New stigmastane type of steroidal glycosides from the roots of Vernonia cumingiana

Stigmastane-type steroid saponins from the leaves of Vernonia amygdalina and their α-glucosidase and xanthine oxidase inhibitory activities

Two new vernonioside K (1) and vernonioside L (2) and four known Δ7,9(11) stigmastane-type steroidal saponins-vernonioside B2 (3), vernoniacum B (4), vernonioside B1 (5), and vernoamyoside A (6)-were isolated from the leaves of Vernonia amygdalina. Their structures were determined by comprehensive spectroscopic analysis with one-dimensional nuclear magnetic resonance, two-dimensional nuclear magnetic resonance, and high-resolution mass spectrometry. All isolated compounds (1-6) were evaluated to determine their inhibitory effects on α-glucosidase and xanthine oxidase. Among them, two new compounds 1 and 2 showed significant inhibition of α-glucosidase with IC50 values of 78.56 ± 7.28 and 14.74 ± 1.57 (μM), respectively, comparable with acarbose as a positive control (127.53 ± 1.73 μM); none of these compounds inhibited xanthine oxidase activity. Compounds 1 and 2 are promising candidates for the development of antidiabetic agents from natural sources.

Tautomeric phytosterols from Vernonia amygdalina Delile and their anti-cervical cancer activity

Vernonia amygdalina Delile is generally used as green vegetables for cuisine in Nigeria and health tea or products in southeast of china. It was also used as folk medicine for the treatment of anti-helminth, febrifuge, digestive tonic and wounds. In this study, eleven undescribed phytosterols (1-2, 4-12) and six known analogues (3, 13-17) were isolated from the stems of V. amygdalina. Their structures including absolute configurations were elucidated by comprehensive spectroscopic methods (1D and 2D NMR, HRESIMS), X-ray diffraction and comparison of their ECD spectra. Besides, the tautomerism of phytosterols (1, 3-6, 12-17) with hemiacetal moiety were analyzed by solution NMR with different deuterated solvent and variable-temperature experiments. In addition, the cytotoxic activities of isolates against HeLa cells were evaluated. As a result, compound 10 exhibited the most potent anti-cervical cancer activity with the IC₅₀ of 22.44 μM. Mechanism studies indicated that 10 triggered HeLa cells apoptosis through activating caspase signaling pathway. Furthermore, 10 could arrest the cell cycle in S phase and suppress the activation of the PI3K/AKT/mTOR pathway, leading to the inhibition of HeLa cells proliferation.

Actaticas A-G, Cycloartane Triterpenes From Actaea asiatica With Their Antiproliferative Activity

Phytochemical studies on the rhizomes of Actaea asiatica led to the isolation of seven new cycloartane triterpenes, actaticas A−G (1−7). Their structures were determined by NMR, HRESIMS, and chemical analysis. All the isolates were evaluated for their antiproliferative activity against HT-29 and McF-7 cell lines. The results showed that all the compounds displayed cytotoxicity. All compounds showed significant inhibitory effects with IC₅₀ values of 9.2–26.4 μM.

Two new polyoxy steroidal glycosides from the roots of Dregea sinensis Hemsl

Two new polyoxy steroidal glycosides, named as 11- O-α-acetyl-12-O-β-tigloyl- 3β,14β-dihydroxy-pregn-5-en-20-one-3-O-β-D-oleadropyranosyl-(1→4)-β-D-6-deoxy-3-O-methyl-allopyanoside (1) and 11- O-α-acetyl -12-O-β-benzoate-3β, 14β-dihydroxy-pregn-5-en- 20-one-3-O-β-D-oleadropyranosyl-(1→4)-β-D-6-deoxy-3-O-methyl-allopyanoside (2) were isolated from the roots of Dregea sinensis Hemsl. Their structures were elucidated by various spectroscopic techniques including UV, IR, HRESIMS, 1 D and 2 D NMR. All the two compounds were tested for their cytotoxic activity in vitro, and the result showed that compounds 1-2 displayed moderated cytotoxic activity against HL-60 cell line with IC₅₀ values of 18.4 μM and 23.9 μM, respectively. [Formula: see text].

Five New Cucurbitane-Type Triterpenoid Glycosides from the Rhizomes of Hemsleya penxianensis with Cytotoxic Activities

Five new cucurbitane-typetriterpenoid glycosides, named Xuedanoside F–J (1–5), were obtained from the rhizomes of Hemsleya penxianensis (Xue dan), which belongs to the family of Cucurbitaceae. These new compounds were elucidated byspectroscopic analysis, including 1D, 2D NMR, and HR-ESI-MS spectra. Additionally, all the isolates were evaluated for cytotoxicity against three human cancer cell lines (Hela, MCF-7, and A-549) with the IC₅₀ ranging from 2.25 to 49.44 µM in vitro with treatment 48 h and showed low cytotoxicity in human normal liver L-02 cells (IC₅₀ > 50 µM). Compound 5 showed the most significant cytotoxic activity with the IC₅₀ value of 2.25, 4.72, and 5.33 µM in 48 h, respectively.

In vitro study on α-amylase and α-glucosidase inhibitory activities of a new stigmastane-type steroid saponin from the leaves of Vernonia amygdalina

Using various chromatographic separations, four compounds, including one new steroid saponin named vernoamyoside E (1), were isolated from the leaves of the Vietnamese medicinal plant Vernonia amygdalina Delile (Asteraceae). Their structures were established by spectroscopic methods such as 1D- and 2D-NMR, HR-ESI-MS, and HPLC analysis. The inhibitory activities against α-glucosidase and α-amylase of the isolated compounds from V. amygdalina were reported for the first time. The results indicated that compound 1 significantly inhibited both against α-amylase and α-glucosidase activity.

Stigmastane-type steroids with unique conjugated Δ7,9(11) diene and highly oxygenated side chains from the twigs of Vernonia amygdalina

Veramyosides A-J, eleven undescribed stigmastane-type steroids, including one aglycone and ten glycosides, along with three known homologues were isolated from the twigs of Vernonia amygdalina Delile (compositae). All compounds featured a stigmastane-type steroid skeleton with a unique conjugated Δ^7,9(11) diene segment and highly oxygenated side chains with a γ-lactone or an α, β-unsaturated five-membered lactone ring. The structures of veramyosides A-J and their absolute configurations were unambiguously elucidated by HR-ESI-MS, extensive NMR spectroscopy, in situ dimolybdenum CD methods, modified Mosher's method, quantum chemical calculation of their ECD curves, and CD comparison methods on basis of their biogenetic pathway. In addition, all isolates were investigated for their effects on RXRα transcription, and their effects on the NF-κB signaling pathway were also evaluated.

New polyoxypregnane glycosides from Aspidopterys obcordata vines with antitumor activity

Nine new polyoxypregnane glycosides, obcordatas A-I (1-9), were isolated from Aspidopterys obcordata Hemsl vines. Their structures were elucidated by extensive spectroscopic methods. Separated compounds were evaluated for antitumor activities against the human cancer cell lines AGS, SW480, HuH-7 and MCF-7, and compounds 1-6 and 9 showed selective cytotoxicity against HuH-7 cells with IC₅₀ values of 8.7, 10.2, 7.5, 12.1, 16.5, 14.3, and 17.4 μM, respectively. Flow cytometry experiments showed that the effects of compound 1 on the cell cycle were attributable to cell cycle arrest at G1/S phase.