The Study Of Extraction And Vasorelaxant Effects On Phenolic Compounds From Canarium Pimela Leenh Leaves

Canarium pimela Leenh.or Chinese black olive is a tree belonging to the Burseraceae family.As recorded in the ancient classics,its leaves can treat urticaria,eczema and athlete’s foot for external use and can clear away heat and toxicity and relieve swell and pain for internal use.Various groups of pharmacological investigation have revealed that the Canarium pimela Leench leaves extraction possess bioactivities on cardiovascular system and antioxidant property.However,little attention has been paid on the chemical compounds of the leaves except for the volatile oil compositional analysis.In order to better explore this natural resources,our study spotted on the phenolic compounds in the leaves and carried our researches as follows.Part I,the phenolic compounds from Canarium pimela Leenh leaves were analysed using UPLC-MS technology.Sixteen compounds were identified or tentative identified including two phenolic acids,quinic acid and chlorogenic acid,four tannins,corilagin,4’-O-methyellagic acid-3-O-α-L-rhamnopyranoside,3,3’-di-O-methyellagic acid-4-Orhamnopyranoside and 3,4,3’-tri-O-methylellagic acid,and nine flavonoids,cinchonain I,cinchonain I isomer,vitexin,isovitexin,hyperoside,rutin,quercetin-3-O-arabinoside,quercetin and amentoflavone,and an anthrone,protohypericin.Part II,six of these compounds,including chlorogenic acid,vitexin,isovitexin,hyperoside,rutin and quercetin were selected as the quantitative analysis markers and simultaneously analyzed by HPLC-UV for the first time.The chromatographic separation was carried out on a C18 column(250 mm x 4.6 mm,5 μm)with the mobile phase consisting of 0.5%(v/v)aqueous phosphoric acid and methanol(B).The gradient elution program was as follows: 0 min,23% B;8 min,32% B;30 min,35% B;50 min,70% B;55 min,23% B.The flow rate was at 1.0 m L/min,the UV detection wavelength was set at 360 nm,the injection volume was 20 m L and the column temperature was maintained at 30 ℃.The result of the method validation revealed that the quantitative chromatographic method showed good precision and accuracy and is available for the quality control of the Canarium pimela Leenh leaves.Part III,a single-factor experiment coupled with a Box-Behnken design response surface methodology had been applied to investigate the influence of the extraction approach,ethanol concentration,liquid-solid ratio and extraction time by evaluating the yield of index components and extraction rate.Results showed that the optimal reflux extraction conditions were as followers: ethanol concentration 56%(V/V),liquid to solid ratio 50: 1(mL/g),extraction time 78 min.Part IV,investigation on the vasorelaxant properties of the crude extract and its purified product from Canarium pimela Leenh leaves had been conducted in isolated rat thoracic aortic rings.The result demonstrated that both the crude and purified extract can elicit the vasorelaxant activity in concentration-dependent manner and the purified extract exhibits more phenolic contents and better vasorelaxant effect than the crude extract.Thus,its material basis is likely due to its phenolic compounds from its leaves.