A field investigation was conducted to assess the breakdown of azadirachtin A in a tropical coastal savanna soil amended with neem leaves （NL） combined with poultry manure （PM） or cow dung （CD） using gas chromat...A field investigation was conducted to assess the breakdown of azadirachtin A in a tropical coastal savanna soil amended with neem leaves （NL） combined with poultry manure （PM） or cow dung （CD） using gas chromatography. Samples in polythene bags 15 cm long and 4.8 cm in diameter were randomly placed to a depth of 14 cm in the soil, and azadirachtin A concentration was assessed on days 0, 14, 28, 42, 56, 70, and 84. Azadirachtin A degradation in the soil followed first-order reaction kinetics with different half-lives obtained for varying combinations of the amendments. Higher neem amendment levels of 100 g gave shorter half-lives of azadirachtin A than the lower levels of 50 g. Within the 50 g NL group the additions of the poultry manure and the cow dung gave significantly shorter （P 〈0.05） half-lives of azadirachtin A than the sole neem amendment, whereas in the 100 g NL group only additions of 10 g CD and 10 g PM were significantly less （P 〈 0.05） than the sole neem amendment. Different changes resulting from the kind and quantity of animal manure added were observed in the half-lives of azadirachtin A. The 100 g NL group had significantly higher （P 〈0.05） moisture content, which, coupled with the likely differeaces in microbial biomass, could be the major factor responsible for variations in the half-llfe of the compound. Therefore, the quantity of the neem leaves applied and the addition of animal manure affected the breakdown of azadirachtin A in the soil amended with neem leaves.展开更多
Azadirachtin,a complex tetratriterpenoid limonin with potent insecticidal properties,is the most widely used biological pesticide worldwide.Its versatile pharmacological applications include the inhibition of tumor gr...Azadirachtin,a complex tetratriterpenoid limonin with potent insecticidal properties,is the most widely used biological pesticide worldwide.Its versatile pharmacological applications include the inhibition of tumor growth and anti-malarial,anti-bacterial,and anti-inflammatory properties.Azadirachtin plays a pivotal role in pest control and novel drug development.The primary source of azadirachtin is the neem tree(Azadirachta indica A.Juss),with an azadirachtin content ranging from 0.3%to 0.5%.Despite the market demand for botanical pesticides reaching approximately 100,000 tons per year,the annual neem production in China is only 1.14 tons.Although azadirachtin can be obtained through plant extraction or chemical synthesis,the quantity obtained does not meet the market demand in China.The sluggish pace of azadirachtin biosynthesis results from the limited availability of genetic information and the complexity of the synthetic pathway.Recent advancements in azadirachtin biosynthesis hold promise as an efficient collection method.In this study,we explored the physicochemical properties,biological activities,mechanisms of action,and acquisition methods of azadirachtin.We also delved into recent progress in azadirachtin biosynthesis and assessed potential future usage challenges.This study aims to establish a theoretical foundation for the scientific application and efficient synthesis of azadirachtin,offering valuable reference information to the industry.展开更多
We studied seed morphometric characters, oil content and azadirachtin content in a medicinally important and insect repellent tree species Azadirachta indica A.Juss. Ten populations were selected from two central Indi...We studied seed morphometric characters, oil content and azadirachtin content in a medicinally important and insect repellent tree species Azadirachta indica A.Juss. Ten populations were selected from two central Indian states of Madhya Pradesh and Chhattisgarh and twenty candidate plus trees were selected from each population based on tree attributes. Azadirachtin content was estimated in seeds, in vitro shoots and callus cultures through HPLC. Significant variation（p ／ 0.05） was observed in seed morphometric characters, oil content and azadirachtin content among the ten populations. Maximum value for 100 seed weight was obtained in seeds of Raigarh（30.51 g） which was on par with seeds of Bargi（28.37 g）and Chhatarpur（26.36 g）. The ratio of highest kernel to seed was also obtained in seeds of Raigarh（60.11%）.Kernels from Chhatarpur population recorded the highest oil content（24.20%）, which was equal