Scorpionicidal activity of secondary metabolites from Paecilomyces sp. CMAA1686 against Tityus serrulatus.

Abstract

INTRODUCTION\nUrban pests pose enormous risks to human health. Control initiatives are carried out in regions of high infestation and incidence of accidents caused by scorpions.\n\n\nOBJECTIVE\nIn this study, we aimed to analyze the anti-scorpionic activity of fungal isolates obtained from a cemetery in Brazil.\n\n\nMATERIALS AND METHODS\nA total of thirteen fungi were subjected to a bioassay test against Tityus serrulatus, and the two isolates with the highest scorpionicidal activity were selected for molecular identification through sequencing of the ITS DNA hypervariable region and large-scale cultivation on liquid medium for secondary metabolite extraction. The crude extracts were partitioned by solid-phase extraction, and the resulting purified extracts were tested for anti-scorpionic activity. The extracts from one of the isolates presented better results and were submitted to UPLC-MS/MS. The metabolomics data were submitted to GNPS website for Molecular Networking and MASST searches. We also performed a MolNetEnhancer analysis to identify the chemical classes of the molecules found in the samples.\n\n\nRESULTS\nThe most promising fungal isolate was identified as Paecilomyces sp. CMAA1686 which has 98% of similarity to Paecilomyces formosus. The sub-fractions C and D had the best activity against the scorpions (54 and 32% mortality, respectively). Molecular Networking and MolNetEnhancer revealed a range of molecular classes in our extracts that are known to include bioactive metabolites from Paecilomyces species.\n\n\nCONCLUSIONS\nThe scorpionicidal activity of Paecilomyces sp. CMAA1686 and its secondary metabolites may provide new alternative compounds for biological and chemical control of scorpions from the species T. serrulatus. Paecilomyces sp. CMAA1686 is an isolate that has great potential for isolation of secondary metabolites.