Trifolium pratense L. as a Potential Natural Antioxidant

The essential oils of three different growth stages of Trifolium pratense L. (TP1, TP2 and TP3) were investigated by gas chromatography-mass spectrometry and tested for their antioxidant and antimicrobial activities. The highest content of volatile compounds was found in the essential oil sample TP1, where terpenes such as beta-myrcene (4.55%), p-cymene (3.59%), limonene (0.86%), tetrahydroionone (1.56%) were highlighted due to their biological activity. The antioxidant activity was determined by following the scavenging capacity of the essential oils for the free radicals DPPH center dot, NO center dot and O-2(center dot-), as well as effects of the investigated oils on lipid peroxidation (LP). In all three cases, the sample TP1 showed the best radical-capturing capacity for DPPH center dot (27.61 +/- 0.12 mu g/mL), NO center dot (16.03 +/- 0.11 mu g/mL), O-2(center dot-) (16.62 +/- 0.29 mu g/mL) and also had the best lipid peroxidation effects in the Fe2+/ascorbate induction system (9.35 +/- 0.11 mu g/mL). Antimicrobial activity was evaluated against the following bacteria cultures: Escherichia coli (ATCC10526), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus (ATCC 11632) and Bacillus cereus (ATCC 10876). None of the examined essential oil samples showed inhibitory effects on the tested bacterial strains

Antioxidant Properties of Marrubium peregrinum L. (Lamiaceae) Essential Oil

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Synthesis and biological evaluation of some 17-picolyl and 17-picolinylidene androst-5-ene derivatives

Starting from dehydroepiandrosterone (1) 17-picolyl (2), 17-picolinylidene (7), 17-picolinylidene-16-one (10 and 11), and 17-picolyl-16-one (15) derivatives of androst-5-ene were synthesized in one, two, four and five steps respectively. By the Oppenauer oxidation or dehydration of 2, 7, 10, and 11 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), the corresponding A and B ring modified derivatives 3, 5, 6, 8, 9, and 12-14 were obtained. The structure of 2 was unambiguously proved by the appropriate X-ray structural analysis. Compounds 3, 5,9,12-14 showed inhibitory activity against the enzyme aromatase. Antibacterial activity toxicity to brine shrimp Artemia salina, antitumor activity against three tumor cell lines (human cervix carcinoma HeLa cells, human melanoma FemX cells, and human myelogenous leukemia K562 cells) and toxicity against peripheral blood mononuclear cells were evaluated. Three tested compounds, namely 11, 13, and 15, showed strong activity against all three cell lines, the IC50 values being in the range of 4-10 mu M. (c) 2006 Elsevier Inc. All rights reserved