Study On Extraction-isolation And Pharmacological Activities Of Total Flavonoids From Oroxylun Indicum(L) Vent

Objective: To provide the scientific basis for further isolating and preparing activitysite or monomer compound of flavonoids from oroxylun indicum,we optimized theconditions for extraction and purification of total flavonoids and determined theircontents. Meanwhile, we studied on the antioxidant activities of total flavonoids fromoroxylun indicum in vitro, anti-apoptosis effect as well as the characteristics ofpharmacokinetics in rats’ body.Methods: The method of solvent extraction and isolation was used to extract andpurify total flavonoids from oroxylun indicum.,The abilities to scavenge the hydroxylradicals, superoxide anion radical and DPPH radical were tested by UV assay. Theinhibition on MCF-7proliferation of OF-60was determined by MTT. Flow cytometrymethods were administrated to analyze the apoptosis rate of MCF-7treated withOF-60. HPLC method was employed to determine the contents of total flavonoids andthe pharmacokinetics of its crude extracts in rat in vivo.Results: The optimum extraction conditions of flavonoids from oroxylun indicumfollowed as70%ethanol solution,70℃, the ratio of1:8with the oroxylun indicumpowders and extractive solution, reflux three times for each two hours by water-soak.The extractive rate of flavonoids from oroxylun indicum was19.50%under theseconditions.The optimum separation and purification conditions of crude flavonoidsfrom oroxylun indicum were determined as macroporous resin of HPD100, the elutedsolution of60%(v/v) ethanol, the speed of elution of1.0BV/h, the volume elution of5.0BV, and the eluted rate exceeded90%.The results of antioxidant assays showedthat the ability of crude flavonoids and elutions with different concentration of ethanolto scavenge the hydroxyl radicals was OF-60> OF-80> OFC> OF-40in successively.The actions to clear superoxide anion radical and to remove the DPPH radical were OF-60> OFC> OF-80> OF-40in successively.The antioxidant capacityenhancement depent on the increasing concentration of flavonoids. The inhibitiveeffect on MCF-7proliferation presented a concentration-dependent manner in a rangeof0-1000μg/mL. The inhibitvie effect on MCF-7proliferation with a concentration of1000μg/mL of OF-60reached to39.94%, which showed a significant diffecence bycomparison with the control group(P＜0.01vs control group）. The results of flowcytometry assays showed that the concentration of0μg/mL,200μg/mL,400μg/mLand600μg/mL of OF-60could induce MCF-7to apoptosis with an apoptosis rate of3.89%,11.07%,21.32%and24.19%, respectively. By detecting the content ofquercetin, the processes of pharmacokinetics in rat of crude flavonoids from oroxylunindicum in vivo were t1/2=2.62±0.26, Cmax=372.93±61.72, V/F=0.41±0.26, which wereconsistent with one-compartment open model.Conclusion: The optimum experimental conditions of flavonoids from oroxylunindicum were70%ethanol solvent extraction and macroporous resin of HPD100forpurification.The flavonoids from oroxylun indicum have strong antioxidantcapacity,including OF-60on MCF-7cells with significantly inhibiting proliferationand inducing apoptosis.The processes of pharmacokinetics in rat of crude flavonoidsfrom oroxylun indicum in vivo were consistent with one-compartment open model bydetecting the content of quercetin.