Synthesis and Antifungal Activities of Trichodermin Derivatives as Fungicides on Rice

Abstract

Twenty new trichodermin derivatives, 2a-5, containing alkoxy, acyloxy, and Br groups in 4-, 8-, 9-, 10- and 16-positions were synthesized and characterized. The antifungal activities of the new compounds against rice false smut (Ustilaginoidea virens), rice sheath blight (Rhizoctonia solani), and rice blast (Magnaporthe grisea) were evaluated. The results of bioassays indicated that the antifungal activities were particularly susceptible to changes at 4-, 8-, and 16-positions, but low to changes at 9- and 10-positions. Most of these target compounds exhibited good antifungal activities at the concentration of 50 mg l(-1) . Compound 4 (9-formyltrichodermin; EC50 0.80 mg l(-1) ) with an CHO group at 9-position displayed nearly the same level of antifungal activity against Ustilaginoidea virens as the commercial fungicide prochloraz (EC50 0.82 mg l(-1) ), while compound 3f ((8R)-8-{[(E)-3-phenylprop-2-enoyl]oxy}trichodermin; EC50 3.58 and 0.74 mg l(-1) ) with a cinnamyloxy group at C(8) exhibited much higher antifungal activities against Rhizoctonia solani and Magnaporthe grisea than the commercial fungicides prochloraz (EC50 0.96 mg l(-1) ) and propiconazole (EC50 5.92 mg l(-1) ), respectively. These data reveal that compounds 3f and 4 possess high antifungal activities and may serve as lead compounds for the development of fungicides in the future.

Synthesis of Trichodermin Derivatives and Their Antimicrobial and Cytotoxic Activities

“…The potency and broad biological activity shown by trichodermin ( 1 ) sparked our interest in amassing adequate amounts of this molecule to complete a study of its biological activity and to perform chemical transformations on the 1 skeleton with a view to modulating or enhancing this biological activity. Several efforts have been made to modulate the activity of trichothecenes as antifungal agents [21,22,23] with promising results. Total synthesis of trichodermin ( 1 ) [24] and trichodermol ( 2 ) [25,26] has been proposed.…”

“…In other studies, compound 10 exhibited good antifungal activity against Ustilaginoidea virens , R. solani , and M. grisea [22].…”

New Trichothecenes Isolated from the Marine Algicolous Fungus Trichoderma brevicompactum

“…In this study, in an attempt to identify bioactive compounds from ethyl acetate extract of the solid culture of T. brevicompactum NTU439 isolated from a marine alga M. rosea, we isolated four new trichothecenes (1-4), together with five known compounds, trichoderminol (5) [17], trichodermarin A (6) [12], trichodermarin E (7) [12], trichodermol (8) [20], and cycloneran-3,7,10,11-tetraol (9) [21] (Figure 1), and identified them by their spectral data and the comparison of spectroscopic data with the literature.…”

Heterologous Biosynthesis of the Fungal Sesquiterpene Trichodermol in Saccharomyces cerevisiae

“…It has attracted much attention due to significant inhibitory effects on some phytopathogenic fungi ( Shentu et al, 2014 ), and potent but selective cytotoxicity toward several human tumor and normal cells ( Su et al, 2013 ; Chien et al, 2017 ), suggesting that it is a promising candidate for the development of agrochemicals and antitumor agents. Although chemical modification of trichodermin has afforded new antifungal derivatives ( Xu et al, 2013 ; Cheng et al, 2015 ), the lack of enough material and reactive sites in its structure has limited further modification and evaluations. Therefore, it is urgent to develop an alternative route for efficient generation of trichodermin and congeners for structure-activity relationship (SAR) study and further development.…”