Reducing effect of Salvia miltiorrhiza extracts on alcohol intake: influence of vehicle.

A previous study demonstrated that an extract of Salvia miltiorrhiza, a medicinal herb highly valued in Chinese folk medicine for the treatment of different pathologies, including insomnia, was capable of reducing voluntary alcohol intake in selectively bred Sardinian alcohol-preferring (sP) rats. The present study was designed to evaluate the suitability of different emulsifying, suspending agents and solvents as vehicles through which Salvia miltiorrhiza extracts can exert their reducing effect on alcohol intake. A single dose (100 mg/kg) of a standardised extract of Salvia miltiorrhiza was dissolved in either pure Polysorbate 80, arachis oil, PEG 400, or Polyoxyl 35 castor oil, or suspended in 0.5% CMC in water, and administered acutely by gavage to sP rats. A significant and specific reduction in alcohol intake was recorded only in rats treated with the combination of Polysorbate 80 plus the Salvia miltiorrhiza extract. A further experiment demonstrated that the ability of the combination of Polysorbate 80 in water plus the Salvia miltiorrhiza extract to decrease alcohol intake was dependent upon the concentration of Polysorbate 80. The results of the present study demonstrate that Polysorbate 80 is a proper vehicle for unravelling the reducing effect of Salvia miltiorrhiza extracts on alcohol intake. The ability of Polysorbate 80 to form micelles with the active ingredient(s) of the Salvia miltiorrhiza may explain these results. They may also offer relevant information for pharmaceutical preparation of Salvia miltiorrhiza extract to be used in future clinical trials.