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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 21permitted 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(IC50value of 5.0 ± 0.8 μM) and 12(IC50value of 5.2 ± 2.0 μM) possessed MDR reversal activities that were as good as that of verapamil (IC50value of 4.7 ± 0.6 μM).

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

Three norditerpenoid alkaloids, nigelladines A–C (1–3), and one pyrroloquinoline alkaloid, nigellaquinomine (4), all possessing new skeletons with highly conjugated systems, were isolated from Nigella glandulifera. The 8aS-configuration for 1and 2was 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.

From 2-amino-3-ethoxycarbonyl-4,5-dimethyl-, -polymethylenethiophenes (1-4) were synthesized 2,3-disubstituted thieno[2,3-d]dihydropyrrolo-, tetrahydropyrido-, and tetrahydroazepino[1,2-a]pyrimidin-4-ones (5-16) for pharmacological investigations. The 12 compounds (5-16) were individually evaluated for their antiproliferative activities on mammalian cancer cell models. All tested compounds showed weak affection on human cervix adenocarcinoma cells (HeLa) whereas some of the tested compounds exhibited more consistent inhibition of cell growth on murine myeloma cells (P3X). In both cases some compounds enhanced cell proliferation.