• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.21-24
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• 2010

In recent years, many agricultural scientists are studying on eco-friendly farming methods. Among of lots of the methods, the natural insecticides are highly motivated and interested due to their safety and biodegradable issues, and readily available source of bioinsecticides. In this study, the crude extract of custard apple (Annona reticulata L.) seed and its three fractions which were separated based on polarity indexes were examined for their insecticidal activities against Myzus persicae Sulzer and Nilaparvata lugens S.. The crude extract (Aceton/MeOH) showed strong insecticidal activities against both insects at 3.00 mg/mL ($LD_{50}$=0.45mg/mL for M. persicae S. and 1.42 mg/mL for N. lugens S.). Furthermore, simple fractionation with hexane, chloroform, and water lead to increase three-folds insecticidal activity on chloroform fraction ($LD_{50}$=0.13mg/mL for M. persicae S. and 1.14 mg/mL for N. lugens S.). The results suggest that A. reticulata extracts might be used to control for M. persicae effectively.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.339-346
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• 2010

The acute toxicity test of high bio-active plant essential oils was conducted with Lavender, Lemon eucalyptus and Cassia oils selected to develop environment-friendly insecticides. The results of acute oral toxicity using rats showed that $LD_{50}$ of over 2,000 mg/kg bw for Lavender, Lemon eucalyptus and Cassia oils. The calculated acute dermal $LD_{50}$ value of all testing materials was over 4,000 mg/kg bw. The Skin irritation test indicated that Lavender and Lemon eucalyptus oil have no irritation while Cassia oil has a moderate irritation. For the Eye Irritation test, the result showed no irritation for Lavender and Lemon Eucalyptus oil and irritation for Cassia oils. However, the irritation was not showed for Eye Irritationwashing test of Cassia oil. Consequently, the Lavender and Lemon eucalyptus oils were showed to be low in toxicity whereas Cassia oil indicated to cause a moderate irritation on the skin and eyes.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.75-82
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• 1998

This study was conducted to find out the biochemical or metabolic resistance mechanism of brown planthopper (BPH) to carbofuran. Differences between resistant ($LD_{50};\;20.3{\mu}g/g$) and susceptible strains($LD_{50};\;0.3{\mu}g/g$) were shown. The amounts of carbofuran metabolite, benzofuranol, and the origin, not developed by Thin Layer Chromatography, were much more in the susceptible strain. But the mother compound, carbofuran, was much more in the resistant strain. The tendencies of metabolism one and three hours after treatment were similar in both strains except for the amounts of metabolites described above. From the study, it is supposed that hydrolytic enzyme, esterase, changes its role from cleaving the esteric bond of carbofuran to making conjugates with carbofuran. This seems to be the main resistance mechanism of BPH to carbofuran. Oxidase and transferase may play little or no role in resistance mechanism. Oxidative and transferring enzymes gave no effects on the metabolism of carbofuran in the resistant strain compared with the susceptible strain.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.53-58
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• 1975

The local variabilities of resistance to Malathion and NAC (Sevin) were studied during 1973 with the strains of small brown planthopper (Laodelphax striatellus Fallen) collected from Jinjoo, Sunsan, Milyang, Kwangjoo and Iri districts of southern part of Korea. The susceptible lab strain used for this study has been reared successively in the laboratory without exposure to any insecticide since 1970. The insecticides were applied topically in acetone to the thoracic sternum of the adult insects. $LD_{50}$ values of Malathion to the insect were varied with the locality of the planthoppers. Relatively high levels of resistance to Malathion were observed in the strains of Jinjoo and Suntan; showing 27.7 times in female and 24.9 times in male for Jinjoo stram and 18.4 times in female and 13.8 times in male for Sunsan strain as compared with the susceptible lab strain, and in other strains of Milyang, Kwangjoo and Iri the levels of resistance to Malathion were still less than 5 times. However, there was no any specific difference among the strains in susceptibility to NAC. The malathion-resistant strain of the small brown planthopper seemed to be still localized in some regions of· Korea. The susceptibility of the planthoppers to Malathion was varied with the sex; $LD_{50}$ values based on the individual (ug/insect) were higher in female than in male, while the values based on the body weight (ug/g) conversely higher in male than in female.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.772-779
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• 2013

