Chemical Constituents Analysis And Studies On The Biological Toxicity Of Oleander

Compared with traditional pesticides,biological pesticides have a unique mode of action,can achieve the same effect at a low dose,and are specific to the target.Nowadays,with the rapid development of science and technology in the world,there are more and more fields involved in biological pesticides,such as plant-based pesticides,insecticides or fungicides,crops with transgenic resistance to harmful organisms,and compounds synthesized by artificial modification or bionics of natural substances,involving many fields such as animals,plants and microorganisms.Plant-derived pesticides,as a type of biological pesticides,are pesticides made from plants or their effective components which are toxic to other plant diseases and insect pests.For the research and development of plant-based pesticides,many types of plants have been used in China,such as Compositae,Euonymaceae,Apocynaceae,etc.The plants used in this study are oleander.As one of the most poisonous plants in the world,oleander contains a variety of toxic substances in its whole plant,some of which are extremely toxic,and may die if taken in small doses,such as cardiac glycosides.Cardiac glycosides belong to natural animal and plant toxins,which can have toxic or positive effects on the heart.These toxins are distributed in every part of oleander.Plutella xylostella is the tested pest in the toxicity test of this study.Plutella xylostella belongs to LEPIDOPTERA,which mainly harms some cruciferous plants.It can migrate around the world,and has small insect body,strong reproductive ability,strong ecological adaptability and strong drug resistance.The oviposition period of overwintering adults can reach three months,and the life cycle is short.In this experiment,the biological toxicity of ethanol extracts from oleander leaves and other plants to Plutella xylostella larvae and the biological toxicity of ethanol extracts from oleander flowers,stems and leaves to Plutella xylostella larvae were studied.The chemical components and relative contents in three parts of oleander were determined by Fourier transform infrared spectroscopy and HPLC-MS,which provided theoretical basis for the production of botanical pesticides from oleander.The research results show that:(1)The solution prepared with ethanol extract of oleander leaves as main raw material and Dafeiyang and Cinnamomum camphora as auxiliary materials has obvious poisoning activity against Plutella xylostella.(2)The ethanol extracts from flowers,stems and leaves of oleander have certain insecticidal activity,and the ethanol extract from the stem of oleander has higher insecticidal activity than the other two parts.The independent regression equation of ethanol extract from dry leaves of oleander is y=-3.316+1.769x,and the LC50 is 0.086 g/mL.(3)According to the absorption peaks of the same peak position in the ethanol extracts of flowers,stems and leaves of oleander,fatty compounds,benzene ring substances and glycosides are found in the ethanol extracts of the three parts.Ethanol extracts from flower and stem contain a certain amount of amino acids.According to the relative peak intensity ratio,it is known that benzene ring substances,glycosides and other potentially toxic substances contain more stems.(4)The ethanol extracts from flowers,stems and leaves of oleander were analyzed by HPLC-MS,and 34,31 and 33 chemical constituents were obtained respectively.It is speculated that eight chemical components,such as oleander B,caffeic acid and caffeic acid ethyl ester,which have the highest content in the ethanol extract of stem,may be the active components for killing Plutella xylostella.In addition,oleanolic acid,oleanolic acid,oleanolic acid,oleanolic acid,oleanolic acid and oleanolic acid may also be the active ingredients for killing Plutella xylostella.