Pharmacokinetics of honokiol in Trachinotus ovatus following administration of honokiol monomer and Magnolia officinalis extracts

Abstract

Honokiol, an active ingredient in Magnolia officinalis, has a good efficacy in controlling Cryptocaryon irritans infection, which can parasitize in the gill and epidermis of fish and cause mass mortality to marine fish cultures. However, the lack of pharmacokinetic information on honokiol in fish has limited its use. Here, a high-performance liquid chromatography (HPLC) method for detecting honokiol in fish tissues was developed and used to compare the pharmacokinetics of honokiol following oral administration of pure honokiol (HTS group) and M. officinalis extracts (METS group) in Trachinotus ovatus at a dose of 12 mg/kg at 27 °C. Honokiol was rapidly absorbed by fish and showed a bimodal phenomenon in the plasma. The maximum concentration (C_max) in plasma was at 0.5 h in both the HTS (38.92 μg/mL) and METS groups (14.58 μg/mL). The C_max of honokiol in the gill and epidermis in the HTS group (239.69 μg/g and 46.39 μg/g, respectively) were higher than in the METS group (9.44 μg/g and 14.30 μg/g, respectively). However, the elimination half-life (t_1/2) of honokiol in the plasma, gill, and epidermis in the HTS group (0.93 h, 1.26 h, and 1.32 h, respectively) were shorter than the METS group (1.12 h, 3.11 h, and 5.14 h, respectively). In both treatment group, honokiol was completely eliminated from all tissues at 12 h post oral administration. Compared with the HTS group, the bioavailability (F_r) of honokiol in the METS group increased in the plasma (105.26 %), liver (489.58 %), and muscle (796.91 %), but decreased in the gill (10.94 %), kidney (74.22 %), and epidermis (93.69 %). This study revealed the pharmacokinetic profile of honokiol and indicates that improved efficacy for controlling C. irritans infestation could be obtained by oral administration of pure honokiol rather than with M. officinalis extracts.