Bioavailability of lycopene in the rat: the role of intestinal lymphatic transport.

OBJECTIVES

As a natural antioxidant derived from dietary sources, lycopene has attracted considerable attention as a potent chemopreventative agent. Lycopene is an extremely lipophilic compound and absorption from dietary sources is estimated to be low and highly variable. As a result, plasma lycopene concentrations are poorly correlated with dietary intake of lycopene rich food stuffs. The development of an oral formulation remains a challenge that requires a better understanding of the mechanisms involved in the intestinal absorption of this compound.

METHODS

The solubility of lycopene in simulated physiological fluids and bile salt mixed micelle formulations was determined. The extent of intestinal lymphatic transport and the absolute bioavailability of lycopene from a range of biorelevant media was evaluated in a mesenteric lymph duct cannulated anaesthetised rat model.

RESULTS

The absolute bioavailability of lycopene after 8 h was 1.85 +/- 0.39%. The overall extent of the intestinal lymphatic transport was in the range of 0.6-3.4% of the administered dose. A strong positive correlation (r(2) > 0.9) between intestinal lycopene levels and intestinal triglyceride levels was demonstrated.

CONCLUSIONS

The intestinal lymphatic route is the major uptake mechanism of lycopene from the gastrointestinal tract. Lycopene transport in intestinal lymph was closely associated with triglyceride transport in the lymph. Formulation strategies designed to promote intestinal lymphatic uptake, such as lipid-based formulations containing long-chain fatty acids (LCFA) or lecithin, may serve to enhance oral bioavailability of lycopene.