Effect of Drought Condition of North Region of Saudi Arabia on Accumulation of Chemical Compounds, Antimicrobial and Larvicidal Activity of Thuja Orientalis

Drought stress and drastic condition of northern region especial high temperature in summer season affect widely on the chemical component of plant and its biological actively plant grow in these condition adapt to this stress by accumulation different compound, thugia it is tree grow in garden and farms, when it grows in desert habitat show different content, Gc-Ms analysis of the terpenoid fraction of the plant where it is best fraction given high antimicrobial and Larvicidal activity was done and show the presence of many promising diterpene compounds, Ferruginol, Torulosol, dihydro, 18-Oxo-kauran-17-yl acetate and Andrographolide. The antibacterial testing showed that, the tested gram-positive bacteria exhibited good susceptibility to the terpenoid fraction of methanol extract, which was Staphylococcus epidermidis and Staphylococcus aureus, recorded 13.0±0.7 and 11.0±0.0 mm inhibition zones, respectively. Indicating promising antibacterial activity against the gram-positive pathogens. While all the tested gram-negative bacteria recorded weak or no susceptibility. The larvicidal activity of plant was studied on Spodoptera littoralis , The lethal concentration was 27.63 % of terpenoid fraction of Thuja orientalis. The plant can considered as a good herbal insecticide instead of synthetic insect side after further studies where the IC50: Botanical pesticides are highly effective, and ecologically acceptable.