Tenebrio molitor beetles have been widely used in traditional and folklore medicines to treat various human diseases worldwide. Alzheimer’s disease (AD) is a neurodegenerative disorder and the most prevalent form of dementia in developed and developing countries. The human β-amyloid cleaving enzyme (BACE-1) is a target for AD treatments. This study was performed to determine BACE-1 inhibitory activity of 12 compounds that were extracted from T. molitor adults and their 65 related compounds using a fluorescence resonance energy transfer-based enzyme assay. The results were compared with those of two positive controls for BACE-1, the cell-permeable isophthalamide BACE-1 inhibitor IV and the natural BACE-1 inhibitor, epigallocatechin gallate (EGCG). Based on IC50 values, linoleic acid, ergosterol, palmitoleic acid, and tryptopol (28.41‒46.16 μM) were the most potent BACE-1 inhibitors and the anti-BACE-1 activity of these compounds was lower than either inhibitor IV (13.13 μM) or EGCG (1.12 μM). Multiple regression analysis of the anti-BACE-1 activities of compounds was examined using their IC50 values and the values of the physical parameters (molecular weight (MW), log P, and molecular refraction (MR)) for the 41 fatty acids (R2 = 0.674 (P = 0.044)) and 29 flavonoids (R2 = 0.587 (P = 0.063)). Correlation coefficient (r) analysis showed that MW, log P, and MR may be positively correlated with IC50 of the fatty acids (MW, r = 0.658; log P, r = 0.471; and MR, r = 0.713) and IC50 of the flavonoids (MW, r = 0.547; log P, r = 0.644; and MR, r = 0.591). Further studies will warrant possible applications of T. molitor adults as therapeutic BACE-1 blocker.

Tenebrio molitor beetles have been widely used in traditional and folklore medicines to treat various human diseases worldwide. This study was performed to determine radical scavenging activity of nine compounds that were extracted from T. molitor adults and their 64 related compounds using a 2,2-diphenyl-1-picrylhydrazyl assay. The results were compared with those of three positive controls, ascorbic acid, butylated hydroxytoluene (BHT), and epigallocatechin gallate (EGCG). Based on IC50 values, linolenic acid (77.65 μM) was the most potent antioxidant and the antioxidant activity of this compound was higher than that of either ascorbic acid, BHT or EGCG. The antioxidant activity of protocatechuic acid (IC50, 153.68 μM) and ascorbic acid did not differ significantly. The antioxidant activity of catechin (IC50, 192.32 μM) was higher than that of either BHT or EGCG. Multiple regression analysis of the antioxidant activities of compounds was examined using their IC50 values and the values of the physical parameters (molecular weight (MW), log P, and molecular refraction (MR)) for the 41 fatty acids (R2 = 0.729 (P = 0.031)) and 29 flavonoids (R2 = 0.521 (P = 0.054)). Correlation coefficient (r) analysis showed that MW, log P, and MR may be positively correlated with IC50 of the fatty acids (MW, r = 0.743; log P, r = 0.642; and MR, r = 0.815) and IC50 of the flavonoids (MW, r = 0.642; log P, r = 0.495; and MR, r = 0.643). Further studies will warrant possible applications of T. molitor adults as an antioxidant.

The effects of some essential oils and Sopophora extract on Frankliniella occidentalis adults, Myzus persicae adults, Plutella xylostella larvae, and Spodoptera exigua larvae were investigated. Insecticidal and phytotoxicity activities of emulsion in water formulations containing the active essential oils as active ingredients under laboratory and pot conditions were also tested. Based on these results, NRS-13 and NRS-24 formulations were selected to further assess as follows; the GC and GC-MS analysis on the active essential oils, the quantity analysis of the major components contained in the formulations, their insecticidal activities under pot and field conditions, and their oral, dermal, skin and eye irritation, and fish toxicities. Thus, the NRS-13 (BaechooSaferTM) and NRS-24 (JindiOutTM) formulations could be considered as insecticides for pest control.

