Antibacterial Activity of 9-Octadecanoic Acid-Hexadecanoic Acid-Tetrahydrofuran-3,4-Diyl Ester from Neem Oil

The 9-octadecanoic acid-hexadecanoic acid-tetrahydrofuran-3,4-diyl ester from neem oil was investigated for antibacterial activity against three bacterial strains viz., Staphylococcus aureus ATCC No. 25923, Escherichia coli ATCC No. 44102 and Salmonella sp. ATCC No. 50 041 in vitro. The minimum inhibitory concentration （MIC） and minimum bactericidal concentration （MBC） values of the 9-octadecanoic acid-hexadecanoic acid-tetrahydrofuran-3,4-diyl ester were determined by using the broth microdilution dilution （BMD） method at different concentrations ranging from 20 to 0.625 mg mL-1. Its time-inhibition curve against E. coli was also tested and showed that the MIC values for the bacterial strains S. aureus, E. coli and Salmonella sp. were 20, 5 and 10 mg mL-1, respectively. Its MBC values were 20, 20 and 10 mg mL-1, respectively. The antibacterial activity of 9-octadecanoic acid-hexadecanoic acid-tetrahydrofuran-3,4-diyl ester against three strain tested showed the relationship with time and concentration.

Hardening Characteristics of Plain Carbon Steel and Ductile Cast Iron Using Neem Oil as Quenchant

The hardening characteristics of medium carbon steel and ductile cast iron using neem oil as quenching medium has been investigated. The samples were quenched to room temperature in Neem oil. To compare the effectiveness of the neem oil samples were also quenched in water and SAE engine oil the commercial quenchants. The microstructures and mechanical properties of the quenched samples were used to determine the quench severity of the neem oil. The result shows that hardness value of the medium carbon steel increased from 18.30HVN in the as-cast condition to 21.60, 20.30and 20.70HVN while that of ductile cast iron samples increased from 18.90HVN in the as-cast condition to 22.65, 20.30 and 21.30HVN for water, neem oil and SAE40 engine oil respectively. The as-received steel sample gave the highest impact strength value and water quenched sample gave the least impact strength. The impact strength of the medium carbon steel samples is 50.84, 41.35, 30.50 and 45.15 Joule and that of ductile iron is 2.71, 1.02, 0.68 and 1.70 Joule for as-cast condition, neem oil, water and SAE 40 engine oil quenched respectively. The microstructure of the samples quenched in the Neem oil revealed the formation of martensite. Hence, neem oil can be used where cooling severity less than that of water but greater than SAE 40 engine oil is required for hardening of plain carbon steels and ductile cast iron.

In vitro activity of neem oil [Azadirachta indica A. Juss (Meliaceae)] on Aspergillus flavus growth, sporulation, viability of spores, morphology and Aflatoxins B1 and B2 production

The effectiveness of neem (Azadiracta indica) oil on the growth, morphology, sporulation, viability of spores, aflatoxin B1 and B2 production by A. flavus on Yeast Extract-Sucrose medium was determined. Neem oil inhibited the fungal growth (i.e. mycelia dry weight, diameter of colony and growth rate) on solid media at concentrations from 0.5 to 5.0% v/v, although it significantly increased sporulation in the same conditions. Spores obtained from cultures grown without neem oil reduced germination when incubated in a neem oil supplemented medium. Colonies grown on solid media and in submerged cultures in the presence of neem oil exhibited morphological alterations, including granular cytoplasm, atypical hyphae branching pattern, abnormal and undifferentiated conidiophores. High Performance Liquid Chromatography was used to measure aflatoxins. In submerged cultures, neem oil at concentrations from 0.5 to 4.0% v/v caused approximately 95% inhibition in Aflatoxin B1 and B2. On other hand, these conditions failed to suppress fungal growth. Current research emphasized that neem oil was not fungistatic or fungicidal, but exhibited anti-aflatoxigenic activity.

Selected physical and chemical properties of mechanically extracted neem seed oil sourced as a preservative for ligno-cellulose in south-western Nigeria

Most of the seeds produced by neem （Azadirachta indica A. Juss） trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this country, especially where it concems the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil （NSO）, mechanically extracted using a cold press at 31.03 N-mm^-2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH.g^-1 and that of iodine 93.12 ± 2.01 g-100 g^- 1, while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g^-1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-eellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.

