In vitro and in vivo antifungal activity of a water-dilutable cassia oil microemulsion against Geotrichum citri-aurantii

BACKGROUND: Recently, food‐grade microemulsions have been of increasing interest to researchers and have shown great potential in industrial applications. In this study a food‐grade water‐dilutable microemulsion system with cassia oil as oil, ethanol as cosurfactant, Tween 20 as surfactant and water was developed and its antifungal activity in vitro and in vivo against Geotrichum citri‐aurantii was assessed. RESULTS: The phase diagram results confirmed the feasibility of forming a water‐dilutable microemulsion based on cassia oil. One microemulsion formulation, cassia oil/ethanol/Tween 20 = 1:3:6 (w/w/w), was selected with the capability to undergo full dilution with water. The average particle size was 6.3 nm. The in vitro antifungal experiments showed that the microemulsion inhibited fungal growth on solid medium and prevented arthroconidium germination in liquid medium and that cassia oil had stronger activity when encapsulated in the microemulsion. The in vivo antifungal experiments indicated that the water‐dilutable microemulsion was effective in preventing postharvest diseases of citrus fruits caused by G. citri‐aurantii. CONCLUSION: The results of this study suggest a promising utilisation of water‐dilutable microemulsions based on essential oils for the control of postharvest diseases. Copyright © 2012 Society of Chemical Industry     

20%三磷·哒乳油对柑桔红蜘蛛毒力测定及田间药效试验

室内毒力测定结果表明,20％三磷·哒乳油对柑桔红蜘蛛有明显的增效作用,其共毒系数为178.6。1999年经江西进贤和湖南洪江两地田间试验表明,三磷·哒乳油对柑桔红蜘蛛有较好的防治效果,75～100mg／kg处理药后1～3天的防效为90.O％～98.0％,药后7天为82.7％～96.2％,药后15天为56.2％～92.3％,药后25天为51.6％～91.0％。     

SPME/GC/MS对比分析不同年份陈皮挥发性成分

利用固相微萃取/气相色谱/质谱联用技术对产自福建的、不同存放年份陈皮的挥发性成分进行了对比分析。结果显示,存放年份对陈皮挥发性成分的种类没有影响,但对各组分质量分数的影响有很大的不同。随存放时间的增加,陈皮挥发性成分的总量有所降低,主要成分柠檬烯的质量分数会增加,香柠檬烯、散花烃等组分的含量也会增加,但β-芳樟醇、α-松油醇、2-甲氨基安息香酸甲酯、α-法呢烯等成分的含量会降低,其余组分变化不大。     

超高效液相色谱-串联质谱法同时测定小吃类食品和火锅底料中5种罂粟壳生物碱和6种工业染料

目的建立超高效液相色谱-串联质谱法(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)同时测定小吃类食品及火锅底料中5种罂粟壳生物碱和6种工业染料。方法样品采用乙腈溶液提取,乙腈层经无水硫酸镁脱水后于40℃下旋转蒸发浓缩至干,用2.0 mL乙腈+0.1%甲酸水(95:5,V:V)溶解残渣,样液过膜后经C_(18)柱分离,电喷雾正、负离子同时扫描模式下多反应监测方式检测,外标法定量。结果 5种罂粟壳生物碱和6种工业染料在2.5~100μg/L的浓度范围内,具有良好的线性关系(相关系数均大于0.9980),在3个添加水平下样品的平均回收率为72.2%~108%,相对标准偏差2.5%~9.6%,罂粟碱、那可丁、蒂巴因、玫瑰红B、酸性橙Ⅱ、碱性嫩黄O、碱性黄1的检出限为1.0μg/kg,吗啡、可待因、碱性橙Ⅱ、苏丹红Ⅳ的检出限为2.5μg/kg。实际样品检测中,检出酸性橙Ⅱ阳性样品6个,含量为0.00706~74.2 mg/kg。结论该方法准确、灵敏、快速,是同时检测小吃类食品和火锅底料中罂粟壳生物碱和工业染料的有效方法。     

Comparative ultrastructure of nonwounded Mexican lime and Yuzu leaves infected with the citrus canker bacterium Xanthomonas citri pv. citri

