Synthesis of (+/-)epipentenomycin I and III

A synthesis of (±) epipentenomycin I and III is reported from a regioselective epoxidation of racemic 3-hydroxy- and 3-acetoxy-2-methylene-4-cyclopentenone, respectively, with dimethyldioxirane followed by hydrolytic ring-opening of the resulting epoxide

Antioxidant, antibacterial, cytotoxic, and apoptotic activity of stem bark extracts of Cephalotaxus griffithii Hook. f

<p>Abstract</p> <p>Background</p> <p><it>Cephalotaxus </it>spp. are known to possess various therapeutic potentials. <it>Cephalotaxus griffithii</it>, however, has not been evaluated for its biological potential. The reason may be the remoteness and inaccessibility of the habitat where it is distributed. The main aim of this study was to: (1) evaluate multiple biological potentials of stem bark of <it>C. griffithii</it>, and (2) identify solvent extract of stem bark of <it>C. griffithii </it>to find the one with the highest specific biological activity.</p> <p>Methods</p> <p>Dried powder of stem bark of <it>C. griffithii </it>was exhaustively extracted serially by soaking in petroleum ether, acetone and methanol to fractionate the chemical constituents into individual fractions or extracts. The extracts were tested for total phenolic and flavonoid content, antioxidant (DPPH radical scavenging, superoxide radical scavenging, and reducing power models), antibacterial (disc diffusion assay on six bacterial strains), cytotoxic (MTT assay on HeLa cells), and apoptotic activity (fluorescence microscopy, DNA fragmentation assay, and flow cytometry on HeLa cells).</p> <p>Results</p> <p>Among the three extracts of stem bark of <it>C. griffithii</it>, the acetone extract contained the highest amount of total phenolics and flavonoids and showed maximum antioxidant, antibacterial, cytotoxic (IC₅₀of 35.5 ± 0.6 μg/ml; P < 0.05), and apoptotic (46.3 ± 3.6% sub-G0/G1 population; P < 0.05) activity, followed by the methanol and petroleum ether extracts. However, there was no significant difference observed in IC₅₀values (DPPH scavenging assay) of the acetone and methanol extracts and the positive control (ascorbic acid). In contrast, superoxide radical scavenging assay-based antioxidant activity (IC₅₀) of the acetone and methanol extracts was significantly lower than the positive control (P < 0.05). Correlation analysis suggested that phenolic and flavonoid content present in stem bark of <it>C. griffithii </it>extracts was responsible for the high antioxidant, cytotoxic, and apoptotic activity (P < 0.05).</p> <p>Conclusions</p> <p>Stem bark of <it>C. griffithii </it>has multiple biological effects. These results call for further chemical characterization of acetone extract of stem bark of <it>C. griffithii </it>for specific bioactivity.</p