Prenylated flavanones isolated from flowers of Azadirachta indica (the neem tree) as antimutagenic constituents against heterocyclic amines

Four prenylated flavanones were isolated from the methanol extract of the flowers of Azadirachta indica (the neem tree) as potent antimutagens against Trp-P-1 (3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole) in the Salmonella typhimurium TA98 assay by activity-guided fractionation. Spectroscopic properties revealed that those compounds were 5,7,4'-trihydroxy-8-prenylflavanone (1), 5,4'-dihydroxy-7-methoxy-8-prenylflavanone (2), 5,7,4'-trihydroxy-3',8-diprenylflavanone (3), and 5,7,4'-trihydroxy-3',5'-diprenylflavanone (4). All isolated compounds were found for the first time in this plant. The antimutagenic IC(50) values of compounds 1-4 were 2.7 +/- 0.1, 3.7 +/- 0.1, 11.1 +/- 0.1, and 18.6 +/- 0.1 microM in the preincubation mixture, respectively. These compounds also similarly inhibited the mutagenicity of Trp-P-2 (3-amino-1-methyl-5H-pyrido[4,3-b]indole) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine). All of the compounds 1-4 strongly inhibited ethoxyresorufin O-dealkylation activity of cytochrome P450 1A isoforms, which catalyze N-hydroxylation of heterocyclic amines. However, compounds 1-4 did not show significant inhibition against the direct-acting mutagen NaN(3). Thus, the antimutagenic effect of compounds 1-4 would be mainly based on the inhibition of the enzymatic activation of heterocyclic amines.     

Influence of operating parameters on the use of the microwave-assisted process (MAP) for the extraction of azadirachtin-related limonoids from neem (Azadirachta indica) under atmospheric pressure conditions

The use of the microwave-assisted process (MAP) for the extraction of azadirachtin-related limonoids (AZRL) from various parts of the neem tree was investigated under different operating conditions. The influence of microwave power, solvent, and irradiation time on the recovery of AZRL was studied. The efficiency of the microwave-assisted extraction (MAE) of the seed kernel, the seed shell, the leaf, and the leaf stem was compared to that of conventional extraction methods. The content of AZRL in the extracts was estimated with a vanillin-based colorimetric assay and a multivariate calibration technique. The results showed that the MAE technique can enhance the extraction of AZRL from different parts of neem possessing microstructures. Investigation of the influence of the solvent also indicted that the solvent used not only influences the efficiency but also affects the selectivity of the MAE.     

Influence of physicochemical parameters of neem (Azadirachta indica A Juss) oils on nitrification inhibition in soil

The technology for the production of neem oil coated urea (NOCU) developed by the Indian Agricultural Research Institute is in the pipeline for adaption by several Indian fertilizer industries. Use of nitrification inhibitors is one of the methods of improving the nitrogen use efficiency (NUE) of nitrogenous fertilizers in agriculture. However, standard specifications for the neem oil as a raw material of NOCU are desired. Accordingly, the present study was undertaken to evaluate 25 samples of neem oils comprising 11 samples of expeller grade (EG) oils, 8 samples of cold-pressed (CP) oils, 3 samples of solvent-extracted oils, and 2 commercial formulations. NOCU was prepared using these oils (5000 ppm of urea-N). The soils fertilized with NOCUs (200 ppm of urea-N) were incubated at 27 degrees C and 50% water-holding capacity for a period of 15 days. Nitrapyrin (0.5% of N) coated urea served as the reference and prilled urea as control. Samples were analyzed for NH4+-N, NO2--N, and NO3--N using standard methods. The percent nitrification inhibition (NI) was calculated, and the results revealed that all of the neem oils caused NI ranging from 4.0 to 30.9%. Two samples of EG oils and two commercial formulations were found to be the best, causing 27.0-30.9% NI. Iodine, acid, and saponification values and meliacin content of all of the oils were analyzed and correlated with NI. The results revealed the direct influence of meliacin content of the neem oils on NI, which, however, was found to be negatively correlated with saponification and iodine values. There is, therefore, a need to introduce new Bureau of Indian Standards (BIS) specifications for neem oils as raw materials of NOCU.     

