Study On The Bioactive Constituents From The Exocarp Of Carya Cathayensis

Carya cathayensis is an apecies of Juglandaceae family, Carya Genus. It's an endemic woody oil plant of China and mainly distributed in the Tianmu Mountainous region between Zhejiang province and Anhui province. It is popular within people not only for its daintiness but also for its nutrition. However its exocarp has not been fully used yet.According to the reports in different countries and the traditional Chinese medicine theory, there are some chemical compounds in the exocarp which are sanative such as sterilization, diminishing inflammation, easing pain, anti-tumor effect. Also its allelopathy effect can be used in insect killing, but there is less research of its chemical constituents.In order to investigate the bioactivities compounds, compounds in the exocarp were studied systematicly, eight compounds were isolated, purified from the exocarp. Their structures were determined by MS,1D and 2D NMR analysis, respectively, one of them was found as a new compound, two of them were first isolated from this Carya Nutt, and others of them had found in preliminary research. The results are showed as follows:1,The chemical constituents in the ethyl acetate extract and petroleum ether extract from the exocarp were separated by chromatography of silica gel, HSCCC, Sephadex LH-20 and Pre-HPLC and yield six compounds:β-Sitosterol (compoundⅠ); 8-hydroxy-2-ethoxy-1,4-naphthoquinone(compoundⅡ); 5-hydroxy-2-ethoxy-1,4-naphthoquinone (compoundⅢ); 4,8-dihydroxy-1-tetralone, sclerone (compoundⅣ); pinostrobin(compound V); quercetin-3-O-β-D-glucopyranoside(compound VI).2,The chemical constituents in the n-butanol extract from the exocarp were purified by D101 macroporous adsorption resin eluted with water,30%,50%,70%and 95% ethanol with different polarity. The fraction of 50% ethanol was isolated by chromatography of silica gel, and compounds quercetin (compound VII) was obtained. The fraction of 70% ethanol was isolated by chromatography of silica gel and Pre-HPLC, obtain compound myricatomentogenin(compoundⅦ) was obtained.3,The experments of anti-tumor biological activity in vitro screening test (MTT method) of 8 compounds from exocarp were carried out. CompoundⅡ,Compound IV and CompoundⅧhad moderate anti-tumor activities against human cervical carcinoma and human hepatocellular carcinoma activities; New compoundⅡhad antiproliferative activity on human cervical carcinoma (Hela, IC5o=43.2±1.8μg/mL); CompoundⅧshowed strong anti-tumor activities against human cervical carcinoma (Hela, IC5o=36.3±4.1μg/mL) activity; CompoundⅣshowed strong anti-tumor activities against human hepatocellular carcinoma (SMMC-7721, IC5o=77.6±3.3μg/mL) activity.The results of the present study will be useful for further phytochemical investigation of exocarp of Carya cathayensis in future.