Green Synthesis, Characterization and Bioactivity of Mangifera indica Seed-Wrapped Zinc Oxide Nanoparticles.

In the realm of nanoparticles, metal-based nanoparticles have traditionally been regarded as the pioneering category. Compared to other nanoparticles, zinc oxide nanoparticles have several advantages, including optical and biological properties, which provide them a significant competitive advantage in clinical and biological applications. In the current investigation, we used an aqueous Mangifera indica seed extract to synthesize nanoparticles of zinc oxide (ZnO NPs). UV-Vis spectroscopy, Fourier transform infrared spectroscopy analysis, atomic force spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to characterize the synthesized ZnO NPs. The nanoparticles were assessed for their potential to inhibit bacterial growth and protect cells from free radical damage. According to the current study's findings, zinc oxide nanoparticles that had been modified with the aid of mango seeds were very efficient in preventing the development of the tested bacteria and were also powerful antioxidants.

Response of hepatic biochemical parameters and neurotoxicity to carbamazepine and ibuprofen in Oreochromis mossambicus.

Globally, the prevalence and pollution of pharmaceutical drugs in aquatic environments have been steadily increasing. This study sought to evaluate the effects of 14 days of exposure to environmental-relevant doses (ibuprofen 0.5, 5, and 50 µg/L, and carbamazepine 0.005, 1, and 10 µg/L) of the nonsteroidal anti-inflammatory drugs ibuprofen and carbamazepine in the freshwater fish Oreochromis mossambicus. The results showed a significant (P < 0.05) decrease in O. mossambicus superoxide dismutase, catalase, biotransformation enzymes, glutathione-s-transferase, glutathione peroxidase, oxidative stress lipid peroxidation, protein carbonyl activity, cellular damage metallothionine, reduced glutathione, immunological activities, and respiratory burst activity. Consequently, the acquired data revealed that O. mossambicus treated with ibuprofen and carbamazepine shows more significant alterations in metabolic depression, biochemical parameters, and oxidative stress. In addition, increased neurotoxic effects were observed in ibuprofen and carbamazepine treated O. mossambicus.

ß-1,3-Glucan binding protein-based silver nanoparticles enhance the wound healing potential and disease resistance in Oreochromis mossambicus against Aeromonas hydrophilla.

Here we attempted to synthesize ß-1,3-glucan binding protein-based silver nanoparticles (Phß-GBP-AgNPs) and evaluate its wound healing and disease resistance prompting ability in Oreochromis mossambicus. Using a column chromatography technique, an immune molecule, Phß-GBP was purified from the haemolymph of rice field crab, Paratelphusa hydrodromus. Phß-GBP-AgNPs were synthesized and described through SDS-PAGE, UV-vis spectroscopy, HR-TEM, XRD and FTIR analysis. HR-TEM revealed that the synthesized Phß-GBP-AgNPs were spherical with a 20-40 nm size range and the particles were not aggregated. Wound and infection were experimentally generated in O. mossambicus and treated with Phß-GBP, chem-AgNPs and Phß-GBP-AgNPs for 20 days. The immune parameters (peroxidase, lysozyme and protease) and antioxidant enzymes (SOD and catalase) were examined in the serum of experimental fish. Phß-GBP-AgNPs elevated the immune and antioxidant enzymes during the healing process and enhanced the wound healing percentage in fish than Phß-GBP and chem-AgNPs. The immune parameters and antioxidant enzymes were declined in the serum of fish (treated with Phß-GBP-AgNPs) after the mid-period of wound healing. Compared to others, relative percentage survival was increased in experimentally wounded and infected fish treated with Phß-GBP-AgNPs against Aeromonas hydrophila. Moreover, Phß-GBP-AgNPs exhibited less toxicity towards Artemia salina than chem-AgNPs during 24 h exposure period. As a result, Phß-GBP-AgNPs may act as an alternative to commercial antibiotics and be considered an effective immunostimulant in treating skin lesions in intensive farming.