Effect of emulsion size and shelf life of azadirachtin A on the bioefficacy of neem (Azadirachta indica A. Juss) emulsifiable concentrates

In a study of 33 recipes of neem oil based emulsifiable concentrates, the specific surface area of the emulsions and cream plus oil layer separation in emulsions at 24 h revealed a correlation of -0.6874 between them and correlations of -0.8940 and 0.6972, respectively, with bioefficacy (LC(50)) against the 3-day-old second-instar larvae of the Bihar hairy caterpillar, Spilosoma obliqua Walker. Nearly 96-99% of azadirachtin A in emulsifiable concentrates (aza-A content = 617.93-1149.65 ppm) degraded during the heat stability test at 54 +/- 1 degrees C for 14 days with half-lives ranging between 1.84 and 4.53 days. The LC(50) values against S. obliqua were, however, statistically at par in both the pre- and the post-heat-treated samples, suggesting a similar effect of azadirachtin A and its degradation products on the bioactivity. The half-life of azadirachtin A could be enhanced by storing the concentrates at lower temperatures. A low pH of the formulation solvent did not check the degradation of azadirachtin A, as reported with aqueous solutions in the literature.     

Citrus limonoids and their semisynthetic derivatives as antifeedant agents against Spodoptera frugiperda larvae. A structure-activity relationship study

The antifeedant activity of Citrus-derived limonoids limonin (1), nomilin (2), and obacunone (3) and their semisynthetic derivatives 4-26 was evaluated against a commercially important pest, Spodoptera frugiperda. Simple chemical conversions were carried out on the natural limonoids obtained from seeds of Citrus limon. These conversions focused on functional groups considered to be important for the biological activity, namely the C-7 carbonyl and the furan ring. In particular, reduction at C-7 afforded the related alcohols, and from these their acetates, oximes, and methoximes were prepared. Hydrogenation of the furan ring was also performed on limonin and obacunone. The known antifeedant properties of the Citrus limonoids are confirmed. Comparison with previously reported data shows that insect species vary in their behavioral responses to these structural modifications. Highly significant antifeedant activity (P < 0.01) for two natural (1 and 3) and three semisynthetic limonoids (4, 8, and 10) was observed against S. frugiperda.     

Growth inhibitory effects on fall armyworm Spodoptera frugiperda of some limonoids isolated from Cedrela spp. (Meliaceae)

Dichloromethane extracts of Cedrela salvadorensis and Cedrela dugessi afforded a photogedunin epimeric mixture, gedunin and cedrelanolide. These compounds and the photogedunin epimeric acetates 3 and 4 at the 23-OH position were evaluated against Spodoptera frugiperda. Toosendanin, isolated from Melia azedarach, was used as a positive control. When tested for activity on neonate larvae into the no-choice bioassays, gedunin, photogedunin epimeric mixture, and photogedunin acetates mixture caused significant larval mortality with LC(50) of 39.0, 10.0, and 8.0 ppm at 7 days, respectively, as well as growth reduction. All the compounds tested inhibited larval growth, compared to the control, in a concentration-dependent manner. In addition, it was possible to observe significant reduced pupal weights and adult emergence. All the tested compounds except cedrelanolide showed comparable activity to that of toosendanin.     

A piperidine amide extracted from Piper longum L. fruit shows activity against Aedes aegypti mosquito larvae

Mosquito larvicidal activity of Piper longum fruit-derived materials against the fourth-instar larvae of Aedes aegypti was examined. A crude methanol extract of P. longum fruits was found to be active against the larvae, and the hexane fraction of the methanol extract showed a strong larvicidal activity of 100% mortality. The biologically active component of P. longum fruits was characterized as pipernonaline by spectroscopic analyses. The LC(50) value of pipernonaline was 0.25 mg/L. The toxicity of pipernonaline is comparable to that of pirimiphos-methyl as a mosquito larvicide. In tests with available components derived from P. longum, no activity was observed with piperettine, piperine, or piperlongumine.     

