Jatrophane Diterpenoids from <i>Euphorbia glomerulans</i>

In a phytochemical investigation of the whole plant of Euphorbia glomerulans, 17 new (1–17) and five known jatrophane diterpenoids (18–22) were identified. The X-ray crystallographic data of compounds 1, 4, and 21 permitted the definition of the absolute configurations of these compounds. The cytotoxicity and multidrug resistance reversal activities of the 17 new compounds were evaluated on multidrug-resistant MCF-7/ADR cells overexpressing P-glycoprotein. Several compounds showed different chemoreversal activities and considerably decreased cytotoxicity. Compounds 11 (IC50 value of 5.0 ± 0.8 μM) and 12 (IC50 value of 5.2 ± 2.0 μM) possessed MDR reversal activities that were as good as that of verapamil (IC50 value of 4.7 ± 0.6 μM)

Jatrophane Diterpenoids from <i>Euphorbia glomerulans</i>

In a phytochemical investigation of the whole plant of Euphorbia glomerulans, 17 new (1–17) and five known jatrophane diterpenoids (18–22) were identified. The X-ray crystallographic data of compounds 1, 4, and 21 permitted the definition of the absolute configurations of these compounds. The cytotoxicity and multidrug resistance reversal activities of the 17 new compounds were evaluated on multidrug-resistant MCF-7/ADR cells overexpressing P-glycoprotein. Several compounds showed different chemoreversal activities and considerably decreased cytotoxicity. Compounds 11 (IC50 value of 5.0 ± 0.8 μM) and 12 (IC50 value of 5.2 ± 2.0 μM) possessed MDR reversal activities that were as good as that of verapamil (IC50 value of 4.7 ± 0.6 μM)

Jatrophane Diterpenoids from <i>Euphorbia glomerulans</i>

In a phytochemical investigation of the whole plant of Euphorbia glomerulans, 17 new (1–17) and five known jatrophane diterpenoids (18–22) were identified. The X-ray crystallographic data of compounds 1, 4, and 21 permitted the definition of the absolute configurations of these compounds. The cytotoxicity and multidrug resistance reversal activities of the 17 new compounds were evaluated on multidrug-resistant MCF-7/ADR cells overexpressing P-glycoprotein. Several compounds showed different chemoreversal activities and considerably decreased cytotoxicity. Compounds 11 (IC50 value of 5.0 ± 0.8 μM) and 12 (IC50 value of 5.2 ± 2.0 μM) possessed MDR reversal activities that were as good as that of verapamil (IC50 value of 4.7 ± 0.6 μM)

Jatrophane Diterpenoids from <i>Euphorbia glomerulans</i>

In a phytochemical investigation of the whole plant of Euphorbia glomerulans, 17 new (1–17) and five known jatrophane diterpenoids (18–22) were identified. The X-ray crystallographic data of compounds 1, 4, and 21 permitted the definition of the absolute configurations of these compounds. The cytotoxicity and multidrug resistance reversal activities of the 17 new compounds were evaluated on multidrug-resistant MCF-7/ADR cells overexpressing P-glycoprotein. Several compounds showed different chemoreversal activities and considerably decreased cytotoxicity. Compounds 11 (IC50 value of 5.0 ± 0.8 μM) and 12 (IC50 value of 5.2 ± 2.0 μM) possessed MDR reversal activities that were as good as that of verapamil (IC50 value of 4.7 ± 0.6 μM)

<i>N</i>-Alkylamides from <i>Piper longum</i> L. and their stimulative effects on the melanin content and tyrosinase activity in B16 melanoma cells

Piper longum L., known as long pepper, is an edible and medicinal plant used as spice and for the treatment of stomach disease and analgesia in traditional Chinese medicine. N-Alkylamides are the major secondary metabolites in this plant. Sixteen known N-alkylamides were isolated from P. longum. Their structures were established on the basis of spectroscopic data and comparison to reported literatures. Among them, five compounds were isolated from this plant for the first time. Ethanol extract, compounds 1, 2, 3, 7 and 11 exhibited potent ability to increase the melanin content and weak stimulative effect on the tyrosinase activity in a concentration-dependent manner. Moreover, compound 2 also presented strong capacity to increase the tyrosinase activity in a concentration-dependent manner. These results indicated that P. longum might be a good natural source of lead compound for skin disorder diseases. </p

Two new glucoside derivatives of truxinic and cinnamic acids from <i>Lavandula angustifolia</i> mill

A phytochemical investigations on the n-butanol fraction of Lavandula angustifolia Mill. residues resulted in the isolation of ten compounds, including two new ones, 4,4′dimethoxy-2,2′di-O-β-d-glucopyranosyl-truxinate (1) and 2-(β-d-glucosyloxy)-trans-cinnamic acid butyl ester (2), along with eight known compounds. The structures of compounds were confirmed by NMR and HR-ESI-MS techniques and comparison with published data. The NMR data for 3 were attributed for the first time. Compound 2 was proofed to be a natural compound in plant rather than a butyl ester artifact formed by esterification reaction with butanol by comparative HPLC-DAD analysis with the ethanol extract which was obtained prior to the application of butanol. All isolated compounds were evaluated for their antioxidant and anti-hypoglycaemic activities. Among them, compounds 4 and 5 showed strong anti-oxidant activities against DPPH with IC50 values of 12.99 and 31.74 μM, respectively. Compound 5 exhibited moderate inhibitory activity against PTP1B with an IC50 value of 31.28 μM.</p

Highly Conjugated Norditerpenoid and Pyrroloquinoline Alkaloids with Potent PTP1B Inhibitory Activity from <i>Nigella glandulifera</i>

Three norditerpenoid alkaloids, nigelladines A–C (<b>1</b>–<b>3</b>), and one pyrroloquinoline alkaloid, nigellaquinomine (<b>4</b>), all possessing new skeletons with highly conjugated systems, were isolated from <i>Nigella glandulifera</i>. The 8a<i>S</i>-configuration for <b>1</b> and <b>2</b> was determined by comparison of the experimental and calculated electronic circular dichroism spectra. These alkaloids exhibited potent protein tyrosine phosphatase 1B (PTP1B) inhibitory activity but are devoid of cytotoxicity against the A431 cell line at 100 μM

Indazole-Type Alkaloids from <i>Nigella sativa</i> Seeds Exhibit Antihyperglycemic Effects via AMPK Activation in Vitro

Six rare naturally occurring indazole-type alkaloids including two new compounds, 17-<i>O</i>-(β-d-glucopyranosyl)-4-<i>O</i>-methylnigellidine (<b>1</b>) and nigelanoid (<b>2</b>), and four known compounds (<b>3</b>–<b>6</b>) were isolated from a defatted extract of <i>Nigella sativa</i> (black cumin) seeds. 17-<i>O</i>-(β-d-Glucopyranosyl)-4-<i>O</i>-methylnigellidine (<b>1</b>) increased glucose consumption by liver hepatocytes (HepG2 cells) through activation of AMP-activated protein kinase (AMPK). Also, this is the first report of compounds <b>4</b> and <b>6</b> from a natural source