| Summary: | 碩士 === 國立陽明大學 === 生命科學系暨基因體科學研究所 === 104 === Gynostemma pentaphyllum (Thunb.) Makino (Jiaogulan) is a perennial creeping herb, which belongs to the Cucurbitaceae family and has been used as folk medicine for a variety of purposes, including liver protection, regulating blood pressure, heat clearing and detoxification. Its chemical constituents contain saponinoids, flavonoids, polysaccharides, etc. Previous investigations have revealed that crude extracts of G. pentaphyllum possess anti-cancer activities, anti-inflammation, anti-hyperlipidemic and hypoglycemic. By a series of chromatography and structure-directed fractionation, sixteen dammarane-type triterpene saponins containing six new compounds, Gypenoside CP1~6 (GP1~6), and ten known constituents, 2α,3β,12β,20S-tetrahydroxydammar-24-ene-3-O-[6-O-acetyl-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl]-20-O-β-D-glucopyranoside (GP7), Gypenoside XLVI (GP8), Gypenoside LVI (GP9), Gypenoside LVII (GP10), Gypenoside LXXVII (GP11), Gypenoside L (GP12), 2α,3β,12β,20S-tetrahydroxydammar-24-ene-3-O-β-D-glucopyranosyl-20-O-β-D-glucopyranoside (GP13), Gypenoside XLII (GP14), Gypenoside Rd (GP15) and 2α,3β,20S-trihydroxydammar-24-ene-3-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl]-20-O-[β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside] (GP16), together with eight flavonoids, quercetin-3-O-α-L- rhamnopyranosyl (1→2)-β-D-galactopyranoside (FA1), quercetin-3-neohesperidoside (FA2), kaempferol-3-O-α-L-rhamnopyranosyl (1→2)-β-D-galactopyranoside (FA3), kaempferol-3-O-α-L-rhamnopyranosyl(1→2)-β-D-glucopyranoside (FA4), quercetin-7-O-β-D-glucoside (FA5), kaempferol-7-O-β-D-galactopyranoside (FA6), kaempferol-7-O-glucoside (FA7) and isorhamnetin-7-O-β-D-glucopyranoside (FA8), two sesquiterpene glucosides, (6R,7E,9R)-9-hydroxy-megastigman-4,7-dien-3-one-9-O-β-D-glucopyranoside (SQ1) and (E)-4-[3′-(β-D-glucopyranosyloxy)butylidene]-3,5,5-trimethyl-2-cyclohexen-1-one (SQ2), were isolated from the 95% EtOH extract of the leaves of G. pentaphyllum.
The structural elucidation of these six new and twenty known compounds were based on spectroscopic analyses, mainly including 1D and 2D NMR techniques (COSY, HMQC, HMBC and NOESY), as well as by MS, UV and IR techniques.
This study also established the HPLC-ELSD fingerprinting profile of the crude extracts and partial purity fraction of G. pentaphyllum in which 26 isolates were identified.
Biological assay of cytotoxicity showed that the GP2, GP5, GP6, GP7, GP11, GP12, GP13 and GP15 possess moderate cytotoxicity against human tumor cell lines (A549, Hep-G2) (Inhibitory rate ＞50%, 100 μg/ml；ED50 = 29~100 μM). However, all the isolates have no anti-NO production effects.
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