泽漆乙醇提取物灭螺机理初步研究

目的观察泽漆对钉螺软体组织糖原的影响,以探讨其灭螺机制。方法采用系统分离法分离泽漆极性部位,按照WHO推荐的"杀螺剂实验室终筛方法"中浸泡方法进行浸杀灭螺试验;蒽酮比色法测定经泽漆乙醇提取物处理后钉螺软体组织的糖原含量变化。结果钉螺经泽漆乙醇提取物400、800 mg/L作用48 h,钉螺死亡率分别为50.43%、77.50%;作用96 h,钉螺死亡率均达100%。钉螺体内糖原含量随药物浓度的增大而逐步降低,800 mg/L时糖原下降最明显,较对照组含量下降69.49%。结论泽漆乙醇提取物能够显著降低钉螺体内的糖原含量,具有较好的灭螺效果。     

灭螺药物研究进展

钉螺是日本血吸虫的惟一中间宿主,消灭钉螺是控制血吸虫病的重要策略和措施之一。灭螺的方法主要有生物灭螺、物理灭螺和药物灭螺。目前采用的主要方法是药物灭螺,灭螺药物包括化学灭螺药和植物灭螺药2类。1化学灭螺药物1.1五氯酚钠1946~1953年美国在实验室共筛选了7000余种化学品,发现五氯酚钠杀螺效果优于其他药物[1]。五氯酚钠易溶于水,对成螺、幼螺和螺卵均有较高杀灭活性,使用方便,在我国曾作为一种主要灭螺药物使用。五氯酚钠实验室浸杀钉螺的LC50为0.54mg/L/、2mg/L48h,浸杀钉螺死亡率达100%。现场灭螺浸杀用药量为10~20mg/L,喷洒…     

醉鱼草内生真菌LL3026杀螺作用实验研究

目的研究醉鱼草(Buddleia lindleyana)内生真菌LL3026(Colletotrichum sp.)发酵液的杀螺作用、活性部位及其热稳定性和光照稳定性。方法采用烧杯浸杀法,观察不同时间、不同浓度LL3026发酵液醇浸膏水溶液对湖北钉螺的杀灭作用,同时设1mg/L氯硝柳胺水溶液和去氯离子水为对照。采用溶剂系统分离法分离LL3026发酵液的不同极性部位,并比较各极性部位的杀螺活性。该菌发酵液醇浸膏水溶液于不同温度(30～100℃)、不同时间(30～150min)处理后,进行杀螺试验,检测其热稳定性。在25℃、不同光照强度(分别照射1～9d)条件下,测定其光照稳定性。结果施药后24、48和72h的半数致死浓度(LC50)分别为50.11、3.43和1.55mg/L。分离LL3026发酵液,获得石油醚、乙醚、乙酸乙酯、正丁醇和水相等不同极性部位,其低极性部位的乙醚相杀螺效果最好,24、48和72h杀螺率均为100%。在80℃加热120min后,发酵液活性物质热稳定性好,杀螺率为100%。3600lx强度光照9d的发酵液的杀螺活性较强,其48h杀螺率为86.7%。结论醉鱼草内生真菌LL3026具有较好的杀螺活性。     

