Guo-Ru Shi

Polycycloiridals A-D, Four Iridal-Type Triterpenoids with an α-Terpineol Moiety from Iris tectorum.

Polycycloiridals A-D, four novel iridals with an unprecedented α-terpineol moiety resulting from cyclization of the homofarnesylside chain, were isolated from the ethanol extract of rhizomes of Iris tectorum. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. The absolute configuration of 1 was determined by the modified Moshers method and comparison of experimental and calculated electronic circular dichroism (ECD) spectrum. A possible biosynthetic pathway was postulated.

Bioactive Iridoid Glycosides from the Whole Plants of Rehmannia chingii

Nine new iridoid glycosides, rehmachingiiosides A-I (1-9), together with 16 known analogues, were isolated from the whole plants of Rehmannia chingii. The structures of compounds 1-9 were elucidated on the basis of spectroscopic data analysis and from chemical evidence. Furthermore, in two vitro assays, compounds 5 and 10 showed an inhibitory effect on LPS-induced NO production with IC50 values of 2.5 and 7.3 μM, and compounds 4, 6, and 10-12 (when evaluated at 10 μM) exhibited evidence of hepatoprotective effects against APAP-induced HepG2 cell damage.

Polycycloiridals with a Cyclopentane Ring from Iris tectorum

Six new iridal-type triterpenoids containing an unprecedented cyclopentane ring, polycycloiridals E-J (1-6), were isolated from a large-scale re-extraction of Iris tectorum. A possible biosynthesis pathway is postulated. The known spirioiridotectal D (7) was also obtained in the current investigation, and its structure was unequivocally defined using X-ray diffraction data. Compound 7 suppressed LPS-activated NO production in the BV2 cell line with an IC50 value of 0.54 μM.

Modification of glycosylation reduces microvilli on rat liver epithelial cells.

Effect of glycosylation modification on the shape of microvillus was investigated on rat liver epithelial cell line WB‐F344. Since rat ER α‐mannosidase has 89% identity to human 6A8 α‐mannosidase, we used an antisense 6A8 cDNA fragment to inhibit expression in WB‐F344 cells. Cells were transfected with antisense 6A8, the relevant sense fragment or the mock plasmid. Genomic PCR for neoR demonstrated integration of the transfected gene into host DNA. Enzymatic activity assay on p ‐nitro‐phenyl‐α‐D‐mannopyranoside showed suppression of ER α‐mannosidase expression in the cells transfected with antisense 6A8. Concanavalin A binding to these cells was enhanced, indicating a modification in glycosylation. Number reduction and blunting of microvillus on these cells was observed. Transduction with the sense fragment or the mock had no effect. Cells with suppressed ER α‐mannosidase expression grew slower in culture. Our results indicate an obvious effect of glycosylation modification on microvilli, which might be related with malfunctioning of cells.

Heliosterpenoids A and B, two Novel Jatrophane-Derived Diterpenoids with a 5/6/4/6 Ring System from Euphorbia helioscopia

Heliosterpenoids A and B (1 and 2), two unprecedented jatrophane-derived diterpenoid esters with a novel 5/6/4/6-fused tetracyclic ring skeleton, were isolated from the whole plants of Euphorbia helioscopia. The structures of 1 and 2 were elucidated by extensive spectroscopic methods and electronic circular dichroism (ECD) analyses. The plausible biogenetic pathways of 1 and 2 were postulated. 1 and 2 were found to be potent inhibitors of P-glycoprotein (ABCB1) and 1 also exhibited cytotoxicity against MDA-MB-231 cell lines.

The unprecedented iridal lactone and adducts of spiroiridal and isoflavonoid from Belamcanda chinensis

Five novel iridal-type triterpenoid derivatives, including three unprecedented adducts of spiroiridal and isoflavonoid, named belamcandanins A–C (1–3), one unprecedented iridal lactone, named belamcanolide A (4), and one new and rare iridal epoxide, named belamcanoxide A (5), have been isolated from the rhizomes of Belamcanda chinensis, along with five known compounds. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compounds 1–3 represent the first meroterpenoids composed of an isoflavonoid linked to a spiroiridal-triterpenoid. To the best of our knowledge, compound 4 is the first example of 5/6-fused bicyclic iridal lactone. Compounds 1–8 were evaluated for their in vitro cytotoxicity against five tumor cell lines. Among them, compounds 5–8 showed moderate cytotoxic activities against five cancer cell lines with IC50 values from 3.26 to 8.63 μM.

Aromatic glycosides from the whole plants of Iris japonica

Abstract Phytochemical investigation on the whole plants of Iris japonica led to the isolation of four new aromatic glycosides. Their structures including the absolute configurations were determined by spectroscopic and chemical methods as (−)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7R,8S)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (1), (−)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7S,8R)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (2), (−)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7R,8R)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (3), (−)-4-hydroxy-3-methoxy acetophenone 4-O-β-d-{6-O-[4-O-(7S,8S)-(4-hydroxy-3-methoxyphenylglycerol-8-yl)-3-methoxybenzoyl]}-glucopyranoside (4), respectively. Graphical abstract

Four new compounds from the rhizome of Aristolochia championii

Abstract Three new flavonoid glycosides (1–3) and one new aristololactam N-glycoside (4) were isolated from the rhizome of Aristolochia championii. The structures of compounds 1–4 were elucidated on the basis of their spectroscopic data and chemical evidence (UV, IR, HR-ESI-MS, 1D and 2D NMR). Their structures were determined as 8-(5-formyl-2-furanmethyl)-isorhamentin 3-O-robinobioside (1), 8-(5-methyl-2-furanoyl)-isorhamentin 3-O-robinobioside (2), 8-formylisorhamentin 3-O-robinobioside (3), and N-β-D-glucopyranosylaristololactam V (4), respectively.

Apocynin derivatives from Iris tectorum

Abstract Phytochemical investigation of the rhizomes of Iris tectorum resulted in the isolation and characterization of three new apocynin derivatives, apocynin-4-O-β-D-(6′-O-syringyl)glucopyranoside (1), scrophenoside C-7-ethyl ether (2, 3), together with a new naturally occurring compound but known by synthesis, apocynin-4-O-β-D-xylopyranoside (4), and five known ones (5–9). Their structures were elucidated on the basis of spectroscopic data interpretation.

Aristolochic acid derivatives from the rhizome of Arisolochia championii

Four new aristolochic acid derivatives aristchamic A (1), aristchamic B (2), aristochamic C (3a), aristchamic D (3b) and one new aristolactam aristolactam-CV (4), together with 10 known compounds (5-14), were isolated from the rhizomes of Aristolochia championii. Their structures were assigned by detailed analysis of MS and NMR spectroscopic data. All of the isolated compounds were evaluated for their cytotoxic activities against HCT-116, HepG2, BGC-823, NCI-H1650, and A2780 cell. Compound 1 exhibited significant cytotoxic activity against HCT-116, HepG2, BGC-823, and NCI-H1650, with IC50 values of 0.50, 7.37, 2.66, and 0.75μM, respectively.