Chemical Composition,Antifeedant, Repellent,and Toxicity Activities of the Rhizomes of Galangal,Alpinia galanga Against Asian Subterranean Termites,Coptotermes gestroi and Coptotermes curvignathus (Isoptera: Rhinotermitidae)

Dual choice bioassays were used to evaluate the antifeedant property of essential oil and methanolic extract of Alpinia galanga (L.) (locally known as lengkuas) against two species of termites, Coptotermes gestroi (Wasmann) and Coptotermes curvignathus (Holmgren) (Isoptera: Rhinotermitidae). A 4-cm-diameter paper disc treated with A. galanga essential oil and another treated with either methanol or hexane as control were placed in a petri dish with 10 termites. Mean consumption of paper discs (miligram) treated with 2,000 ppm of essential oil by C. gestroi was 3.30 ± 0.24 mg and by C. curvignathus was 3.32 ± 0.24 mg. A. galanga essential oil showed significant difference in antifeedant effect, 2,000 ppm of A. galanga essential oil was considered to be the optimum concentration that gave maximum antifeedant effect. The essential oil composition was determined using gas chromatography-mass spectrometry. The major component of the essential oil was 1,8-cineol (61.9%). Antifeedant bioassay using 500 ppm of 1,8-cineol showed significant reduction in paper consumption by both termite species. Thus, the bioactive agent in A. galangal essential oil causing antifeeding activity was identified as 1,8-cineol. Repellent activity shows that 250 ppm of 1,8-cineol caused 50.00 ± 4.47% repellency for C. gestroi, whereas for C. curvignathus 750 ppm of 1,8-cineol was needed to cause similar repellent activity (56.67 ± 3.33%). C. curvignathus is more susceptible compare to C. gestroi in Contact Toxicity study, the lethal dose (LD₅₀) of C. curvignathus was 945 mg/kg, whereas LD₅₀ value for C. gestroi was 1,102 mg/kg. Hence 1,8-cineol may be developed as an alternative control against termite in sustainable agriculture practices.     

Creams Formulated with Ocimum gratissimum L. and Lantana camara L. Crude Extracts and Fractions as Mosquito Repellents Against Aedes aegypti L. (Diptera: Culicidae)

Mosquitoes are the most deadly vectors of parasites that cause diseases such as malaria, yellow fever, and filariasis. In view of the recent increased interest in developing plant origin insecticides as an alternative to chemical insecticides, the objective of this study was to determine the repellent activity of creams formulated with methanol crude extract (MCE), hexane fraction (HF), and ethyl acetate fractions (EAFs) of Ocimum gratissimum and Lantana camara leaves in single and combined actions against female Aedes aegypti. Evaluation was carried out in the net cages (30 by 30 by 30 cm) containing 60 blood-starved female mosquitoes each and were assayed in the laboratory condition following World Health Organization 2009 protocol. All formulations (single and mixture) were applied at 2, 4, 6, and 8 mg/cm² in the exposed area of human hands. Only acetone + white soft paraffin served as negative control and odomos (12% DEET) as positive control. All the formulations presented good protection against mosquito bites without any allergic reaction by the human volunteers. The repellent activity was dependent on the strength of the extracts and fractions. Among the tested formulations, the maximum protection time was observed in MCE (120 min) and EAF (150 min) of O. gratissimum; MCE:MCE (150 min) and HF:HF (120 min) mixtures of both plants. In addition, MCE:MCE and HF:HF mixtures from both plants showed possible synergistic effect. From the results, the combination of O. gratissimum and L. camara to formulate natural mosquito repellent using small amount of extracts can be encouraging to be an alternative to conventional DEET.     

