Phenolic glycosides from <i>Lavandual angustifolia</i>

<p>Four new phenolic glycosides (<b>1–4</b>), together with 12 known ones (<b>5–16</b>), were isolated from the essential oil extraction waste of <i>Lavandula angustifolia</i>. Their structures were unequivocally determined by extensive spectroscopic analysis (1D and 2D NMR, HR-ESI-MS, UV, and optical rotation), chemical method, and comparison with data reported in the literature. The antioxidant activities of all compounds and new compounds’ influence on melanin content in B16 melanoma cells were examined, which indicated that compounds <b>1</b>, <b>8</b>, <b>13</b> had a certain degree of DPPH free radical scavenging activities, while only compound <b>2</b> could increase the melanin content with a dose-dependent manner.</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