Phytochemical Profile and Insecticidal Potential of Two Halophytes, Atriplex halimus and Suaeda fruticosa, Against...

This study aimed to investigate the phytochemical profile and evaluate the in vitro and in silico insecticidal activities of methanolic extracts from two halophytes, Atriplex halimus (A. halimus) and Suaeda fruticosa (S. fruticosa). The investigations included phytochemical screening, determination of total phenolic, flavonoid, and tannin contents, as well as compound identification by high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS). The insecticidal activity was assessed through direct-contact bioassays against adults of Tribolium confusum. In addition, a molecular docking study was performed targeting the acetylcholinesterase enzyme (AChE). Phytochemical screening revealed the presence of several bioactive compounds in both plant extracts. A. halimus showed the highest flavonoid content, whereas S. fruticosa exhibited the highest levels of total phenolics and tannins, corresponding to superior insecticidal effect, as evidenced by its lower lethal concentration 50% (LC₅₀) value after 96 h of treatment. HPLC-ESI-QTOF-MS analysis in negative ion mode led to the identification of 24 bioactive constituents in A. halimus and 29 in S. fruticosa. The in silico study confirmed that most of the identified polyphenols exhibited binding affinity toward insect acetylcholinesterase, including kaempferol 3-O-rutinoside-7-O-glucoside, naringin, feruloyltyramine, and rutin.