Phenolic secondary metabolites from Acorus calamus (Acorales: Acoraceae) rhizomes: the feeding deterrents for Spodoptera litura (Lepidoptera: Noctuidae).

Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is one of the most destructive pests of various crops cultivated in Thailand. Spodoptera litura larvae, at early stages, attack the leaves and feed on every part of infested crops in later stages. Acorus calamus essential oil contains toxic asarones, which are generalistic cytotoxic compounds. However, the present study is the first attempt to look at safer metabolites from the rhizomes that could deter insect feeding. The objective was to use such compounds as safer residues on crops that would prevent the feeding of herbivorous lepidopterans. Accordingly, phenolic metabolites were isolated and evaluated to establish the feeding deterrence against polyphagous S. litura larvae. Methanol extract of A. calamus, chrysin, and 4-hydroxy acetophenone compounds were the most effective feeding deterrents with FD50 of 87.18, 10.33, and 70.77 µg/cm2, respectively, after 4 h of feeding on treated kale leaves in a no-choice leaf disc assay. Chrysin also reduced carboxylesterase activities (1.37-fold), whereas A. calamus methanol extract reduced glutathione-S-transferase activities (1.44-fold). Some larvae were also seen dead if they consumed the treated kale leaves. Feeding deterrent activity in the methanol extract of A. calamus was due to chrysin and 4-hydroxy acetophenone. The large-scale utilization of such compounds could help develop feeding deterrent strategies in the integrated pest management of lepidopterans.

Insecticidal efficacy and possibility of Combretum trifoliatum Vent. (Myrtales: Combretaceae) extracts in controlling Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae).

BACKGROUND: The fall armyworm Spodoptera frugiperda (J.E. Smith), is an important pest of agronomical crops. It is interesting to discover secondary metabolites in plants that are environmentally safer than synthetic pesticides. For this purpose, Combretum trifoliatum crude extract and its isolated compounds were investigated for their insecticidal activities against S. frugiperda. RESULTS: The median lethal dose (LD50 ) was evaluated in the second-instar larvae using the topical application method. The isolated compounds, apigenin and camphor, demonstrated a highly toxic effect on larvae at a lower LD50 dose than crude extract. Moreover, when the larvae were exposed to crude extract concentrations, the development to pupa and adult stages was reduced by more than 50%. The ovicidal toxicity was examined using a hand sprayer. The extract concentration 5, 10, and 20 µg/egg significantly decreased the egg hatchability. In addition, crude extract showed a significant difference in inhibiting acetylcholinesterase (AChE) activity while crude extract and camphor showed significant inhibitory effects on carboxylesterase (CE) and glutathione-S-transferase (GST) activities. CONCLUSION: The crude ethanol extract of Combretum trifoliatum was toxic to S. frugiperda in terms of larval mortality, negatively affecting biological parameters, and decreasing egg hatchability. Additionally, the activities of cholinergic and detoxifying enzymes were affected by crude extract and its isolated compounds. These results highlight that Combretum trifoliatum might be efficient as a bioinsecticide to control S. frugiperda. © 2023 Society of Chemical Industry.

Potential insecticidal extracts from Artocarpus lacucha against Spodoptera litura (Lepidoptera: Noctuidae) larvae.

Artocarpus lacucha, a plant in the Moraceae family, has traditionally been used in Southeast Asian medicine to treat various ailments. This study investigated the insecticidal potential against Spodoptera litura of several compounds extracted from A. lacucha using a topical application method. A sequential extraction method was employed with A. lacucha stems to identify the most toxic crude extract by using hexane, dichloromethane, ethyl acetate, and methanol solvents. Subsequently, the most toxic crude extract was analyzed for chemical composition by HPLC, followed by the isolation process. Among these crude extracts, the ethyl acetate crude extract was the most toxic to second-instar S. litura larvae (24-h LD50 value of ~9.07 µg/larva). Our results showed that the catechin isolated from the ethyl acetate crude extract exhibited the highest toxicity against this insect (24-h LD50 value of ~8.37 µg/larva). Additionally, catechin significantly decreased the activities of acetylcholinesterase, carboxylesterases, and glutathione S-transferase in the larvae. These findings suggest that catechin isolated from A. lacucha could be a potential insecticidal agent against S. litura. However, the toxicity and persistence of catechin under field conditions need to be further investigated to develop this novel insecticide.

