Studies On Chemical Constituents And Biological Activities Of The Leaves Of Ananas Comosus

Ananas comosus L. is one of the most popular tropical and subtropical fruits, whichbelongs to the family Bromeliaceae. Besides agricultural utilities, some folk medicinal useswere found. For example, it was used as an indigenous medicine for the treatment of dysuria.In China, its cortexes were used as alexipharmic, antitussive and antidiarrhea agents, while itsleaves usually served as antidyspepsia and antidiarrhea agents in Chinese TraditionalMedicine. At present, chemical compositions and bioactivities of A. comosus were studiedlimitedly. Phenolicacid compounds were obtained by Wang Wei, such as caffeic acid andp-coumaric acid. There was no sunscreen activity reasearch reported previously on the leavesof A. Comosus, so it was highly significant to research sunscreen activity on the leaves of A.Comosus.Under the guidance of the sunscreen activity, the EtOAc fraction of the leaves of A.comosus was purified by means of silica gel column chromatography, Sephadex LH-20andpreparative thin layer chromatography etc. Thirty one compounds (1-31) were isolated andpuried from the leaves of A. comosus, including4glucosides,2flavones,14phenylpropenoids,4steroids,6benzene derivatives and one furfural. Compounds1–3,20were new ones. All compounds except of8,10,12,17,19were isolated from the leaves of A.comosus for the first time.The sunscreen activity of ethanol extract, polarity parts, compounds1-20,25and26were studied by evaluating the absorbance value at UVA、UVB、UVC. Compounds9,10,19,20had well sunscreen activity, with absorbance value were all higher than1, but lower thanpositive control Rutin(1.9083，2.0849，1.9142) a little.The antioxidant activities of ethanol extract, polarity parts, compounds14,16and18were studied, the EtOAc extract and compounds16exhibited well scavenging effect againstDPPH radical. The IC50were80.90,68.59μg/mL, respectively.Studied antibacterial activities of the ethanol extract, polarity parts, compounds1-15,17and25using microdilution method, the EtOAc extract showed the best antibacterial activityamong the extrats, MIC value against Staphylococcus aureus and Bacillus cereus were3.12mg/mL. And compounds1-5,12,15,17exhibited well antibacterial activity. MIC againstStaphylococcus aureus was0.156μg/mL.