| Objective: Fennel is the dried ripe fruit of the umbelliaceae herb fennel(Foeniculum vulgare Mill.),which is widely cultivated worldwide.It has very important edible and medicinal values in addition to being used as a spice.Fennel has anti-inflammatory,anti-cancer,antioxidant and gastrointestinal regulating functions,and its main active components are polyphenols and volatile oil.There is evidence that Fennel volatile oil has cytotoxic activity against various tumor cells.However,volatile oil is mostly small molecules volatile components with poor stability which limits its application in vivo.Therefore,this study aims to optimize the best extraction method of Fennel volatile oil,and prepare Fennel volatile oil into nanoparticles and optimize the preparation conditions.The antitumor activity of nanoparticles loaded with Fennel volatile oil on human colon cancer RKO cells is also explored.Methods: Fennel volatile oil was extracted by steam distillation,microwave assisted extraction and enzymolysis+microwave assisted extraction.The chemical composition of Fennel volatile oil was analyzed by gas chromatography-mass spectrometry(GC-MS).The chemical composition and the content of anisole were used as indexes to optimize the best extraction method.Single factor test and response surface method(RSM)were used to determine the optimal extraction conditions of the above extraction method.Using Eudragit S100(ES100)as the carrier material,nanoparticles loaded with fennel volatile oil were prepared by nano-precipitation method and the preparation technology was optimized by single factor experiment.The morphology of nanoparticles was observed by transmission electron microscope and Malvern partilce size meter.The release in vitro was measured by dialysis method.The stability of nanoparticles at different temperatures was investigated.The effect of nanoparticles loade with fennel volatile oil on proliferation,migration and invasion of human colon cancer RKO cells were detected by MTT assay,scratch assay and Transwell assay,respectivelyResults: The results of GC-MS showed that 10 compounds,5 compounds and 5compounds were detected in Fennel volatile oil extracted by steam distillation,microwave-assisted extraction and enzymatic hydrolysis+microwave-assisted extraction,and the content of anisole was 57.12%,60.49% and 90.59,respectively.The optimal extraction process of Fennel volatile oil by enzymolysis+microwave-assisted extraction was as follows: liquid-solid ratio 13:1,adding 5% cellulase,enzymolysis at 30℃ for 15 min at p H5.70,followed by microwave extraction for 37 min at 410 W.Under these conditions,the extraction rate of dill volatile oil was 1.58±0.027%.the optimal preparation conditions were as follows: the volume ratio of organic phase to aqueous phase was 1:2,the concentration of ES100 was 14mg/m L,the temperature was 30℃,the stirring speed was 1500 rpm,and the dosage ration of fennel volatile oil to ES100 was 4:7.The prepared nanoparticles loaded with fennel volatile oil had good morphology,high encapsulation rate and drug loading,and can be released in the environment of p H7.4 that was suitable to play a role in the colon.The nanoparticles were stable for 5 weeks at 25℃.It was also found that nanoparticles loaded with fennel volatile oil could significantly inhibit the proliferation,migration and invasion of colon cancer RKO cells,showing excellent anti-colon cancer activity in vitro.Conclusion: Enzymatic hydrolysis and microwave-assisted extraction is suitable for the extraction of Fennel volatile oil.The method is green and pollution-free,with high extraction rate and high content of anisole.Fennel volatile oil nanoparticles prepared by ES100 have good quality and stable properties,and can significantly inhibit the proliferation,migration and invasion of human colon cancer RKO cells,which can be used in the targeted therapy of colon cancer.These results provide important theoretical basis for the development and utilization of Fennel volatile oil and the discovery of new drugs for the treatment of colon cancer. |
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