Cytotoxic Constituents of the Bark of Hypericum roeperianum towards Multidrug-Resistant Cancer Cells

Figure 1

Chemical structures of phytochemicals isolated from the bark methanol extract of Hypericum roeperianum. 1: Trichadonic acid; 2: fridelan-3-one; 3: 2-hydroxy-5-methoxyxanthone; 4 : 1,3,6,7-tetrahydroxyxanthone or norathyriol; 5 : 1,3,5,6-tetrahydroxyxanthone; 6: betulenic acid; and 7 : 3′-hydroxymethyl-2′-(4″-hydroxy-3″,5″-dimethoxyphenyl)-5′,6′:5,6-(6,8-dihydroxyxanthone)-1′,4′-dioxane; 8 : 3′-hydroxymethyl-2′-(4″-hydroxy-3″,5″-dimethoxyphenyl)-5′,6′:5,6-(xanthone)-1′,4′-dioxane.