芒果叶提取物体外抑菌及抑制鸡新城疫病毒增殖试验研究

进行了芒果叶水提物对部分畜禽常见致病菌的体外抑制试验以及对10日龄鸡胚人工感染鸡新城疫病毒(NDV)的抑制试验。抑菌试验结果表明,芒果叶水提物对大肠杆菌、多杀性巴氏杆菌、鸡白痢沙门氏菌、猪丹毒杆菌43-6混43-8、金色葡萄球菌86003、鸭疫里默氏杆菌、链球菌等致病菌有良好的抑菌效果。抑制NDV增殖试验结果表明,NDV强毒组在48h时的鸡胚保护率为10.00%,2.500g/mL芒果叶生药+NDV组的鸡胚保护率为63.64%,两者差异显著(P<0.05);1.250g/mL+NDV组、0.625g/mL+NDV组、0.313g/mL+NDV组的鸡胚保护率分别为72.72%、70.00%、69.23%,与强毒组相比,差异极显著(P<0.01),可见芒果叶水提物对NDV增殖具有抑制作用。     

Isolation of nematicidal compounds from Tagetes patula L. yellow flowers: structure-activity relationship studies against cyst nematode Heterodera zeae infective stage larvae

Bioassay-guided isolation studies on the extracts of yellow flowers of Tagetes patula L. against the Heterodera zeae were carried out to identify phytochemicals lethal to this economically important cyst nematode. In vitro investigation of a polar extract and fractions showing activity led to the isolation of phenolic compounds (flavonoids and phenolic acids). In the nonpolar extract, a few fatty acids, their methyl esters, and thiophenes (including α-terthienyl) were detected. In studies of compounds obtained commercially, α-terthienyl and gallic and linoleic acids showed 100% mortality at concentrations of 0.125% after 24 h. Assessment of structure-activity relationships revealed that an increase in the number of hydroxyl groups in phenolic acids increased the activity; with fatty acids, activity depended on chain length and the number and position of double bonds. Crude extracts of the flowers of different colors also have promising activity.     

抗青枯病转群体感应猝灭基因烟草的培育

利用具有猝灭青枯菌群体感应信号分子功能的aac基因构建高效植物表达载体,通过农杆菌介导的方法转化烟草,获得了卡那霉素抗性植株57株。经PCR及RT-PCR检测,筛选得到30株阳性转基因再生苗,并证实了目的基因已经整合到烟草基因组中,且在转录水平上得到表达。转基因植株苗期抗青枯病试验表明,16天后转基因烟草较对照植株病情指数降低了51,相对病情指数为56.5％。     

Physical and chemical properties,plant growth,and radionuclide accumulation effects from mixing phosphogypsum with some soils

Abstract

Large areas of salt‐affected soils exists in Syria. Besides, large quantities of phosphogypsum (PG) are stacked in areas close to the fertilizer factories (radioactivity 350 to 400 Bq kg^‐1) that may pose a negative impact on the environment. Different rates of PG (0, 0.25, 2.5, 5, and 25%) were mixed with three soils characterized by different level of salinity (EC_e 5.25, 9.44 and 17.66 dS m^‐1) to monitor the effect of mixing PG on the physical and chemical properties of the soils, plant growth and the accumulation of radionuclides in soils and plants. The high PG application rates (2.5, 5, and 25%) were used to monitor the effects of adding the normal application rate of PG (5 T ha^‐1) for 10, 20, and 100 consecutive years. Soil‐PG mixtures were put in 8.5 kg pots where trifolium (Trifolium pilulare) and barley (Hordium vulgare var. Arabi Abyad) were seeded. The results showed that mixing PG increased the saturated hydraulic conductivity, reduced Cl^‐1 and increased SO^2‐ ₄ concentrations in the saturated extracts and increased the available phosphorus (P). Mixing PG increased plant height, shoot number and dry weigh of both plants. Barley grain weight increased by 62.0, 49.8, and 39.5% in Ramet‐Leha, Maskane, and Beni‐Taghleb soils, respectively. The radioactivity of barley grains and the vegetative parts of the two plants grown in these mixtures were below the detective level (1.1 Bq kg^‐1 of dry weight).     

