•Five previously undescribed steroidal saponins were characterized from Ophiopogon japonicus.•Three of these compounds are rare naturally occurring C29 steroidal glycosides.•Cytotoxic activities of isolated compounds were tested on two human cancer cell lines.Phytochemical investigation of the tubers of Ophiopogon japonicus led to the isolation of five previously undescribed steroidal saponins, ophiojaponins A–E, together with twelve known ones. The structures of these isolated compounds were elucidated by detailed spectroscopic analyses and chemical methods. Ophiojaponins A–C are rare naturally occurring C29 steroidal glycosides possessing a homo-cholestane skeleton with an aromatized ring E. Ruscogenin 1-O-α-L-rhamnopyranosyl-(1 → 2)-4-O-sulfo-β-D-fucopyranosido-3-O-β-D-glucopyranoside was isolated as single component and its full spectroscopic data was reported for the first time. The isolated steroidal saponins were evaluated for their cytotoxicities against two human tumor cell lines MG-63 and SNU387. Among them, five known spirostane-type glycosides showed cytotoxic activity against both MG-63 and SNU387 cell lines with IC50 values ranging from 0.76 to 27.0 μM.Seventeen steroidal saponins, including five previously unreported, were isolated from the tubers of Ophiopogon japonicus. The isolates were evaluated for their cytotoxicities against two human tumor cell lines.Download high-res image (329KB)Download full-size image

•Four new 4-deoxy-4β-phorbol diesters were isolated from the seeds of Croton tiglium.•The structures of the new compounds were elucidated by 1D and 2D-NMR data.•Compound 4 showed cytotoxic activity against the SNU387 with IC50 value of 0.71 μM.Phytochemical investigation of the seeds of Croton tiglium resulted in the isolation and structure elucidation of four new 4-deoxy-4β-phorbol diesters (1–4) named as 12-O-tiglylphorbol-4-deoxy-4β-phorbol-13-acetate (1), 12-O-tiglylphorbol-4-deoxy-4β-phorbol-13-hexadecanoate (2), 13-O-acetylphorbol-4-deoxy-4β-phorbol-20-oleate (3) and 13-O-acetylphorbol-4-deoxy-4β-phorbol-20-linoleate (4), respectively. The structures of the new compounds were established by 1D, 2D-NMR and HR-ESI–MS spectroscopic data and chemical degradation experiments. The cytotoxic activities of compounds 1–4 were evaluated against hepatic tumor cell lines (SNU387 and SNU398). Among these compounds, compound 4 exhibited the most potent activity against the SNU387 with IC50 value of 0.71 μM.

Chemical investigation of the seeds of Croton tiglium afforded eight new phorbol diesters (three phorbol diesters, 1–3, and five 4-deoxy-4α-phorbol diesters, 4–8), together with 11 known phorbol diesters (nine phorbol diesters, 9–17, and two 4-deoxy-4α-phorbol diesters, 18 and 19). The structures of compounds 1–8 were determined by spectroscopic data information and chemical degradation experiments. The cytotoxic activities of the phorbol diesters were evaluated against the SNU387 hepatic tumor cell line, and compound 3 exhibited the most potent activity (IC50 1.2 μM).

•Six new phenanthrene glycosides were isolated from the stem of Dendrobium denneanum.•Their structures were deduced by extensive spectroscopic analysis.•Some compounds showed moderate cytotoxic activities against SNU387 tumor cells.Five new phenanthrene glycosides, denneanosides A–E (1–5), and one new 9,10-dihydrophenanthrene glycoside, denneanoside F (6) were isolated from the stem of Dendrobium denneanum. The chemical structures of the new compounds were established on the basis of extensive spectroscopic data. The isolated compounds were evaluated for their in vitro cytotoxic activity against SNU387 hepatocellular carcinoma cell line. Compounds 1–3 showed moderate cytotoxic activities while compounds 4–6 showed weak activities.

Electrospray ionization ion-trap tandem mass spectrometry (ESI-MSn) was first employed for reinvestigating the structures of hupehensis saponin F and G previously isolated from Anemone hupehensis in our lab. Hupehensis saponin G was determined to contain one more trisaccharide unit (Rha-(1→4)-Glc-(1→6)-Glc-), not a glucose residue, than saponin F based on their molecular weights deduced from their [M+Na]+ ions in ESI-MS spectra. The 2,4A4α-ion at m/z 551.3 formed by retro-Diels–Alder (RDA) rearrangement in positive mode illustrated that the C-28 sugar chains of the two saponins were composed of trisaccharide repeating moieties with (1→4) linkages rather than (1→3) linkages. The interpretation of 2D-NMR spectra of the two compounds also confirmed the results obtained by ESI-MSn. Moreover, from the water soluble part of A. hupehensis, two novel triterpene saponins were tentatively characterized to contain 4 and 5 (1→4)-linked above trisaccharide repeating moieties at C-28 position according to their ESI-MSn behaviors, respectively.Graphical abstractHighlights► The chemical structures of hupehensis saponin F and G were revised by ESI-MSn. ► The linkages between the repeated trisaccharide units were (1→4), not (1→3). ► Saponin G was deduced to contain 12 sugar residues, rather than 10 ones. ► Two novel saponins were detected and identified by ESI-MSn.

Three new triterpenoid saponins, named raddeanoside R20 (1), raddeanoside R21 (2) and raddeanoside R22 (3), were isolated from the water soluble part of Anemone raddeana. The chemical structures of these new compounds were elucidated by chemical and spectroscopic methods.Graphical abstractThree new triterpenoid saponins were isolated from the roots of Anemone raddeana. The chemical structures of these compounds were determined based on chemical methods and various spectroscopic data.Highlights► Three new triterpenoid saponins were isolated from the roots of Anemone raddeana. ► All the compounds contain at least 8 sugar residues. ► Their structures were deduced from chemical methods and spectroscopic analysis.

A new triterpenoid bisglycoside, named raddeanoside R19, was isolated from the roots of Anemone raddeana. Its structure was elucidated on the basis of ESI-MS, 13C NMR, and chemical methods.

Four new C21 steroidal glycosides (1–4), named perisepiumosides FI (1–4) together with six known steroidal glycosides (5–10) and four oligosaccharides (11–14), were isolated from the root bark of Periploca sepium. Their structures were characterized on the basis of 1D and 2D–NMR spectroscopic data as well as HR-ESI-MS analysis. The evaluation of inhibition activity against human A-549 and HepG2 cell lines indicated that compounds 2, 8, 10 and 13 showed different levels of cytotoxic activities with IC50 values ranging from 0.61 to 7.86 μM.Download high-res image (131KB)Download full-size image

•Six new cucurbitane glycosides were isolated from the fruit of Siraitia grosvenori.•The structures of the new compounds were elucidated by 1D and 2D-NMR data.•All the compounds increase the glucose uptake in HepG2 cells in vitro.The mogrosides in the fruit of Siraitia grosvenori can serve as a sugar substitute for diabetics due to their sweetness, low calorie and positive effects on blood glucose level control. The present study was to purify the mogrosides from the fruit of S. grosvenori and evaluate their enhancement of glucose uptake rate in HepG2 cells in vitro. As a result, eighteen mogrosides were isolated, including six new ones and a known but new naturally occurring compound. The chemical structures of the new compounds were identified by 1D, 2D-NMR and HR-ESI-MS techniques, together with chemical methods. Compared to the positive control (metformin), all the obtained mogrosides showed equivalent or more potent effects on the glucose uptake in HepG2 cells in vitro. These results suggested the mogrosides in the fruit of S. grosvenori were worthy of further research to confirm their potential benefits for obese and diabetic patients.