Further lignans from Haplophyllum cappadocicum

(A-)-4,4',9-trihydroxy-3,3'-dimethoxy-9,9' epoxylignan (1), a 9,9'-epoxylignan encompassing a rather rarely encountered dibenzylbutyrolactol structure, has been isolated from Haplophyllum cappadocicum (Rutaceae) of Turkish origin. Since 1 is so far reported only from a Pinus species, this is the first isolation of this compound from the Rutaceae. The title plant also afforded (-)-tuberculatin (4), a b-D apioside of diphyllin, which has been isolated previously from two other Haplophyllum species, suggesting that this glycoside may be a common element of the Haplophyllum genus. Structure elucidation was done by extensive spectral analyses.