Long-term effects of heavy metals from composted municipal waste on some enzyme activities in a cultivated soil

A 3-year field experiment on a calcareous Fluventic Xerochrept planted with corn (Zea mays L.) was carried out to evaluate the effects of amending the soil with high and low rates of composted municipal waste on soil enzyme activities (alkaline phosphomonoesterase, phosphodiesterase, arylsulphatase, dehydrogenase, and l-asparaginase). These enzyme activities all increased when compost was added at rates of up to 90 t ha^-1, and the phosphatases continued to show a linear increase with compost rates of up to 270 t ha^-1. The addition of mineral fertilizer increased enzyme activities in unamended soil, and masked the stimulating effect of compost on the amended soils. Heavy metals did not affect soil enzyme activities up to a compost addition of at least three times the amount specified by Italian law.     

Chemistry of Cr in some Swedish soils. 6. Native P transformation and changes in pH and cation exchange capacity in two soils incubated with potassium chromate

Abstract

Transformation of native P and changes in water pH and cation exchange capacity (CEC‐pH 7) were investigated in acid (I) and neutral (IV) soil incubated with 0, 50 and 100 mg Cr/kg for 3 months. Phosphorus was sequentially obtained as P‐resin, P‐NaHCO₃, P‐NaOH and P‐HCl, with the P‐NaHCO₃ and P‐NaOH being separated into organic and inorganic fractions. The low Cr level had little impact on the parameters. The high level increased the pH from 5.1 to 7.3 and from 6.8 to 7.5 in soils I and IV, respectively, while also significantly (P=5%) increasing CEC and decreasing P‐resin content. Subsequent to the Cr treatment, total P‐NaHCO₃ significantly declined in Soil I, but did not change markedly in Soil IV. Although total P‐NaOH was not affected by the Cr applications, its inorganic form doubled in Soil IV. Most of the total P‐NaHCO₃ and P‐NaOH was in organic form. Whereas P‐HCl was stable in Soil IV, the P nearly doubled in Soil I at the expense of P‐NaHCO₃ (r = ‐0.94**). pH was correlated with CEC (0.62*), total P‐NaHCO₃ (‐0.83**) and P‐HCl (0.76**), while CEC was correlated with P‐resin (‐0.70**), total NaHCO₃ (‐0.88**) and P‐HCl (0.94**).     

Different effects of five catechins on 6-hydroxydopamine-induced apoptosis in PC12 cells.

Five catechins [(-)-epigallocatechins gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epicatechin (EC), and (+)-catechin (C)] were compared with regard to their effects on 6-hydroxydopamine (OHDA)-induced apoptosis in PC12 cells--the vitro model of Parkinson's disease. Measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 6-OHDA inhibited cell viability in a time- and concentration-dependent manner. When PC12 cells were pretreated with the five catechins for 30 min before exposure to 250 microM 6-OHDA, MTT results showed that the five catechins had different effects: EGCG and ECG had obvious concentration-dependent protective effects at 50-400 microM; EC and (+)-C had almost no effects; and EGC especially decreased cell viability. Catechins also had different effects on apoptotic morphology. Only 200-400 microM EGCG and ECG kept cells adhering well. When pretreated with other catechins at any concentration, PC12 cells became round and some of them were detached as when treated with 6-OHDA. In addition, typical apoptotic characteristics of PC12 cells were determined by fluorescence microscopy, flow cytometry, and DNA fragment electrophoresis after the cells were treated with 250 microM 6-OHDA for 24 h or pretreated with catechins before it. Preincubation with 200-400 microM EGCG and ECG led to significant inhibitory effects against PC12 cell apoptosis, as shown by flow cytometry. The other catechins have little protective effect. Therefore, at 200-400 microM, the classified protective effects of the five catechins were in the order ECG > EGCG > EC > (+)-C > EGC. The data also indicated that EGCG and ECG might be potent neuroprotective agents for Parkinson's disease. The results of fluorescence microscopy and DNA fragment analysis supported the conclusion.     