to that in Sihore（23.75%） and Katni（21.75%）. We recorded highly significant variation in azadirachtin content in seed samples,in vitro shoot samples and callus cultures. Maximum azadirachtin was present in the seeds of Gwalior（0.882%）which was on par with azadirachtin content in seeds of Chhatarpur, Katni, Sihore, Shahdol and Chhindwara.Maximum azadirachtin in the in vitro shoots was present in the cultures of Gwalior（0.218%） which was statistically on par with Sihore（0.176%）. Similarly, in callus cultures of nodal segments maximum azadirachtin was recorded in the Gwalior population（0.033%） which was statistically on par with Sihore（0.028%）. The trees of Gwalior and Sihore populations can be produced in large numbers through vegetative propagation to obtain seeds with higher azadirachtin content.展开更多
Dual-choice behavioral assays and electrophysiological tip-recording technique were used to investigate the taste adaptation of different diet-experienced frith instar larvae of Helicoverpa armigera to azadirachtin. T...Dual-choice behavioral assays and electrophysiological tip-recording technique were used to investigate the taste adaptation of different diet-experienced frith instar larvae of Helicoverpa armigera to azadirachtin. The behavior test showed that the larvae reared with normal artificial diets were highly deterred by aza- dirachtin. However, the larvae reared with the artificial diets containing low concentration of azadirachtin showed insensitivity to asadirachtin. The electrophysiological tests showed that there was a changed responsiveness in the deterrent neuron responding to asadirachtin in the lateral sensilla styloconica of different diet-experienced larvae. It indicated that there was a taste adaptation to azadiraehtin in different diet-experienced larvae of H. armigera and this taste adaptation was correlated with desensitization of related taste neurons.展开更多
The stereoselective synthesis of substituted [2,2,1]-bicyclo- heptan-2-one 12,a supposed intermediate to the spiroketal fragment of azadi- rachtin was described.When 12 was treated with mCPBA in CH_2Cl_2 in the pres- ...The stereoselective synthesis of substituted [2,2,1]-bicyclo- heptan-2-one 12,a supposed intermediate to the spiroketal fragment of azadi- rachtin was described.When 12 was treated with mCPBA in CH_2Cl_2 in the pres- ence of excess amount of solid sodium bicarbonate,only 13 was obtained.The spiroketal intermediate 20 was converted from 9 through 5 steps by an alterna- tive route.展开更多
基金Project supported by the Centre for School and Community Science and Technology Studies (SACOST), University of Education, Winneba, Ghana.
文摘A field investigation was conducted to assess the breakdown of azadirachtin A in a tropical coastal savanna soil amended with neem leaves （NL） combined with poultry manure （PM） or cow dung （CD） using gas chromatography. Samples in polythene bags 15 cm long and 4.8 cm in diameter were randomly placed to a depth of 14 cm in the soil, and azadirachtin A concentration was assessed on days 0, 14, 28, 42, 56, 70, and 84. Azadirachtin A degradation in the soil followed first-order reaction kinetics with different half-lives obtained for varying combinations of the amendments. Higher neem amendment levels of 100 g gave shorter half-lives of azadirachtin A than the lower levels of 50 g. Within the 50 g NL group the additions of the poultry manure and the cow dung gave significantly shorter （P 〈0.05） half-lives of azadirachtin A than the sole neem amendment, whereas in the 100 g NL group only additions of 10 g CD and 10 g PM were significantly less （P 〈 0.05） than the sole neem amendment. Different changes resulting from the kind and quantity of animal manure added were observed in the half-lives of azadirachtin A. The 100 g NL group had significantly higher （P 〈0.05） moisture content, which, coupled with the likely differeaces in microbial biomass, could be the major factor responsible for variations in the half-llfe of the compound. Therefore, the quantity of the neem leaves applied and the addition of animal manure affected the breakdown of azadirachtin A in the soil amended with neem leaves.
基金supported by the Scientific and Technological Innovation Project of the Chinese Academy of Chinese Medical Sciences (C12021A04111 and C12021A04116)the Fundamental Research Funds for the Central Public Welfare Research Institutes (ZZ14-YQ-031 and ZZ13-YQ-040)+1 种基金the National Key Research and Development Project (2019YFC19066)the National Natural Science Foundation of China (32200308).