The Effect of Chemical Composition and Bioactivity of Several Essential Oils on Tenebrio molitor (Coleoptera: Tenebrionidae)

The major chemical components of four essential oils (EOs) extracted from dry leaves of Citrus limonum, Cymbopogon citratus, Litsea cubeba, and Muristica fragrans were analyzed with gas chromatograph-mass spectrometer and their fumigant, contact, and repellent activities against 10th instar and adults of Tenebrio molitor were also assayed. The results indicated that the major constituents of C. limonum and Cy. citrates were D-limonene (38.22%) and 3,7-dimethyl-6-octenal (26.21%), while which of L. cubeba and M. fragrans were (E)-3, 7-dimethyl-2, 6-octadienal (49.78%) and (E)-cinnamaldehyde (79.31%), respectively. Contact activities of L. cubeba and C. limonum with LC₅₀ values of 21.2 and 13.9 µg/cm² at 48 h and repellence activities (>89.0% repellence indexes) (P < 0.05) at 12 h on 10th instar were better than those of the other two EOs. Nevertheless, the fumigation activities of L. cubeba on 10th instar and adults (LC₅₀ = 2.7, 3.7 μl/liter) were stronger than those of C. limonum (LC₅₀ = 10.9, 12.0 μl/liter) at 96 h and significant (not overlapping confidence intervals). The EOs of L. cubeba and C. limonum have clearly elongated the growth and development of larvae, egg, and slightly shorten pupae and adults of T. molitor compared with the control. The mainly active ingredients of L. cubeba and C. limonum, including D-limonene and β-pinene, were demonstrated to coinhibit the actives of AChE and enhance the toxicities on 10th instar of T. molitor. These results indicate that the EOs of L. cubeba and C. limonum could have great potential as botanical insecticides against T. molitor.     

Insecticidal Activity and Insect Repellency of Four Species of Sea Lily (Comatulida: Comatulidae) From Taiwan

The methanol and ethyl acetate (EA) extracts of four species of sea lily (Himerometra magnipinna, Comaster multifidus, Comanthina sp., and Comatella maculata) were evaluated for their insecticidal activity against Yellow-fever mosquito larvae (Aedes aegypti) and their repellency against adult Asian Tiger mosquitoes (Aedes albopictus). The 24-hr minimum inhibition concentration (MIC) data revealed that the extracts from H. magnipinna and the C. maculata were the most active, killing mosquito larvae at 12.5 ppm. The toxicity of the extracts from these four sea lilies in descending order was H. magnipinna (12.5 ppm), C. maculata (12.5 ppm), C. multifidus (100 ppm), and Comanthina sp. (200 ppm). Furthermore, no significant difference in toxicity was found using either EA or methanol as the extraction solvent. The MIC at 12.5 ppm is promising as an insecticide lead. The repellency study results show that EA is a better solvent for one species (H. magnipinna), but the methanol is a better solvent overall. The repellency of these sea lily extracts in descending order was Comanthina sp. MeOH (ED₅₀ at 0.32%), followed by H. magnipinna EA (ED₅₀ at 0.38%), C. multifidus MeOH (ED₅₀ at 0.57%), C. maculata MeOH (ED₅₀ at 0.76%), C. multifidus EA (ED₅₀ at 1.25%), and H. magnipinna MeOH (ED₅₀ at 1.67%). A compound with ED₅₀ <0.5% is considered to be a promising repellant. Among the studied sea lilies, both Comanthina sp. and H. magnipinna have potential to be further developed as mosquito control agents due to their favorable toxicity and repellency.     

Laboratory Evaluation of Acute Toxicity of the Essential Oil of Allium tuberosum Leaves and Its Selected Major Constituents Against Apolygus lucorum (Hemiptera: Miridae)

The aim of this research was to evaluate acute toxicity of the essential oil of leaves of Chinese chives, Allium tuberosum Rottler ex Spreng (Asparagales: Alliaceae) and its major constituents against Apolygus lucorum Meyer-Dür (Hemiptera: Miridae). The essential oil of A. tuberosum leaves was obtained by hydrodistillation and analyzed by gas chromatography and gas chromatography-mass spectrometry. The major constituents of the oil were sulfur-containing compounds, including allyl methyl trisulfide (36.24%), diallyl disulfide (27.26%), diallyl trisulfide (18.68%), and dimethyl trisulfide (9.23%). The essential oil of A. tuberosum leaves exhibited acute toxicity against Ap. lucorum with an LD₅₀ value of 20.03 μg per adult. Among the main compounds, diallyl trisulfide (LD₅₀ = 10.13 μg per adult) showed stronger acute toxicity than allyl methyl trisulfide (LD₅₀ = 21.10 μg per adult) and dimethyl trisulfide (LD₅₀ = 21.65 μg per adult). The LD₅₀ value of diallyl disulfide against Ap. lucorum was 28.10 μg per adult. The results indicated that the essential oil of A. tuberosum and its major constituents may have a potential to be developed as botanical insecticides against Ap. lucorum.     