Molecular interaction analysis of ß-1, 3 glucan binding protein with Bacillus licheniformis and evaluation of its immunostimulant property in Oreochromis mossambicus.

Analyzing the health benefits of any two immunostimulants (synbiotics) in combined form and information on their interactions gain more visibility in the usage of synbiotics in aquafarms. With this intention, the current work explores the immunostimulant effect and structural interaction of synbiotic (ß-1, 3 glucan binding protein from marine crab, Portunus pelagicus (Ppß-GBP) and Bacillus licheniformis) on Oreochromis mossambicus. The experimental diet was prepared with Ppß-GBP and B. licheniformis, and nourished to the fingerlings of O. mossambicus for 30 days. After the experimental trial, a higher growth rate and immune reactions (lysozyme, protease, myeloperoxidase and alkaline phosphatase activity) were noticed in the fish nourished with synbiotic (B. licheniformis and Ppß-GBP) enriched diet. Moreover, the synbiotic enriched diet elevated the antioxidant responses like glutathione peroxidase (GSH-Px) and catalase (CAT) activity in the experimental diet-nurtured fish. At the end of the feed trial, synbiotic diet nourished fish shows an increased survival rate during Aeromonas hydrophila infection, reflecting the disease resistance potential of experimental fish. Also, the interaction between Ppß-GBP and Bacillus licheniformis was analyzed through computational approaches. The results evidenced that, Ppß-GBP interacts with the B. licheniformis through sugar-based ligand, ß-glucan through a hydrogen bond with a good docking score. Thus, the synbiotic diet would be an effective immunostimulant to strengthen the fish immune system for better productivity.

Synthesis and physicochemical characteristics of Ag-doped hydroxyapatite nanoparticles, and their potential biomedical applications.

In this present scenario, hydroxyapatite (HAp) nanostructures were synthesized through green routes for biomedical applications, particularly remediation towards human pathogens and cancer cells. The present study aims at forming non-toxic and eco-friendly silver (Ag+) doped HAp using Polyethylene glycol (PEG), Cetyl Trimethyl ammonium bromide (CTAB) and curcumin. Ag+ doped HAp nanoparticles (NPs) were prepared by the sol-gel method with a cube and rod-like morphology. Ag-HApNPs showed a sharp and well-defined diffraction peak, which possesses the hexagonal crystalline structure with space group P63/m. The Fourier-transform infrared spectroscopy and Raman spectra confirmed the formation of Ag-HApNPs, and the bandgap values were obtained using UV-DRS analysis. The Ag-HApNPs with PEG, CTAB and curcumin might be fabricated materials were examined against antibacterial, antifungal, antioxidant, and cytotoxic activities, which provided exemplary biomedical applications. Overall, Ag-HApNPs can be used as potential drug delivery and perspectives to control multidrug-resistant pathogens.

Azadirachta indica-wrapped copper oxide nanoparticles as a novel functional material in cardiomyocyte cells: An ecotoxicity assessment on the embryonic development of Danio rerio.

This research reports on the production of copper oxide nanoparticles (CuO NPs) through the green synthesis method using Azadirachta indica (Ai) flower extract. Synthesized Ai-CuO NPs are characterized by Zeta Potential, TGA, SEM and TEM analysis. The Ai-CuO NPs gave a maximum peak at 270 nm. As per XRD studies, the Ai-CuO NPs obtained were crystalline. FTIR spectrum Ai-CuO NPs showed the presence of functional groups like the O-H group, aromatic group, etc. TEM and SEM assist in investigating the size and morphology of the Ai-CuO NPs, which were spherical and varied in size between 10.11 nm and 17.54 nm. EDAX showed that Ai-CuO NPs were pure with no impurities. The synthesized Ai-CuO NPs were then analyzed for their cytotoxicity at various concentrations (5, 10, 20, 30, 40 and 50 µg/mL) against H9c2 cardiomyocyte cells using MTT assay. DOX-induced H9c2 cell damage of apoptosis and ROS. The nanoparticle formed by Ai-CuO was cured with different concentrations (5, 10 and 20 µg/mL). In zebrafish, 48 hpf and 72 hpf were measured at 75 µM to reduce dysfunction and mortality during organ development. These results can have a beneficial impact on eco-toxicological effects.

