Study On Chemical Constituents And Biological Activities Of Total Flavonoids In The Peel Of Passiflora Purpurea From Guangxi

Passiflora edulis Sims belongs to Passiflora Linn.Native to South America,are mainly distributed in tropical and subtropical regions.And now have been planted in Guangxi,Guangdong,Hainan,Fujian and other places in the south of China.Fresh fruits taste unique,juice has sour and sweet taste.There are many kinds of flavonoids in Passiflora edulis Sims peels(PESP),which have antioxidant,hypoglycemic,bactericidal and anti-inflammatory effects.In this paper,the extraction technology,chemical composition and biological activity of total flavonoids from PESP in China were comprehensively studied.In order to provide theoretical reference for the comprehensive utilization of PESP.The main research contents and results are as follows.We used ultrasonic-assisted ethanol extraction method to extract the total flavonoids from PESP in Guangxi Province,and through single factor experiment to optimize the extraction conditions.The results showed that the yield was 13.08%.The total flavonoids from the PESP was determined by AICl3 colorimetric method with rutin and orientin as the standard.The total flavonoids in peels was 8.53 mg RT/g DW(Rutin)and 5.66 mg OR/g DW(Orientin).On response surface methodology,extract yield,total flavonoid content and DPPH activity were selected to optimize the extraction conditions for the first time.The optimaized extraction conditions of total flavonoids from PESP was the ratio of liquid to material 40:1(mL/g),ultrasonic time 30 min and ethanol concentration 67%.Under such conditions,the extraction yeild in PESP was 12.58%,the total flavonoid content was 11.56 mg RT/g DW and SC50 of DPPH was 0.186 mg/mL.The flavonoids composition of PESP in China was analyzed by LC-MS for the first time.A total of 19 compounds were identified,including 11 flavonoids and their glycosides:Luteolin-6-C-fucoside(4),Isoorientin(5),Orientin(6),Luteolin-7-O-glucoside(19),Apigenin(27),Vitexin(29),Apigenin-6,8-C-di-glucoside(34),Vitexin-2"-O-glucoside(43),Chrysin(50),Chrysin-6-C-hexoside(51)and Chrysin-6,8-C-di-hexoside(52).4 flavonols and their glycosides:Rutin(59),Quercetin-7-O-glucoside(61),Quercetin-3,7-di-O-glucoside(63)and Kaemp ferol-3-O-glucoside(68).4 anthocyanins and their glycosides:The compounds are contained Delphindin-3-O-glucoside(80),Pe.onidin-3-O-glucoside(82),Petunidin-3-O-glucoside(85),Pelargonidin-3-O-rutinoside(88),Among them,Luteolin-6-C-fucoside(4)and Luteolin-7-O-glucoside(19)were reported for the first time in PESP in China.The study evaluated antioxidant activity in FRAP,neuroprotective activity and anti-inflammatory activity of the PESP total flavonoids from China for the first time.The antioxidant,antibacterial and ?-glucosidase activities of PESP were studied comprehensively.In antioxidant test,PESP showed the antioxidant activities in DPPH(SC50=0.179 mg/mL),ABTS(0.17 mM TE/g),Fe3+ reduction ability(2.35 mM Fe2+/g)and neuronal oxidative stress protection.In the test of zone of inhibition(ZOI)and minimum inhibitory concentration(MIC),PESP showed antibacterial activity on four tested bacteria(ZOI:5.10±0.42?8.03±0.21 mm,MIC:312.5?2500 ?g/mL).While PESP showed the strongest antibacterial activity against Micrococcus tetragenus(ZOI=8.03±0.21 mm,MIC=312.5?g/mL).In ?-glucosidase inhibition test,PESP showed significant ?-glucosidase inhibition activity(IC50=3.064 mg/mL).In anti-inflammatory test in vitro,PESP showd anti-inflammatory activity,the relative expression of 1L-6,1L-1? and TNF-? decreased significantly with 1.0 mg/mL PESP solution.The above results of this paper indicating that the PESP in China is one of the effective natural sources of flavonoids.PESP has the potential to be developed as a natural food additive and functional food.