Insecticidal activity of isolated gingerols and shogaols from Zingiber officinale Roscoe rhizomes against Spodoptera spp. (Lepidoptera: Noctuidae).

The discovery of eco-friendly plant-based insecticides is currently booming in research with an attempt to replace synthetic chemical insecticides causing tremendous adverse effects. The present work studied the insecticidal potential of ginger, an important medicinal plant. Four crude extracts from Zingiber officinale rhizomes were evaluated for their contact toxicity against second instars of Spodoptera litura, Spodoptera exigua and Spodoptera frugiperda using the topical application. The hexane extract exhibited the strongest toxicity to S. exigua with the LD50 of 9.92 and 8.40 µg/larva at 24 and 48 h posttreatment, respectively, followed by S. frugiperda. Comparative toxicity of the most abundant secondary metabolites from the hexane extract, gingerols and shogaols, against both insects concluded that 8-shogaol (5) was identified as the most active compound against S. frugiperda with the LD50 of 7.68 and 3.96 µg/larva at 24 and 48 h posttreatment, respectively.

Investigation of genotoxicity, mutagenicity, and cytotoxicity in erythrocytes of Nile tilapia (Oreochromis niloticus) after fluoxetine exposure.

Fluoxetine (FLX) is an antidepressant that is increasingly being detected in aquatic environments. However, this contaminated FLX can affect aquatic organisms. Therefore, the aim of this study was to evaluate the genotoxic, mutagenic, and cytotoxic potential of FLX on erythrocytes in Nile tilapia (Oreochromis niloticus) after acute exposure. Fish were exposed to different concentrations of FLX (10, 100 and 1000 µg/L) for 96 h. Then, the condition factor (K value) was used to assess the general fish condition. The genotoxicity was investigated using a comet assay, and the mutagenicity was examined using micronucleus (MN) and erythrocytic nuclear abnormalities (ENAs) assays. In addition, the cytotoxicity was analyzed by erythrocyte morphometry and erythrocyte maturity index (EMI). The results showed that FLX did not affect the fish's health. Nevertheless, 100 and 1000 µg/L FLX significantly increased DNA damage. Furthermore, a higher concentration of FLX presented a significantly increased frequency of MNs and ENAs, also leading to changes in some erythrocyte morphometric indices and significantly decreased mature erythrocytes. In conclusion, our results indicate that FLX induces genotoxic, mutagenic, and cytotoxic effects in erythrocytes of O. niloticus.

Insecticidal and growth inhibitory effects of some thymol derivatives on the beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae) and their impact on detoxification enzymes.

BACKGROUND: Thymol is a known natural product with insecticidal activity against several insect species. A recent study on structural modifications of thymol to thymyl esters and their efficacy against Spodoptera litura suggested that such an approach could develop generalized novel insecticides/insect growth inhibitors and requires further studies to establish the efficacy against lepidopterans. RESULTS: Thymol and structurally modified eight esters were evaluated against beet armyworm, Spodoptera exigua using the topical application. Thymyl butanoate was the most toxic compound with a median lethal dose (LD50 ) of 2.33 and 1.62 µg/larva after 24 and 48 h posttreatment, respectively. All thymyl esters were potentially better than the parent compound thymol, except thymyl dibromoacetate, in their efficacy against Spodoptera exigua. Essentially, there were three levels of activity vis-à-vis the compounds used, that is, with the LD50 range of 1.5 to 5.0, 7.0 to 15.0, and > 20 µg/larva, respectively. Ovicidal activity and reduction in larval growth were also determined by treating third instars at sub-lethal doses, that is, LD50 doses of second instars. Thymyl butanoate treated larvae inhibited glutathione S-transferase, carboxylesterase, and acetylcholinesterase activities, whereas the other thymyl esters induced these enzymes. CONCLUSION: Thymyl butanoate exhibited higher toxicity against Spodoptera exigua and is the first to report about > 15.5× more toxicity than thymol and > 6.5× than thymyl cinnamate, which suggests that the efficacy was species-specific versus the chemical structural variation of the esters. © 2021 Society of Chemical Industry.

