Studies On The Chemical Constituents From The Stem Of Siraitia Grosvenorii And Its Anti-oxidant Activities

Siraitia grosvenorii is a perennial vine belonging to the genus Siraitia in Cucurbitaceae.It is the first batch of dual-purpose plants with "homologous medicine and food" in China.According to the Pharmacopoeia,it has the effects of moistening intestines and defecating,relieving cough and moistening lung.Siraitia grosvenorii is rich in triterpenoid saponins,which is a low calorie and high sweetener.Therefore,the research on Siraitia grosvenorii mostly focuses on the fruit part of Siraitia grosvenorii.Siraitia grosvenorii is a kind of perennial vine traditional Chinese medicine.After the fruit is picked,a large number of stems on the ground are directly discarded.Based on the comprehensive utilization of traditional Chinese medicine resources,a series of studies were carried out on the stem of Siraitia grosvenorii to improve the comprehensive utilization of Siraitia grosvenorii.1.The chemical components of Siraitia grosvenorii stem were extracted by ultrasonic extraction with 80% methanol.The extract of Siraitia grosvenorii stem was detected and analyzed by HPLC-Q-TOF MS.Cording to TIC and EIC,the candidate compounds were selected in combination with the screening procedure.Then,through the analysis of relevant literature and the cleavage methods and characteristic fragment ions(MS/MS)of 9 standards,55 compounds were preliminarily identified,including 46 flavonols,flavonol glycosides and 9 rohanoic acids.This provides a theoretical basis for the comprehensive utilization of Siraitia grosvenorii stem.2.The 5 kg dry stem of Siraitia grosvenorii was fully extracted by ethanol heating reflux extraction method.After being extracted with petroleum ether,ethyl acetate and n-butanol respectively,the compounds in each extraction layer were separated by multistage silica gel column chromatography.The isolated compounds with high purity were identified and analyzed by HPLC-Q-TOF MS and NMR.Four compounds were isolated and identified,namely quercetin,p-hydroxybenzaldehyde,kaempferol-3,7-O-L-rhamnose and kaempferol.At the same time,the compounds contained in each component were preliminarily analyzed.3.The stem of Siraitia grosvenorii was extracted by refluxing with pure water and ethanol,and then the two extracts were gradiently eluted on a macroporous adsorption resin AB-8 column with water,20%-80% ethanol solution and absolute ethanol.The antioxidant activity of fraction from the column was detected by FRAP total antioxidant kit,so as to explore the superior extraction and purification process.It was found that the two total extraction processes of Siraitia grosvenorii stem had antioxidant activity,and the antioxidant activity of alcohol extract was better than that of water extract.However,when the water extract was purified by adsorption resin,the antioxidant activity was the strongest after elution with 60% ethanol solution.