The human β-amyloid (Aβ) cleaving enzyme (BACE-1) is a target for Alzheimer’s disease (AD) treatments. This study was conducted to determine if acacetin extracted from the whole Agastache rugosa plants had anti-BACE-1 and behavioral activities in Drosophila AD models and to determine acacetin’s mechanism of action. Acacetin (100, 300, and 500 μM) rescued amyloid precursor protein (APP)/BACE1-expressing flies and kept them from developing both eye morphology (dark deposits, ommatidial collapse and fusion, and the absence of ommatidial bristles) and behavioral (motor abnormalities) defects. The RT-PCR and Western blot analysis revealed that the protective effect of acacetin on Aβ production is mediated by transcriptional regulation of BACE-1 and APP, resulting in decreased APP protein expression and BACE-1 activity, and reduced Aβ production by interfering with BACE-1 activity and APP synthesis, resulting in a decrease in the levels of the APP carboxy terminal fragments and the APP intracellular domain, and finally, resulting in a decrease in the number of amyloid plaques.

Aedes aegypti and Aedes albopictus and Culex pipiens pallens mosquitoes transmit dengue fever and West Nile virus diseases, respectively. This study was conducted to determine the toxicity and mechanism of action of four flavonoids and seven fatty acids from Millettia pinnata (Fabaceae) seed as well as four fatty acid esters toward third instar larvae from insecticide-susceptible C. p. pallens and A. aegypti as well as wild A. albopictus. Potent toxicity was produced by karanjin, oleic acid, karanjachromene, linoleic acid, linolenic acid, pongamol, pongarotene, and elaidic acid toward C. p. pallens larvae (24 h LC50, 14.61–28.22 mg/L) and A. aegypti larvae (16.13–37.61 mg/L). Against wild A. albopictus larvae, oleic acid (LC50, 18.79 mg/L) and karanjin (35.26 mg/L) exhibited potent toxicity. Acetylcholinesterase (AChE) is the main site of action of the flavonoids, oleic acid, and palmitic acid.,Linoleic acid and linolenic acid might act on both AChE and octopaminergic receptor. Further studies will warrant possible applications of M. pinnata seed-derived products as potential larvicides for the control of mosquito populations.

Propolis collected from botanical sources by honey bee, has been used as a popular natural remedies in folk medicine throughout the world. This study was conducted to assess growth inhibitory effects of ethanol extracts of propolis (EEPs) from 20 different regions in South Korea on human intestinal bacteria as well as BACE-1, AChE inhibitory, antioxidant, antiproliferative, and anti-human rhinovirus activities. Correlation coefficient (r) analysis of the biological activities of EEP samples was determined using their 50% inhibition concentration or minimal inhibitory concentration values and their polyphenol or flavonoid contents in 20 Korean EEP samples. Correlation coefficient analysis showed that total polyphenol contents may be negatively correlated with DPPH free radical scavenging activity (r = –0.872) and total flavonoid content has no correlation with the activity (r = 0.071). No direct correlation between BACE-1 inhibition, AChE inhibition, or antiproliferative activity and total polyphenol or total flavonoid content in Korean EEP samples was found.

This study was conducted to determine the toxicity to adult Myzus persicae (Sulzer) and Aphis gossypii Glover of 88 plant essential oils and six experimental spray formulations containing bitter orange or marjoram oil was examined using the vapor-phase mortality and spray bioassays. Results were compared with those of two conventional insecticides deltamethrin and dichlorvos. As judged by 24 h LC50 values, bitter orange oil (0.0212 and 0.0192 mg/cm3) was the most active material, followed by marjoram, celeryseed, and cypress oils (0.0239-0.0508 and 0.0209-0.0542 mg/cm3). These essential oils were significantly less toxic than dichlorvos, respectively. These essential oils were consistently more toxic to adult M. persicae in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapor. Bitter orange oil and marjoram oil applied as 1% spray provided complete mortality toward two aphid species adults. Reasonable aphid control in greenhouses can be achieved by a spray formulation containing the 1% oil as potential contact-action fumigant.