Insecticidal effects of Ungernia severtzovii bulb extracts against the grain aphid Schizaphis graminum (Rondani)

Insecticidal effect of Ungernia severtzovii bulbs extract has been investigated against the grain aphid Schizaphis graminum. LC₅₀ value of the ethanolic extract of U. severtzovii against the female aphids was 0.235% (2.35 g/l). There was 100% mortality of the subsequent nymphs of the treated females at 0.25-1.0%. The extract was equally active against the nymphs at the highest concentrations. Hexane and ethanolic extracts were the most active against the aphids of all the extracts. Fractionation of the hexane extract by TLC yielded three fractions. Fraction II was the most active (>90% mortality) against the aphids. Xanthoxylin was identified as the major constituent in fraction II of the hexane extract and may be responsible for the insecticidal effect of U. severtzovii.     

Fumigant Toxicity and Repellence Activity of Camphor Essential Oil from Cinnamonum camphora Siebold Against Solenopsis invicta Workers (Hymenoptera:Formicidae)

The red imported fire ant (RIFA) Solenopsis invicta Buren causes severe damage to humans and animals as well as the environment. Chemical treatment is the main strategy of RIFA management, which also is potentially toxic to the environment. Plant essential oils (EOs) are considered as potential substance that can be used to control insects. This study aimed to identify the chemical composition of camphor EO and investigate the insecticidal activity on RIFAs. The chemical composition of the EO was analyzed by gas chromatography/mass spectrometry and gas chromatography with flame ionization detection. Results revealed that 36.61% camphor and 30.05% cineole were the major components. The insecticidal activity of camphor EO was assessed against RIFA workers by conducting two different bioassays: fumigant toxicity and repellence. Fumigant toxicity assay results showed that the lethal dose (LC₅₀) of the EO at 24 h was 1.67 and 4.28 μg/ml for minor and major workers, respectively; knockdown time (KT₅₀) was 10.82 and 14.73 h. At 2.55 μg/ml, the highest average mortality of the ants was 84.89% after 72 h. Camphor EO exhibited fumigant toxicity against minor and major workers as indicated by the effects on attacking, feeding, and climbing behaviors. This EO was also strongly repellent to the two size workers of the colony as observed in their behavior against Tenebrio molitor treated with 5 µl EO. The fumigant toxicity and repellence of camphor EO against RIFA indicated that this substance could be a potential alternative for the development of eco-friendly products used to control pests.     

The Toxicity and Detoxifying Mechanism of Cycloxaprid and Buprofezin in Controlling Sogatella furcifera (Homoptera: Delphacidae)

The effects of cycloxaprid (a modified neonicotinoid insecticide) and buprofezin (a thiadiazine insecticide) on mortality of the white-backed planthopper (WBPH), Sogatella furcifera, were determined in laboratory assays. Cycloxaprid killed WBPH nymphs and adults but buprofezin killed only nymphs, and cycloxaprid acted faster than buprofezin. One day after infestation, mortality of third-instar nymphs was >65% with cycloxaprid at 125 mg liter⁻¹ but was <38% with buprofezin at 148 mg liter⁻¹. By the 4th day after infestation, however, control of nymphs by the two insecticides was similar, and cycloxaprid at 125 mg liter⁻¹ caused ≥80% mortality of adults but buprofezin at 148 mg liter⁻¹ (the highest rate tested) caused almost no adult mortality. LC₅₀ values for cycloxaprid were lowest with nymphs, intermediate with adult males, and highest with adult females. Although buprofezin was slower acting than cycloxaprid, its LC₅₀ for nymphs 5 d after infestation was 3.79-fold lower than that of cycloxaprid. Mean carboxylesterase (CarE) specific activity of nymphal WBPH treated with cycloxaprid and buprofezin was higher than that of control, but there was no significant difference between cycloxaprid and control (no insecticide), and it was significantly higher for buprofezin than those of cycloxaprid and control. For glutathione S-transferase and mixed function oxygenase, the specific activity of nymphal WBPH treated with buprofezin was significantly higher than those of cycloxaprid and control, too.     

