Triterpenoids and an alkamide from Ganoderma tsugae

Abstract Ganoderma tsugae is a medicinal mushroom. In a continual study on the bioactive constituents of this fungus, a new lanostanoid, 3 β -acetoxy-16 α -hydroxy-24ξ-methyl-5α-lanosta-8,25-dien-21-oic acid, named tsugaric acid F ( 1 ) and a novel palmitamide, N -(3′ α ,4′ β -dihydroxy-2′ β -(hydroxymethyl)-1′ β -(cyclobutyl)palmitamide ( 2 ) were isolated and characterized from the fruit bodies of G. tsugae , and three novel seco -lanostanoids, 3,4- seco -8α,9α-epoxy-5 α -lanosta-21-oic acid 3,4 lactone ( 5 ), 3,4- seco -5 β -lanosta-7,9(11),4(29)-trien-3,21-dioic acid-3-methyl ester ( 6 ), 3,4- seco -5 β -lanosta-7,9(11),4(29)-trien-3,21-dioic acid ( 7 ), and a known compound, 3-oxo-5α-lanosta-8-en-21-oic acid ( 4 ) were prepared from 3 . The structures of new compounds, 1 , 2 , 5 – 7 were determined by spectroscopic methods. Compounds 1 and 4 showed inhibitory effects on xanthine oxidase (XO) with an IC 50 values of 313.3 ± 80.0 and 43.9 ± 29.9 μM, respectively when 7 exhibited potent inhibitory effect on superoxide anion generation in rat neutrophils stimulated with formyl-Met-Leu-Phe (fMLP)/cytochalasin B (CB) with an IC 50 values of 1.3 ± 0.2 μM. Compounds 4 – 7 showed weak cytotoxic activities against PC3 cells. These results indicated that 4 and 7 may be used as cancer chemopreventive agents.