This study was aimed at assessing the fumigant toxicity to adult Thrips palmi and Orius strigicollis of basil (Ocimum basilicum) essential oil compounds and structurally related compounds using vapour-phase toxicity bioassays. Results were compared with those for dichlorvos. Against adult T. palmi, linalool (LD50, 0.0055 mg cm–3) was the most toxic fumigant and was 15.2–fold more effective than dichlorvos (0.0837 mg cm–3). Strong fumigant toxicity was also observed in pulegone (0.0095 mg cm–3), (±)-camphor (0.0097 mg cm–3) and 1,8-cineole (0.0167 mg cm–3). Moderate toxicity was produced by camphene, 3-carene, (–)-menthone, (+)-α-pinene, (+)-β-pinene, α-terpineol and (–)-α-thujone (0.0215–0.0388 mg cm–3). Against adult O. strigicollis, dichlorvos (LD50, 9.0 ×10–10 mg cm–3) was the most toxic fumigant, whereas the LD50 values of these compounds ranged from 0.0127 to >0.23 mg cm–3. Based upon selective toxicity ratio (STR, O. strigicollis LD50/T. palmi LD50), the compounds described (STR, 0.7–>10.7) are more selective than dichlorvos (STR, 10.8×10–9 mg cm–3). Basil oil compounds described merit further study as potential insecticides for control of T. palmi in greenhouses because of their generally lower toxicity to O. strigicollis and their greater activity as a fumigant than dichlorvos.

The toxicity of cade oil (Juniperus oxycedrus), its constituents and structurally related compounds toward adult house dust mite Dermatophagoides farina was examined. Results were compared with two commercially available acaricides, benzyl benzoate and deet. The cade oil constituents were identified by GC-MS analysis. Citral (LC50, 1.13 μg cm–2) and methyleugenol (LC50, 5.78 μg cm–2) were the most toxic compounds, followed by eugenol (LC50,12.52 μg cm–2), nerol (LC50, 21.4 μg cm–2) and terpinen-4-ol (LC50, 29.55 μg cm–2) were shown significant mortality against adult of D. farina. Toxicity of citral, methyleugenol were higher than that of benzyl benzoate, and above listed compounds was all more toxic than deet. Given the result of vapour-phase mortality tests that these compounds were more toxic in closed containers than in open ones, we concluded that vapour action plays a great role in their mode of delivery. Cade applied as 3 and 4% experimental sprays provided 96 and 100% mortality against the mites respectively, whereas permethrin (cis:trans, 25:75) 2.5 g/l spray treatment resulted in 17% mortality. Cade oil, and its constituents shown their potentials as effective alternatives for harmful synthetic acaricides for the control of Dermatophagoides populations as fumigants in contact and therefore illustrated the need for further study of this essential oil.

Alzheimer’s disease (AD) is the most common type of presenile and senile dementia. Human β-amyloid precursor cleavage enzyme (BACE-1) is a key enzyme responsible for amyloid plaque production. We assessed anti-BACE-1 and behavioral activities of curcuminoids from Curcuma longa, curcumin (CCN), demethoxycurcumin (DMCCN), and bisdemethoxycurcumin (BDMCCN) against AD fly models. Neuro-protective ability of curcuminoids was assessed using fly model system overexpressing BACE-1 and its substrate APP in compound eyes and entire neurons. BDMCCN has the strongest inhibitory activity toward BACE-1 with 17 μM IC50, which was 20 and 13 times lower than those of CCN and DMCCN respectively. Expression of APP/BACE-1 resulted in the progressive and measurable defects in morphology of eyes and locomotion. Supplementing diet with either 1 mM BDMCCN or CCN rescued APP/BACE1 expressing flies and kept them from developing both morphological and behavioral defects. Structural characteristics and hydrophobicity appear to play a role in determining inhibitory potency of curcuminoids on BACE-1.