Linkage disequilibrium (LD) plays an important role in genomic selection and mapping quantitative trait loci (QTL). In this study, the pattern of LD and effective population size ($N_e$) were investigated in Chinese beef Simmental cattle. A total of 640 bulls were genotyped with IlluminaBovinSNP50BeadChip and IlluminaBovinHDBeadChip. We estimated LD for each autosomal chromosome at the distance between two random SNPs of <0 to 25 kb, 25 to 50 kb, 50 to 100 kb, 100 to 500 kb, 0.5 to 1 Mb, 1 to 5 Mb and 5 to 10 Mb. The mean values of $r^2$ were 0.30, 0.16 and 0.08, when the separation between SNPs ranged from 0 to 25 kb to 50 to 100 kb and then to 0.5 to 1 Mb, respectively. The LD estimates decreased as the distance increased in SNP pairs, and increased with the increase of minor allelic frequency (MAF) and with the decrease of sample sizes. Estimates of effective population size for Chinese beef Simmental cattle decreased in the past generations and $N_e$ was 73 at five generations ago.

• Journal of Conservation Science
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• v.33 no.4
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• pp.255-266
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• 2017

Chemically derived pesticides have been used to prevent biological damage to domestic cultural property. However, their use is gradually being restricted due to the harmful effects on the human body and environment. Therefore, there is a growing interest in the search for new antifungal biopharmaceuticals whose safety has been confirmed by toxicity evaluation through animal experiments. This paper presents methods of toxicity evaluation of natural biocides using Sprague-Dawley rats and New Zealand White (NZW) rabbits. Safety of the natural biocide extract of Asarum sieboldii was evaluated using single-dose oral and dermal toxicity tests in Sprague-Dawley rats, and eye and skin irritation tests in NZW rabbits. The extract has proven antimicrobial and insecticidal activities against wood-rotting fungi and termites. After single oral administration to rats, the $LD_{50}$ values were determined to be over 4,000 and 2,000 mg/kg for males and females, respectively. After single dermal administration to rats, the $LD_{50}$ values exceeded 10,000 mg/kg for both males and females. The extract was identified to be non-irritant to the rabbit eye, and only slightly irritant to the rabbit skin. In this study, we confirmed the safety of the A sieboldii extract through animal testing. Due to the harmfulness of humidifier disinfectants, focus is on the safety of chemical pesticides, and toxicity evaluation is suggested as the basic method for hazard evaluation.

• The Korean Journal of Pesticide Science
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• v.15 no.3
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• pp.231-237
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• 2011

Highly bio-active plant essential extracts and oils from pepper, clove bud, rosemary and origanum which are selected to develop environment-friendly insecticides was studied for their acute toxicity. The results of acute oral toxicity using rats showed $LD_{50}$ value of over 2,000 mg/kg bw for pepper, clove bud, rosemary and origanum oils. The calculated acute dermal $LD_{50}$ value of pepper was over 4,000 mg/kg bw and anther testing materials was over 4,000 mg/kg bw. The skin irritation test showed that pepper, clove bud and rosemary oils had no irritation while origanum oil had a moderate irritation. According to the eye irritation test, it showed that there was no irritation for pepper and rosemary oils, while there were irritation for clove bud and origanum oils. Consequently, pepper and rosemary oils were shown to be low in toxicity whereas clove bud oil was indicated to cause a mild eye irritability and origanum oil, causing a moderate skin and eye irritability.

• Korean journal of applied entomology
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• v.40 no.4
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• pp.337-344
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• 2001