商陆根际真菌Aspergillus fumigatus SL-30杀螺有效成分MI的生物安全性

目的了解商陆(Phytolacca acinosa)根际真菌Aspergillus fumigatus SL-30杀螺有效成分硫代二酮哌嗪类化合物(MI)的生物安全性。方法将MI用去氯水配制成0.01至0.60 mg/L等一系列浓度,采用浸杀法测定MI杀灭钉螺(Oncomelania hupensis)活性,分别于24、48和72h统计各组钉螺死亡率并计算半数致死浓度(LC50);采用半静态法测定0.5～4.0 mg/L等一系列浓度MI对斑马鱼(Brachydanio rerio)、河虾(Macrobrachium nippoensis)和泽蛙(Rana lim-nochris)蝌蚪的急性毒性,于24、48和72 h观察实验动物的反应并统计死亡情况;采用自然土壤法测定1 mg/kg和10 mg/kg MI对蚯蚓(Eisenia fetida)的影响,于第7和14天各观察1次,统计各处理组蚯蚓的死亡和中毒情况;采用密闭碱液直接吸收法测定10 mg/kg MI对土壤微生物的影响,分别于第2、5、7、10、12和15 d测定并计算每100 g干土的CO2释放量。结果24、48和72 h MI杀灭钉螺的LC50分别为0.101、0.062和0.022 mg/L;斑马鱼、河虾和泽蛙蝌蚪的死亡率均随药物浓度升高而增高,各实验动物24、48和72 h的LC50值分别为1.941、1.755和1.219 mg/L(斑马鱼),3.170、2.720和2.419 mg/L(河虾),2.109、1.751和1.288 mg/L(泽蛙蝌蚪)。MI对蚯蚓的LC50>10.0 mg/kg。MI为10 mg/kg时,15 d内对微生物呼吸的抑制率均低于50%。结论 MI对斑马鱼、河虾和泽蛙蝌蚪的毒性远低于对钉螺的毒性,在有效杀螺浓度范围内,MI对供试水生非靶生物是安全的;MI对蚯蚓和土壤微生物属低毒级。     

黄果茄植物灭螺成份的提取及灭螺效果研究

目的提取黄果茄植物灭螺有效成份并观察其灭螺效果。方法利用有机溶剂对黄果茄植物果实提取并获得原粉;经电子轰击质谱(EI-MS)测定分子量;采用浸杀法、喷洒法和喷粉法观察黄果茄植物灭螺有效成份的灭螺效果。结果黄果茄灭螺有效成份的分子量为722。湖北钉螺在4.3200mg／L浓度中,室温25C±1C条件下,浸泡24h、48h的死亡率分别是96.7％、100％;其24h、48h、72h的LC50分别为0.621、0.332、0.181mg／L。结论黄果茄原粉为一种新的植物提取物,对湖北钉螺有较好的杀灭效果。     

氯硝柳胺悬浮剂浸杀钉螺螺卵和幼螺效果的研究

目的了解氯硝柳胺悬浮剂(SCN)杀灭钉螺螺卵、幼螺等不同生长发育阶段的效果。方法分别称取SCN和氯硝柳胺乙醇胺盐可湿性粉剂(WPN),采用实验室螺卵、幼螺浸杀法,并比较两者对杀灭螺卵和幼螺的不同效果。结果SCN0.25mg/L浸杀螺卵24h,螺卵死亡率为100%;WPN0.50mg/L浸杀24h,螺卵死亡率为100%。SCN浸杀螺卵24、48、72h的LC50值分别为0.0506、0.0496、0.0473mg/L;WPN浸杀螺卵24、48、72h的LC50值分别为0.1030、0.0962、0.0869mg/L。SCN和WPN0.25mg/L浸杀幼螺死亡率均为100%;SCN浸杀幼螺24、48、72h的LC50值分别为0.0625、0.0474、0.0442mg/L;WPN浸杀幼螺24、48、72h的LC50值分别为0.1088、0.0825、0.0825mg/L。结论氯硝柳胺悬浮剂对钉螺螺卵、幼螺均具有较好的杀灭作用。     

密达杀灭钉螺效果的研究

目的评价密达不同剂型杀灭钉螺效果,有关因素的影响以及对非靶水生物的毒性.方法分别采用泥盘接触法、烧杯浸杀法和斑马鱼实验法,观察密达5种剂型杀灭钉螺效果,了解泥土湿度和温度对密达杀螺作用的影响,测定密达2种剂型的急性鱼毒.结果施药后5 d和7 d,5种剂型杀螺效果均有明显差异,其中75%可湿性粉剂的生物活性最高,泥盘接触法3 d、5 d和7 d的LC 50分别为3.93 g/m2、0.91 g/m2和0.69 g/m2;实验表明密达杀钉螺效果有随泥土湿度和温度提高而增强的趋势;密达10%沙粒剂和75%可湿性粉剂24 h、48 h、72 h和96 h对斑马鱼的LD50均＞10mg/L.结论密达各剂型对钉螺均具有不同程度的杀灭作用,其中以75%可湿性粉剂杀螺效果最好;湿度和温度对密达杀螺效果影响较大,实际使用时须掌握条件;密达为一类低毒杀螺剂,适用于水产养殖地区及其它特定环境的灭螺处理.     