An assessment is made of the anti-proliferative activity of cicada slough-derived materials against 10 human cancer cell lines, including PC-3 and DU145 prostate cancer cell lines, using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Results were compared with those of the commercially available anticancer agent with broad spectrum cisplatin. The ethanol extract of Cryptotympana spp. slough was proved to have anti-proliferative activity against A549 lung, AGS stomach, PC-3 and DU145 prostate, Hela cervix, HT-29 colon, MCF-7 breast, and SK-Hep-1 liver cancer cell lines except for Hep-2 larynx and SK-OV-3 ovary cancer cell lines. The biologically active constituent was characterized as the nonprotein α-amino acid theanine [2-amino-4-(ethylcarbamoyl)butyric acid] by spectroscopic analysis, including EI-MS and NMR. Theanine was isolated from the cicada slough as a new cytotoxic principle. Fifty percent inhibition concentration (IC50) values of the constituent against PC-3 was 6.52 μg/mL, respectively. The activity of theanine (IC50,6.52μg/mL) did not differ significantly from that of the anticancer agent cisplatin (IC50,7.39μg/mL) toward PC-3. In conclusion, further studies on the cicada slough-derived materials containing theanine as potential anticancer products or a lead molecule for the prevention or eradication from human prostate cancer.

Lung cancer caused by diverse changes in cells resulted by exposure to carcinogens found in tobacco smoke, the environment, or sequential accumulation of genetic changes to the normal epithelial cells of the lung. An assessment was made of the anti-proliferative activity of constituents from silkworm feces against 11 human cancer cell lines, including A549 and H727 lung cancer cell lines, using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. The ethanol extract of silkworm feces was proved to have anti-proliferative activity against all 11 species of human cancer cell lines. The biologically active constituent was characterized as vomifoliol (blumenol A) (1) and stigmasterol (2) by spectroscopic analysis ,including MS and NMR. In conclusion, global efforts to reduce the level of antitcancer agents justify further studies on the silkworm feces-derived materials containing vomifoliol and stigmasterol as potential anticancer products or lead compounds for the prevention or eradication from human lung cancer.

The toxicity of bay leaf (Pimenta racemosa) and palmorasa (Cymbopogon martini) essential oils, and its constituents, and structurally related compounds to adult American house dust mites, Dermatophagoides farinae was examined. Both bay leaf (24 h LC50, 131.95 μg/cm2) and palmorosa (24 h LC50, 116.10 μg/cm2) essential oils were toxic to mites. The most active principles were determined to be citral, methyleugenol, eugenol, and geranyl acetate from both bay leaf and palmorosa oils. Citral (24 h LC50, 1.13 μg/cm2), methyl eugenol (5.78 μg/cm2), eugenol (24 h LC50, 12.52 μg/cm2) and geranyl acetate (24 h LC50, 18.79 μg/cm2) were the most toxic. The toxicity of these compounds was more toxic than that of commercially available acaricides such as, benzylbenzoate (LC50,8.41μg/cm2) and deet (37.67 μg/cm2). Potent toxicity was also observed with nerol, linalool and geraniol (LC50, 21.44–54.61 μg/cm2). These compounds were consistently more toxic in closed versus open containers, indicating that their mode of delivery was largely a result of vapour action. Both bay leaf and palmorosa oil, and their constituents shown their potentials as effective alternatives for harmful synthetic acaricides for the control of Dermatophagoides populations as fumigants in contact and therefore illustrated the need for further study of these essential oils.

An assessment was made of beta-site amyloid precursor protein (APP) cleaving enzyme (BACE1) inhibitory, feeding, climbing activities and lifespan of the diarylalkyls curcumin (CCN), demethoxycurcumin (DCCN) and bisdemethoxycurcumin (BDCCN) identified in the rhizomes of Curcuma longa. Based on IC50 values, BDCCN (0.024 mM) was the most inhibitory constituent, followed by DCCN (0.31 mM) and CCN (0.59 mM). Overall the three curcuminoids were significantly less inhibitory than BACE1 inhibitor IV isophthalamide (8.5 × 10-5 mM). The expression of human APP and BACE1 in compound eye of Drosophila melangaster presented rough abnormal ommatidial lattice. Co-expression of APP and BACE1 within the developing nervous system of drosophila showed climbing defects. These transgenic flies kept on media containing 1 mM of CCN and BDCCN were observed to ameliorate eye degeneration, significantly suppress locomotive dysfunctions, and increase media life time, as well as isophthalamide. CCN and BDCCN as human BACE1 inhibitory constituents may be used as potential therapeutics or lead molecules to develop Alzheimer's disease treatment drugs.

