Separation and purification of tanshinone from Salvia miltiorrhiza by combination of silica gel and high-speed counter-current chromatography Pharmacokinetics of main components in Salvia Miltiorrhizae Radix et Rhizoma diterpene quinones composition and its solid dispersion micro-pellets in rats in vivo Separation and purification of tanshinone from Salvia miltiorrhiza by combination of silica gel and high-speed counter-current chromatography