed at obtaining, for the first time, the pharmacokinetic profile of lemongrass infusion after a single dose oral administration to rats. All in vivo experimental procedures were approved by the Portuguese Veterinary General Division. Male Wistar rats were administered with a single oral dose of lemongrass infusion (68.24 mg/kg) and aliquots of plasma were collected at 0.5, 1, 1.5, 2, 4, 8, 12 and 24 h post-dosing. Liver and kidney samples were collected at 1, 2, 4, 8 and 24 h post-dosing. Plasma and tissues homogenates were processed and luteolin (LUT), luteolin 7-O-glucuronide (L7G), chrysoeriol (CHR), diosmetin (DIO) and luteolin 3’-O-sulphate (L3’S) were quantified employing a RP-HPLC-DAD method. The mean concentration-time profiles obtained were analyzed by a noncompartmental pharmacokinetic analysis using the WinNonlin®. The pharmacokinetic studies revealed the presence of LUT, L7G, CHR, DIO and L3’S. L7G and L3’S were rapidly detected, with maximum plasma concentrations at 30 min after oral administrations. The concentration-time profile of liver samples evidenced compounds undetected in plasma: LUT, CHR and DIO. L7G, CHR and L3’S were detected in the liver from the first hour and stayed in the tissue until at least 24h.The kidney concentration-time profile revealed the presence of the same compounds detected in plasma. The pharmacokinetic analysis showed that the compounds present in lemongrass infusion are not present in plasma, liver or kidneys. On the other hand, L7G and L3’S were the major metabolites found in plasma and tissues, suggesting that lemongrass polyphenols are promptly metabolized in vivo and their metabolites may be the ones responsible for the anti-inflammatory activity of C. citratus, when orally administered.