ANTIOXIDATIVE COMPONENTS OF TANSHEN (SALVIA-MILTIORRHIZA BUNG)

Rhizomes of tanshen (Salvia miltiorrhiza Bung) were pulverized and extracted with diethyl ether. The extract was washed with 5% sodium carbonate solution, freed of solvents, and applied to a silica gel column. Seven colorful bands ranging from light yellow to dark brown were resolved and collected. After certain purification procedures, such as stepwise recrystallization and preparative TLC, seven crystalline quinone-type compounds were obtained, namely tanshinone I, dihydrotanshinone I, tanshinone IIa, tanshinone IIb, methylenetanshinquinone, cryptotanshinone, and danshenxinkun B, all of which had color. Confirmation of the identifications was carried out by mass spectroscopy and infrared spectrometry. Measurement of the antioxidant activity in lard of these quinones was performed with two methods, the Rancimat method and the Shaal oven method in conjunction with peroxide value determination. Except for tanshinone IIA, all the quinones exhibited antioxidant activities, of which dihydrotanshinone I, tanshinone I, methylenetanshinquinone, and cryptotanshinone showed strong activities comparable to that of BHA and BHT. These compounds may have the potential of being used as natural antioxidants in foods and cosmetics. © 1990, American Chemical Society. All rights reserved.