Insecticidal activity of isolated phenylpropanoids from Alpinia galanga rhizomes against Spodoptera litura.

Botanical insecticides as a means of controlling insects present an alternative approach that is safer than the use of synthetic insecticides. The present study identified the insecticidal activity of extracts of the rhizomes of Alpinia galanga (L.) Willd. and seven isolated phenylpropanoids against the second instar of Spodoptera litura Fab. by topical application. The ethyl acetate extract had the highest toxicity on this insect with LD50 values of 1.68 and 1.25 µg/larva after 24 and 48 h posttreatment, respectively. Among the seven phenylpropanoids separated from the ethyl acetate extract, 1'S-1'-acetoxychavicol acetate was identified as the most active compound with LD50 values of 1.63 and 1.40 µg/larva after 24 and 48 h posttreatment, respectively, followed by p-coumaryl diacetate. In addition, the two active compounds decreased glutathione S-transferase activity and increased acetylcholinesterase activity. p-Coumaryl diacetate also decreased carboxylesterase activity.

A Novel Insecticidal Molecule Extracted from Alpinia galanga with Potential to Control the Pest Insect Spodoptera frugiperda.

Spodoptera frugiperda, a highly polyphagous insect pest from America, has recently invaded and widely spread throughout Africa and Asia. Effective and environmentally safe tools are needed for successful pest management of this invasive species. Natural molecules extracted from plants offer this possibility. Our study aimed to determine the insecticidal efficacy of a new molecule extracted from Alpinia galanga rhizome, the 1'S-1'-acetoxychavicol acetate (ACA). The toxicity of ACA was assessed by topical application on early third-instar larvae of S. frugiperda. Results showed that ACA caused significant larval growth inhibition and larval developmental abnormalities. In order to further explore the effects of this molecule, experiments have been performed at the cellular level using Sf9 model cells. ACA exhibited higher toxicity on Sf9 cells as compared to azadirachtin and was 38-fold less toxic on HepG2 cells. Inhibition of cell proliferation was observed at sublethal concentrations of ACA and was associated with cellular morphological changes and nuclear condensation. In addition, ACA induced caspase-3 activity. RT-qPCR experiments reveal that ACA induces the expression of several caspase genes. This first study on the effects of ACA on S. frugiperda larvae and cells provides evidence that ACA may have potential as a botanical insecticide for the control of S. frugiperda.

Neuroprotective effects of Tiliacora triandra leaf extract in a mice model of cerebral ischemia reperfusion.

OBJECTIVE: The present study investigated possible neuroprotective effects of ethanolic extract of Tiliacora triandra leaf against cerebral ischemic-reperfusion injury in mice. MATERIALS AND METHODS: Forty male Institute of Cancer Research (ICR) mice were randomly divided into five groups: (1) Sham + 10% Tween 80, (2) bilateral common carotid artery occlusion (BCCAO) + 10% Tween 80, (3) BCCAO + T. triandra 300 mg/kg, (4) BCCAO + T. triandra 600 mg/kg and (5) BCCAO + quercetin 10 mg/kg. Cerebral ischemic-reperfusion (IR) was induced by 30 min of BCCAO followed by 45 min of reperfusion. After IR induction, total brain protein, calcium, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH), as well as brain infraction and histopathological changes in vulnerable brain areas, such as the cerebral cortex and hippocampus, were evaluated. RESULTS: The results showed that 2 weeks of pretreatment with T. triandra leaf extract at doses of 300 and 600 mg/kg significantly reduced calcium and MDA, but increased GSH and SOD and CAT activities. The extract significantly attenuated brain infarction and neuronal death in the cerebral cortex and hippocampus. CONCLUSION: We demonstrated the neuroprotective effects of T. triandra leaf extract against cerebral IR injury in mice.