Biological Properties of Fucoxanthin in Oil Recovered from Two Brown Seaweeds Using Supercritical CO2 Extraction

The bioactive materials in brown seaweeds hold great interest for developing new drugs and healthy foods. The oil content in brown seaweeds (Saccharina japonica and Sargassum horneri) was extracted by using environmentally friendly supercritical CO₂ (SC-CO₂) with ethanol as a co-solvent in a semi-batch flow extraction process and compared the results with a conventional extraction process using hexane, ethanol, and acetone mixed with methanol (1:1, v/v). The SC-CO₂ method was used at a temperature of 45 °C and pressure of 250 bar. The flow rate of CO₂ (27 g/min) was constant for the entire extraction period of 2 h. The obtained oil from the brown seaweeds was analyzed to determine their valuable compounds such as fatty acids, phenolic compounds, fucoxanthin and biological properties including antioxidant, antimicrobial, and antihypertension effects. The amounts of fucoxanthin extracted from the SC-CO₂ oils of S. japonica and S. horneri were 0.41 ± 0.05 and 0.77 ± 0.07 mg/g, respectively. High antihypertensive activity was detected when using mixed acetone and methanol, whereas the phenolic content and antioxidant property were higher in the oil extracted by SC-CO₂. The acetone–methanol mix extracts exhibited better antimicrobial activities than those obtained by other means. Thus, the SC-CO₂ extraction process appears to be a good method for obtaining valuable compounds from both brown seaweeds, and showed stronger biological activity than that obtained by the conventional extraction process.     

Contact Toxicity and Repellency of the Main Components From the Essential Oil of Clausena anisum-olens Against Two Stored Product Insects

The essential oil of Clausena anisum-olens (Blanco) Merr. showed strong contact toxicity and repellency against Lasioderma serricorne and Liposcelis bostrychophila adults. The components of the essential oil obtained by hydrodistillation were determined by gas chromatography-mass spectrometry. It was found that the main components were myristicin (36.87%), terpinolene (13.26%), p-cymene-8-ol (12.38%), and 3-carene (3.88%). Myristicin and p-cymene-8-ol were separated by silica gel column chromatography, and their molecular structures were confirmed by means of physicochemical and spectrometric analysis. Myristicin and p-cymene-8-ol showed strong contact toxicity against L. serricorne (LD₅₀ = 18.96 and 39.68 μg per adult) and Li. bostrychophila (LD₅₀ = 20.41 and 35.66 μg per adult). The essential oil acting against the two grain storage insects showed LD₅₀ values of 12.44 and 74.46 μg per adult, respectively. Myristicin and p-cymene-8-ol have strong repellent toxicity to Li. bostrychophila.     

Isolation,Characterization, Kinetics,and Enzymatic and Nonenzymatic Microbicidal Activities of a Novel c-Type Lysozyme from Plasma of Schistocerca gregaria (Orthoptera: Acrididae)

A protein, designated as Sgl, showing a muramidase lytic activity to the cell wall of the Gram-positive bacterium Micrococcus lysodeikticus was isolated for the first time from plasma of Escherichia coli-immunized fifth instar Schistocerca gregaria. The isolated Sgl was detected as a single protein band, on both native- and SDS-PAGE, has a molecular weight of ∼15.7 kDa and an isoelectric point (pI) of ca 9.3 and its antiserum has specifically recognized its isolated form. Fifty-nine percentage of Sgl lytic activity was recovered in the isolated fractions and yielded ca 126-fold increase in specific activity than that of the crude. The partial N-terminal amino acid sequence of the Sgl has 55 and 40% maximum identity with Bombyx mori and Gallus gallus c-type lysozymes, respectively. The antibacterial activity against the Gram-positive and the Gram-negative bacteria were comparatively stronger than that of the hen egg white lysozyme (HEWL). The detected Sgl poration to the inner membrane that reach a maximum ability after 3 h was suggested to operate as a nonenzymatic mechanism for Gram-negative bacterial cell lysis, as tested in a permease-deficient E. coli, ML-35 strain. Sgl showed a maximal muramidase activity at pH 6.2, 30–50°C, and 0.05 M Ca²⁺ or Mg²⁺; and has a K_m of 0.5 μg/ml and a V_max of 0.518 with M. lysodeikticus as a substrate. The Sgl displayed a chitinase activity against chitin with a K_m of 0.93 mg/ml and a V_max of 1.63.     

