Study On The Chemical Constituents And Antioxidative Activity From The Leaves Of Castanopsis Ceratacantha

The Fagaceae of Castanopsis is the primary constituent tree species of subtropical evergreen broad-leaved forest and tropical mountain rain forest.It is distributed in the south and southeast of Asia,and there are about 120 species in the world.It is often used as Chinese herbal medicine in Guangxi Zhuang,Yao and other minority areas.The leaves and skins can be used for medicinal purposes.It has the functions of clearing away heat and detoxification,astringent blood vessels and hemostasis.It is mainly used for treating tumors,chronic ulcers,hemostasis and detumescence,detoxification,etc.Its curative effect is significant.It has been passed down from generation to generation in the folk and has a long history of use.At present,our research group has systematically studied the chemical constituents of Castanopsis sclerophylla,Castanopsis fordii Hance,Castanopsis tibetana Hance,Castanopsis carlesii and Castanopsis eyrei.There are many polyphenols,flavonoids and ellagannins by founded in Castanopsis.Triterpene ellagannins that has chemicial taxonomic significance.Triterpene ellagannins,which were synthesized by esterification of ellagannins and triterpenes that has unique space structure and many pharmacological activities.Castanopsis ceratacantha belong to Castanopsis.In the early stage,HPLC and TLC analysis were carried out on Castanopsis ceratacantha,and it was found that there were also triterpene ellagannins in this plant.In this study,the chemical constituents of the leaves were separated,their structures were identified and their antioxidant properties were studied.Based on the study of the chemical constituents of Castanopsis,this paper provides evidence for the systematic position of Castanopsis in the Fagaceae,which is controversial in the classical classification.The main contents and conclusions are as follows:1.Isolation and structure identification of the chemical constituents of Castanopsis hystrix.3.5 kg about Castanopsis ceratacantha eaves were cut into pieces,then soaked and extracted with ethanol-H₂O?80-20 v/v?for two times at room temperature about seven days each time.Then the filterate was decompressed and concentrated to give the extract weighted 481.3 g.The extract was dissolved with water adequately,which was separated by semi-preparation high performance liquid chromatography and some column chromatography materials,for instance,Sephadex LH-20,Diaion HP20SS,MCI,Chromatorex C18,Toyopearl HW-40F and the like.Whereafter the structures of the compounds were identified by spectral techniques,¹H-NMR,¹³C-NMR,HR-MS and the like.Twenty-eight compounds were isolated.There are thirteen phenolic acids involved:protocatechuic acid?CC-1?,gallic acid?CC-2?,caffeic acid?CC-3?,1-?3',4-dihydroxycinnamoyl?-cyclopenta-2,3-diol?CC-4?,chlorogenic acid?CC-5?,chlorogenic acid methyl ester?CC-6?,6-O-galloylarbutin?CC-7?,3-methoxy-4-hydroxyphenol 1-O-?-D-?6'-O-galloyl?glucopyranoside?CC-8?,aviculin?CC-9?,pedunculagin?CC-10?,praecoxin A?CC-11?,1,2,3,4,6-penta-O-gally-?-D-glucopyranose?CC-12?,casuarictin?CC-13??Eight flavonoids:kaempferol?CC-14?,isoquercitrin?CC-15?,kaempferol3-O-?-D-glucuronopyranoside?CC-16?,quercetin3-O-?-D-glucuronopyranoside?CC-17?,quercetin 3-O-?-D-glucuronide-6''-methyl ester?CC-18?,rutin?CC-19?,quercetin 5-O-[?-L-rhamnopyranosyl-?1?6?]-?-D-glucopyranoside?CC-20?,kaempferol 3-O-{?-D-xylopyranosyl-?1?2?-[?-L-rhamnopyranosyl-?1?6?]-?-D-glucopyranoside?CC-21??Seven Tannic tannins:dilactona doácido valoneico?CC-22??castalin?CC-23??vescalin?CC-24??castalagin?CC-25??vescalagin?CC-26??chinquapinic acid?CC-27??castacrenin D?CC-28??All compounds were isolated from this plant for the first time.2.Determination of total flavonoids in the leaves of Castanopsis ceratacantha.The ultrasonic extraction method,reflux extraction method and immersion method were used to compare the extraction process of total flavonoids in Castanopsis ceratacantha.Rutin was used as the control,and the content of total flavonoids in Castanopsis ceratacantha was determined by ultraviolet spectrophotometry.The linear equation is Y=0.0845X+0.0003?R²=0.9999?.The results showed that the content of total flavonoids in different extraction methods was the highest,54.01%,50.50%and 49.87%respectively.Because the results of the three methods are similar,and there are many solvents used in the immersion method,and the reflux extraction method takes a long time,while the ultrasonic extraction method is simple,less consumables,shorter time,and more controllable factors,so the ultrasonic extraction method is selected to select the optimal extraction conditions.In the single factor experiment,the optimal conditions were extraction time 15 min,ethanol concentration 50%,material liquid ratio 1:40?g/m L?.3.Study on the antioxidation of pyramidal leaves in Castanopsis ceratacantha.In this paper,the scavenging capacity and reducing power of DPPH and hydroxyl radicals in different extraction methods and polar parts of washancone were studied.VC was used as control.The results showed that the total flavone had a strong scavenging ability to DPPH free radicals and reducing power,and had a certain scavenging ability to hydroxyl radicals,but all of them were lower than VC;the results showed that the DPPH radical scavenging ability,hydroxyl radical scavenging ability and reducing power of different polar parts of Washan cone were better,and the DPPH radical scavenging effect of fr.3-6 was stronger than VC,and the reducing power of fr.4-6 was stronger than VC.