Antibiofilm and anticancer potential of ß-glucan-binding protein-encrusted zinc oxide nanoparticles.

ß-Glucan-binding protein (ßGBP) is important for the rational expansion of molecular biology. Here, zinc oxide nanoparticle (ZnONP) was synthesized using ßGBP from the crab Scylla serrata (Ss-ßGBP-ZnONP). Ss-ßGBP-ZnONP was observed as a 100 kDa band on sodium dodecyl sulfate polyacrylamide gel and characterized with UV-vis spectroscopy at 350 nm. X-ray diffraction analysis displayed values consistent with those for zincite. Fourier transform infrared spectroscopy revealed the presence of functional groups, including amide, alcohol, alkane, alkyl halide, and alkene groups. The zeta potential (-5.36 mV) of these particles indicated their stability, and transmission electron microscopy revealed the presence of 50 nm nanocones. Ss-ßGBP-ZnONPs were tested at 100 µg/mL against the gram-positive Enterococcus faecalis and gram-negative Pseudomanas aeruginosa using confocal laser scanning microscopy and the bacterial viability assay was also performed. The growth of MCF7 breast cancer cells was inhibited following treatment with 75 µg/mL Ss-ßGBP-ZnONPs. Thus, Ss-ßGBP-ZnONPs have the ability to control the growth of pathogenic bacteria and inhibit the viability of MCF7 breast cancer cell lines.

Isolation of ß-glucan from Eleusine coracana and its antibiofilm, antidiabetic, antioxidant, and biocompatible activities.

Eleusine coracana (Finger millet) has high nutritional value with numerous health benefits and is of low cost. Isolation of beta-glucan (ßG) from E. coracana (Ec-ßG) has gained increasing research attention. UV-vis spectroscopy used to measure the surface plasmon resonance at 361 nm to confirm the presence of polysaccharides (glucan molecules) in Ec-ßG. X-ray diffraction analysis of Ec-ßG displayed a crystalline nature and confirmed the presence of the ßG molecule. Further, the bioactive compounds of Ec-ßG were screened using gas chromatography-mass spectrometry. The antibacterial activity of Ec-ßG against both Gram-positive (Lysinibacillus fusiformis, Enterococcus faecalis) and Gram-negative (Proteus vulgaris, Shigella sonnei) bacteria were assessed through minimum inhibitory concentrations <70 µg/ml of Ec-ßG. In addition, the antibiofilm activity and bacterial viability of Ec-ßG at 100 µg/ml was confirmed by light and confocal laser scanning microscopy. Furthermore, Ec-ßG inhibits α-amylase and α-glucosidase at an IC50 -value of 1.23 and 1.42 µg/ml, respectively. Superoxide anion scavenging activity at IC50-1.4 µg/ml and DPPH radical scavenging activity at IC50-1.2 µg/ml showed that Ec-ßG had potential antioxidant property. The in vitro hemolysis assay for biocompatibility of Ec-ßG at 200 µg/ml showed 0.06 ± 0.09%. Therefore, Ec-ßG has the potential to act as a suggestive agent for antibacterial, antidiabetic, and antioxidant activity.

ß-glucan extracted from eukaryotic single-celled microorganism Saccharomyces cerevisiae: Dietary supplementation and enhanced ammonia stress tolerance on Oreochromis mossambicus.