Identification and Characterization of Bacillus cereus SW7-1 in Bombyx mori (Lepidoptera: Bombycidae)

The bacterial diseases of silkworms cause significant reductions in sericulture and result in huge economic loss. This study aimed to identify and characterize a pathogen from diseased silkworm. SW7-1, a pathogenic bacterial strain, was isolated from the diseased silkworm. The strain was identified on the basis of its bacteriological properties and 16S rRNA gene sequence. The colony was round, slightly convex, opaque, dry, and milky on a nutrient agar medium, the colony also exhibited jagged edges. SW7-1 was Gram-positive, without parasporal crystal, and 0.8–1.2 by 2.6–3.4 µm in length, resembling long rods with rounded ends. The strain was positive to most of the physiological biochemical tests used in this study. The strain could utilize glucose, sucrose, and maltose. The results of its 16S rRNA gene sequence analysis revealed that SW7-1 shared the highest sequence identity (>99%) with Bacillus cereus strain 14. The bacterial strain was highly susceptible to gentamycin, streptomycin, erythromycin, norfloxacin, and ofloxacin and moderately susceptible to tetracycline and rifampicin. It exhibited resistance to other antibiotics. SW7-1 had hemolytic activity and could produce extracellular casease, lipase, and amylase. SW7-1 could reproduce septicemia-like symptoms with high mortality rate when re-fed to healthy silkworm. .The median lethal concentration (LC₅₀) was 5.45 × 10⁴ cfu/ml. Thus, SW7-1 was identified as B. cereus, which is a pathogen for silkworm and human infections are possible.     

Demographic Parameters of Nezara viridula (Heteroptera: Pentatomidae) Reared on Two Diets Developed for Lygus spp.

Two artificial diets developed for rearing Lygus spp., a fresh yolk chicken egg based-diet (FYD) and a dry yolk chicken egg based-diet (DYD), were evaluated as an alternative food source for rearing the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae). Survival to adult was 97.3 and 74.67%, respectively, on the fresh and dry yolk diets. Insects fed FYD had 100% survival of nymphs from first through fourth instars. Adult development was significantly shorter on FYD (30.37 ± SE 0.30 d) as compared with DYD (32.77 ± SE 0.16 d). Increased male and female longevity, higher fecundity, and larger egg mass sizes were also observed with N. viridula-fed FYD. However, fertility and hatchability was higher on DYD. A complete cohort life table was constructed to describe the development of N. viridula on both diets.     

Antiviral Sulfoquinovosyldiacylglycerols (SQDGs) from the Brazilian Brown Seaweed Sargassum vulgare

Total lipids from the Brazilian brown seaweed Sargassum vulgare were extracted with chloroform/methanol 2:1 and 1:2 (v/v) at room temperature. After performing Folch partition of the crude lipid extract, the lipids recovered from the Folch lower layer were fractionated on a silica gel column eluted with chloroform, acetone and methanol. The fraction eluted with methanol, presented a strong orcinol-positive band characteristic of the presence of sulfatides when examined by TLC. This fraction was then purified by two successive silica gel column chromatography giving rise to fractions F4I86 and F4II90 that exhibited strong activity against herpes simplex virus type 1 and 2. The chemical structures present in both fractions were elucidated by ESI-MS and ¹H/¹³C NMR analysis HSQC fingerprints based on their tandem–MS behavior as sulfoquinovosildiacylglycerols (SQDGs). The main SQDG present in both fractions and responsible for the anti-herpes activity observed was identified as 1,2-di-O-palmitoyl-3-O-(6-sulfo-α-d-quinovopyranosyl)-glycerol.     

