| Ardisia brevicaulis, a widely occurring shrub, belongs to genus Ardisia(Myrsinaceae family) and is distributed mainly in southern China. The herbs ofthis plant have been used as traditional folk medicines for the treatment of sorethroat, traumatic injury, arthritis as well as cough. Clematis argentilucida, aperennial woody climber plant, belongs to genus Clematis (Ranunculacea family)and is widely distributed across the China, having the effect of analgesic,detoxification, and activating blood circulation. The rhizome of the plant hasbeen used as traditional folk medicines for the treatment of wound, rheumatism,arthralgia, aphonia hoarseness as well as limb numbness. The chemicalconstituents and pharmacologies of the two plants have rarely been reportedexcept our research team. Hence a thorough research is necessary due to the factthat the effective biochemical constituents of these plants have not been clearlyidentified. And it has been recorded in literatures that most saponins isolated fromplants belonging to both genus Ardisia and genus Clematis have significantantitumor effect. For the purpose of providing detailed chemical evidences for in-depth research of these two plants as well as valuable lead compounds for exploitation of new antitumor drugs, the chemical constituents (saponin constituents) of70%EtOH extract of these two plants have been systematically studied. Besides, several compounds identified from Clematis argentilucida have also been studied on anticancer activities in this paper. Some significant outcomes this paper has achieved are the following:1. The chemical structure category and biological activities of the chemical compounds isolated from Ardisia and Clematis plant have been elaborated in the paper.2. The chemical constituents of70%EtOH extract of Ardisia brevicaulis have been investigated by using macroporous resin (D-101) column chromatography silica gel column chromatography, Sephadex LH-20and HPLC. To date, six compounds have been isolated from the70%ethanol extract of Ardisia brevicaulis and their structures were identified with the help of physico-chemical constants, spectroscopic data and chemical evidences. They are two phenols:(Z)2-methyl-5-[14"-(1’,3’-dihydroxyphenyl) tetradec-8"-enyl] resor-cinol (A1),3-Methoxy-2-methyl-5-pentylphenol (A3); one lignin:(+)-iso-laricire-sinol (A2); three triterpenoid saponins:cyclamiritin A-3β-O-α-L-rhamnopyra-nosyl-(1â†'2)-β-D-glucopyranosyl-(1â†'4)-[β-D-glucopyranosyl-(1â†'2)]-α-L-ara-binopyranoside (A4),3β-O-{α-L-rhamnopyranosyl-(1â†'2)-β-D-glucopyranosyl-(1â†'4)-[β-D-glucopyranosyl-(1â†'2)]-α-arabinopyranosyl}-3β,16α,28-trihydro xy-12-oleanene (A5),3β-O-{α-L-rhamnopyranosyl-(1â†'2)-β-D-glucopyranosyl-(1â†'4)-[β-D-glucopyranosyl-(1â†'2)]-α-L-arabinopyranosyl}-3β,28-dihydroxy-12-olenene (A6). Among the above, compounds A2is the first report of isolation from the Ardisia, and all compounds are isolated from this plant for the first time.It has been recorded in literatures that saponins A4and A5exhibit significant cytotoxicity againt human glioblastoma U-251MG cell lines while A6exhibits moderate cytotoxicity. This paper provides valuable information for further research on Ardisia brevicaulis and scientific evidences for more in-depth study on the Ardisia.3. Bioassay-guided fractionation was performed on70%EtOH extract of Clematis argentilucida roots collected from Taibai, Tsinling Mountains. The systematic chemical constituents of the active fractions were studied by using multiple chromatography techniques, physico-chemical constants, spectroscopic data and chemical evidences. To date, eleven compounds were isolated and their structures were identified to be oleanane type triterpenoid saponins which are3β-O-[β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-β-D-xylopyrano-syl] oleanolic acid (C1),3β-O-[β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranos-y1-(1v2)-α-L-arabinopyranosyl] hederagenin (C2),3β-O-[β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-α-L-arabinopyranosyl] oleanolic acid (C3),3β-O-[β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-α-L-arabinopyra-nosyl] hederagenin-11,13-dien-28-oic acid (C4), oleanolic acid28-O-α-L-rham-nopyranosyl-(1â†'4)-β-D-glucopyranosyl-(1â†'16)-α-D-glucopyranoside (C5),3β-O-{β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-[β-D-glucopyranos-y1-(â†'4)]-β-D-xylopyranosyl} oleanolic acid (C6),3β-O-[β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-α-L-arabinopyranosyl] oleanolic acid28-O-α-L-rhamnopyranosyl-(1â†'4)-β-D-glucopyranosyl-(1â†'6)-β-D-glucopyranoside (C7),3β-O-[β-D-ribopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-α-L-arabi-nopyranosyl] oleanolic acid28-O-β-5-D-glucopyranoside (C8),3β-O-[α-L-rhamn-opyranosyl-(1â†'2)-α-L-arabinopyranosyl] oleanolic acid28-O-α-L-rhamnopyr-anosyl-(1â†'4)-β-D-glucopyranosyl-(1â†'6)-β-D-glucopyranoide (C9),3β-O-[α-L-rhamnopyranosyl-(1â†'2)-α-L-arabinopyranosyl] hederagenin28-O-α-L-rhamn- opyranosyl-(1â†'4)-β-D-glucopyranosyl-(1â†'-6)-β-D-glucopyranoside (C10),3β-O-[β-D-xylopyranosyl-(1â†'3)-α-L-rhamnopyranosyl-(1â†'2)-α-L-arabinopyrano-syl] hederagenin28-O-α-L-rhamnopyranosyl-(1â†'4)-β-D-glucopyranosyl-(1â†'6)-β-D-glucopyranoside (C11). Among the above, saponins C4and C6are new compounds that have never been reported in literatures while C5and C10are the first report of isolation from the Clematis.4. Eight triterpenoid saponins (C1-C6, C9, C10) isolated from the roots of Clematis argentilucida have been tested on anticancer activities against three different tumor cell lines, including human leukemia HL-60cell lines, human hepatocellular carcinoma Hep-G2cell lines and human glioblastoma U-251MG cell lines by using MTT colorimetric assay. The result showed that compounds C1, C2, C3, C4and C6exhibited significant cytotoxicity against HL-60cell lines and Hep-G2cell lines with C3most actively, while against U-251MG cell lines moderate cytotoxicity was exhibited for all four compounds. The IC50values for the three types of cell lines are2.97±0.24,1.83±0.21and6.62±0.17μmol/L. Compounds C9and C11exhibited inactive cytotoxicity against all the three cancer cell lines. This paper has a preliminary structure-activity relationship discussion on the forementioned triterpenoid saponins. We speculate that the hydroxyl group at C-23has a negative effect on the cytotoxic activity while the presence of a free carboxylic group at C-28is crucial to active cytotoxicity.This paper used bio assay-guided fractionation to study the saponin constituent and antitumor activity of Clematis argentilucida. It provides valuable information for further research on Clematis argentilucida and scientific evidences for more in-depth study on the Clematis. Meanwhile it also provides valuable lead compounds for exploitation of new antitumor drugs. |
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