杀虫丁与氯硝柳胺室内杀螺效果的观察

目的观察杀虫丁对山丘地区残存钉螺的杀螺效果。方法采用室内浸杀和喷洒方法,与氯硝柳胺灭螺效果进行比较,并设清水对照组,观察不同浓度的钉螺死亡率。结果室內浸杀杀虫丁2.0mg/L48h钉螺死亡率为99％,氯硝柳胺2h 1.0mg/L、2.0mg/L和48h各浓度组钉螺死亡率均达99％以上,两种药物浸杀灭螺效果除2.0mg/L组浸杀48h差异无显著性(x~2=0.00005,P>0.25)外,其余差异有高度显著性(P<0.01);室内喷洒杀虫丁和氯硝柳胺24h和48h各浓度组钉螺死亡率均达99％以上,两种药物的喷洒灭螺效果差异无显著性(P>0.05);杀虫丁具有较好的抑制钉螺爬动作用。结论杀虫丁的灭螺效果喷洒优于浸杀。建议浸杀灭螺浓度应大于2.0mg/L,喷洒剂量为2g/m~2。     

硼镁石粉杀灭钉螺效果和急性鱼毒的评价

目的评价硼镁石粉杀灭钉螺效果和现场推广应用前景,了解其对鱼类的急性毒性.方法 采用撒粉法进行实验室和不同类型现场杀螺试验,用斑马鱼进行急性鱼毒试验.结果硼镁石粉在实验室撒粉施药后3、7、15 d的LC5.分别为228.19、34.89、12.47 g/m2,显示该药具有明确的量-效和时-效关系.江滩地区200 g/m2的杀螺效果较好,180 d钉螺校正死亡率和活螺密度下降率均达100.0%;山丘地区200 g/m2 210 d活螺密度下降96.1%;沿海高沙土地区灭螺效果较差,80 g/m2几乎无杀螺效果,200 g/m2钉螺死亡率也很低.现场观察发现硼镁石粉对植物有毒害作用,并随剂量增加而毒害加重;同时,施用硼镁石粉后土壤碱性明显增加,且随剂量增加而碱性增加.急性鱼毒显示48、72、96 h LC50分别为964.32、633.66、523.74 mg/L.结论硼镁石粉现场杀螺作用缓慢,用量大,对鱼类安全,对植物及土壤有损害.硼镁石粉中有杀螺作用的成分亟待研究阐明.     

50%氯硝柳胺乙醇胺盐可湿粉剂冬季浸杀钉螺效果观察

目的 在冬季对50%氯硝柳胺乙醇胺盐可湿粉剂（wettable powder of niclosamide ethanolamine salt,WPNES）的浸杀灭螺效果进行观察,以探索冬季开展药物灭螺工作的可行性。方法 于冬季设置室外观察组（-2～10 ℃）和室内对照组（19～25 ℃）观察50%WPNES浸杀灭螺效果,2组均包含6个浓度的施药组（按照有效含量从高到低分别为1.000 0、0.500 0、0.250 0、0.125 0、0.062 5、0.031 3 mg/L）和1个脱氯水空白对照组。观察并计算各组24、48和72 h的钉螺死亡率和半数致死浓度（LC50）。结果 室外观察组各浓度浸杀24、48和72 h钉螺死亡率均低于室内对照组,但随着时间延长,两组LC50差距逐渐缩小。1.000 0 mg/L50%WPNES浸杀72 h时,室外观察组钉螺死亡率达到100.00%,LC50为0.153 3 mg/L,符合中华人民共和国农业行业标准《农药登记用杀钉螺剂药效试验方法和评价》（NY/T 1617—2008）要求。结论 冬季低温条件下50%WPNES浸杀灭螺具有可行性,但其现场条件下的灭螺效果尚需进一步验证。     

Extracellular localization of pokeweed antiviral protein.