Ammonia is a widespread pollutant that is toxic to living organisms in aquaculture. This study aimed to evaluate the effects of a diet supplemented with beta-glucan from yeast, Saccharomyces cerevisiae (Sc-ßG), on the stress response of Oreochromis mossambicus (Tilapia) to ammonia. Fish were divided into four groups, including a control fed a basal diet and three experimental groups fed diets supplemented with Sc-ßG at 2, 5 and 10 mg/g respectively. After 8 weeks, experimental groups were exposed to ammonia at 100 mg L-1 for 1 week. Growth was measured after the 8-week feeding trial and serum, mucus, and liver tissue were sampled before and after the ammonia challenge. Compared with the control diet, feed supplemented with Sc-ßG at 10 mg/g significantly (p < 0.05) improved growth performance (7.8-9.9 g increase in weight). The cellular immune responses (myeloperoxidase, reactive oxygen species, and reactive nitrogen species), humoral immune responses (alkaline phosphatase, lysozyme, and peroxidase inhibition), and antioxidant response (catalase, superoxide dismutase, and glutathione) were tested in serum, mucus and liver tissue. Compared with the control, these responses were significantly (p < 0.05) enhanced at 10 mg/g supplementation with Sc-ßG. This study demonstrates that Sc-ßG may be applied to induce stress tolerance and improve growth performance in aquaculture.

Impact of pesticide monocrotophos on microbial populations and histology of intestine in the Indian earthworm Lampito mauritii (Kinberg).

Soil contamination has enlarged over the decades due to intensive use of pesticides and chemical fertilizers in agronomy. Earthworms are significant organisms in the soil community. Earthworms are the major role in soil fertility in most ecological system and the production of biogenic structures. Moreover, earthworm gut mucus enhances the beneficial soil microorganism potential biological activities. They are used as model organisms for assessing the ecological risks of chemicals. Enrichment of essential nutrients in soil through earthworm is a cost-effective and eco-friendly approach. In India, the organophosphorus pesticide monocrotophos is commonly used to control agricultural pests. Hence, it is important to study the effect of monocrotophos on the gut microbiota in Lampito mauritii. A 15-day exposure to a low (1/10th of the LC50 after 96 h i.e., 0.093 ppm kg-1) and high sublethal concentration (1/3rd of the LC50 after 96 h i.e., 0.311 ppm kg-1) of monocrotophos led to reduced proliferation of the gut microbiota in L. mauritii. However, exposure for 30 days led to a recuperation of the microbial populations to near control values. Among the eight bacterial and five fungal species that inhabit the gut of L. mauritii, only six bacterial and three fungal species were able to survive after exposure to monocrotophos. In addition to the study, histopathological changes were observed in the intestine of L.mauritii after application of lower sublethal concentration of monocrotophos. Severe pathological changes such as vacuolization, degenerated nuclei, damaged villi and congestion of the blood sinuses were noticed in the intestine on 1st and, 5th day of the experiment. But in 30th day the damages were slowly recovered due to degradation of monocrotophos by the presence of some pesticides degrading bacterial and fungal species and regenerative capability of chloragogen cells in the intestine. The results suggested that reduced microbial populations and pathological damages in intestine were observed during the application of monocrotophos. So, the monocrotophos have several harmful impacts on earthworms.

Synthesis of chitosan-alginate microspheres with high antimicrobial and antibiofilm activity against multi-drug resistant microbial pathogens.

The successful treatment of multi-drug resistant microbial pathogens represents a major challenge for public health management. Here, chitosan-alginate (CS/ALG) microspheres with narrow size distribution were fabricated by ionically cross linking method using Ca2+ ions as agents for polymer solidification. The physicochemical properties of CS/ALG microspheres, such as surface morphology and size, were studied by SEM. The functional group interactions were confirmed by Fourier transform infrared (FTIR) spectroscopy. SEM revealed that the CS/ALG microspheres were spherical in shape with smooth surfaces, size was 50-100 µm. The synthesized CS/ALG microspheres showed antibacterial and antibiofilm activity on bacteria of public health relevance. CS/ALG microspheres exhibited antibacterial activity at the concentration of 5-20 µg, with significant inhibitory zones on multiple antibiotic resistant pathogens, including Gram positive Staphylococcus aureus, Enterococcus faecalis, and Gram negative Pseudomonas aeruginosa and Proteus vulgaris. Furthermore, in situ light microscopy and confocal laser scanning microscopy (CLSM) showed that CS/ALG microspheres inhibited the bacterial biofilm formation in S. aureus, E. faecalis P. aeruginosa and P. vulgaris after a single treatment with 40 µg. Overall, our findings underlined that chemically synthesized CS/ALG biomaterial has high antibacterial and antibiofilm activity against a number of microbial pathogens of interest for human health, thus this synthesis route can be further exploited for drug development in current biomedical science.