Enzyme-Assisted Extraction of Bioactive Material from Chondrus crispus and Codium fragile and Its Effect on Herpes simplex Virus (HSV-1)

Codium fragile and Chondrus crispus are, respectively, green and red seaweeds which are abundant along the North Atlantic coasts. We investigated the chemical composition and antiviral activity of enzymatic extracts of C. fragile (CF) and C. crispus (CC). On a dry weight basis, CF consisted of 11% protein, 31% neutral sugars, 0.8% sulfate, 0.6% uronic acids, and 49% ash, while CC contained 27% protein, 28% neutral sugars, 17% sulfate, 1.8% uronic acids, and 25% ash. Enzyme-assisted hydrolysis improved the extraction efficiency of bioactive materials. Commercial proteases and carbohydrases significantly improved (p ≤ 0.001) biomass yield (40%–70% dry matter) as compared to aqueous extraction (20%–25% dry matter). Moreover, enzymatic hydrolysis enhanced the recovery of protein, neutral sugars, uronic acids, and sulfates. The enzymatic hydrolysates exhibited significant activity against Herpes simplex virus (HSV-1) with EC₅₀ of 77.6–126.8 μg/mL for CC and 36.5–41.3 μg/mL for CF, at a multiplicity of infection (MOI) of 0.001 ID₅₀/cells without cytotoxity (1–200 μg/mL). The extracts obtained from proteases (P1) and carbohydrases (C3) were also effective at higher virus MOI of 0.01 ID₅₀/cells without cytotoxity. Taken together, these results indicate the potential application of enzymatic hydrolysates of C. fragile and C. crispus in functional food and antiviral drug discovery.     

Biological Activity of trans-2-Hexenal Against Bradysia odoriphaga (Diptera: Sciaridae) at Different Developmental Stages

trans-2-Hexenal, one of the C6 green leaf volatiles, is potentially useful for the control of Bradysia odoriphaga Yang et Zhang. In this study, the biological activity of trans-2-hexenal on B. odoriphaga was assessed in the laboratory. trans-2-Hexenal was observed to kill B. odoriphaga in different developmental stages at a relatively low concentration under fumigation. The respiration rate in the male treatment group decreased from 131.44 to 4.07 nmol/g·min with a prolonged fumigation time, while the respiration rate in females decreased from 128.82 to 24.20 nmol/g·min. Male adults exhibited a more sensitive electroantennogram response at 0.05–500 μl/ml at the dose of 10.0 μl than female adults. Moreover, trans-2-hexenal had a repellent effect on adults based on the results with a Y-tube olfactometer at 10.0 μl, as shown by the deterrent rate of male and female adults with 96.67% and 98.33%, respectively. The results showed that trans-2-hexenal had good biological activity in different developmental stages of B. odoriphaga, which could reduce the need for, and risks associated with, the use of traditional insecticides and enable nonharmful management.     

Insights into the Toxicological Properties of a Low Molecular Weight Fraction from Zoanthus sociatus (Cnidaria)

The phylum Cnidaria is an ancient group of venomous animals, specialized in the production and delivery of toxins. Many species belonging to the class Anthozoa have been studied and their venoms often contain a group of peptides, less than 10 kDa, that act upon ion channels. These peptides and their targets interact with high affinity producing neurotoxic and cardiotoxic effects, and even death, depending on the dose and the administration pathway. Zoanthiniaria is an order of the Subclass Hexacorallia, class Anthozoa, and unlike sea anemone (order Actiniaria), neither its diversity of toxins nor the in vivo effects of the venoms has been exhaustively explored. In this study we assessed some toxicological tests on mice with a low molecular weight fraction obtained by gel filtration in Sephadex G-50 from Zoanthus sociatus crude extract. The gel filtration chromatogram at 280 nm revealed two major peaks, the highest absorbance corresponding to the low molecular weight fraction. The toxicological effects seem to be mostly autonomic and cardiotoxic, causing death in a dose dependent manner with a LD₅₀ of 792 μg/kg. Moreover, at a dose of 600 μg/kg the active fraction accelerated the KCl-induced lethality in mice.     

Different Culture Metabolites of the Red Sea Fungus Fusarium equiseti Optimize the Inhibition of Hepatitis C Virus NS3/4A Protease (HCV PR)

