Improvement Of Flavonoid And Anthraquinone Compound Accumulation In Adventitious Roots Of Oplopanax Elatus

Opolopanax elatus is a rare plant species belonging to Araliacea,which has extremely high medicinal value.However,the wild resource of O.elatus has dramatically reduced and its artificial cultivation has not been completely established at present.Hence,the culture of adventitious roots using plant tissue culture technology has been considered an effective method for producing the raw plant material.This approach has a significant meaning for development and product production of O.elat O.During the adventitious root culture,elicitors can efficiently improve the accumulation of bioactive compounds,thus,the present study used methyl jasmonate(MeJA)and salicylic acid(SA)as the elicitor to investigate the effect of concentrations and treatment days of MeJA and SA on contents of flavonoids and anthraquinones to select a suitable elicitor and its using method.The present study can provide a technical support and theoretical basis to explore and produce the products of O.elatus.In the first experiemt,the present study investigated conditions of high performance liquid chromatography(HPLC)analysis for flavonids and antiraquinone determination.To correctly analyze flavonoids(quercetin and kaempferide)and anthraquinones(aloe-emodin,rhein,and emodin),the HPLC analysis of adventitious root samples prepared using different methods was performed.The result showed that the peak shape was presented well for flavoniod analysis when the sample prepared using the SP-3 method,namely,powdered adventitious roots were soaked in the solution of 80%methanol and 5%hydrochloric acidunder a reflux condenser at 60℃ for 1 h before extracting with ethyl acetate;for anthraquinone analysis,when the sample prepared using the SP-5 method,namely,powdered adventitious roots were soaked in mixture solution of trichloromethane and methanol with equal proportionby ultrasonic treatment for 30 min,clear peaks of HPLC appearred.Furthermore,the effect of concentrations of MeJA and SA on flavonoid and anthraquinone contents was determined.The contents of flavonoids(quercetin and kaempferide)and anthraquinones(aloe-emodin,rhein,and emodin)were maximum when adventitious roots were treated with 200 μM MeJA,this concentration was obviously better than other MeJA concentrations.In addition,the concentration of 100 μM was the optimal SA concentration.The 8-day treatment of both elicitors was the most favorable for increasing flavonoid and anthraquinone accumulation.Compared with SA,MeJA was more effective,contents of quercetin and kaempferide in adventitious roots were 2.7-fold and 2.1-fold,and contents of aloe-emodin,rhein,and emodin were 2.1-fold,1.5-fold,and 2.6-fold more than the control group(untreated with an elicitor),respectively.The 2.4 g·L-1 of quercetin,2.2 g·L-1 of kaempferide,1.5 g·L-1of aloe-emodin,5.9 g·L-1of rhein,and 2.6 g L-1of emodin were produced.Thus,the method that 30-day-old adventitious roots were treated with 200 μM MeJA for 8 days,can efficiently enhance the flavonoids and anthraquinones in adventitious roots of O.elatus.