Insecticidal activity of camphene, zerumbone and α-humulene from Cheilocostus speciosus rhizome essential oil against the Old-World bollworm, Helicoverpa armigera.

The fast-growing resistance development to several synthetic and microbial insecticides currently marketed highlighted the pressing need to develop novel and eco-friendly pesticides. Among the latter, botanical ones are attracting high research interest due to their multiple mechanisms of action and reduced toxicity on non-target vertebrates. Helicoverpa armigera (Lepidoptera: Noctuidae) is a key polyphagous insect pest showing insecticide resistance to several synthetic molecules used for its control. Therefore, here we focused on the rhizome essential oil extracted from an overlooked Asian plant species, Cheilocostus speciosus (J. Konig) C. Specht (Costaceae), as a source of compounds showing ingestion toxicity against H. armigera third instar larvae, as well as ovicidal toxicity. In acute larvicidal assays conducted after 24h, the C. speciosus essential oil achieved a LC50 value of 207.45µg/ml. GC and GC-MS analyses highlighted the presence of zerumbone (38.6%), α-humulene (14.5%) and camphene (9.3%) as the major compounds of the oil. Ingestion toxicity tests carried out testing these pure molecules showed LC50 values of 10.64, 17.16 and 20.86µg/ml, for camphene, zerumbone and α-humulene, respectively. Moreover, EC50 values calculated on H. armigera eggs were 35.39, 59.51 and 77.10µg/ml for camphene, zerumbone and α-humulene, respectively. Overall, this study represents the first report on the toxicity of C. speciosus essential oil against insect pests of agricultural and medical veterinary importance, highlighting that camphene, zerumbone and α-humulene have a promising potential as eco-friendly botanical insecticides.

Larvicidal activity of Blumea eriantha essential oil and its components against six mosquito species, including Zika virus vectors: the promising potential of (4E,6Z)-allo-ocimene, carvotanacetone and dodecyl acetate.

The effective and environmentally sustainable control of mosquitoes is a challenge of essential importance. This is due to the fact that some invasive mosquitoes, with special reference to the Aedes genus, are particularly difficult to control, due to their high ecological plasticity. Moreover, the indiscriminate overuse of synthetic insecticides resulted in undesirable effects on human health and non-target organisms, as well as resistance development in targeted vectors. Here, the leaf essential oil (EO) extracted from a scarcely studied plant of ethno-medicinal interest, Blumea eriantha (Asteraceae), was tested on the larvae of six mosquitoes, including Zika virus vectors. The B. eriantha EO was analyzed by GC and GC-MS. The B. eriantha EO showed high toxicity against 3rd instar larvae of six important mosquito species: Anopheles stephensi (LC50=41.61 µg/ml), Aedes aegypti (LC50=44.82 µg/ml), Culex quinquefasciatus (LC50 =48.92 µg/ml), Anopheles subpictus (LC50=51.21 µg/ml), Ae. albopictus (LC50=56.33 µg/ml) and Culex tritaeniorhynchus (LC50=61.33 µg/ml). The major components found in B. eriantha EO were (4E,6Z)-allo-ocimene (12.8%), carvotanacetone (10.6%), and dodecyl acetate (8.9%). Interestingly, two of the main EO components, (4E,6Z)-allo-ocimene and carvotanacetone, achieved LC50 lower than 10 µg/ml on all tested mosquito species. The acute toxicity of B. eriantha EO and its major constituents on four aquatic predators of mosquito larval instars was limited, with LC50 ranging from 519 to 11.431 µg/ml. Overall, the larvicidal activity of (4E,6Z)-allo-ocimene and carvotanacetone far exceed most of the LC50 calculated in current literature on mosquito botanical larvicides, allowing us to propose both of them as potentially alternatives for developing eco-friendly mosquito control tools.