Inhibition of acetylcholinesterase (AChE) is one of the important modes of action available for the control of insects. An assessment was made of the electric eel AChE inhibitory activity of 55 endophytic fungi isolated from the leaves of Huperzia serrata collected in Eunshi, Hubei Province, China. Of 55 mycelial extracts and 55 ethyl acetate-soluble fractions from liquid culture of the fungi, the ethyl acetate-soluble fraction of strain ES056 exhibited strong AChE inhibitory activity (88%) at a concentration of 100 μg/mL. Based on morphological characteristics and nuclear ribosomal DNA ITS sequence analysis, this fungus showed greatest similarity to members of the order Eurotiales and was shown to be most closely related to members of the Aspergillus aculeatus group. It was designated Aspergillus sp. MY056. This strain merits further study as a potential anti-AChE product.

An assessment was made of the toxicity of hiba, Thujopsis dolabrata var. hondai, oil and 24 oil constituents and control efficacy of four experimental spray formulations containing the oil (0.5. 1, 2, and 3% sprays) to adult American house dust mite (AHDM), Dermatophagoides farinae, and copra mite (CM), Tyrophagus putrescentiae. Results were compared with those of three conventional acaricides benzyl benzoate, N,N-diethyl-3-methylbenzamide (deet), and permethrin. Based on 24 h LC50 values, (–)-thujopsene was the most toxic constituent against AHDM (9.82 μg/cm2) and CM (10.92 μg/cm2) and the toxicity of the compound was nearly identical to that of benzyl benzoate (9.33 and 10.14 μg/cm2). High toxicity was also observed with (–)-(E)-pinocarveol, carvacrol, (+)-terpinen-4-ol, β-thujaplicin, cedrol, α-terpineol, (+)-ledene, thymol, and 2,4-di-tert-butylphenol against both mite species (LC50, 11.92–19.19 and 12.49–22.97 μg/cm2). These constituents were more toxic than deet (LC50, 35.53 and 38.42 μg/cm2). Hiba applied as 2 and 3% sprays provided >95% mortality against both mite species, whereas permethrin (cis:trans, 25:75) 2.5 g/L spray treatment resulted in ca 11% mortality. Global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments justify further studies on hiba oil preparations containing the constituents described as potential contact-action fumigants or lead molecules for the control of mite populations.

The yellow fever mosquito, Aedes aegypti, is a vector for transmitting dengue fever and yellow fever. An assessment was made of the histopathological and molecular effects of pellitorine, an isobutylamide alkaloid, on third instar Ae. aegypti larvae. At 5 mg/L concentration of pellitorine, whole body of the treated larvae became dark in color, particularly damaged thorax and abdominal regions. Pellitorine targeted mainly on midgut epithelium and anal gills, indicating variably dramatic degenerative responses of the midgut through a sequential epithelial disorganization. The anterior and posterior midgut was entirely necrosed, bearing only gut lumen residues inside the peritrophic membranes. Pellitorine caused comprehensive damage of anal gill cells and branches of tracheole and the debris was found in hemolymph of anal gills. RT-PCR analysis indicates that the compound inhibited gene expression encoding V-type H+-ATPase and aquaporine 4 after treatment with 2.21 mg/L pellitorine. The results provide a fact that pellitorine merits further study as a potential larvicide with a specific target site or a lead molecule for the control of mosquito populations.

