Comparison of antioxidative properties of carbazole alkaloids from Murraya koenigii leaves

A new dimeric carbazole alkaloid, 8,10′-[3,3′,11,11′ -tetrahydro-9,9′-dihydroxy-3,3′,5,8′-tetramethyl-3, 3′-bis(4-methyl-3-pentenyl)]bipyrano[3,2-a]carbazole (12), was isolated from the CH2Cl2 extract of Murraya koenigii together with six known carbazole alkaloids, koenimbine (6), O-methylmurrayamine A (7), O-methylmahanine (8), isomahanine (9), bismahanine (10), and bispyrayafoline (11). Their structures were determined on the basis of 1H and 13C NMR spectroscopic and mass spectrometric (MS) data. The antioxidative properties of 12 carbazole alkaloids isolated from leaves of M. koenigii were evaluated on the basis of the oil stability index together with their radical scavenging ability against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. On the basis of the lag time to reach a steady state, the 12 carbazoles were classified into three groups. It is suggested that an aryl hydroxyl substituent on the carbazole rings plays a role in stabilizing the thermal oxidation and rate of reaction against DPPH radical

食育に関する一考察 : フランスにおける「食育」に関する取り組みの一場面

　成人のみでなく子どもにまでメタボリックシンドロームやその他の生活習慣病が激増している今日、その因子の一つである食生活の改善による予防が期待されている。食生活指針や食事バランスガイドなどの啓蒙施策が図られてきたが、2005年に食育基本法が施行された。その経緯を概観する。また「味覚の週間」などで食育活動を進めているフランスのディジョン（味覚科学センター）における研究活動を紹介する

Antioxidative activity of carbazoles from Murraya koenigii leaves

The antioxidative properties of the leaves extracts of Murraya koenigii using different solvents were evaluated based on the oil stability index (OSI) together with their radical scavenging ability against 1-1-diphenyl-2-picrylhydrazyl (DPPH). The methylene chloride (CH2Cl2) extract and the ethyl acetate (EtOAc) soluble fraction of the 70% acetone extract significantly prolonged the OSI values comparable to those of α-tocopherol and BHT. Five carbazole alkaloids were isolated from the CH2Cl2 extract and their structures were identified to be euchrestine B (1), bismurrayafoline E (2), mahanine (3), mahanimbicine (4), and mahanimbine (5) based on 1H and 13C NMR and mass (MS) spectral data. The OSI value of carbazoles at 110 °C decreased in the order 1 and 3 > α-tocopherol > BHT > 2 > 4, 5 and control. It is assumed that compounds 1 and 3 contributed to the high OSI value of the CH2Cl2 extract of M. koenigii. The DPPH radical scavenging activity for these carbazoles was in the order ascorbic acid > 2 > 1, 3 and α-tocopherol > BHT > 4 and 5

The antioxidative components from Alpinia nutans

The methylene chloride extract of Alpinia nutans was investigated for its antioxidant constituents. 5,6-Dehydrokawain (1), flavokawin-B (2), 1,7-diphenyl-5-hydroxy-6-hepten-3-one (3), (-)-pinocembrin (4) and a mixture of stigmasterol and β-sitosterol were isolated. The antioxidant activity was measured on isolates 1-4 using ferric thiocyanate (FTC) and diphenylpicrylhydrazyl (DPPH) free radical scavenging techniques

Screening of Zingiberaceae extracts for antimicrobial and antioxidant activities

Dichloromethane and methanol extracts of 13 Zingiberaceae species from the Alpinia, Costus and Zingiber genera were screened for antimicrobial and antioxidant activities. The antimicrobial activity of most of the extracts was antibacterial with only the methanol extract of Costus discolor showing very potent antifungal activity against only Aspergillus ochraceous (MID, 15.6 μg per disc). All the extracts showed strong antioxidant activity comparable with or higher that of α-tocopherol

Antioxidant and antitumor promoting activities of the flavonoids from Hedychium thyrsiforme

Five flavonoids, including 3,7,4′-trimethoxy-5-hydroxyflavone (1), 3,4′-dimethoxy-5,7-dihydroxyflavone (2), 5,7,4′-trimethoxy-3-hydroxyflavone (3), 3,5,7,4′-tetramethoxyflavone (4), and 7,4′-dimethoxy-3,5-dihydroxyflavone (5), were isolated from the rhizome of Hedychium thyrsiforme and assayed for antioxidant and antitumor promoting activities. The antioxidant assays showed that 5,7,4′-trimethoxy-3-hydroxyflavone, 7,4′-dimethoxy-3,5-dihydroxyflavone and 3,4′-dimethoxy-5,7-dihydroxyflavone had strong activities. Only two compounds, 5,7,4′-trimethoxy-3-hychoxyflavone and 7,4′-dimethoxy-3,5-dihydroxyflavone, were found to be strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavengers with fifty percent inhibition concentration (IC50) values of 92 and 119 μM, respectively. Antitumor promoting assays indicated that all the flavonoids showed strong inhibition activity towards Epstein-Barr virus (EBV) activation in Raji cells