Optimized preparation of quassinoids rich Eurycoma longifolia Jack, TAF2-phospholipid complex and its effects on oral bioavailability

Eurycoma longifolia Jack is a plant of the genus Eurycoma in Simaroubaceae. Eurycomanone is one of the main quassinoids of E. longifolia. Unfortunately, these quassinoids exhibit low bioavailability . In the present study, a phospholipid complex (TAF2-PC) was prepared to improve the oral bioavailability of TAF2 (Tongkat Ali Fraction 2). The complexation rate of eurycomanone and phospholipid was used as the index of success in the phospholipid complexes. The effects of reaction solvent, reaction temperature, drug concentration, drug-lipid ratio and reaction time on thecomplexation rate were investigated. Response Surface-Box-Behnken Design Method was performed to optimize the preparation technology and the pharmacokinetics of phospholipid complex of TAF2 were studied in rats. Our results showed that the optimum preparation condition of TAF2-phospholipid complex were as follows: reaction solvent, anhydrous ethanol; reaction time, 1 h; the ratio of TAF2 to phospholipid, 2.28; reaction temperature, 40.85 ℃; TAF2 concentration, 32.66 mg/ml; and complexation rate, 95.04 ± 0.4% (n=3).The results of pharmacokinetic study showed that the relative bioavailability was increased to 209.20% in the TAF2-phospholipid complex-treated rats.Thus,this phospholipid-complex-technique shows potential for enhancing oral bioavailability of poorly absorbed quassinoid-rich E. longifolia extract, TAF2.