Complexation with phosphatidyl choline as a strategy for absorption enhancement of boswellic acid

Boswellic acids (BAs) are isolated from oleo gum resin of Boswellia serrata and are reported to be effective as anti-inflammatory, hypolipidemic, immunomodulatory, and anti-tumor. Pharmacokinetic studies of boswellic acid reveal its poor absorption through the intestine. The objective of the present study is to enhance bioavailability of boswellic acid by its complexation with phosphatidylcholine. A complex of boswellic acid was prepared with phosphatidylcholine and characterized on the basis of solubility, melting point, TLC, and IR. An everted intestine sac technique was used to study ex-vivo drug absorption of boswellic acid-phosphatidylcholine (BA-PC) complex and plain boswellic acid. Anti-inflammatory activity of the complex was compared with boswellic acid in carrageenan-induced paw edema in rats. Hypolipidemic activity was also evaluated in Triton-induced hyperlipidemia. The complex was also converted into vesicles (phytosomes) and compared with other vesicular systems (liposomes and niosomes) by evaluating its anti-inflammatory effect. Analytical reports along with spectroscopic data revealed the formation of a complex. The results of ex-vivo study show that BA-PC complex has significantly increased absorption compared with boswellic acid, when given in equimolar doses. The complex showed better anti-inflammatory and hypolipidemic activity as compared to BA. Among all vesicular systems phytosomes showed maximum anti-inflammatory activity. Enhanced bioavailability of the BA-PC complex may be due to the amphiphilic nature of the complex, which greatly enhance the water and lipid solubility of the boswellic acid. The present study clearly indicates the superiority of complex over boswellic acid, in terms of better absorption, enhanced bioavailability and improved pharmacokinetics.