Ultrastructural aspects of citrus canker development were investigated in nonwounded leaves of citrus species by transmission electron microscopy (TEM). A susceptible species Mexican lime and a resistant species Yuzu were spray-inoculated with a virulent strain of Xanthomonas citri pv. citri. Initial symptoms occurred on Mexican lime ∼9 days after inoculation, whereas they appeared on Yuzu mostly 11 days after inoculation. In Mexican lime leaves, the bacterial invasion was usually accompanied by host cell wall dissolution and cellular disruption. Fibrillar materials from degenerated cell walls were usually found in intercellular spaces. Damaged host cells with necrotic cytoplasm showed the localized separation of plasma membrane from the cell wall. Bacterial multiplication and electron-transparent capsule-like structures around bacteria were commonly observed. Meanwhile, cell wall protuberances were prominent outside host cell walls in response to bacterial invasion in Yuzu leaves. Occlusion of intercellular spaces was also formed by the fusion of two or more individual cell wall protuberances originated from two adjacent host cells. Papillae-like materials accumulated locally within host cells in close proximity to bacteria. Some bacteria were found to be undergoing degeneration in xylem vessels. Also, the shrunken, inactive bacteria were surrounded by electron-translucent fibrillar materials in intercellular spaces, implying bacterial immobilization. These cellular responses are thought to be the consequences of defense responses of Yuzu leaves to invading bacteria. In both citrus species, X. citri pv. citri contained polyphosphate bodies showing electron-dense and elliptical structures in cytoplasm. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc.     

陈皮酚类化合物调控AHR和NF-κB通路抗苯并芘诱导的肺上皮细胞损伤

本文研究了苯并芘(Bap)诱发肺上皮细胞炎性损伤的作用机制及陈皮中的酚类化合物的抗炎活性及作用机制。通过从陈皮中分离出来酚类化合物并用于抗Bap诱导的人肺上皮II型细胞(A549)损伤的活性研究,检测Bap对细胞炎症因子、NF-κB、芳基烃受体(AHR)通路相关蛋白表达的影响及陈皮酚类化合物对Bap造成损伤的保护作用。本文从陈皮中分离得到6个酚类化合物,研究表明,其中aspidin BB可降低3.74%由Bap诱导的A549细胞凋亡。aspidin BB可抑制Bap诱导的NO及炎症因子(IL-1β、IL-6和TNF-α)分泌,分别降低了49.22%、26.79%、37.86%和42.94%。Westernblotting结果显示,aspidinBB可抑制Bap诱导的AHR和NF-κB相关蛋白的激活,增强A549细胞的抗炎作用。因此得出陈皮酚类化合物aspidin BB可通过减少Bap诱导的炎性因子分泌,调控AHR、NF-κB通路发挥抗炎及抗氧化损伤的功能。     

柚皮苷二氢查尔酮的制备及其呈甜机理研究

利用化橘红醇提水沉法制备柚皮苷,并将柚皮苷催化加氢制备柚皮苷二氢查尔酮,并用SYBYL-X及Discovery Studio 2.5软件对柚皮苷二氢查尔酮的呈甜机理进行了研究。结果表明,化橘红醇提水沉法可以制备纯度大于95%的柚皮苷单体,该单体催化加氢后可制备纯度大于95%的柚皮苷二氢查尔酮,SYBYL-X及Discovery Studio 2.5软件能有效地解释柚皮苷二氢查尔酮的呈甜机理。     

红树植物提取物的杀螨活性试验

采用叶片残毒法测定了16种红树植物甲醇提取物对柑橘红蜘蛛的杀螨活性。结果表明,海芒果、苦槛蓝、苦榔树和黄槿对柑橘红蜘蛛雌成螨的触杀活性高,药液质量浓度为10g/L时,24h的校正死亡率达90%以上;榄李、海漆和水黄皮有中等杀螨活性,校正死亡率为66.90%～74.19%;其余植物的杀螨活性低,校正死亡率在50%以下。海芒果、苦槛蓝、苦榔树、黄槿和榄李对雌成螨的致死中浓度(LC50值)分别为1.8416、2.8757、2.9218、4.9325、6.5728g/L。红树植物提取物对柑橘红蜘蛛卵也有触杀活性,其中苦槛蓝、苦榔树、木榄、海漆、老鼠簕、海芒果、白骨壤和草海桐的杀卵活性高,药液质量浓度为10g/L时,校正死亡率在80%以上。