| Pyhscion is a kind of monoanthracene nucleus 1,8-dihydroxyanthraquinone derivative extracted from Polygonum cuspidatum and other plants,as well as one of the important ingredients of rhubarb,with anticancer,antitumor,antivirus,repair damaged DNA,antifungal,antiviral,anti-inflammatory,antioxidant,enzyme inhibition,lipid regulation,neuroprotection and other functions.Pyhscion has been registered as a green bio-source pesticide in China and used to control wheat powdery mildew.And it is called a special medicine for powdery mildew,which has the characteristics of good effect,low toxicity to humans and animals,and high environmental compatibility.Amino acid is also a common small molecule compound with important physiological and structural functions in nature.It is often used as an important chemical raw material to be widely used in the creation of new pesticides.Compounds containing an amide structure have certain biological activities in weeding,insecticide and sterilization.So,In order to find novel anthraquinone compounds with high fungicidal activity,a series of novel physcion-amino acid derivatives 2a?6p were designed and synthesized by introducing the amino acids into the lead compound Physcion by etherification,hydrolysis and acid chloride reaction according to the method of active substructure combination.The structures of the target compounds were confirmed by ~1H NMR and HRMS.A total of 25 new compounds were synthesized in this experiment,including 2intermediates,9 amino acids containing L configuration,8 acids after hydrolysis,3amino acids with D configuration,and 3 acids after hydrolysis.The preliminary bioassay data showed that all the target products exhibited certain fungicidal activities against the six kinds of plant pathogens at 0.2mmo L/L.Compounds(6e~1+6e~2)had the highest inhibitory activities against Rhizoctonia solani and Colletotrichum gloeosporioides with 69.93%and 67.18%,respectively.Compounds(5a~1+5a~2)?(6a~1+6a~2)and(6c~1+6c~2)had moderate inhibitory activities against Rhizoctonia solani with 60.51%,53.28%and 58.50%,respectively.The inhibitory activities of compounds(6a~1+6a~2)and(6c~1+6c~2)against Colletotrichum gloeosporioides were 49.25%and47.61%,respectively.The above compounds showed significantly higher fungicidal activities than the lead compound physcion.Compared with the amino acid ester coupling of pyhscion and the amino acid coupling of Pyhscion with different optical configurations,there was no significant difference in the antifungal activity,indicating that L-configuration and D-configuration had no effect on the anti activity of the coupling.In addition,the D-configuration pyhscion-amino acid compounds have better antifungal activity than the esters before hydrolysis,which is consistent with the results of the L-configuration coupling.Among them,the best effect is(6k~1+6k~2),and the antifungal activity against Rhizoctonia solani and Colletotrichum gloeosporioides is68.95%and 65.68%,respectively.The preliminary analysis of structure effective relationship showed that the introduction of amino acids at the hydroxyl position of physcion can enhance its fungicidal activity on Rhizoctonia solani,Pyricularia oryzae,Sclerotinia sclerotiorum,Alteraria alternate and Colletotrichum gloeosporioide.The phloem conductance of(6a~1+6a~2),(6b~1+6b~2)and(6d~1+6d~2)in castor oil seedling was determined by Thermo Ulti Mate3000 TSQ-Guantis.The results showed that none of the three compounds had phloem conductance under the condition of this experiment... |
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