STUDIES ON THE ACTIVE PRINCIPLES OF DAN-SHEN Ⅴ. ISOLATION AND STRUCTURES OF PRZEWAQUINONE A AND PRZEWAQUINONE B

Two new diterpenequinones named przewaquinone A and przewaquinone B were isolated from Salvia przewalskii Maxim. var. mandarinorum (Diels) Stib.The structures of przewaquinone A (C₁₉ H₁₈ O₄, mp 173-5℃) and przewaquinone B (C₁₈ H₁₂ O₄, mp 242-3℃)were elucidated as (Ⅰ) and (Ⅱ_b) by spectral analyses and chemical methods, respectively.Przewaquinone A was shown to have antitumor activities on mice and to exhibit stronger inhibition against Staphylococcus aureus than cryptotanshinone.