Peptide fraction from latex of Calotropis procera exhibits antifungal and insecticidal activities

Abstract

Latex is an endogenous fluid exuded by some plants after injury. It is rich in different molecules and has shown many biological activities against different fungi and insects. This work aimed to isolate a peptide fraction from Calotropis procera (PepCp) latex and to evaluate its activity against two fungi and an insect. The chromatographic profile showed that PepCp is constituted mainly by 7 kDa peptides. PepCp showed a low effect against the spore germination of both fungi Colletotrichum gloeosporioides and Fusarium solani. However, PepCp (1.25 mg mL−1) inhibited the mycelial growth of C. gloeosporioides by 80%. On the other hand, PepCp, 0.05% (w/w), reduced the larval weight of Callosobruchus maculatus by 90%, and at 0.2%, no larva was found. At 0.05%, there was a delay of 2 days in the emergence of adult insects, while at 0.1%, no emergence of adult insects was noticed. Our results corroborate the hypothesis of the defense role played by latex and that PepCp can be an interesting biological source of new fungicidal or insecticidal peptides.