苦楝果实中苦楝素的分离及鉴定

报道了有机溶剂提取法提取苦楝果实中的天然杀虫活性成分,并采用结晶法从浓缩液中成功地分离出苦楝素晶体.采用差示扫描量热仪(DSC)测定苦楝素晶体基本的理化常数──熔点.通过红外吸收光谱(IR)、紫外吸收光谱(UV)、有机质谱(ESI-MS)对苦楝素晶体进行波谱分析,其数据和文献报道的苦楝素光谱数据完全一致.     

The Development of a Green Innovative Bioactive Film for Industrial Application as a New Emerging Technology to Protect the Quality of Fruits

Today, the most significant challenge encountered by food manufacturers is degradation in the food quality during storage, which is countered by expensive packing, which causes enormous monetary and environmental costs. Edible packaging is a potential alternative for protecting food quality and improving shelf life by delaying microbial growth and providing moisture and gas barrier properties. For the first time, the current article reports the preparation of the new films from Ditriterpenoids and Secomeliacins isolated from Melia azedarach (Dharek) Azadirachta indica plants to protect the quality of fruits. After evaluating these films, their mechanical, specific respirational, coating crystal elongation, elastic, water vapor transmission rate (WVTR), film thickness, and nanoindentation test properties are applied to apple fruit for several storage periods: 0, 3, 6, 9 days. The fruits were evaluated for postharvest quality by screening several essential phytochemical, physiological responses under film coating and storage conditions. It was observed that prepared films were highly active during storage periods. Coated fruits showed improved quality due to the protection of the film, which lowered the transmission rate and enhanced the diffusion rate, followed by an increase in the shelf life. The coating crystals were higher in Film-5 and lower activity in untreated films. It was observed that the application of films through dipping was a simple technique at a laboratory scale, whereas extrusion and spraying were preferred on a commercial scale. The phytochemicals screening of treated fruits during the storage period showed that a maximum of eight important bioactive compounds were present in fruits after the treatment of films. It was resolved that new active films (1–5) were helpful in the effective maintenance of fruit quality and all essential compounds during storage periods. It was concluded that these films could be helpful for fruits growers and the processing industry to maintain fruit quality during the storage period as a new emerging technology.     

Two new limonoids from Melia toosendan

Two new limonoid-type triterpenoids, named 12-o-ethyl-l-deacetylnimbolinin B and 1-o-tigloyl-1-o-debenzoylohchinal, have been isolated from the fruit of Melia toosendan Sieb. et Zucc. Their structures were elucidated by spectral methods, including 2D-NMR spectra.     

苦楝果实的生物活性成分

报道了江西省产苦楝（ＭｅｌｉａａｚｅｄａｒａｃｈＬ．）果实中的生物活性成分，从果实中分离出四种化合物，采用ＴＬＣ，ＩＲ，１ＨＮＭＲ，ＨＰＭＳ等技术确定了它们的结构。这四种化合物分别为１，４－苯二甲酸二甲酯（Ⅰ）、苦楝酮（Ⅱ）、苦楝醇（Ⅲ）和苦楝二醇（Ⅳ）。其中１，４－苯二甲酸二甲酯（Ⅰ）为苦楝果实中首次报道的成分。通过生物活性测试，这四种化合物对菜青虫均有拒食和胃毒活性。     

楝属植物研究与应用概况

楝属植物具有广泛的使用价值。参考国内外有关楝属植物的大量研究资料，对其化学成分、药理、杀虫等研究和应用进行综述，并提出今后发展与研究的浅见。     

六种植物提取物对马尾松毛虫的抑食作用及毒性

通过生物测定检验了合欢、木槿、皂荚、川楝、苦楝和苦豆草六种植物的提取物对马尾松毛虫的抑食作用和毒性。木槿和合欢的提取物对松毛虫取食无显著影响，也不具毒性。皂荚的乙醇提取物对松毛虫有抑食作用，但不具毒性。川楝、苦楝的石油醚提取物及川楝的乙醇提取物在较高浓度下抑制松毛虫的取食并对它们具毒性。苦豆草总生物碱的水溶部分对松毛虫有显著的抑食作用。水溶性生物碱、苦参碱、Ｎ－氧化苦参碱、槐定碱，野靛碱、苦豆碱均对松毛虫有不同程度的抑食作用和毒性。其中，Ｎ－氧化苦参碱和槐定碱表现出较强的抑食作用，槐定碱和苦豆碱对松毛虫表现出较高的毒性。     

苦楝叶乙醇浸提物对几种作物种子萌发及幼苗生长的影响

以苦楝（Melia azedarach）叶乙醇浸提物处理大豆（Glycine mac）、水稻（Oryza stativa）、小麦（Triticum aes-tivum）及玉米（Zeamays）种子,观察浸提物对几种作物种子萌发及幼苗生长的影响。结果表明,在62.5～1000μg/mL浓度范围内,浸提物对几种作物种子的萌发及幼苗生长具有一定的抑制作用,但对水稻和小麦的抑制作用较强,对玉米和大豆的抑制作用稍弱,在1000μg/mL浓度时,浸提物可完全抑制水稻和小麦种子萌发及幼苗的生长,而大豆和玉米的萌发率仍超过70%,对大豆幼苗的苗高和根长,玉米幼苗的苗高抑制作用均低于50%。     

Meliarachins A–K: Eleven Limonoids from the Twigs and Leaves of Melia azedarach

Eleven new limonoids, meliarachins A–K ( 1 – 11 , resp.), together with five known ones, were isolated from the twigs and leaves of Melia azedarach. The structures of the new compounds were elucidated on the basis of spectroscopic analysis. Compounds 4 and 8 exhibited moderate antibacterial activities against Gram‐positive bacteria.     

Cytotoxic,antibacterial and antioxidant activities of extracts of the bark of Melia azedarach (China Berry)

Nature provides a variety of drugs and medicinal agents derived from plants. This study was conducted to determine antimicrobial, antioxidant and cytotoxic activities of extracts of Melia azedarach bark with methanol/water (9:1 v/v), chloroform, butanol, hexane, water and ethyl acetate. For the determination of the antimicrobial activities, the agar well diffusion method was employed. Cytotoxicity was studied by brine shrimp lethality assay; antioxidant activities were measured using 1,1-diphenyl-2-picrylhydrazyl. The chloroform extract was active against Enterobacter aerogenes and Proteus mirabilis, the ethyl acetate extract had highest antibacterial spectrum against Pseudomonas aeruginosa, the n-hexane extract had highest inhibition against E. aerogenes, the aqueous extract showed highest activities against P. mirabilis, the butanol fraction showed highest activities against E. aerogenes and the methanolic extract was highly active against P. mirabilis.