Studies On The Antifungal Activity Of4Kinds Of Chinese Herbs And The Preparation Of Chitosan Microspheres

Funycides derived from Green Plant is paid more attention by a lot of countries in the world,due to its lower toxicity,lower depositiono,accordance with the environment and need of the modern env ronmental protection and human health.At present,it is one of important approaches to develop botanical fungicide from Chine seherbs。First, Fungal inhibitory activity of4plants including Coptis chinensis, Tripterygium wilfkrdii,Artemisia apiacea, Melia toosendan extracts against Alternaria solani, Monilinia fructicola,Vermicularia capsicisyd,Botrytis cinerea were determined using a growth rate method.with a concentration of1g/ml.The results showed that ethanol extracts(1g/ml)from4Chinese herb medicines had different antimicrobial effect every12hours. Antimicrobial rates of Coptis chinensis extract produced100.%inhibition of mycelium growth rates in Monilinia fructicola and50%inhibition of mycelium growth rates in Botrytis cinerea. Coptis chinensis and Tripterygium wilfkrdii extract against Alternaria solani were more than60%. Artemisia apiacea and Melia toosendan have good inhibition effects. Toxicity to three pathogenic fungi of Coptis chinensis and Melia toosendan was also respectively determined for further study on the inhibition effect.with a concentration of0-100mg/ml, the better inhibition effect was,the higher concentration was.The EC50of Coptis chinensis against Alternaria solani and Monilinia fructicola were14.09mg/ml and0.91mg/ml respectively. The EC50of Melia toosendan against Vermicularia capsici and Alternaria solani were8.21mg/ml and20.02mg/ml respectively.Berberine is the main ingredient of Coptis chinensis. The inhibitory effects of berberine and chitosan against Alternaria solani, Monilinia fructicola,Vermicularia capsici,Botrytis cinerea were tested. The MIC of the berberine affecting Monilinia fructicola was2.8125/6mg/ml. Berberine has significant inhibitory effects on sporangia germinati.Considering to the inhibitory effects of berberine and chitosan against mildew and the inducement to plant.The chitosan microspheres containing berberine were prepared by emulsion-chemical crosslink technique.Basic uniform-sized microencapsulation conditions were established by the primary experimentrcertain reaction temperature45℃, pH5.1, reaction time3h.The better preparation procedure with respect to particles size distribution, embedding rate and drug loading were optimized by the orthogonal experimental design:chitosan0.2g,berberine0.02g, bean oil70ml,2%acetometer solution50%10ml, glutaraldehyde1.2ml.The chitosan micro spheres containing berberine was shown to have good spherical geometry,a smooth surface and suitable size distribution under microscope and scanning electron micrographs. Average diameter of microspheres was15μm,drug loading was4.78%,embedding rate was78.98%.The result of FT-IR suggested that there is not new chemical bond between chition and berberine.In vitro drug released80%slowly in the phosphate buffered saline (pH6.8) by30days. Fungal inhibitory activity of microspheres against Alternaria solani, Monilinia fructicola, Vermicularia capsicisyd, Botrytis cinerea was determined using a growth rate method with a concentration of5jug/ml, microspheres produced100.%inhibition against Monilinia fructicola and65.%inhibition against Alternaria solani.From above,we can see that berberine-loaded chitosan microspheres could be used for fungicide.