Two New Citrinin Dimers from a Volcano Ash‐Derived Fungus, Penicillium citrinum HGY1‐5

Two new citrinin dimers, penidicitrinin A ((2 R ,3 S ,5a S ,9 R ,10 S ,12a R ,12b R )‐2,3,5a,6,9,10,12a,12b‐octahydro‐7,12a‐dihydroxy‐12b‐methoxy‐2,3,4,9,10,11‐hexamethyl‐5 H ‐difuro[2,3‐ b : 2′,3′‐ h ]xanthen‐5‐one; 1 ) and penidicitrinin B ((1 S ,3 R ,4 S )‐1‐{2,6‐dihydroxy‐4‐[(1 S ,2 R )‐2‐hydroxy‐1‐methylpropyl]‐3‐methylphenyl}‐3,4‐dihydro‐3,4,5‐trimethyl‐1 H ‐2‐benzopyran‐6,8‐diol; 2 ), together with three known citrinin monomers were isolated from a volcano ash‐derived fungus, Penicillium citrinum HGY1‐5. Their structures were established by spectroscopic methods, and they showed no cytotoxicity against two tumor cell lines.