Bioactive components in Psidium guajava extracts elicit biotoxic attributes and distinct antioxidant enzyme modulation in the larvae of vectors of lymphatic filariasis and dengue.

Control of mosquito vectors, which have caused a global disease burden, has employed various methods. However, the challenges posed by current physical and chemical methods have raised concerns about vector control programs, leading to the search for alternative methods that are less toxic, eco-friendly, and cost-effective. This study investigated the larvicidal potential of aqueous, methanol, and ethylacetate extracts of Guava (Psidium guajava) against Aedes aegypti and Culex quinquefasciatus larvae. Functional group and phytochemical characterization were performed using Fourier-Transform Infrared Spectroscopy (FTIR) and GC-MS analysis to identify the bioactive compounds in the extracts. Larval bioassays were conducted using WHO standard procedures at concentrations of 12.5, 25, 50, 125, and 250 mg/L, and mortality was recorded after 24, 48, and 72 h. Additionally, antioxidant enzyme profiles in the larvae were studied. All of the solvent extracts showed larvicidal activity, with the methanol extract exhibiting the highest mortality against Ae. aegypti and Cx. quinquefasciatus larvae, followed by aqueous and ethylacetate extracts. FTIR spectroscopic analysis revealed the presence of OH, C-H of methyl and methylene, CO and CC. The GC-MS analysis indicated that the methanol, aqueous, and ethylacetate extracts all had 27, 34, and 43 phytoactive compounds that were effective at causing larvicidal effects, respectively. Different concentrations of each extract significantly modulated the levels of superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione in larvae. This study's findings indicate the potential for developing environmentally friendly vector control products using the bioactive components of extracts from P. guajava leaves.

Silver nanoparticles strengthen Zea mays against toxic metal-related phytotoxicity via enhanced metal phytostabilization and improved antioxidant responses.

This study investigated the phytostabilization and plant-promoting abilities of silver nanoparticles (AgNPs). Twelve Zea mays seeds were planted in water and AgNPs (10, 15 and 20 mg mL-1) irrigated soil for 21 days on soil containing 0.32 ± 0.01, 3.77 ± 0.03, 3.64 ± 0.02, 69.91 ± 9.44 and 13.17 ± 0.11 mg kg-1 of As, Cr, Pb, Mn and Cu, respectively. In soil treated with AgNPs, the metal contents were reduced by 75%, 69%, 62%, 86%, and 76%. The different AgNPs concentrations significantly reduced accumulation of As, Cr, Pb, Mn, and Cu in Z. mays roots by 80%, 40%, 79%, 57%, and 70%, respectively. There were also reductions in shoots by 100%, 76%, 85%, 64%, and 80%. Translocation factor, bio-extraction factor and bioconcentration factor demonstrated a phytoremediation mechanism based on phytostabilization. Shoots, roots, and vigor index improved by 4%, 16%, and 9%, respectively in Z. mays grown with AgNPs. Also, AgNPs increased antioxidant activity, carotenoids, chlorophyll a and chlorophyll b by 9%, 56%, 64%, and 63%, respectively, while decreasing malondialdehyde contents in Z. mays by 35.67%. This study discovered that AgNPs improved the phytostabilization of toxic metals while also contributing to Z. mays' health-promoting properties.

Enhanced phytoremediation strategies, which use nanoparticles to boost and facilitate the phytoremediation capacity of plants, are being recommended due to the limitations of traditional phytoremediation employing hyperaccumulating plants alone. Nanoparticles enhance phytoremediation potentials by directly reducing phytoavailable pollutants and promoting plant growth. Silver nanoparticles (AgNPs) are recognized as possessing the ability to enhance the phytoremediation of heavy metals HMs by converting them to a less toxic form and immobilizing the remaining phytoavailable HMs. This is in addition to their potential to modify plant biochemical and physiological properties to counteract HM toxicity.

An overview of biogenic metallic nanoparticles for water treatment and purification: the state of the art.