Synthesis of thymyl esters and their insecticidal activity against Spodoptera litura (Lepidoptera: Noctuidae).

BACKGROUND: Thymol, a natural phenolic monoterpene originating from Thymus vulgaris, is recognized as a safe and potent botanical insecticide to many insects. The structural modification of thymol into thymyl esters is a potential approach for the development of novel insecticides, which showed more toxicity than thymol. However, there are no reports on the insecticidal activity of thymyl esters to control Spodoptera litura. RESULTS: Thymol was structurally modified into ten thymyl esters by esterification using a new reagent, PPh3 /Br3 CSO2 Ph. The insecticidal activity of these compounds was examined against the second instars of Spodoptera litura using a topical application. Among the ten thymyl esters evaluated, thymyl cinnamate was the most toxic with LD50  = 0.41 and 0.34 µg/larva after 24 and 48 h posttreatment, respectively. In addition, thymyl cinnamate-treated larvae showed increasing carboxylesterase and acetylcholinesterase activities in vivo experiment, whereas glutathione S-transferase activity showed no significant difference. CONCLUSION: Thymyl cinnamate were first reported to exhibit toxicity against S. litura 2.41-2.46 fold more efficient than thymol. However, the detailed biochemical interactions are necessary for further development of novel insecticides. © 2019 Society of Chemical Industry.

Cytotoxic effects of ß-asarone on Sf9 insect cells.

ß-Asarone is the predominant component of the essential oil of rhizomes of Acorus calamus Linn ( Sweet flag). Although rhizome extracts from this plant have long been used for insect pest control, their cytotoxic effects on insect cells are not well understood. In this study, we evaluated the potency of ß-asarone as a natural insecticide by using a Spodoptera frugiperda cell line (Sf9). To assess the cytotoxic effects of ß-asarone on Sf9 cells, we observed morphologic changes in treated cells and performed a cell proliferation assay and a DNA fragmentation assay. After 24 and 48 h of treatment with ß-asarone, the proliferation of the Sf9 cells was inhibited in a dose-dependent manner, with IC50 values of 0.558 mg/ml at 24 h and 0.253 mg/ml at 48 h. Morphologic changes in ß-asarone-treated cells were typical of apoptosis and included loss of adhesion, cell shrinkage, and small apoptotic bodies. The DNA laddering present in ß-asarone-treated SF9 cells and annexin V assay confirmed that this compound can induce apoptosis in insect cells. Together, these findings suggest that apoptosis induction may be one mechanism through which ß-asarone inhibits the proliferation of insect cells and thus exerts insecticidal effects.

Effect of Plant Essential Oils and Their Major Constituents on Cypermethrin Tolerance Associated Detoxification Enzyme Activities in Spodoptera litura (Lepidoptera: Noctuidae).

Essential oils are well known to act as biopesticides. This research evaluated the acute toxicity and synergistic effect of essential oil compounds in combination with cypermethrin against Spodoptera litura Fabricius (Lepidoptera: Noctuidae). The effects of distillation extracts of essential oils from Alpinia galanga Zingiberaceae (Zingiberales) rhizomes and Ocimum basilicum Lamiaceae (Lamiales) leaves; one of their primary essential oil compounds 1,8-cineole; and linalool were studied on second-instar S. litura by topical application under laboratory conditions. The results showed that A. galanga had the highest control efficiency, whereas1,8-cineole provided a moderate efficacy. The mixtures of linalool, 1,8-cineole, O. basilicum, or A. galanga with cypermethrin were synergistic on mortality. Activity measurements of the main detoxification enzymes show that linalool and 1,8-cineole inhibit the activity of cytochromes P450 and carboxylesterases, which could explain their synergistic effect. Based on our results, the use of these mixtures represents an ideal eco-friendly approach, helping to manage cypermethrin resistance of S. litura.