Toxicity of herbal extracts used in ethno-veterinary medicine and green-encapsulated ZnO nanoparticles against Aedes aegypti and microbial pathogens.

Dengue and chikungunya are arboviral diseases mainly vectored by the mosquito Aedes aegypti. Presently, there is no treatment for these viral diseases and their prevention is still based on vector control measures. Nanopesticides fabricated using herbal extracts as reducing and capping agents currently represent an excellent platform for pest control. In this scenario, the present study assessed the acute toxicity of seven plants employed in ethno-veterinary medicine of southern India, as well as the green synthesis of zinc oxide nanoparticles, on third-instar larvae of A. aegypti. Larvae were exposed to extracts of the seven plants obtained with solvents of different polarity (acetone, ethanol, petroleum ether, and water) for 24 h. Maximum efficacy was observed for Lobelia leschenaultiana leaf extracts prepared using all the four solvent extracts (LC50 = 22.83, 28.12, 32.61, and 36.85 mg/L, respectively). Therefore, this plant species was used for the synthesis and stabilization of ZnO nanoparticles based on its maximum efficacy against third-instar larvae of A. aegypti. L. leschenaultiana-encapsulated ZnO nanoparticles showed 100% mortality when tested at 10 mg/L, the LC50 was extremely low,  1.57 mg/L. Zinc acetate achieved only 65.33% when tested at 60 mg/L, with a LC50 of 51.62 mg/L. Additionally, ZnO nanoparticles inhibited growth of Pseudomonas aeruginosa, Proteus vulgaris, Shigella sonnei, and Vibrio parahaemolyticus and also inhibited biofilm formation on selected microbila pathogens, showing impact on EPS production and hydrophobicity. Overall, our results suggest that L. leschenaultiana-fabricated ZnO nanoparticles have a significant potential to control A. aegypti mosquitoes and Gram-negative bacterial pathogens.

Toxicity of ar-curcumene and epi-ß-bisabolol from Hedychium larsenii (Zingiberaceae) essential oil on malaria, chikungunya and St. Louis encephalitis mosquito vectors.

Mosquitoes act as vectors of key pathogens and parasites. Plant essential oils have been recognized as important sources of biopesticides, which do not induce resistance and have limited toxic effects on human health and non-target organisms. In this research, we evaluated the larvicidal and oviposition deterrence activity of Hedychium larsenii essential oil (EO) and its major compounds ar-curcumene and epi-ß-bisabolol. Both molecules showed high toxicity against early third instars of Anopheles stephensi (LC50=10.45 and 14.68µg/ml), Aedes aegypti (LC50=11.24 and 15.83µg/ml) and Culex quinquefasciatus (LC50=12.24 and 17.27µg/ml). In addition, low doses of ar-curcumene and epi-ß-bisabolol were effective as oviposition deterrents against the three tested mosquito species. Notably, the acute toxicity of H. larsenii oil and its major compounds against the mosquito biocontrol agent Poecilia reticulata was low, with LC50 higher than 1500ppm. Overall, the results from this study revealed that ar-curcumene and epi-ß-bisabolol from the H. larsenii oil can be considered for the development of novel and effective mosquito larvicides.

Green synthesis of silver, gold and silver/gold bimetallic nanoparticles using the Gloriosa superba leaf extract and their antibacterial and antibiofilm activities.

The green fabrication of metal nanoparticles using botanical extracts is gaining increasing research attention in nanotechnology, since it does not require high energy inputs or the production of highly toxic chemical byproducts. Here, silver (Ag), gold (Au) and their bimetallic (Ag/Au) nanoparticles (NPs) were green synthesized using the Gloriosa superba aqueous leaf extract. Metal NPs were studied by spectroscopic (UV-visible spectroscopy, fluorescence spectroscopy, FT-IR spectroscopy, XRD and EDX) and microscopic (AFM and TEM) analysis. AFM and TEM showed that Ag and Au NPs had triangular and spherical morphologies, with an average size of 20 nm. Bimetallic Ag/Au NPs showed spherical shapes with an average size of 10 nm. Ag and Ag/Au bimetallic NPs showed high antibacterial and antibiofilm activities towards Gram-positive and Gram-negative bacteria. Overall, the proposed synthesis route of Ag, Au and Ag/Au bimetallic NPs can be exploited by the pharmaceutical industry to develop drugs effective in the fight against microbic infections.

