New antimicrobial metabolites from the medicinal herb Artemisia herba-Alba.

Artemisia herba-alba is widely used in traditional medicines for the treatment of several diseases. From the aerial parts organic extract of A. herba-alba, two new compounds, 1,3,8-trihydroxyeudesm-4-en-7α,11ßH-12,6α-olide (1) and 5-ß-​D-​glucopyranosyloxy​-​7-methoxy-​6H-​benzopyran-​2-​one (2), respectively, together with five known metabolites: 3α,8ß-dihydroxygermacr-4(15),9(10)-dien-7ß,11αH,12,6α-olide (3), 1ß,8α-dihydroxy-11α,13-dihydrobalchanin (4), 11-epiartapshin (5), tomenin (6) and benzoic acid, p-​(ß-​D-​glucopyranosyloxy)​-​methyl ester (7), were isolated and identified. The chemical structures were proven depending upon spectroscopic analysis, including 1 D/2D NMR as and ESI-MS. Compound 1 inhibited Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus. Compounds 2 and 3 exhibited antibacterial activity against both gram-positive and gram-negative bacteria.

Cytotoxicity of 40 Egyptian plant extracts targeting mechanisms of drug-resistant cancer cells.

BACKGROUND: The multidrug resistance (MDR) phenotype encounters a major challenge to the success of established chemotherapy in cancer patients. We hypothesized that cytotoxic medicinal plants with novel phytochemicals can overcome MDR and kill MDR-cells with similar efficacy as drug sensitive cells. PURPOSE: We evaluated plant extracts from an unexplored ecosystem in Egypt with unusual climate and nutrient conditions for their activity against sensitive and multidrug-resistant cancer cell lines. MATERIAL AND METHODS/STUDY DESIGN: Methylene chloride: methanol (1:1) and methanol: H2O (7:3) extracts of 40 plants were prepared resulting in a sum of 76 fraction containing compounds with varying polarity. The resazurin reduction assay was employed to evaluate the cytotoxicity of these extracts on five matched pairs of drug-sensitive and their drug-resistant cell lines. Flow cytometry and Western blotting was used to determine cell cycle analyses, apoptosis, and autophagy. Reactive oxygen species (ROS) were measured spectrophotometrically. RESULTS: Extracts derived from Withania obtusifolia (WO), Jasonia candicans (JC), Centaurea lippii (CL), and Pulicaria undulata (PU) were the most active ones among 76 extracts from 40 Egyptian medicinal plants. They showed a significant reduction of cell viability on drug-sensitive CCRF-CEM leukemia cell line with IC50 values less than 7 µg/ml. Low cross-resistance degrees were observed in multidrug-resistant CEM/ADR5000 cells towards CL (1.82-fold) and JC (6.09-fold). All other drug-resistant cell lines did not reveal cross-resistance to the four extracts. Further mechanistic assessment have been studied for these four extracts. CONCLUSION: The methylene chloride: methanol (1:1) fractions of WO, JC, CL, and PU are promising cytotoxic extracts that could be used to combat MDR cancer cells through different cell death pathways.