Comparative efficacy of neem and dimethyl phthalate (DMP) against malaria vector,Anopheles stephensi (diptera:culicidae)

Malaria is one of the most important parasitic diseases in the world which is transmitted by the Anopheles mosquitoes. There are several methods for malaria control.One of them is application of repellents on skin in malarious area as an intergrated vectro management measures.This study evaluated two repellents of DMP as a synthtic and locally product of neem oil as a botanical repellent against Anopheles stephensi.The modified method of K & D was used for the tests.Probing/biting rates on the shaved belly of white rabbits were counted. ED50 and ED95 values were calculated by probit statistic software.Calculation of effective dose(ED50, ED90 ) on human volunteer and white rabbit was performed using regression line.Protection and failure time of DMP and neem oil was also determined.ED50 value of DMP and neem oil was determined as 0.0076 and 0. 159 mg/cm respectively on white rabit.The figures of ED90 value of DMP and neem oil was determined as 0. 046 and 1.388 mg/cm^2.DMP and neem oil showed repellency effects against An.stephensi on human volunteers with ED50 value of 0.0037 and 0.127 mg/cm^2 respectively.ED90 value of DMP was determined as 0. 032 mg/cm^2.neem oil exhibited a ED90 value of 1.066 mg/cm^2 on human volunteer.The protection time of 6-7 hours for DMP and 31 minute for neem oil was determined.The failure times for DMP and Neem was 9 hours and 65 minutes rspectively on human bait.Our results exhibited that plant-based repellent is generally less effective than synthetic repellents.However,use of locally made botanical materials would be of great advantages for personal protection against mosquito biting.

In vitro antiproliferative and apoptosis inducing effect of a methanolic extract of Azadirachta indica oil on selected cancerous and noncancerous cell lines

Objective: To find the cytotoxic and apoptotic effects of neem oil extract on the selected cancerous(A-549, PC-3 and DU-145) and noncancerous(NIH3T3 and CCD-18Co) cell lines.Methods: Viability and cytotoxic effect induced by the extract was measured by using MTT assay and apoptotic effect of the extract was evaluated by using Hoechst 33342 and propidium iodide dual staining through a fluorescent microscope and activity of caspases 3, 8 and 9 through colorimetric assay kits. Results: The results showed that neem oil extract significantly reduced the viability in all selected cancer cells treated with varying concentrations of extract as compared with untreated cells and had less effect on noncancerous cell lines. It significantly increased the percentage of necrotic and apoptotic cells, and caspases 3, 8 and 9 activities in all cancer cells treated with extract as compared with untreated cells whereas no effect on noncancerous cell lines. It suggested that neem oil extract exerted a higher cytotoxic effect on cancer cells than normal cells and lower concentration induced apoptosis only in cancer cells.One of the apoptosis-inducing mechanism was through the activation of caspases signaling pathways. Conclusion: Conclusively, it implies that neem oil extract may contain one or more potential agents that can be used as a safe and effective anticancer therapy.

华南地区桔小实蝇对几种农药的抗药性研究

采用药膜法测定了广东、海南、福建、广西等4省(区)桔小实蝇Bactrocera dorsalis种群对敌百虫、高效氯氰菊酯、阿维菌素的抗性.结果表明,除了部分地区的种群已达到低水平的抗性外,如福州种群对阿维菌素抗性达到5.01倍,澄海、闽南桔小实蝇种群对敌百虫抗性达到4.56和4.07倍,大部分地区桔小实蝇种群对上述3种杀虫剂抗药性尚处于敏感阶段. 2003～2004年监测了广州郊区桔小实蝇成虫对敌百虫、高效氯氰菊酯、阿维菌素、乐斯本、印楝素的抗药性变化,结果显示除敌百虫外,桔小实蝇对其他4种药剂抗药性变化不明显.

印楝油对兔疥螨幼虫的体外杀螨活性

将兔疥螨幼虫置于聚苯乙烯小平皿中,分别加入不同浓度的印楝油液体石蜡溶液,以天然除虫菊酯和阿维菌素为阳性对照,蒸馏水和液体石蜡为阴性对照,观察记录不同时间段的螨虫死亡数,以死亡率、半数致死时间(LT50)和半数致死浓度(LC50)为指标评价了印楝油对兔疥螨幼虫的离体杀螨活性。结果显示,未稀释的印楝油能在25 min内杀死所有幼螨,其杀螨活性显著强于500 g/L的天然除虫菊酯(825 min,P<0.01),而与25 g/L的阿维菌素无显著差异(19 min,P>0.05);500、250和125 mL/L印楝油对兔疥螨幼虫的LT50分别为1、2、5 h;24 h的LC50和LC95分别为2.908和12.018 mL/L。结果证实,印楝油对兔疥螨幼虫具有较好的离体杀螨活性。

