β‐Resorcylic Acid Derivatives, with Their Phytotoxic Activities, from the Endophytic Fungus Lasiodiplodia theobromae in the Mangrove Plant Xylocarpus granatum

Abstract Nine new β ‐resorcylic acid derivatives, (15 S )‐ de ‐ O ‐methyllasiodiplodin ( 1 ), (13 S ,15 S )‐13‐hydroxy‐ de‐O ‐methyllasiodiplodin ( 2 ), (14 S ,15 S )‐14‐hydroxy‐ de‐O ‐methyllasiodiplodin ( 3 ), (13 R ,14 S ,15 S )‐13,14‐dihydroxy‐ de‐O ‐methyllasiodiplodin ( 4 ), ethyl ( S )‐2,4‐dihydroxy‐6‐(8‐hydroxynonyl)benzoate ( 5 ), ethyl 2,4‐dihydroxy‐6‐(8‐hydroxyheptyl)benzoate ( 6 ), ethyl 2,4‐dihydroxy‐6‐(4‐methoxycarbonylbutyl)benzoate ( 7 ), 3‐(2‐ethoxycarbonyl‐3,5‐dihydroxyphenyl)propionic acid ( 8 ), and isobutyl ( S )‐2,4‐dihydroxy‐6‐(8‐hydroxynonyl)benzoate ( 9 ), together with a known ethyl 2,4‐dihydroxy‐6‐(8‐oxononyl)benzoate ( 10 ) were obtained from Lasiodiplodia theobromae GC‐22. The structures of these compounds were elucidated by extensive spectroscopic analyses. Compounds 1 , 3 , and 6 showed growth inhibitory effects against Digitaria ciliaris . Conversely, treatment with compounds 5 , 6 , 7 , 9 , and 10 stimulated elongation activity toward the root of Lactuca sativa . These data expand the repertoire of new β ‐resorcylic acid derivatives that may function as lead compounds in the synthesis of new agrochemical agents.