The house fly (Musca domestica L.) strains were derived from the Yumenoshima III strain by selecting with cypermethrin and methomyl for 19 and 16 generations, respectively. The resulting strains, cypermethrin resistance strain (Cyp-R19) and methomyl resistance strain (Met-R16), showed high level of resistance by 12906 and 51 times, respectively, comparing with the susceptible SRS strain. The Cyp-R19 strain was resistant to synthetic pyrethroids such as deltamethrin, esfenvalerate, fenpropathrin, $\beta$-cyfluthrin, showing > 11000, 1231, 103, 292 times higher $LD_{50}$ values than the SRS strain, respectively. It was also resistant to 3 organophosphates and 2 carbamates such as fenitrothion, profenofos, pyridaphenthion, benfuracarb, methomyl, showing resistance ratios fo 51, 17, 49, 39 and 62 comparing to SRS strain. The Met-R16 strain was resistant to synthetic carbamate benfuracarb, showing 6 times higher $LD_{50}$ value than SRS strain. It was also resistant to 4 organophosphates such as acephate, fenitrothion, profenofos and pyridaphenthion, showing > 40, 103, 19, 60 times higher $LD_{50}$ value. It was also resistant to 5 pyrethroids and a pyrrole such as cypermethrin, deltamethrin, esfenvalerate, fenpropathrin, $\beta$-cyfluthrin and chlorfenapyr, showing 3030, 249, 4063, 34, 330 and 86 times higher $LD_{50}$ values than the SRS strain. Cyp-R14 strain which was selected for 14 generations by cypermethrin and developed 11014 times higher resistance to the SRS strain was used in the dominance and linkage group analysis. Cypermethrin resistance inheritance was incompletely dominant in house fly as judged by the reciprocal cross between the resistant and susceptible strains. The linkage group analysis for the major factors responsible for this resistance was carried out by the$ F_1$male-backcross method, using susceptible multi-chromosomal marker aabys strain. The major factors for cypermethrin resistance were located on the 1st, the 3rd and the 4th chromosomes, and the effect of the 3rd chromosome was most prominent.

• Journal of Life Science
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• v.23 no.11
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• pp.1388-1396
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• 2013

This study used an S-180 cell-injected mouse model to evaluate the antitumor effects of the acute and subacute toxicity of Keumsa (Phellinus linteus) extract intravenously administrated in ICR mice. When administered intravenously (31.3-250 mg/kg body weight), Keumsa (Phellinus linteus) extract significantly inhibited the growth of the solid tumor cell. The antitumor activity of Keumsa (Phellinus linteus) extract increased in a dose-dependent manner. The highest dose (250 mg/kg body weight) was highly effective, reducing tumor formation by 42.7% compared with the control group. In the acute toxicity test, $LD_{50}$ of the Keumsa (Phellinus linteus) extract showed 632.84 mg/kg (♂) and 814.48 mg/kg (♀) after intravenous administration. In addition, liver and spleen weight were increased in a dose-dependent manner. In the subacute toxicity test, the mice were intravenously administered over the course of 28 days. The $LD_{50}$ of the Keumsa (Phellinus linteus) extract showed 355.41 mg/kg (♂) and 383.53 mg/kg (♀) after intravenous administration. The liver and spleen weight also increased in a dose-dependent manner. In the case of the group that received more than 125 mg/kg of intravenous administration, exercise capacity, such as jumping ability and agility, were significantly increased. These results suggest that Keumsa (Phellinus linteus) extract can be regarded as a potent enhancer of the innate immune response, and it can be considered as a new natural product with low toxicity that may be used as a candidate for antitumor action.

• Journal of Pharmaceutical Investigation
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• v.9 no.3
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• pp.9-21
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• 1979

This study was undertaken to establish the different pharmaceutical properties between promethazine HCl and promethazine pamoate. First, promethazine pamoate was prepared by using the modified method of Saias. Second, in order to study the different pharmacokinetics between promethazine pamoate and promethazine HCl, absorption rate, plasma concentration, and distribution, as well as urinary excretion of the both compounds were examined in rabbits as an experimental animal: The results were as follows. 1. In the in vitro isolated intestine of rabbit, the rate constant for absorption of promethazine pamoate was $0.347hr^{-1}$ and that of promethazine HCl was $0.532hr^{-1}$. 2. After oral administration of promethazine pamoate, the increase of plasma concentration of promethazine was much slower than that of promethazine HCl. 3. The urinary excretion rate of promethazine pamoate was significantly low in comparison to that of promethazine-HCl; i. e. about 50% of promethazine HCl was excreted within 3 hours, and 5 to 15 hours for that of promethazine pamoate. 4. The tissue concentration of promethazine after oral administration of promethazine pamoate in rabbit was steadily increased for 5 hours. However, promethazine HCl concentration reached to maximum 1 hour after administration, then decreased slowly. 5. A significant amount of promethazine was mainly distributed in spleen, kidney, lung, liver and heart in this order, rather than other organs, such as brain, and muscle. 6. In the toxicity test by using mouse, $LD_{50}$ for promethazine pamoate was 3,250 mg/kg, while $LD_{50}$ for promethazien HCl was 298mg/kg.