The endophytic fungus Fusarium equiseti was isolated from the brown alga Padina pavonica, collected from the Red Sea. The fungus was identified by its morphology and 18S rDNA. Cultivation of this fungal strain in biomalt-peptone medium led to isolation of 12 known metabolites of diketopeprazines and anthraquinones. The organic extract and isolated compounds were screened for their inhibition of hepatitis C virus NS3/4A protease (HCV PR). As a result, the fungal metabolites showed inhibition of HCV protease (IC₅₀ from 19 to 77 μM), and the fungus was subjected to culture on Czapek’s (Cz) media, with a yield of nine metabolites with potent HCV protease inhibition ranging from IC₅₀ 10 to 37 μM. The Cz culture extract exhibited high-level inhibition of HCV protease (IC₅₀ 27.6 μg/mL) compared to the biomalt culture extract (IC₅₀ 56 μg/mL), and the most potent HCV PR isolated compound (Griseoxanthone C, IC₅₀ 19.8 μM) from the bio-malt culture extract showed less of an inhibitory effect compared to isolated ω-hydroxyemodin (IC₅₀ 10.7 μM) from the optimized Cz culture extract. Both HCV PR active inhibitors ω-hydroxyemodin and griseoxanthone C were considered as the lowest selective safe constituents against Trypsin inhibitory effect with IC₅₀ 48.5 and 51.3 μM, respectively.     

Disruption of Darna pallivitta (Lepidoptera: Limacodidae) by Conventional and Mobile Pheromone Deployment

Identification of the Darna pallivitta (Moore) pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOn-Bu) has made it possible to investigate communication disruption to control this lepidopteran pest. Conventional communication disruption trials showed marked decreases in the mean number of male moths captured in E7,9-10:COOnBu-treated fields compared with control fields. For traps baited with E7,9-10:COOnBu, percent disruptions were 94.4% and 92.1% for septa (1 g pheromone/ha, 1-wk trial duration) and spirals (6 g pheromone/ha, 8-wk trial duration) respectively. For traps baited with virgin female moths, percent disruption was 73.3% using septa disruptors (1 g pheromone/ha, 1-wk trial duration). Mobile communication disruption using Bactrocera cucurbitae (Coquillett) as carriers for E7,9-10:COOn-Bu was evaluated in the following three areas: fly survivorship, attraction of male moths to treated flies, and moth disruption in a small-scale field trial. Topical application of E7,9-10:COOnBu showed no significant decrease in survivorship at 50 and 80 µg/fly. However, decreased survivorship was observed at 100 µg/fly and linear regression showed E7,9-10:COOnBu dose was significantly correlated with B. cucurbitae survivorship. Traps containing honey–pheromone-fed flies attracted and caught D. pallivitta over a 1-wk period, demonstrating the attractiveness of the carrier. Releasing E7,9-10:COOnBu-fed B. cucurbitae (∼2 g pheromone/ha, 1-wk trial duration) resulted in significantly reduced trap catches in treatment fields compared with control fields on the first 2 d of the field trial. Percent disruptions were 84.7% (day 1) and 56.0% (day 2). These results suggest that both conventional communication disruption and mobile communication disruption have potential to control D. pallivitta.     

Evaluation of Macroalgae Sulfated Polysaccharides on the Leishmania (L.) amazonensis Promastigote

The sulfated polysaccharides from Solieria filiformis (Sf), Botryocladia occidentalis (Bo), Caulerpa racemosa (Cr) and Gracilaria caudata (Gc) were extracted and extensively purified. These compounds were then subjected to in vitro assays to evaluate the inhibition of these polysaccharides on the growth of Leishmania (L.) amazonensis promastigotes. Under the same assay conditions, only three of the four sulfated polysaccharides were active against L. amazonensis, and the polysaccharide purified from Cr was the most potent (EC₅₀ value: 34.5 μg/mL). The polysaccharides derived from Bo and Sf demonstrated moderate anti-leishmanial activity (EC₅₀ values of 63.7 μg/mL and 137.4 μg/mL). In addition, we also performed in vitro cytotoxic assays toward peritoneal macrophages and J774 macrophages. For the in vitro cytotoxicity assay employing J774 cells, all of the sulfated polysaccharides decreased cell survival, with CC₅₀ values of 27.3 μg/mL, 49.3 μg/mL, 73.2 μg/mL, and 99.8 μg/mL for Bo, Cr, Gc, and Sf, respectively. However, none of the sulfated polysaccharides reduced the cell growth rate of the peritoneal macrophages. These results suggest that macroalgae contain compounds with various chemical properties that can control specific pathogens. According to our results, the assayed sulfated polysaccharides were able to modulate the growth rate and cell survival of Leishmania (L.) amazonensis promastigotes in in vitro assays, and these effects involved the interaction of the sulfated polysaccharides on the cell membrane of the parasites.