Research On The Active Ingredient And Volatile Components Of Lycium Ruthenicum Murr

Lycium ruthenicum (Murr.) belongs to the genus Lycium of the family Solanaceae. In China, it is mainly distributed in the western region and mostly used in the folk medicine or tea. The theoretical study of L.ruthenicum mainly focuses on the chemical constituents, like polysaccharides, brass, anthocyanins, etc., but few study have been reported on the active ingredients and the volatile components.This paper was focus on the effects of chemical extraction(i.e.,extracts) and in vitro digestion(i.e.,digesta) methods on the polyphenol content of Lycium ruthenicum Murr.. Four different methods including DPPH, FRAP, ABTS, and ORAC were used to measure its antioxidant activity. Meanwhile, the major components of anthocyanins were identified, and the effects of different brewing process on the anthocyanin content and antioxidant were studied. Finally, this study analysed the aroma composition and content in infusions by using SPME/GC-MS and sensory evaluation. The main conclusions of this paper are as follows:1. In this paper, two methods including in vitro digestion and chemical extraction were used to extracting polyphenols in L.ruthenicum. Overall, the antioxidation of chemical extraction method was higher than that in in vitro digestion. Compared with chemical extraction, in vitro digestion had less total phenols, total anthocyanins, flavonoids and ascorbic acid, but more free phenolic acids. It indicated that pH and enzymes played an important role in damaging phenolics, anthocyanins, flavonoids and ascorbic acid, but creating more free phenolic acids in in vitro digestion process. The results showed that using in vitro method was more comprehensive to determine the active ingredient content of L.ruthenicum than traditional extraction methods.2. As the Antioxidant mechanism and applicable scope was different among ABTS, FRAP, ABTS and ORAC, there were slight differences in the results. But on the whole, the antioxidant activity of chemical extraction was higher than that of in vitro digestion, probablily because the variation of pH and enzyme in in vitro digestion lead to reducation of phenolics. Total phenolic content(TPC) and total anthocyanin content(TAC) both had high correlation with antioxidant activity(R2>0.83) in two extraction methods. And in in vitro digestion, free phenolic acids(TPA) was more correlated the antioxidant activity(R2>0.68) than the chemical method(R2>0.03). The result of high correlation between TPC, TAC and antioxidant activity, but low correlation between FPAande antioxidant activity showed that TPC and TAC contributed greater than FPA to the antioxidation of L.ruthenicum. According to the linear correlation between chemical method and antioxidant activity, different chemical antioxidant metheds were selected to determine polyphenol content of the feedstock.3. L.ruthenicum which is dark purple is signifiant different from Lycium chinese Mill. which is red. Investigated by HPLC-DAD-ESI-MS/MS method, the main anthocyanins of L.ruthenicum was petunidin derivatives ((glycosyl/glycosyl with acy). Among them, Pentunidin-3-0-p-coumaroylrutinoside-7-0-glucosides and Pentunidin-3-0-p-coumaroylrutin--oside-5-0-glucosides, which were isomers, were the most abundant anthocyanin in L.ruthenicum. Meanwhile, L.ruthenicum is a natural functional food widely used as tea. L.ruthenicum brewing method was different with Lycium chinense Miller.. L.ruthenicum contained a lot of anthocyanins which was easily damaged and sensitive to brewing temperature, time and frequency. The study suggested that the brewing time was about30min, while the temperature of60-90℃was best.4. In order to analyze the difference of volatile compounds of Lycium species, three different samples were analyzed by SPME/GC-MS. Total of50components were identified, including19esters,6ketones,5alkenes,4arenes,2alkanes,8aldehydes,2alcohols,3acids and1ethers. Lycium ruthenicum Murr. from Xinjiang had33kinds of volatile components, more than Lycium ruthenicum Murr. from Qinghai(28) and Lycium chinense Miller from Xinjiang(26). And three samples had9same kinds of ingredients. Different origins had a great impact on type and content of volatile components in Lycium ruthenicum Murr.. Lycium ruthenicum Murr. was based on esters and alkanes, while Lycium chinense Miller was based on alkanes and aldehydes. As to sensory evaluation, the flavor of Lycium ruthenicum Murr. was typically sweet like fruit flavor and fermented, while Lycium chinense Miller’s fragrance was more like licorice and ginseng. The overall flavor was weak.