Pokeweed antiviral protein is an enzyme of Mr 29,000 known to inactivate a wide variety of eukaryotic ribosomes. We have used electron microscopy to show that the antibody specific for the protein is bound within the cell wall matrix of leaf mesophyll cells from Phytolacca americana. Any penetration or breakage of the cell wall and membrane could allow the enzyme to enter the cytoplasm, where it is likely to inhibit protein synthesis in the damaged cell. We speculate that pokeweed antiviral protein is a defensive agent whose principal function is probably antiviral.     

化学发光免疫法检测美洲大蠊sIgE水平的研究

将6只美洲大蠊全虫用液氮研磨提取粗浸液，用阴离子交换剂（DEAE, Sephadex A-50）纯化后测定蛋白浓度，并配制成不同浓度梯度，分别将粗浸液及纯化后的不同浓度变应原点于硝酸纤维膜（NC膜）上，依次加入不同蟑螂过敏患者血清、生物素-亲和素系统的IgE二抗和辣根过氧化物酶（HRP），以及鲁米诺化学发光底物进行化学发光反应。结果表明，化学发光免疫法可检测美洲大蠊粗浸液最低蛋白浓度为0.87 μg/ml。在此浓度下，其检出结果与皮试阳性患者血清符合率为90％，与皮试阴性及健康人血清的符合率均为100％。     

Formulation and evaluation of herbal gel of Pothos scandens Linn

ObjectiveTo formulate Pothos scandens Linn (P. scandens) leaf extract in to a gel and investigate their burn wound healing activity.MethodsEthanolic extract of dried leaves of P. scandens were subjected to priliminery phytochemical evaluation and wound healing activities studies. Different gel formulations of ethanolic extract of P. scandens (4% w/v) were prepared using polymers carbopol 934 and carbopol 940 by varying their concentration. These formulations were evaluated for physical parameters, drug content, pH, viscosity, extrudability, spreadability, primary skin irritation, pharmacological activity and stability.ResultsWound healing studies of ethanolic extract revealed that P. scandens treated animals were found to epithelise in 22 days while the solvent control and the untreated rats epithelise within 35 and 40 days respectively. The formulation with 1.5% w/w carbopol 934 was found to be more promising as it shows better physicochemical characteristics, higher pharmacological activity and stability compared to other formulations.ConclusionsP. scandens alcoholic extract shows significant improvement in burn wound contraction and hence this is a promising candidate in burn wound healing.     

Phytochemical screening and evaluation of anti-inflammatory activity of methanolic extract of Abroma augusta Linn

ObjectiveTo evaluate the Phytochemical and anti-inflammatory property of the different parts of methanolic extracts of Abroma augusta Linn.Materials and methodsAbroma augusta Linn (Family-Malvaceae) commonly known as Ulatkambal in Hindi and Devil's cotton in English, found in tropical Asia, South and eastern Africa, and Australia. It is mainly used for dysmenorrhoea, ammenorrhoea, sterlilty and other menstrual disorder. The present study aimed at evaluation of Phytochemical and anti-inflammatory study of different parts of Abroma augusta Linn methanolic extract by the carrageenan induced rat paw oedema method.ResultsThe result showed significant anti-inflammatory property of different parts of Abroma augusta Linn methanolic extract.ConclusionsThe methanolic extract of different parts of Abroma augusta Linn showed potent activity comparing with the standard drug diclofenac sodium perhaps due to the alkaloids and flavonoids present in the plant.     

In vitro anthelmintic activity of Barleria buxifolia on Indian adult earthworms and estimation of total flavonoid content

ObjectiveTo study the anthelmintic activity of Barleria buxifolia leaf and to estimate the total flavonoid content.MethodsThe aqueous and ethanolic leaf extracts were prepared and these were analyzed for total flavonoid content by aluminium chloride colorimetric method and Pheretima posthuma was used for anthelmintic activity by using the different concentrations (10, 20, 40, 80 and 100 mg/mL).ResultsAll the investigational extracts showed an anthelmintic activity at concentration of 10 mg/mL. The ethanolic extract of 100 mg/mL has produced an significant effect (P<0.001) when compared to aqueous extract. The total flavonoid content was found to be 5.67 mg QE/100 g.ConclusionsFrom the above study, the leaf extract has shown a good anthelmintic activity.     

