Endophytic fungi as enhancers of secondary metabolite production in Duroia saccifera cell suspension

The chemical response of callogenic suspension cultures of the plant Duroia saccifera was evaluated through elicitation by the endophytes Colletotrichum dianesei and Xylaria sp. Dried mycelia and methanolic extracts of dried mycelia from both fungi were used as elicitators. D. saccifera calli were multiplied in Murashige and Skoog medium with growth regulators, while endophytic fungi were cultivated in three different media: potato-dextrose (PD), czapek (CZ) or sabouraud (SB). Part of mycelia cultured in PD medium were dried and autoclaved. The remaining mycelia from the PD, and those from SB and CZ media were filtered, dried, weighed, and extracted with methanol (MeOH). The methanol fungal extracts used as elicitors were chemically analized by 1H nuclear magnetic resonance (1H-NMR) and thin layer chromatography (TLC) and their toxicity was evaluated using Artemia salina as a bioindicator. For elicitation, 100 mg of mycelium or 20 mg of fungal extract were used for 2 grams of friable callus. After 30 days, the elicited callogenic suspensions were filtered, weighed, dried, and extracted with methanol. The culture medium obtained from filtration was lyophilized and partitioned with ethyl acetate (EtOAc). Analyzes were performed using TLC and 1H-NMR. As results, it was observed that fungal extracts of C. dianesei and Xylaria sp. intensified the classes of metabolites already produced by the callus culture, with exception of the extract from Xylaria sp. grown in PD medium, which yielded the production of different aromatic substances did not present in the callus control extract. This fungal extract also exhibited high toxicity against Artemia salina. This suggests a correlation between the level of extract toxicity and the callus elicitation response.