Insecticidal Effects of Triterpene Glycosides Extracted From Holothuria atra (Echinodermata: Holothuroidea) Against Spodoptera litura (Lepidoptera: Noctuidae).

Spodoptera litura (Fabricius) is economically important in many countries. Many biopesticides have been developed and studied to control this pest species; however, few natural products from marine organisms have been studied for their pesticidal efficiency. This study compared the acute contact toxicity of solvent extracted from the viscera of Holothuria atra and isolated triterpene glycoside compounds on third-instar S. litura. Our results showed that crude methanolic extracts were the most toxic to the larvae (LC50 ~ 10.37 mg/ml) compared with other crude extracts and contained the bioactive compound 3,4-dihydroxybenzoic acid (LC50 ~ 6.01 mg/ml). All crude extracts and isolated triterpene glycoside compounds inhibited carboxylesterase activity. The efficiency and effectiveness of H. atra extractions and triterpene glycoside compounds against S. litura indicate their potential use in integrated pest management programs and the overall value of marine species as natural sources of insecticidal compounds.

The Study of Isolated Alkane Compounds and Crude Extracts From Sphagneticola trilobata (Asterales: Asteraceae) as a Candidate Botanical Insecticide for Lepidopteran Larvae.

The antifeedant and contact toxicity of Sphagneticola trilobata L. (Asterales: Asteraceae) extracts and isolated alkane compounds were investigated. Leaves of S. trilobata were sequentially extracted with hexane, dichloromethane, ethyl acetate, and methanol. Each extract and the compounds isolated were evaluated against the third instars of Spodoptera litura (F.) (Lepidoptera: Noctuidae), Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), and Plutella xylostella L. (Lepidoptera: Yponomeutidae). Ethyl acetate extract and isolated alkanes were feeding deterrents as well as contact toxins against all the three species evaluated (FI50 ~ 0.27-2.34 mg/ml; LD50 ~ 0.88-4.2 µg/larvae for ethyl acetate extract, and FI50 ~ 0.06-4.35 mg/ml; LD50 ~ 0.72-3.54 Ethyl acetate extract for isolated alkane). Impact on detoxifying enzymes was variable. The ethyl acetate crude extract reduced carboxylesterase activity in S. litura and P. xylostella while in S. exigua the enzyme was induced. In contrast, glutathione-S-transferase activity was induced in S. exigua but no significant difference in P. xylostella and S.litura was observed. Our results suggest that the S. trilobata extracts have multiple biological activities that contribute to the toxicity in lepidopterans. Variable enzyme responses to the products evaluated in different lepidopteran species also confirm that some species-specific inductions do occur, suggesting the possibility of resistance development in the future, which cannot be summarily ignored. However, for this detailed biochemical studies are required. Multiple bioefficacies of S. trilobata makes it a potential botanical for further exploitation on larger scale so that field potential can be established in any integrated pest management (IPM) system.

The Possibility of Using Isolated Alkaloid Compounds and Crude Extracts of Piper retrofractum (Piperaceae) as Larvicidal Control Agents for Culex quinquefasciatus (Diptera: Culicidae) Larvae.

Culex quinquefasciatus is a common domestic mosquito that is widespread in many areas of Thailand and serves as a southeastern vector of Japanese encephalitis. The present study investigated the acute toxicity of crude extracts and alkaloid compounds of Piper retrofractum (Piperales: Piperaceae) in Cx. quinquefasciatus third instar larvae. P. retrofractum was sequentially extracted using hexane, dichloromethane, ethyl acetate, and methanol, and the crude extracts were tested on mosquito larvae. Detoxification and neuroenzymes were analyzed to establish the mode of action. Acute toxicity was assessed on Poecilia reticulata (Cyprinodontiformes: Poeciliidae) to determine the possibility of toxicity in a nontarget species. Our results showed crude hexane extract had the highest toxicity in Cx. quinquefasciatus (0.9 ppm). Piperine and piperanine, which are alkaloid compounds from the crude hexane extract, showed LC50 values of 0.27 and 2.97 ppm, respectively, after 24 h of exposure. All the crude extracts showed low toxicity in P. reticulata compared with that in the mosquito larvae. The carboxylesterase, glutathione-S-transferase, and acetylcholinesterase activities in Cx. quinquefasciatus were reduced after treatment with all the extracts and the two alkaloid compounds. Thus, P. retrofractum shows larvicidal effects against Cx. quinquefasciatus and low toxicity for nontarget species. Thus, P. retrofractum could be a choice for controlling Cx. quinquefasciatus.