Cardiovascular effects of Persea americana Mill (Lauraceae) (avocado) aqueous leaf extract in experimental animals

The cardiovascular effects of Persea americana Mill (Lauraceae) aqueous leaf extract (PAE) have been investigated in some experimental animal paradigms. The effects of PAE on myocardial contractile performance was evaluated on guinea pig isolated atrial muscle strips, while the vasodilatory effects of the plant extract were examined on isolated portal veins and thoracic aortic rings of healthy normal Wistar rats in vitro. The hypotensive (antihypertensive) effect of the plant extract was examined in healthy normotensive and hypertensive Dahl salt-sensitive rats in vivo. P americana aqueous leaf extract (25-800 mg/ml) produced concentration-dependent, significant (p < 0.05-0.001), negative inotropic and negative chronotropic effects on guinea pig isolated electrically driven left and spontaneously beating right atrial muscle preparations, respectively. Moreover, PAE reduced or abolished, in a concentration-dependent manner, the positive inotropic and chronotropic responses of guinea pig isolated atrial muscle strips induced by noradrenaline (NA, 10(-10)-10(-5) M), and calcium (Ca(2+), 5-40 mM). PAE (50-800 mg/ml) also significantly reduced (p < 0.05-0.001) or abolished, in a concentration-dependent manner, the rhythmic, spontaneous, myogenic contractions of portal veins isolated from healthy normal Wistar rats. Like acetylcholine (ACh, 10(-8)-10(-5) M), the plant extract (25- 800 mg/ml) produced concentration-related relaxations of isolated endothelium-containing thoracic aortic rings pre-contracted with noradrenaline. The vasorelaxant effects of PAE in the isolated, endothelium-intact aortic rings were markedly inhibited or annulled by N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-5) M), a nitric oxide synthase inhibitor. Furthermore, PAE (25-400 mg/kg iv) caused dose-related, transient but significant reductions (p < 0.05-0.001) in the systemic arterial blood pressure and heart rates of the anaesthetised normotensive and hypertensive rats used. The results of this laboratory animal study indicate that PAE caused bradycardia, vasorelaxation and hypotension in the mammalian experimental models used. The vasorelaxant action of PAE was endothelium dependent, and was, therefore, possibly dependent on the synthesis and release of nitric oxide (NO). The vasorelaxant effects of PAE appeared to contribute significantly to the hypotensive (antihypertensive) effects of the plant extract. However, the findings of this study tend to suggest that P americana leaf could be used as a natural supplementary remedy in essential hypertension and certain cases of cardiac dysfunctions in some rural Africa communities.     

Anti-diabetic effect of Thunbergia laurifolia Linn. aqueous extract

Several kinds of medicinal plants have been used to treat diabetes mellitus. In the present study, Thunbergia laurifolia Linn. (purple flower strain) were tested for hypoglycemic activity in rats. The effects on the reproductive system and the histology of the pancreas were also investigated. The hypoglycemic properties of the aqueous extract from the leaves (60 mg/ml/day) were evaluated in normoglycemic and alloxan-induced diabetic rats. The results showed that high blood glucose levels of diabetic rats were associated with severe destruction of beta-cells (insulin-secreting cells) in the islet of Langerhans. The 15-day-treatment of T. laurifolia extract decreased levels of blood glucose in diabetic rats. The recovery of some beta-cells was found in diabetic rats treated with the extract, although not completely normal. Whether T. laurifolia leaf contains insulin-like substance(s) which directly act as hypoglycemic agents, or contains substances that induce the regenerative process of beta-cells remains to be further investigated. Alteration of the reproductive system was also observed in diabetic rats, but it was not improved by treatment with T. laurifolia extract.     