Green synthesis and characterization of silver nanoparticles fabricated using Anisomeles indica: Mosquitocidal potential against malaria, dengue and Japanese encephalitis vectors.

Mosquitoes (Diptera: Culicidae) represent a key threat for millions of people worldwide, since they act as vectors for devastating parasites and pathogens. In this scenario, eco-friendly control tools against mosquito vectors are a priority. Green synthesis of silver nanoparticles (AgNP) using a cheap, aqueous leaf extract of Anisomeles indica by reduction of Ag(+) ions from silver nitrate solution has been investigated. Bio-reduced AgNP were characterized by UV-visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDX) and X-ray diffraction analysis (XRD). The acute toxicity of A. indica leaf extract and biosynthesized AgNP was evaluated against larvae of the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus and the Japanese encephalitis vector Culex tritaeniorhynchus. Both the A. indica leaf extract and AgNP showed dose dependent larvicidal effect against all tested mosquito species. Compared to the leaf aqueous extract, biosynthesized AgNP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with LC50 values of 31.56, 35.21 and 38.08 µg/mL, respectively. Overall, this study firstly shed light on the mosquitocidal potential of A. indica, a potential bioresource for rapid, cheap and effective AgNP synthesis.

α-Humulene and ß-elemene from Syzygium zeylanicum (Myrtaceae) essential oil: highly effective and eco-friendly larvicides against Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus (Diptera: Culicidae).

Mosquitoes transmit serious pathogens and parasites to humans and animals, including malaria, dengue, Japanese encephalitis and filariasis. The extensive use of chemical pesticides leads to the development of resistance in mosquito vector populations and serious non-target effects on human health and the environment. Myrtaceae plants can be a useful reservoir of natural products effective against Culicidae young instars. In this research, we evaluated the mosquitocidal potential of the essential oil (EO) from Syzygium zeylanicum leaves against larvae of three mosquitoes of medical and veterinary importance, the malaria vector Anopheles subpictus, the dengue vector Aedes albopictus, and the Japanese encephalitis vector Culex tritaeniorhynchus. The chemical composition of the EO was analyzed by gas chromatography-mass spectroscopy. GC-MS revealed that the S. zeylanicum EO contained at least 18 compounds. The major chemical components were α-humulene (37.8.5 %) and ß-elemene (10.7 %). The EO had a significant toxic effect against early third-stage larvae of An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus, with LC50 values of 83.11, 90.45, and 97.96 µg/ml, respectively. The two major constituents extracted from the S. zeylanicum EO were tested individually for acute toxicity against larvae of the three mosquito vectors. α-Humulene and ß-elemene appeared highly effective against An. subpictus (LC50 = 6.19 and 10.26 µg/ml, respectively), followed by Ae. albopictus (LC50 = 6.86 and 11.15 µg/ml) and Cx. tritaeniorhynchus (LC50 = 7.39 and 12.05 µg/ml). Furthermore, the EO and its major components was safe towards the non-target fish Gambusia affinis; LC50 values were 20374.26, 1024.95, and 2073.18 µg/ml, respectively for EO, α-humulene and ß-elemene. Overall, this study highlighted that the acute toxicity of S. zeylanicum EO towards mosquito larvae was mainly due to the presence of α-humulene and ß-elemene. Furthermore, we pointed out the concrete possibility to exploit these two compounds from S. zeylanicum EO as highly effective larvicides against young instars of An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus, with little effect on non-target organisms.

Artemisia absinthium-borne compounds as novel larvicides: effectiveness against six mosquito vectors and acute toxicity on non-target aquatic organisms.

