Insecticidal potential of an endophytic Cladosporium velox against Spodoptera litura mediated through inhibition of alpha glycosidases

•Endophytic Cladosporium velox with alpha glucosidase inhibitory activity was used in the study.•Partially purified active fractions evaluated for insecticidal potential against Spodoptera lituraSpodoptera litura•Survival, development and reproductive potential of females adversely affected•The active component was identified to be chlorogenic acid.•Chlorogenic acid also inhibited alpha glycosidases of S. litura (in vivo).

Alpha glucosidase inhibitory activity was exhibited by partially purified fractions obtained from an endophytic Cladosporium velox, isolated from Tinospora cordifolia. Taking into account the increasing importance of digestive enzyme inhibitors as insecticidal agents, the entomopathogenic potential of the fractions obtained was evaluated against Spodoptera litura (Fab.), a polyphagous pest. Considerable mortality was obtained when the larvae were fed on diet supplemented with the partially purified extract. All the concentrations of the extract significantly prolonged the overall developmental period of S. litura. At higher concentrations, the extract influenced the longevity of females as well as their reproductive potential. Phytochemical analysis revealed the presence of phenolic compounds in the active fraction. The phenolic compound responsible for the bioactivities was purified and identified to be chlorogenic acid using HPLC and MS analysis. The content of chlorogenic acid in the extract was quantified to be 250 μg/ml. The purified compound also demonstrated inhibition of alpha glycosidases in vivo. The present study indicates that the endophyte imparted resistance to the insects in the plants could be mediated through chlorogenic acid targeting the alpha glycosidases present in the gut of the insect. The isolate obtained can be exploited for the production of chlorogenic acid, which has the potential to be exploited as a biocontrol agent against S. litura.

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