Antifungal Effects of Drimane Sesquiterpenoids Isolated from Drimys winteri against Gaeumannomyces graminis var. tritici

Abstract

Gaeumannomyces graminis var. tritici (Ggt) is a soil-borne pathogen which causes ‘take-all’ disease affecting cereal roots. In wheat, Ggt is the most important biotic factor causing around 30-50% of yield losses. The chemical control of this fungal disease is difficult, due to Ggt is able to reside for a long time in soils. Therefore, the development of biotechnological strategies environmentally friendly to diminish the incidence of soil-borne diseases is highly desirable. Natural products are promissory strategy to biocontrol of plants pathogens. Special emphasis in medicinal plants due their fungitoxic effects have been reported. Drimys winteri (Canelo) is a medicinal plant widely used by the “mapuche” ethnic group from Chile due to its anti-inflammatory activity. In addition, inhibitory effects from canelo against phytopathogenic fungi and pest insects have been reported. In this study, we isolated, purified and identified six compounds of drimane sesquiterpenoid skeleton from canelo (drimenin, drimenol, polygodial, isodrimeninol, valdiviolide and drimendiol). Then, their antimicrobial effect against Ggt was evaluated. Compounds were identified by comparison of FTIR and the retention time by TLC, contrasting with pure standards. The putative antagonistic effects were confirmed by hyphal cell wall damage using confocal microscopy and lipid peroxidation. Here, we reported the high potential of drimane sesquiterpenoids as a natural antifungal against Ggt. Polygodial and isodrimeninol were the more effectives with an activity of LC50 between 7 and 10 μL-1 and higher fungal lipid peroxidation. Accordingly, natural sesquiterpenoids purified from canelo are biologically active against Ggt and could be used as natural biofungicide to sustainable agriculture. Importance More than two billion tons of pesticides are used every year worldwide. An interesting, sustainable alternative to control plant pathogens is the use of natural products obtained from plants, mainly in the case of medicinal plants that offer important secondary metabolites to human/animal health. In this study, we isolated, identified six pure drimane sesquiterpenoids obtained from barks of Drimys winteri. Additionally, we evaluated their antifungal activity against Gaaeumannomyces graminis, Ggt (the main biotic factor affecting cereal production, especially wheat) by the wall-fungus and lipid peroxidation. Obtained compounds showed important antifungal properties against Ggt, mainly isodrimenol which is the second compound more active before polygodial with an activity against Ggt LC50 around 9.5 ug mL-1. This information could be useful for the development of new natural or hemi-synthetic antifungal agents against soil-borne phytopathogens which could be used in a green agriculture

The Most Important Fungal Diseases of Cereals—Problems and Possible Solutions

“…Furthermore, synthetic plant protection products, natural plant extracts with fungitoxic activity can also be used. Paz et al [73] demonstrated the effective action of sesquiterpenoid drimans extracted from Drimys winteri, a natural antifungal agent against Gaeumannomyces graminis. Their action is based on the cell walls of the hyphae and consequently on their destruction.…”

In Silico Docking Studies of Bioactive Compounds in Ocimum gratissimum Essential Oil againstCandidapepsin-1 Enzyme from Candida albicans

“…tritici. 29 This fungus that attacks the roots of grass and cereal plants in temperate climates. The interactions of drimenin and Fluconazole with the amino acid residues in the enzyme are shown in Figure 4.…”

Drimane Sesquiterpene Aldehydes Control Candida Yeast Isolated from Candidemia in Chilean Patients

“…Moreover, polygodial displays potent antifungal activities against a broad spectrum of filamentous fungi including Botrytis cinerea [ 17 ], Gaeumannomyces graminis var. tritici [ 18 ] and parasitic yeast as Candida albicans with an IC50 of 3.13 µg/mL [ 19 ]. This activity is also enhanced in mixtures with anethole or miconazole.…”