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, Escherichi...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.展开更多
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 effectiven...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.展开更多
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 co...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.展开更多
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 inhib...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.展开更多
Applications of nanotechnology in agriculture will result in the development of efficient and potential approaches towards the management of insect pests.The toxicity effects of four essential oils peppermint,thyme,ca...Applications of nanotechnology in agriculture will result in the development of efficient and potential approaches towards the management of insect pests.The toxicity effects of four essential oils peppermint,thyme,camphor and sage oils were tested against the fourth instar larvae of Agrotis ipsilon to select the most effective essential oil to be converted to the nano form.According to the results obtained,peppermint oil was the most toxic compound,which has been used in the present investigation compared with neem oil.The toxicity of bulk and nano-formulations of neem and pepper mint oils were tested against 2nd and 4th instar larvae of A.ipsilon under laboratory conditions of 25±2°C&65-70%R.H.relative humidity The results show that the LC50 value(the concentration used which kill 50%of the tested individuals)of loaded neem or pepper mint were lower(0.62 and 36.47 ppm)compared with neem or pepper mint oil nano-emulsion and bulk neem for the second larval instar.The different formulations of neem are more potent than in case of peppermint oil,as LC50 and LC90 values were significantly lower.The same trend was found concerning the 4th larval instar.Age of treated larvae had a detrimental effect on the response to the compounds tested.It was noticed that the younger larvae were much more sensitive to the prepared compounds compared to the older ones.The least LC50 value for loaded neem nano-emulsion was 6.68 ppm compared with the highest value for bulk neem oil(16.68 ppm).Also,LC90 values followed the same trend as in case ofLC50.Again,the toxicity of loaded peppermint oil had the most insecticidal activity as expressed by the lowest LC50 value(51.9 ppm)with more insecticidal effect than the bulk(125.43 ppm)or nano-emulsion(85.43 ppm).The present results indicated that these novel systems could be used in integrated pest management program for A.ipsilon control.展开更多
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 ...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.展开更多
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 ind...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.展开更多
基金supported by the program for Changjiang Scholars and Innovative Research Team in University,China (PCSIRT0848)Sichuan Agricultural University Youth Fundation,China(2006C18)the State Key Laboratory of Veterinary Etiologocal Biology,Lanzhou Veterinary Research Institute,Chinese Acad-emy of Agricultural Sciences(SKLVEB2009KFKT022)
文摘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.
文摘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.
文摘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.
文摘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.
文摘Applications of nanotechnology in agriculture will result in the development of efficient and potential approaches towards the management of insect pests.The toxicity effects of four essential oils peppermint,thyme,camphor and sage oils were tested against the fourth instar larvae of Agrotis ipsilon to select the most effective essential oil to be converted to the nano form.According to the results obtained,peppermint oil was the most toxic compound,which has been used in the present investigation compared with neem oil.The toxicity of bulk and nano-formulations of neem and pepper mint oils were tested against 2nd and 4th instar larvae of A.ipsilon under laboratory conditions of 25±2°C&65-70%R.H.relative humidity The results show that the LC50 value(the concentration used which kill 50%of the tested individuals)of loaded neem or pepper mint were lower(0.62 and 36.47 ppm)compared with neem or pepper mint oil nano-emulsion and bulk neem for the second larval instar.The different formulations of neem are more potent than in case of peppermint oil,as LC50 and LC90 values were significantly lower.The same trend was found concerning the 4th larval instar.Age of treated larvae had a detrimental effect on the response to the compounds tested.It was noticed that the younger larvae were much more sensitive to the prepared compounds compared to the older ones.The least LC50 value for loaded neem nano-emulsion was 6.68 ppm compared with the highest value for bulk neem oil(16.68 ppm).Also,LC90 values followed the same trend as in case ofLC50.Again,the toxicity of loaded peppermint oil had the most insecticidal activity as expressed by the lowest LC50 value(51.9 ppm)with more insecticidal effect than the bulk(125.43 ppm)or nano-emulsion(85.43 ppm).The present results indicated that these novel systems could be used in integrated pest management program for A.ipsilon control.
文摘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.
基金supported by the Global Research and Development Center(GRDC)Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(grant No.2017K1A4A3014959)
文摘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.
