Activity Of Sugarcane Molasses Volatile Components And Preparation Of Slow-Release Mosquito Repellent Cream

This study mainly evaluated the extraction process,compositions,biological activities（antibacterial,anti-inflammatory and antioxidant activities）of sugarcane molasses volatile components（SMVC）,and prepared slow-release mosquito repellent cream.This study provides a theoretical basis for the further development and utilization of sugarcane molasses and SMVC.The specific research results are as follows:1.Study on extraction and preparation technology of SMVC.The traditional hydrodistillation（HD）method and microwave-assisted hydrodistillation（MAHD）method were used to extract SMVC from sugarcane molasses.Compared with the HD method,the MAHD method could significantly shorten the extraction time and increase the yield of SMVC.The optimized extraction process of SMVC by MAHD method were as followings:extraction time of 60 min,microwave power of 500W,and liquid-material ratio of 1.95 m L/m L.Under the optimal extraction conditions,the yield of SMVC reached 0.0788±0.002%,which was close to predicted value（0.0789%）.The 37 and 32 chemical components were identified respectively by GC-MS from SMVC extracted by HD and MAHD method.The main components of SMVC extracted by the two methods are isoamyl alcohol,ethyl acetate,isobutanol,isovaleraldehyde,2-methylbutanal,furfural,and 2-acetylpyrrole,but their content was different.2.Study on antibacterial activity and action mechanism of SMVC.The result in vitro antibacterial experiments showed the antibacterial activity of SMVC against Escherichia coli,Staphylococcus aureus,Pseudomonas aeruginosa,and Salmonella typhimurium.The results showed that SMVC had broad-spectrum antibacterial activity against four food-borne bacteria,and the antibacterial ability of SMVC against four food-borne bacteria were in the order of Salmonella typhimurium>Staphylococcus aureus>Escherichia coli>Pseudomonas aeruginosa.The SMVC prepared by MAHD method showed lower MIC and MBC against four bacteria than SMVC prepared by HD method.As time went by and temperature increased,the antibacterial activity of SMVC gradually decreased against four bacteria.Compared with normal bacteria,four bacteria treated with SMVC showed sparse number of bacteria,greatly reduced number of communities,and irregular distribution through microscopic observation.The submicroscopic structure of Escherichia coli and Staphylococcus aureus treated with SMVC were observed by scanning electron microscope（SEM）,and the result showed that the treated Escherichia coli and Staphylococcus aureus had wrinkles on the bacterial surface,the boundary between cells was not obvious,and some of cells were seriously damaged,the contents of cell cavity flow out,the integrity of the cell was severely damaged,and the bacterial body was seriously deformed.This suggested that the antibacterial mechanism of SMVC against Escherichia coli and Staphylococcus aureus might be due to the changes of cell membrane and mitochondrial membrane,which resulted in the leakage of cell contents,leading to cell death.3.Anti-inflammatory in vivo and anti-oxidative in vitro study of SMVC.The anti-inflammatory and antioxidant activities of SMVC were investigated by in vivo anti-inflammatory and in vitro antioxidant experiments.The results of in vivo anti-inflammatory experiments showed that SMVC could significantly inhibit xylene-induced ear swelling inflammation in mice,acetic acid-induced abdominal permeability increase inflammation in mice,and granulomatosis hyperplasia inflammation in mice,and the inhibitory effect of SMVC gradually decreases with decrease of concentration.The inhibitory effect of the dose group（0.2 m L/kg）was almost the same as that of the positive control（aspirin）,and respectively reached 66.0±4.611%,43.27±6.337%,and 14.06±3.340%.The results of in vitro antioxidant experiments showed that SMVC had strong scavenging ability on ABTS and DPPH free radicals,and the IC₅₀ of SMVC were 2.21±0.122 mg/m L and9.28±0.122 mg/m L against ABTS and DPPH free radicals.In conclusion,SMVC has strong anti-inflammatory activity,and the DPPH and ABTS free radical scavenging ability of SMVC might be conducive to the recovery of inflammation.4.Preparation and characterization of SMVC nanometer drug-loaded microcapsules.The nano-drug-loaded microcapsules（MCM-41-SMVC）was prepared and characterized by ultraviolet（UV）spectroscopy,infrared（IR）spectroscopy,microscopic imaging（MI）,SEM,thermogravimetric analysis（TGA）,and pore size analysis.The results showed that SMVC had been successfully adsorbed in the mesopores of MCM-41,and had good thermal stability.In addition,the MCM-41-SMVC also had high drug loading and good sustained release performance.5.Formulation screening and quality evaluation of SMVC slow-release mosquito repellent cream.The optimal prescription of the nano-slow-release mosquito repellent cream was screened by single factor and orthogonal experiments,and the drug loading,stability,safety on mice skin,and mosquito repellent activity of nano-slow-release mosquito repellent cream were also evaluated.The results of prescription screening experiment showed that the optimal prescription of nano-slow-release mosquito repellent cream was the ternary oil phase ratio of liquid paraffin∶stearic acid∶cetanol（5.5∶1.2∶2.2）,and the binary water phase ratio of glycerol∶deionized water（3∶7）,and the ratio of oil phase-water phase（1∶5）,under these conditions,the score of nanometer sustained-release mosquito repellent cream was 18.5±0.611.The stability,drug loading,and safety test of nano-slow-release mosquito repellent cream results showed that nano-slow-release mosquito repellent cream had good stability,and the overall score of nano-slow-release mosquito repellent cream is the highest with drug loading of 5%.In addition,the nano-slow-release mosquito repellent cream did not affect intact skin of mice（no any erythema and edema）,and had slight irritation on damaged skin of mice.The results of the mosquito repellent experiment showed that the complete repelling time（2 h）and effective repelling time（4 h）of nano-slow-release mosquito repellent cream surpassed SMVC and Liushen toilet water against Aedes albopictus,and the effective repelling time reached the B level of the international repellent evaluation,so the mosquito repellent effect of nano-slow-release mosquito repellent cream was not only strong,but also long-lasting.