Tiliacora triandra (Colebr.) Diels leaf extract enhances spatial learning and learning flexibility, and prevents dentate gyrus neuronal damage induced by cerebral ischemia/reperfusion injury in mice.

OBJECTIVE: The present study investigated the effects of a local Thai vegetable, Tiliacora triandra (Colebr.) Diels, also known as Yanang, against cerebral ischemia/reperfusion injury in mice. MATERIALS AND METHODS: Thirty male ICR mice were divided into three experimental groups of BLCCAO + 10% Tween 80, BLCCAO + T. triandra 300 mg/kg, and BLCCAO + T. triandra 600 mg/kg. Cerebral ischemia/reperfusion was induced by three minutes of bilateral common carotid artery occlusion (BLCCAO) followed by 18 days of reperfusion. Leaf extract was administered orally 24 hours after arterial occlusion and continued for 18 consecutive days. Cognitive abilities were evaluated using the Morris water maze. Histological analysis was conducted in the dorsal hippocampus subregions CA1, CA3, and DG and white matter regions (the corpus callosum, internal capsule, and optic tract) using 0.1 % cresyl violet and 0.1% Luxol fast blue staining. RESULTS: Results showed that T. triandra leaf extract at the doses of 300 and 600 mg/kg significantly enhanced spatial learning, and learning flexibility, and prevented neuronal death in the DG of mice following ischemia/reperfusion. CONCLUSION: T. triandra leaf extract enhanced spatial learning, and learning flexibility, and prevented DG neuronal death in a mice model of cerebral ischemia/reperfusion.

Antifeedant activity of Jatropha gossypifolia and Melia azedarach senescent leaf extracts on Spodoptera frugiperda (Lepidoptera: Noctuidae) and their potential use as synergists.

BACKGROUND: To reduce rates of synthetic insecticide applications, natural product alternatives and synergists are needed. A study has been made of the toxicity of ethanolic senescent leaf extracts (SLEs) of Jatropha gossypifolia and Melia azedarach on larvae of the noctuid pest Spodoptera frugiperda. Their effects as syngergists and inhibitors of several enzyme activities are also reported. RESULTS: When added to the diet, M. azedarach SLE showed lower toxicity than J. gossypifolia SLE. However, after 2 weeks on the diet, the M. azedarach SLE proved to be lethal to 100% of the larval population. Artificial diets with both SLEs have an antifeedant effect on armyworm larvae. Acute toxicity after topical application in a dipping assay was relatively low for both J. gossypifolia and M. azedarach SLEs (LC(50) of 2.6 and 1.4 g L(-1), respectively, after 24 h). However, mixtures of the SLEs of M. azedarach and J. gossypifolia had a strong synergistic effect with cypermethrin. Synergism was higher with the J. gossypifolia SLE, perhaps because it contains several natural products with a methylenedioxyphenyl moiety. Both extracts inhibited P450, general esterase and acetylcholinesterase activities in vitro and in vivo. CONCLUSION: Both J. gossypifolia and M. azedarach SLEs are antifeedants to armyworm larvae when present in the food, and also have a synergistic effect with cypermethrin in topical assays. Although the synergistic effect is less than with piperonyl butoxide, both SLEs have some inhibitor activity against detoxification enzymes and acetylcholinesterase. Thus J. gossypifolia and M. azedarach SLEs may be considered as ecofriendly approaches for the control of S. frugiperda in order to reduce cypermethrin usage.