印楝油氯仿提取物对雄性小鼠的抗生育作用

给昆明种雄性小鼠口服印楝油氯仿提取物2g·kg-1d-1,连续1周,停药后第3周取材,研究了其抗生育作用。结果表明小鼠口服印楝油氯仿提取物后抗生育作用肯定;半数致死量为33g·kg-1;血清中转氨酶的活性在停药后的1～3个月升高,停药后的4～6个月基本恢复至正常,血清中睾丸酮含量在服药前后,无明显改变;流式细胞术研究结果表明:印楝油氯仿提取物引起睾丸组织生精细胞减少,细胞凋亡率升高;对变态期精子细胞核蛋白转换的影响表现为总碱性核蛋白含量减少47.11%,总组蛋白精核蛋白比值升高82.25%。研究表明,印楝油氯仿提取物有较好的抗生育作用,其作用机制主要是干扰精子核蛋白的转换,另外还可能与细胞免疫介导有关,对于控制鼠害有一定的意义。

阿维菌素与印楝油对柑桔红蜘蛛的增效作用

室内测定阿维菌素与印楝油对柑桔红蜘蛛的毒力及其复配组合的联合作用。毒力测定结果表明,阿维菌素与印楝油对柑桔红蜘蛛雌成螨处理后24 h的LC50分别为0.01μg/mL和6 579.87μg/mL。以共毒因子法评价阿维菌素与印楝油6种复配组合的联合作用,结果显示,二者以1∶100和1∶125两种比例复配对柑桔红蜘蛛雌成螨的共毒因子分别为24.50和31.08,具增效作用;进一步以共毒系数法确定阿维菌素与印楝油以1∶125的比例复配增效作用最为显著,共毒系数为160.76。

印楝油微胶囊的制备与生物活性研究

以异氰酸酯、聚乙烯醇、丙三醇等为壁材,利用聚合方法制备了印楝油微胶囊.探讨了反应条件对制备印楝油微胶囊的影响,并利用正交试验确定了最佳试验条件.结果表明,质量分数分别为15%的聚乙烯醇(polyvinyl alco-hol,PVA)溶液、20%甲苯-2,4-二异氰酸酯(toluene-2,4-d iiso-cyanate,TD I)、65%印楝油(neem oil)混合为最佳配比,此时具有73.29%的包埋率.以黄曲条跳甲Phyllotreta striolata成虫作试虫的生物活性测试显示,与直接使用印楝油相比,在一定时间里,微胶囊化后的印楝油更能减少黄曲条跳甲成虫的落虫量、产卵量和成虫的取食面积.其中,对成虫落虫量和产卵量的减少可持续4 d,对成虫取食面积的减少可至少持续6 d.微胶囊有效地保持了生物活性,延长了药效作用时间,减少了对环境的污染.

印楝油氯仿提取物杀螨活性成分的分离纯化及其生物学活性

将印楝油氯仿提取物经硅胶柱层析和丙酮重结晶进行生物活性跟踪分离纯化,并运用互补重对数模型(CCL模型)分析活性化合物的离体生物活性,求出半数致死浓度(LC50)和半数致死时间(LT50)。结果显示,从印楝油氯仿提取物中分离出一种白色雪花状丙酮结晶物,熔点为60～61℃,经结构鉴定为18-碳酸-3,4-呋喃二酯,其对兔疥螨幼虫的杀螨活性呈时间浓度依赖性,24h的LC50和LC90分别为0.0818和9.8424g/L,7.500g/L时的LT50和LT90分别为15.3324h和24.6784h。这表明印楝油氯仿提取物的杀螨活性成分主要为酯类物质,对兔疥螨具有较强的杀螨活性。

气相色谱-质谱联用法测定印度楝树油中高级脂肪酸组分含量

对印度楝树油中高级脂肪酸成分进行分析,经甲酯化后用气相色谱-质谱联用仪鉴定了其中所含高级脂肪酸的成分,用气相色谱法-火焰离子化检测器对其成分进行定量分析。溶剂浸泡萃取和二氧化碳超临界萃取两种不同方法得到的脂肪酸成分基本相同,其中油酸相对含量为51.15%,硬脂酸相对含量为19.13%,棕榈酸相对含量为16.78%,亚油酸相对含量为9.86%,花生酸相对含量为1.24%,其他含量低于1%的高级脂肪酸还有顺-3-辛基-环氧乙烷-辛酸,山萮酸,9-十八(碳)烯酸,11-二十碳二烯酸,9-十六碳烯酸,十七(烷)酸等。

