Phytotoxic, cytogenotoxic, and insecticidal activities of compounds from extracts of freshwater Lyngbya sp

Abstract

The development of agroecology has promoted the discovery of new bioactive compounds that might act as biocides to control infections and microbial contamination. Algae belonging to Lyngbya genus produce several allelochemicals, which are compounds with crop protection potential. The present study aimed to examine primary and secondary compounds derived from Lyngbya sp. extracts (aqueous and hydroethanolic) on phytotoxic, cytogenotoxic, and insecticidal activities. Determination of compounds indicated the presence predominantly of proteins and flavonoids. The extracts presented physicochemical characteristics that produced (1) 89% germination inhibition using hydroethanolic extract and (2) diminished development of seedlings of L. sativa by hydroethanolic extract as evidenced by reduced radicles length in 83.54%. Aqueous and hydroethanolic Lyngbya sp. extracts significantly interfered with meristematic cells of A. cepa, as evidenced by chromosomal alterations and aberrant mitotic phases in cells. Extracts also exhibited pro-oxidative activity and a potent insecticidal potential on S. zeamais, indicating that the hydroethanolic extract produced 100% insect mortality at 75 mg/ml after 48 hr while the aqueous extract initiated 90% mortality at the same concentration after 82 hr. Therefore, data demonstrate that Lyngbya genus provides basic information for new environmental and ecotoxicological studies to seek a possible source of proteins and flavonoids to be used in agroecological management.