北方稻田和茭白田二化螟越冬幼虫生物学特性的比较

在冬初(11月中旬)和冬后(3月上旬)调查了北方稻田和茭白田二化螟越冬幼虫的生物学特性.二化螟越冬幼虫龄期均在4龄以上,茭白田冬初6龄幼虫的比例比稻田高17.5%;冬后稻田和茭白田高龄幼虫比例均高于冬初.冬初和冬后稻田二化螟雌雄比分别为1:2.0和1:1.7,茭白田分别为1:1.4和1:1.2.冬初幼虫历期高于冬后,同一时期不同寄主田之间无显著差异,但冬初茭白田幼虫历期比稻田长14.0%;稻田幼虫体重和蛹重均显著低于茭白田.冬初采集越冬幼虫的死亡率在65%以上,茭白田幼虫的主要致死因子为真菌,其致死率在90%以上;稻田幼虫的主要致死因子是寄生蜂和细菌,其致死率分别在50%和25%以上,其中二化螟绒茧蜂和中华钝唇姬蜂是优势寄生蜂.     

苜蓿改良的盐碱土壤施肥对小麦的效应研究--II.对小麦生理特性的影响

盐栽试验结果表明,苜蓿改良的盐碱土壤施N肥能使小麦旗叶叶水势升高,叶片水分保持较好,叶绿素总含量提高l3％～80％(以叶绿素b为主),叶片光合速率和蒸腾强度增加,蒸腾效率提高,施N肥配合补P肥效果更好,这些变化构成了在该类地区施N肥补P肥增产的生理基础。     

Protective effects of fermented filtrate from Antrodia camphorata in submerged culture against CCl4-induced hepatic toxicity in rats

The protective effects and the possible mechanisms of dry matter of fermented filtrate (DMF) from Antrodia camphorata in submerged culture (ACSC) on H(2)O(2)-induced cytotoxicity in HepG2 and carbon tetrachloride (CCl(4))-induced hepatotoxicity in Sprague-Dawley rats were investigated. The results showed that the inhibitory effect of DMF and its crude triterpenoids on lipid peroxidation occurred in a dose-response manner in an AAPH/linoleic acid system. When HepG2 cells were pretreated with DMF at the concentration of 0.10 mg/mL for 4 h and then induced by 1 h of treatment with H(2)O(2) (100 microM), lipid peroxidation was significantly (p < 0.05) decreased, as measured by the formation of malondialdehyde. The oral pretreatment with DMF [0.25 and 0.50 mg/kg of body weight (bw)] for 5 consecutive days prior to the administration of a single dose of 40% CCl(4) (0.10 mL/100 g of bw, ip) significantly prevented the increase in serum levels of hepatic enzyme markers (alanine and aspartate aminotransferase) and liver lipid peroxidation (p < 0.05). Histopathological evaluation of the rat liver revealed that DMF reduced the incidence of liver lesions, including neutrophil infiltration, hydropic swelling, and necrosis induced by CCl(4) in rats. Moreover, reduced glutathione (GSH)-dependent enzymes (glutathione peroxidase, glutathione reductase, and glutathione S-transferase) and the GSH/GSSG ratio were significantly improved in the oral pretreatment DMF of rats (p < 0.01). The results suggest that DMF may play a role in preventing oxidative damage in living systems by up-regulating hepatic GSH-dependent enzymes to preserve the normal GSH/GSSH ratio and scavenging free radicals formed during CCl(4) metabolism.     

Excess trace metal effects on cotton: 6. Nickel and cadmium in yolo loam soil

Abstract

Two cultivars of cotton (Gossypium spp.) were grown in Yolo loam soil in a glasshouse to determine phytotoxicity effects of excesses of Ni and Cd. A 200 μg/g level of Ni in soil reduced yield by 60% in Acala SJ‐2 and by 83% in Giza 45. The leaf Ni concentrations, respectively, were 146 and 165 μg/g‐ The 300 μg/g level of Cd decreased leaf yields by 60% and 75% for the two cultivars, respectively. Leaf concentrations of Cd, respectively, were 43 and 63 μg/g. There was a stem to leaf gradient of Cd for all cases. High Cd did not depress Mn concentrations in plants . as in other species but there were many mineral element interactions.