印楝油两性不育灭鼠颗粒剂对小鼠摄食系数与抗生育作用

鼠害一直影响我国林业的发展,传统的灭鼠药物由于对环境的破坏过大且有长期毒副残留的危害,因而现有灭鼠制剂已逐渐开始向天然灭鼠剂转变,其中通过抗生育机制控制害鼠的繁殖力度是一种有效又不破坏生态环境和生态链的灭鼠方法（尤德康等，2006；孙红专等，2006）。

快速搅拌法室温浸提印楝油和印楝素

在室温下用间歇式快速搅拌法从印楝种仁中浸提印楝油和印楝素。讨论了料液比以及浸提时间对得率的影响。结果表明:印楝种仁300g,以750mL石油醚做溶剂,在快速搅拌条件下浸提21min时印楝油得率最高;将300g去油后的印楝种仁以900mL甲醇做溶剂,在快速搅拌下浸提21min时印楝素得率最高。由此得出,快速搅拌法浸提印楝油的最佳条件是:溶剂石油醚、料液比1∶2.5(g∶mL,下同)、时间每次7min、浸提3次,出油率30.4%;快速搅拌法浸提印楝素的最佳条件是:溶剂为甲醇、料液比1∶3、时间每次7min、浸提3次,印楝素A的得率为0.438%,印楝素B的得率为0.142%。

缅甸印楝籽油中的高级脂肪酸成分

对印楝油进行皂化得到了印楝油的总脂肪酸,将总脂肪酸甲酯化得到总脂肪酸甲酯,用GC-MS联用仪测定其中所含高级脂肪酸.结果表明印楝油中含有油酸,亚油酸,棕榈酸,硬脂酸,花生酸等十种高级脂肪酸成分.

印楝油对作物病虫害的生物活性研究概况

印楝油对农作物害虫具有防治作用,而且具有抗菌、抗病毒的能力,还可用于线虫的防治。所以印楝油应用于杀虫剂、杀菌剂等植物源生物农药的制备。本文对印楝油在作物病虫害防治上的研究及应用做了介绍。

印楝油对褐稻虱雌虫求偶鸣声和交尾行为的影响

笔者用印楝(Azadirachta indica A.Juss)油点滴褐稻虱[Nilaparvata lugens(stil)]初羽化雌虫背部,点滴量分别为1.0、2.5及5.0μg,或将试虫饲养在分别用3％、6％及9％印楝油乳液喷雾处理过的稻株上。结果表明印楝油对褐稻虱雌虫正常的发声和交尾行为有明显干扰。8.3—25.0％的处理雌虫不能发声,也不交尾;8.3—58.3％发出不正常的求偶鸣声;其余鸣声虽基本正常,但脉冲重复频率增高,鸣叫持续时间缩短。后者可完成交尾,交尾前历时明显延长,但交尾时间与对照无显著差异。

微波辐射印楝油甲酯化响应曲面模型研究

以微波辐射印楝油甲酯化制取生物柴油,通过单因素实验,找到醇油物质的量比、催化剂用量、反应温度和反应时间的较佳取值范围。根据Box-Behnken实验设计原理设计实验,以印楝油转化率为响应值,建立反应的回归模型,进行响应面分析和优化。结果表明,微波辐射印楝油甲酯化反应的最佳工艺条件为:醇油物质的量比5.4∶1,催化剂KOH用量1.36%,反应温度50℃,反应时间68 min。在此条件下,印楝油的转化率为93.17%,与理论预测值93.78%的相对误差为0.65%。

两性不育灭鼠剂印楝油对高原鼠兔摄食量的影响及药效试验研究

通过对高原鼠兔野外饲养和印楝油摄食量的药效观察试验,选取高原鼠兔90只,分成2个试验组和1个对照组,各试验组投药浓度为30%和40%的印楝油;对照组饲喂青草,用药7d。试验期间观察各组鼠兔的临床表现,每天记录颗粒剂的采食量,并计算摄食系数;停药后27d处死,剖检雄雌鼠,做病理切片,剖开雌鼠子宫,统计怀孕率。结果表明,高原鼠兔对主药浓度为30%、40%的颗粒剂的摄食率分别为11.09%和25.10%,差异显著(P<0.05);筛选出主药浓度为40%的印楝油两性不育灭鼠颗粒剂适口性良好,对高原鼠兔有良好的抗生育作用。