Study On Extraction Of Cucurbitacin B From Watermelon (Citrullus Colocynthis) Vine And Functional Properties Of Solid Lipid Nanoparticles Of Cucurbitacin B

Cucurbitacin B was extracted from watermelon(Citrullus colocynthis)vines by the ultrasonic-assisted extraction.The ultrasonic-assisted extraction was optimized by the combination of the single-factor experiment and response surface methodology.The results showed that the ultrasonic temperature was the key factor affecting the cucurbitacin B extraction rate,while the ethanol concentration and ultrasonic time showed less influence on the extraction rate.The extraction rate of the cucurbitactin B reached to 84.7%when the ethanol concentration was 85%with the ultrasonic temperature of 80? for 30min.The solid lipid nanoparticle of cucurbitacin B was prepared by high pressure homogenization.The solid lipid nanoparticle of cucurbitacin B was constituted by the cucurbitacin B,lipid(monoglyceride)and emulsifier(the mixture of soybean lecithin and poloxamer 188).The parameters of the high pressure homogenization were optimized by response surface methodology with the homogenization pressure,lipid content and emulsifier content as the main factors,and the encapsulation efficiency as the response.The homogenization pressure was the key factor affecting the encapsulation efficiency of cucurbitacin B,followed by the lipid content and emulsifier content.When the homogenization pressure was 74.8MPa,and the ratio of the lipid:emulsifier:cucurbitacin B was 12.6:10.3:1,the encapsulation efficiency of cucurbitacin B reached the maximum of 92.4%.The validation experiment showed that the relative deviation between real and theoretical value was only 1.62%.The regression model was reliable.Finally,the physical properties and vitro functional properties of the prepared cucurbitacin B solid lipid nanoparticles were evaluated.The average particle size of the cucurbitacin B lipid nanoparticles prepared by the optimal formulation and process was 72 nm.Diameter uniformity and Zeta potential value of-27.0mv,the encapsulation efficiency of 90.93%,drug loading 1.5%.CuB-SLN was basically stable storaging for 3months in 4?.Toxicity and proliferation inhibition in vitro showed that the proliferation of HepG2 cells treated with cucurbitacin B and cucurbitacin B lipid nanoparticles was significantly inhibited and the inhibitory effect was concentration dependent.Hoechst 33258 fluorescent staining showed that human liver cancer HepG2 cells treating with different concentrations(50,100,150,200nM)cucurbitacin B lipid nanoparticles after 24h appeared to have the typical characteristics of apoptosis,chromatin edge set,nuclear condensation,nuclear Fragmented,and apoptotic bodies produced,the proportion of apoptotic cells increased with the increase of cucurbitacin B concentration.The results of Western blotting showed that the increase of cucurbitacin B could decrease the expression of P-JAK2 and P-STAT3 protein in a concentration-dependent manner,which indicated that cucurbitacin B could effectively inhibit the proliferation of JAK2/STAT3 pathway.