Bioactivity and phenolic composition of extracts of noni (Morinda citrifolia L., Rubiaceae) in tomato moth (Tuta absoluta Meyrick, 1917) (Lepidoptera: Gelechiidae)

Abstract

We evaluated the bioactivity of Morinda citrifolia L., Rubiaceae on Tuta absoluta (Lepidoptera: Gelechiidae) and quantified the phenolic components. Ethanolic extracts of leaves and fruits were used in five concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 mg / L). The leaves of the plants were immersed in the solution (10 s) and placed in contact with five caterpillars of the same instar in Petri dishes. The caterpillars were kept under controlled conditions, temperature of 25 ± 1 ° C, and relative humidity of 65 ± 10%, photophase of 12 h. The experimental design was completely randomized with five concentrations, five replicates with two different extracts, the control being distilled water. The phenolic composition of the extracts was determined by high-performance liquid chromatography (HPLC) based on the retention times using the standard external method. Leaf extracts and fruits of M. citrifolia had bioinseticidal activity against caterpillars (leaves at 0.02 mg / L gave 100% mortality and fruits at 0.03 mg / L gave 46.08% mortality). The greater efficiency of leaves can be attributed to their high percentage of phenolic compounds and flavonoids. Eleven phenolic compounds were identified and quantified in extracts of leaves and fruits that showed significant bioactivity.

Chemical characterization of the species Raphanus sativus L. under different conditions of fertilization and water stress conditions

“…The total phenolic content was quantified by the method described by Barros et al (2018) with some adaptations. For the gallic acid calibration curve (R 2 = 0.995), 0.04 g of gallic acid was weighed in 8 ml MeOH (stock solution).…”

“…The flavonoid quantification was performed according to the methodology of Barros et al (2018). 1 mg quercetin was weighed and diluted in 1 mL MeOH.…”