Chemical Constituents From Fruits Of Vitex Trifolia L. And Metabolism Of Casticin

Vitex trifolia L.（Verbenaceae） is recorded in the first part of Pharmacopoeia（2010edition）. It is distributed widely in Yunnan, Guangxi, and Guangdong provincesof mainland China. Both the fruits of V. trifolia and the related V. rotundifolia areknown as “Manjingzi”, and are used commonly in traditional Chinese medicine forthe treatment of dizziness, headache, migraine, cancer, and eye pain. Crude extractsfrom V. trifolia have been found to be cytotoxic against several cancer cell lines and topossess antimicrobial activity. Some have shown interesting biological activities invitro such as cytotoxicity against mammalian cancer cells and inhibition ofmosquito-borne diseases. In order to develop the Vitex trifolia, this project is mainlyto isolate and identify its chemical compounds. Some compounds isolated wereevaluated for their cytotoxicity against a small panel of cancer cell lines and study ofthe metabolic fate of casticin to develop new drug. Our study are mainly threeaspects:1.Study on chemical constituents of Vitex trifolia L. fruits.The fruits of Vitex trifolia L. were extracted by80%EtOH, each extractionperiod lasting1h and were extracted by3times. The rest was suspended inwater,then, ues different solvent from ether, CH₂Cl₂, EtOAc to n-butanol accordingtheir character. The n-butanol and CH₂Cl₂-soluble part were subjected to TLC,preparative high performance liquid and column chromatography. A total of7newwith43known compounds were isolated from these active fractions. The structures ofall were elucidated by spectroscopic data interpretation and their structures were elucidatedby detailed spectroscopic analyses. The types of compounds were fifteen labdane-typediterpenoids, eleven flavones, twelve phenolic small molecular compounds, fourpentacyclic triterpenoids, four lignans, three steroids and one saccharide.2. Anti-tumour research of labdane-type diterpenoidsIn vitro, the15labdane type diterpenoids come from the fruits of Vitex trifolia L.were found to possess signifcant anti-tumour activity. Fifteen labdane-typediterpenoids were evaluated in vitro for their inhibitory ability against the growth ofhuman lung adenocarcinoma （A-549）, human colon carcinoma （HCT-116）, humanbreast carcinoma （ZR-75-30） and human promyelocytic leukaemia （HL-60） cell lines.All the isolates were evaluated for their cytotoxicity against four human cancer celllines, among which six compounds showed moderate cytotoxicity against all the tested cell lines, with IC50values ranging from6.11to24.79μg/mL. Thestructure–activity relationship （SAR） analysis of these structural analogues indicatedthat the terminal conjugated ring system （α, β-unsaturated-γ-lactone or furan ring） isthe key structural element for the cytotoxicity and a hydroxyl or methoxyl group atC-16plays an key role in these diterpenoids.3.Study on metabolism of casticin in Rats.Casticin has been revealed to possess various kinds of pharmacological activities,including immunomodulatory, anti-hyperprolactinemia, anti-tumor andneuroprotetective activities. In order to gain an understanding of thebiotransformation of casticin in vivo, a systematic method based on liquidchromatography–electrospray ionization tandem mass spectrometry （LC-ESI-MSn）was developed to identify the metabolites of casticin in rats after oral administrationof single dose of casticin at200mg/kg. By comparing their changes in molecularmasses （ΔM）, retention times and spectral patterns with those of the parent drug, theparent compound and25metabolites were identied in rat plasma, urine and sixselected tissues. This is the first systematic metabolism study of casticin in vivo. Theresults indicated that methylation, demethylation, glucuronidation and sulfation werethe main biotransformation pathways of casticin in vivo.