Studies on mosquito larvicidal properties of Eucalyptus citriodora Hook (family-Myrtaceae)

Hexane extract obtained from leaves of Eucalyptus citriodora Hook was tested against larvae of Anopheles stephensi Liston, Culex quinquefasciatus Say and Aedes aegypti Linn to assess its toxicity and growth inhibiting activity. The results showed better activity of hexane extract against larvae of An. stephensi Liston as compared to the larvae of Cx. quinquefasciatus Say and Ae. aegypti Linn. The LC50 values against IVth instar larvae of three species were 69.86, 81.12 & 91.76 ppm respectively after 24 hours and 26.7, 29.9 & 38.8 ppm respectively after 72 hours. At lowest concentration viz. 10 ppm, 73% larvae of An. stephensi Liston failed to emergence as adult mosquito while in Cx. quinquefasciatus Say and Ae. aegypti Linn only 10 & 6% larvae failed to emerge. Further observations showed some morphological abnormalities in same pupae which could not moult normally. These results clearly indicated growth inhibition effect of the hexane extract of Eucalyptus against mosquito larvae, particularly Anopheles species. Thus Eucalyptus citriodora Hook, which is commonly found in Northern India, has a great potential for the development of an eco-friendly herbal insecticidal product for control of mosquito breeding.     

Acute and chronic toxicity studies of hydromethanol leaf extract of Helianthus annuus Linn.in rats

Objective:To investigate the safety levels of hydromethanol leaf extract of Helianthus annuus Linn.(H.annuus) in rat.Methods:Acute oral toxicity test of hydromethanol leaf extract of H.annuus was conducted through up and down method at 2.00 g/kg dose limit in rats.The chronic toxicity study was conducted by administering different concentrations(0.25,0.50 and 1.00 g/kg) of hydromethanol extract of H.annuus in feed,for 90 consecutive days.On days 30,60 and 90,blood samples were collected from the retro-orbital plexus of the rats for determination of serum biochemical parameters.Histopathological examination of the pancreas,livers,kidneys and testis were also conducted.Results:The LD_(50) of the hydromethanol extract of H.annuuswas greater than 2.00 g/kg and it significantly(P 0.05) reduced serum cholesterol.On days 60 and 90,the serum urea and creatinine levels of hydromethanol extract of H.annuustreated groups were elevated when compared with the control group.There were fibrosis in the kidneys and livers;degeneration and necrosis in the testis and significant dose-dependent increases in number and size of pancreatic islet of langerhans.Conclusions:The findings suggest that hydromethanol extract of H.annuus is tolerated in short term administration,but long term(up to 90 days) administration at high doses,may elicit hepatic,testicular and nephrotic disorder.     

Isolation and characterization of pokeweed antiviral protein mutations in Saccharomyces cerevisiae: identification of residues important for toxicity.

Pokeweed antiviral protein (PAP), a 29-kDa protein isolated from Phytolacca americana inhibits translation by catalytically removing a specific adenine residue from the 28S rRNA of eukaryotic ribosomes. PAP has potent antiviral activity against many plant and animal viruses, including human immunodeficiency virus. We describe here development of a positive selection system to isolate PAP mutants with reduced toxicity. In vitro translation in the presence or absence of microsomal membranes shows that PAP is synthesized as a precursor and undergoes at least two different proteolytic processing steps to generate mature PAP. The PAP cDNA was placed under control of the galactose-inducible GAL1 promoter and transformed into Saccharomyces cerevisiae. Induction of PAP expression was lethal to yeast. The PAP expression plasmid was mutagenized and plasmids encoding mutant PAP genes were identified by their failure to kill S. cerevisiae. A number of mutant alleles were sequenced. In one mutant, a point mutation at Glu-177 inactivated enzymatic function in vitro, suggesting that this glutamic acid residue is located at or near the catalytic site. Mutants with either point mutations near the N terminus or a nonsense mutation at residue 237 produced protein that was enzymatically active in vitro, suggesting that the toxicity of PAP is not due solely to enzymatic activity. Toxicity of PAP appears to be a multistep process that involves possibly different domains of the protein.