The eco-friendly control of mosquito vectors is a crucial challenge of public health importance. Here we evaluated the larvicidal potential of Artemisia absinthium essential oil (EO) and its three major chemical constituents against six mosquito vectors: Anopheles stephensi, Anopheles subpictus, Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Culex tritaeniorhynchus. The EO was obtained by leaf hydro-distillation. Its chemical composition was analyzed using gas chromatography-mass spectrometry. Major components were (E)-ß-farnesene (31.6 %), (Z)-en-yn-dicycloether (11.12 %), and (Z)-ß-ocimene (27.8 %). The EO was toxic effect against larval populations of An. stephensi, An. subpictus, Ae. aegypti, Ae. albopictus, Cx. quinquefasciatus, and Cx. tritaeniorhynchus, with LC50 values of 41.85, 52.02, 46.33, 57.57, 50.57, and 62.16 µg/ml. (E)-ß-farnesene, (Z)-en-yn-dicycloether, and (Z)-ß-ocimene were highly effective on An. stephensi (LC50 = 8.13, 16.24 and 25.84 µg/ml) followed by An. subpictus (LC50 = 10.18, 20.99, and 30.86 µg/ml), Ae. aegypti (LC50 = 8.83,17.66, and 28.35 µg/ml), Ae. albopictus (LC50 = 11.38,23.47, and 33.72 µg/ml), Cx. quinquefasciatus (LC50 = 9.66, 19.76, and 31.52 µg/ml), and Cx. tritaeniorhynchus (LC50 = 12.51,25.88, and 37.13 µg/ml). Notably, the EO and its major compounds were safer to the non-target organisms Chironomous circumdatus, Anisops bouvieri and Gambusia affinis, with LC50 values ranging from 207.22 to 4385 µg/ml. Overall, our results highlight that (E)-ß-farnesene, (Z)-en-yn-dicycloether, and (Z)-ß-ocimene from the A. absinthium EO represent promising eco-friendly larvicides against six key mosquito vectors with moderate toxicity against non-target organisms.

Facile biosynthesis of silver nanoparticles using Barleria cristata: mosquitocidal potential and biotoxicity on three non-target aquatic organisms.

Mosquitoes (Diptera: Culicidae) act as vectors of important pathogens and parasites, such as malaria, dengue, chikungunya, Japanese encephalitis and lymphatic filariasis. The use of synthetic mosquitocides often leads to high operational costs and adverse non-target effects. Recently, plant-borne compounds have been proposed for rapid extracellular biosynthesis of mosquitocidal nanoparticles. However, the impact of these nanomosquitocides against biological control agents of mosquito larval populations has been poorly studied. In this research, we biosynthesized silver nanoparticles (Ag NP) using the Barleria cristata leaf extract as a reducing and stabilizing agent. The biosynthesis of Ag NP was confirmed analyzing the excitation of surface plasmon resonance using ultraviolet-visible (UV-vis) spectrophotometry. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed the clustered and irregular shapes of Ag NP. The presence of silver was confirmed by energy-dispersive X-ray (EDX) spectroscopy. Fourier transform infrared (FTIR) spectroscopy investigated the identity of secondary metabolites, which may also act as Ag NP capping agents. The acute toxicity of B. cristata leaf extract and biosynthesized Ag NP was evaluated against larvae of Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus. Compared to the leaf aqueous extract, biosynthesized Ag NP showed higher toxicity against An. subpictus, Ae. albopictus, and Cx. tritaeniorhynchus with lethal concentration (LC)50 values of 12.46, 13.49, and 15.01 µg/mL, respectively. Notably, biosynthesized Ag NP were found safer to non-target organisms Diplonychus indicus, Anisops bouvieri, and Gambusia affinis, with respective LC50 values ranging from 633.26 to 866.92 µg/mL. Overall, our results highlight that B. cristata-fabricated Ag NP are a promising and eco-friendly tool against young instar populations of mosquito vectors of medical and veterinary importance.