Phenolic profile and biopesticidal potential of Moringa oleifera extracts: antioxidant and insecticidal activities against stored pests

This study investigated the phenolic composition of Moringa oleifera organ extracts via RP-HPLC. In addition, their antioxidant and insecticidal potential were assessed. Polyphenols, flavonoids and condensed tannin levels depend on the different plant parts. Phenolic composition was distinguished by the presence of quercetin-3-O-galactoside as the major compound with high insecticidal activity due to their phenolic composition. So, repellent proprieties against two stored pest species Tribolium castaneum and Sitophilus oryzae without food substrate were assessed. In addition, contact toxicity toward T. castaneum with wheat flour substrate was investigated. The repulsive dose of Moringa extracts from different morphological organs was more marked for leaves compared to stems, seeds and flowers with the lowest repulsive dose (RD50 = 0.069 µl/cm2) for T. castaneum. Moreover, M. oleifera MeOH extracts from different morphological organs exhibited a contact toxicity potential against T. castaneum with and without wheat flour substrate. MeOH extracts of M. oleifera from leaves caused the highest mortality percentages (83.33%) after 48 h of exposure for both concentrations of 0.9 and 1.9 µl/cm2 towards T. castaneum on wheat flour substrate. To reduce pesticide, Drumstick could offer an effective protection to T. castaneum and S. oryzae.