Impact of botanical extracts derived from leaf extracts Melia azedarach L. (Meliaceae) and Amaranthus viridis L. (Amaranthaceae) on populations of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae) and detoxification enzyme activities.

Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), an important insect pest of many field crops, has developed resistance to various insecticides, making its control increasingly difficult. This study explored the effects of senescent Leaf Melia azedarach L. (Meliaceae) and Amaranthus viridis L. (Amaranthaeae) extract on second instar S. exigua Larvae survival by the dipping method. We also analyzed detoxification enzyme activities of carboxylesterase and gLutathione-s-transferase in in vitro tests with extract-treated insects. The leaf extract showed strong insecticide activity with a LC50 value of 9.793 mg/ml (r2 = 0.965) and 50.5702 mg/mi (r2 = 0.95) at 24 after exposure for M. azedarach L. and A. viridis L. extract, respectivrly but no significant increase in toxicity over time. The M. azedarach L. extract strongly inhibited all enzyme activities. In contrast with A. viridis L. extract, they inhibit only glutathione-s-transferase. This is the first report of highly effective insecticidal activity of the senescent leaf extract of A. viridis and M. azedarach L. against S. exigua. Both plant materials are a less expensive (0.5 $US per 1 kg leaf), suggesting this extract is a promising alternative tool for the management of this pest.

Insecticidal activity of Jatropha gossypifolia L. (Euphorbiaceae) and Cleome viscosa L. (Capparidacae) on Spodoptera litura (Lepidoptera: Noctuidae). Toxicity and carboxylesterase and glutathione-S-transferase activities studies.

The naturally occurring phytocidal chemical components of some Thai plant-species are responsible for controlling and repelling insects from the host plants. The aim of this study was to evaluate the insecticidal activity of Jatropha gossypifolia L. Leaf extracts and the senescent leaf Cleome viscosa L. (Capparidacae) against S. litura and detoxification enzyme activities. Laboratory no-choice bioassays showed treatment of second instars Spodoptera litura by dipping in extracts from senescent Leaves of Jatropha gossypifolia L. at 3000-10000 ppm had significant toxicity with LC50 of 6.56 mg/ml(-1) (r2=0.88) at 24 hours after exposure. The toxicity of Cleome viscosa L. extract in terms of LC50 values ca. 34 mg ml(-1) (r2=0.95) at 24 after exposure by the dipping method. ALso, S. litura Larvae surviving treatment of both extract showed a dramatic decrease in carboxylesterase and glutathione-s-transferase activities. This extract showed strong insecticidal activity and may play an alternative role as a pesticide against Spodoptera litura.

Investigation of acute toxicity of Jatropha gossypifolia L. (Euphorbiaceae) and Cleome viscosa L. (Capparidacae) extract on guppies, Poecilia reticulate.

Jotropha gossypifolio L. (Etphorbiaceae) and Cleome viscosa, L. (Capparidacae), Thai-plant species, have phytocidal chemical components and responsible for controlling and repelling insects from the host plants. To avoid potential toxic pollutant contaminating aquatic ecosystems, this present study was investigated for acute toxicity. Guppy fish (Poecilia reticulata) were selected for the bioassay experiments. The experiments were repeated 5 times and the 24-h LC50 was determined for the guppies. The acute toxicity experiments were carried out by static method and behavioral changes in guppies were determined for each Jatropha gossypifolia L. and Cleome viscosa, L. concentration extract which extracted by Soxhlet extraction method with ethanol as solvent. Water temperature was regulated at 20 +/- 1 degrees C. Data obtained from the acute toxicity tests were evaluated using the probit analysis statistical method. The 24-h LC50 value for guppy was estimated as ca. 3100 ppm (r2=0.95) and 5300 ppm ((r2=0.96) for Jatropha gossypifolia L. and Cleome viscosa, L. extract, respectively. However, in this concentration, no mortality was observed at higher concentration for 30 second.