Characterization of Terpenoids from the Ambrosia Beetle Symbiont and Laurel Wilt Pathogen Harringtonia lauricola .

Little is known concerning terpenoids produced by members of the fungal order Ophiostomales, with the member Harringtonia lauricola having the unique lifestyle of being a beetle symbiont but potentially devastating tree pathogen. Nine known terpenoids, including six labdane diterpenoids ( 1 - 6 ) and three hopane triterpenes ( 7 - 9 ), were isolated from H. lauricola ethyl acetate (EtOAc) extracts for the first time. All compounds were tested for various in vitro bioactivities. Six compounds, 2 , 4 , 5 , 6 , 7 , and 9 , are described functionally. Compounds 2 , 4 , 5 , and 9 expressed potent antiproliferative activity against the MCF-7, HepG2 and A549 cancer cell lines, with half-maximal inhibitory concentrations (IC 50 s) ~12.54-26.06 μM. Antimicrobial activity bioassays revealed that compounds 4 , 5 , and 9 exhibited substantial effects against Gram-negative bacteria ( Escherichia coli and Ralstonia solanacearum ) with minimum inhibitory concentration (MIC) values between 3.13 and 12.50 μg/mL. Little activity was seen towards Gram-positive bacteria for any of the compounds, whereas compounds 2 , 4 , 7 , and 9 expressed antifungal activities ( Fusarium oxysporum ) with MIC values ranging from 6.25 to 25.00 μg/mL. Compounds 4 , 5 , and 9 also displayed free radical scavenging abilities towards 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide (O 2- ), with IC 50 values of compounds 2 , 4 , and 6 ~3.45-14.04 μg/mL and 22.87-53.31 μg/mL towards DPPH and O 2- , respectively. These data provide an insight into the biopharmaceutical potential of terpenoids from this group of fungal insect symbionts and plant pathogens.