Study On Extraction Technology And Bioactivities Of Effective Components From Perilla Leaves

Perilla frutescens, belonging to the Labiatae family, is an annual herbaceous plant andhas a cultivation history of more than2000years in China, which is one of medicinal andedible plants promulgated firstly by the Chinese Ministry of Health. Recently, perilla withhigh economic value is increasingly concerned about the world due to the unique naturalactive ingredients in its leaves. In this research, the extraction technology and biologicalactivities of rosmarinic acid extracts, essential oils and anthocyanins in leaves of differentperilla varieties were studied, this can provide theoretical basis for the development andutilization of perilla. The results as follows:Firstly, the rosmarinic acid extracts in leaves were obtained by ultrasound assistedsolvent extraction method from ten perilla varieties and the antioxidant activities, antibacterialactivities and cytotoxic activities were determinated furtherly. The results showed that therewere significant differences in the extraction rates and the contents of rosmarinic acid in therosmarinic acid extracts from leaves among ten varieties. The PX-1had the highest extractionrate, up to5.34%, and the ZY-10-1had the highest content of rosmarinic acid in therosmarinic acid extract, up to18.7%. There were significant differences in antioxidantactivities, antibacterial activities and cytotoxic activities among ten varieties. The rosmarinicacid extract of ZY-10-1has the strongest activity of scavenging radicals and the IC50values ofDPPH, hydroxyl radicals and superoxide anion are0.203,1.056and0.130g/L, respectively.That of ZY-10-1had the strongest inhibiting activities to E.coli, Staphylococcus aureus,Bacillius subtilis and Yeast, its inhibition zone diameter were9.3,8.7,9.3and11.8mm, andthe MIC were32.381,29.783,8.867and6.790mg/L, respectively. The ZY-10, ZB-1andZB-10-1rosmarinic acid extracts had stronger lethal effect of shrimp and their LC50were0.864g/L,0.429g/L and1.398g/L, respectively. Notable positive correlation existed betweenthe rosmarinic acid content in perilla leaves and its antioxidant activities, antibacterial activities and cytotoxic activities, respectively.Secondly, The essential oils in leaves were obtained by steam distillation method and theantioxidant activities, antibacterial activities were determined. The results showed that therewere significant differences in the extraction rates, antioxidant activities and antibacterialactivities of leaves essential oils among nine perilla varieties. The CR-1had the highestextraction rate, up to1.043%. The ZY-10-1essential oil had the strongest activities ofscavenging DPPH and superoxide anion radicals, and the IC50values were0.241and0.053g/L, respectively. The ZY-10-1and ZB-1essential oils had the strongest activities ofscavenging hydroxyl radicals, and the IC50values were0.084and0.081g/L, respectively. TheZY-10-1essential oil had the strongest inhibiting activities to E.coli, Staphylococcus aureus,Bacillius and subtilis, the inhibition zone diameter were22.9,25.7and22.2mm, and the MICwere0.272,0.225and0.281g/L, respectively.Thirdly, The perilla leaves anthocyanins extracted by ultrasound assisted citricacid-ethanol method were purified with macroporous resin and thieir antioxidant activitieswere furtherly determinated. The optimal extraction conditions of anthocyanin wereextraction temperature50℃, extraction time30min, liquid-solid ratio30:1, citric acidconcentration90g/L, the extraction rate was5.511mg/100g. The optimal purifyingconditions were adsorption resin AB-8, liquid-solid ratio80:1, adsorption time21h, theanthocyanin purity of B-1was improved from0.748%up to5.347%. There were significantdifferences in the extraction rates and antioxidant activities of leaves anthocyanin among ninevarieties. The CR-1anthocyanins had the highest extraction rate,33.064mg/100g. PX-1andB-1had the strongest antioxidant activities, and the IC50of scavenging DPPH radicals,hydroxyl radicals, superoxide anion radicals were respectively6.055,2.273and9.780mg/Lfor PX-1and5.983,2.173and31.132mg/L for B-1. Notable positive correlation existedbetween perilla anthocyanin content and its antioxidant activities.