Obovatol and obovatal, novel biphenyl ether lignans from the leaves of Magnolia obovata Thunb.

Abstract

Two new biphenyl ether lignans, named obovatol and obovatal, were isolated from the leaves of M. abovata Thunb. (Magnoliaceae), and their chemical structures were determined to be 4'',5''-diallyl-2,3-dihydroxybiphenyl ether and 3,4-dihydroxy-5-(p-allylphenoxy)cinnamic aldehyde, respectively, by means of chemical and spectral studies. The former substance showed antibacterial activity against a cariogenic bacterium, Streptococcus mutans, but was less active than magnolol and honokiol.