文摘Azadirachtin,a complex tetratriterpenoid limonin with potent insecticidal properties,is the most widely used biological pesticide worldwide.Its versatile pharmacological applications include the inhibition of tumor growth and anti-malarial,anti-bacterial,and anti-inflammatory properties.Azadirachtin plays a pivotal role in pest control and novel drug development.The primary source of azadirachtin is the neem tree(Azadirachta indica A.Juss),with an azadirachtin content ranging from 0.3%to 0.5%.Despite the market demand for botanical pesticides reaching approximately 100,000 tons per year,the annual neem production in China is only 1.14 tons.Although azadirachtin can be obtained through plant extraction or chemical synthesis,the quantity obtained does not meet the market demand in China.The sluggish pace of azadirachtin biosynthesis results from the limited availability of genetic information and the complexity of the synthetic pathway.Recent advancements in azadirachtin biosynthesis hold promise as an efficient collection method.In this study,we explored the physicochemical properties,biological activities,mechanisms of action,and acquisition methods of azadirachtin.We also delved into recent progress in azadirachtin biosynthesis and assessed potential future usage challenges.This study aims to establish a theoretical foundation for the scientific application and efficient synthesis of azadirachtin,offering valuable reference information to the industry.
基金supported by Indian Council of Forestry Research and Education,Dehradun(Project No:159/TFRI/2010/Gen.-2(19))
文摘We studied seed morphometric characters, oil content and azadirachtin content in a medicinally important and insect repellent tree species Azadirachta indica A.Juss. Ten populations were selected from two central Indian states of Madhya Pradesh and Chhattisgarh and twenty candidate plus trees were selected from each population based on tree attributes. Azadirachtin content was estimated in seeds, in vitro shoots and callus cultures through HPLC. Significant variation（p ／ 0.05） was observed in seed morphometric characters, oil content and azadirachtin content among the ten populations. Maximum value for 100 seed weight was obtained in seeds of Raigarh（30.51 g） which was on par with seeds of Bargi（28.37 g）and Chhatarpur（26.36 g）. The ratio of highest kernel to seed was also obtained in seeds of Raigarh（60.11%）.Kernels from Chhatarpur population recorded the highest oil content（24.20%）, which was equal to that in Sihore（23.75%） and Katni（21.75%）. We recorded highly significant variation in azadirachtin content in seed samples,in vitro shoot samples and callus cultures. Maximum azadirachtin was present in the seeds of Gwalior（0.882%）which was on par with azadirachtin content in seeds of Chhatarpur, Katni, Sihore, Shahdol and Chhindwara.Maximum azadirachtin in the in vitro shoots was present in the cultures of Gwalior（0.218%） which was statistically on par with Sihore（0.176%）. Similarly, in callus cultures of nodal segments maximum azadirachtin was recorded in the Gwalior population（0.033%） which was statistically on par with Sihore（0.028%）. The trees of Gwalior and Sihore populations can be produced in large numbers through vegetative propagation to obtain seeds with higher azadirachtin content.
基金Supported by National Natural Science Foundation of China(31201750)Natural Science Foundation of Hunan Province(2016JJ4009)
文摘Dual-choice behavioral assays and electrophysiological tip-recording technique were used to investigate the taste adaptation of different diet-experienced frith instar larvae of Helicoverpa armigera to azadirachtin. The behavior test showed that the larvae reared with normal artificial diets were highly deterred by aza- dirachtin. However, the larvae reared with the artificial diets containing low concentration of azadirachtin showed insensitivity to asadirachtin. The electrophysiological tests showed that there was a changed responsiveness in the deterrent neuron responding to asadirachtin in the lateral sensilla styloconica of different diet-experienced larvae. It indicated that there was a taste adaptation to azadiraehtin in different diet-experienced larvae of H. armigera and this taste adaptation was correlated with desensitization of related taste neurons.
文摘The stereoselective synthesis of substituted [2,2,1]-bicyclo- heptan-2-one 12,a supposed intermediate to the spiroketal fragment of azadi- rachtin was described.When 12 was treated with mCPBA in CH_2Cl_2 in the pres- ence of excess amount of solid sodium bicarbonate,only 13 was obtained.The spiroketal intermediate 20 was converted from 9 through 5 steps by an alterna- tive route.