An assessment was made of the biological control potential of mud loaches, Misgurnus mizolepis, toward Culex pipiens molestus, in laboratory condition and septic tank and rainwater storage tank (RST) systems. Results were compared with those of temephos 20% emulsifiable concentrate (EC) and Bacillus thuringiensis israelensis (BTI). In the laboratory tests, all M. mizolepis survived on waters from the settling tank of aerobic septic tank (AST), sump tank of AST, and RST. However, all M. mizolepis died within 3 h after introduction in the settling tank and sump tank waters of anaerobic septic tank (AnAST). Gill or dorsal fin inflammation was detected in the dead mud loaches. M. mizolepis consumed an average of 968–1087, 901–986, and 993–1087 of 1500 third instars of Cx. p. molestus in AST settling tank, AST sump tank, and RST waters, respectively. In the AST and RST systems, predation of Cx. p. molestus by mud loaches at a release rate of 900 larvae/fish resulted in complete mosquito control from the first wk after treatment through the end of the survey period for 16 wk. The average mosquito reduction rates by temephos 20% EC and BTI treatments were 28.6 and 2.1% 2 wk post-treatment, respectively. Mud loaches merit further study as a potential biological control agent for the control of mosquito populations in light of global efforts to reduce the level of highly toxic synthetic insecticides in the aquatic environment.

The toxicity of materials derived from the seed of Pongamia pinnata to third instars of insecticide-susceptible Culex pipiens pallens and Aedes aegypti and wild Aedes albopictus was examined using a direct contact bioassay. Results were compared with those of the currently used insecticides fenthion and temephos. The active principles of Pongamia pinnata were identified as the karanjin (1), karanjachromene (2), pongamol (3), pongarotene (4), oleic acid (5), and palmitic acid (6) by spectroscopic analysis. Based on 24 h LC50 values, karanjin (14.61 and 16.13 mg/L) was the most toxic compound, followed by oleic acid (18.07 and 18.45 mg/L) and karanjachromene (18.74 and 20.57 mg/L). These constituents were less toxic than either fenthion (LC50, 0.0031 and 0.0048 mg/L) or temephos (0.021 and 0.050 mg/L) against Ae. aegypti and Cx. p. pallens. Low toxicity was produced by pongamol (LC50, 23.95 and 25.76 mg/L), pongarotene (25.52 and 37.61 mg/L), and palmitic acid (34.50 and 42.96 mg/L). Against A. alpopictus instars, oleic acid (LC50, 18.79 mg/L) was most toxic. Low toxicity was observed with the other five constituents (LC50, 35.26- 85.61 mg/L). P. pinnata seed-derived active principles, particularly karanjin, karanjachromene, and oleic acid, merits further study as potential mosquito larvicides for the control of mosquito populations in light of global efforts to reduce the level of highly toxic synthetic larvicides in the aquatic environment.

The toxicity of red pine needle hydrodistillate (RPN-HD), 19 RPN-HD constituents and 12 structurally related compounds and control efficacy of four experimental spray formulations containing RPN-HD (0.5. 1, 2 and 3% sprays) to adult Dermatophagoides farinae was evaluated. RPN-HD (24 h LC50,68.33 μg cm–2) was toxic. Menthol was the most toxic compound (12.69 μg cm–2) and the toxicity of this compound and benzyl benzoate did not differ significantly from each other. High toxicity was also produced by α-terpineol, bornyl acetate, geranyl acetate, thymol, linalyl acetate, terpinyl acetate, citral, linalool and camphor (18.79–36.51 μg cm–2). These compounds were more toxic than either deet or dibutyl phthalate. In vapour-phase mortality tests, these compounds were consistently more toxic in closed versus open containers, indicating that their mode of delivery was largely a result of vapour action. RPN-HD 3% experimental spray provided 95% mortality against adult D. farinae, whereas permethrin (cis:trans,25:75)2.5gL–1 spray treatment resulted in 0% mortality. In the light of global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments, RPN-HD and the compounds described merit further study as potential biocides for the control of Dermatophagoides populations as fumigants with contact action.