Chemical Constituents Of Two Radula Species And Their Cytotoxic Activities

The bryophytes are a group of higher plants with short vascular tissues and without flowering structures,including three major groups:the mosses,the liverworts and the hornworts.It is abundant in species,with 191 families,1233 genera and more than 23,000 species in the world,second only to seed plants.In the folk,bryophytes are widely used to treat burns,bruises,trauma,snake bites,tuberculosis,neurasthenia,fractures,convulsions,burns,pneumonia,neurasthenia,and so on.Along with the diversification of separation means and the improvement of activity evaluation,many aromatic and terpenoids compounds with novel structures and various activities have been obtained from bryophytesIn the second chapter of this paper,the extraction,isolation and cytotoxic activity of the Chinese liverworts Radula constricta Stephani collected form Foping Nature Reserve in Shaanxi Province were introduced.Twenty compounds were isolated and identified from R.constricta,including nine new compounds,six of which were in the pairs of racemates.We tested the cytotoxic activity of these compounds by MTT assay.Among them,two prenylated bibenzyls showed the cytotoxicity to nine cell lines(NCI-H1299,A549,HepG-2,SMMC-7721,MCF-7,U251,SW620,HT29,PC-3)Compound 10 attracted our attention for it significantly inhibited the survival rate of the tumor cell lines measured,and rapidly induced the accumulation of cytoplasmic vacuoles within 3 hours.Therefore,we selected 10 as a potential anticancer agent for further research.First of all,we used AnnexinV/PI staining,broad-spectrum inhibitors Z-VAD-FMK,and detector PARP,these results indicated that compound 10 causes cell death maybe a non-apoptotic process.Then we used mitochondrial fluorescence tracing,HMGB1 protein,and JC-1 dyes to study mitochondrial membrane potential(MMP).These results clearly indicated that compound 10 leads to cell death by inducing mitochondrial membrane potential reduction and ROS levels increase.In the third chapter,we introduced the extraction,isolation and antitumor activity from liverwort of the Radula apiculata Sande Lac.ex Stephani.We obtained 14 compounds through a series of separation methods,such as MCI column chromatography,silica gel column chromatography,reversed-phase column chromatography,dextran gel column,high-performance liquid and so on.Further their absolute configurations were determined by high-resolution mass spectrometry,ultraviolet,infrared,nuclear magnetic resonance data,electronic circular dichroism(ECD)as well as comparing with the literature data of known compounds.The structures of these obtained compounds all belong to prenylated monobenzyl,11 of them are new compounds,including 5 isopentened dimer-benzyls,of which 6 new compounds are racemates.We selected part compounds to evaluate the antitumor activity using MTT assay,and the results also showed that these dimers showed significant cytotoxic activity,the mechanisms will be explored during the doctorate period.