The environment is fundamental to human existence, and protecting it from dangerous contaminants should be a top priority for all stakeholders. Reducing garbage output has helped, but as the world's population grows, more waste will be generated. Tons of waste inadvertently and advertently received by environmental matrixes adversely affect the sustainable environment. The pollution caused by these activities affects the environment and human health. Conventional remediation processes ranging from chemical, physical, and biological procedures use macroaggregated materials and microorganisms to degrade or remove pollutants. Undesirable limitations of expensiveness, disposal challenges, maintenance, and formation of secondary contaminants abound. Additionally, multiple stages of treatments to remove different contaminants are time-consuming. The need to avoid these limitations and shift towards sustainable approaches brought up nanotechnology options. Currently, nanomaterials are being used for environmental rejuvenation that involves the total degradation of pollutants without secondary pollution. As nanoparticles are primed with vast and modifiable reactive sites for adsorption, photocatalysis, and disinfection, they are more useful in remediating pollutants. Review articles on metallic nanoparticles usually focus on chemically synthesized ones, with a particular focus on their adsorption capacity and toxicities. Therefore, this review evaluates the current status of biogenic metallic nanoparticles for water treatment and purification.

Foliar application of silver nanoparticles differentially intervenes remediation statuses and oxidative stress indicators in Abelmoschus esculentus planted on gold-mined soil.

The study assessed the intervention of foliar application of silver nanoparticles (AgNPs) on heavy metal toxicity and phytoremediation status of Abelmoschus esculentus planted in gold-mined soil. The green synthesized AgNPs absorbed maximally at 425 nm, had an average particle size of 55 ± 2.3 nm and peaks at 3,443 and 1,636 cm-1. A. esculentus seeds were grown in gold-mined soil and its seedlings were wetted with water and different concentrations of AgNPs (0.75, 0.50 and 0.25 mg/mL). Foliar applications of AgNPs significantly improved percentage heavy metal remediation and reduced contamination intensity by 60% and 44%, respectively in A. esculentus. Heavy metals induced oxidative stress in A. esculentus wetted with water which manifested in the reduction of growth performance and photosynthetic pigments by 43% and 15% in that order. Significant overexpression of superoxide dismutase activity and malondialdehyde by 70% and 86%, respectively together with a significant reduction in carotenoid contents and antioxidant activity by 92% and 15%, respectively were obtained for A. esculentus in control. The intervention of foliar application considerably protected A. esculentus with improved physiology, enzymic and non-enzymic antioxidant activities. These results conclude that foliar application AgNPs beneficially mediated toxicities of heavy metals in plants. Novelty statementGold mining is an economic venture but contamination of ecological matrixes by heavy metals usually accompanies it. Farming on either an active or abandoned gold site can predispose residents to the toxicity of heavy metals. Therefore, remediation before or during cultivation is key to ensuring safety. Silver nanoparticles have proved effective in remediating heavy metals and improving biochemical activities in plants due to their intrinsic properties and adsorptive potentials.

Bioaccumulation of Silver and Impairment of Vital Organs in Clarias gariepinus from Co-Exposure to Silver Nanoparticles and Cow Dung Contamination.

This study reports the implications of silver nanoparticles (AgNPs) and cow-dung contamination on water quality and oxidative perturbations in antioxidant biomarkers in the exposed Clarias gariepinus. Sixteen samples of C. gariepinus were exposed to fresh-water, 0.75 mg/mL each of AgNPs, cow-dung and a mixture of AgNPs-cow dung dosed water for 10 days. Cow-dung significantly (p < 0.05) depleted dissolved oxygen (DO) and increased biochemical oxygen demand (BOD) by 14% and 75% respectively. The trends of abundance and bioaccumulation of Ag in C. gariepinus exposed to different treatments followed kidney > muscle > gill > liver, implying the kidney was the worst affected organ. The AgNPs significantly (p < 0.05) perturbed vital organs in C. gariepinus by altering activities of antioxidant biomarkers, whereas AgNPs-cow dung had reduced perturbations implying organic matter bound Ag+ to reduce toxicity. These results conclude that AgNPs posed a challenging environment for C. gariepinus to thrive.

Silver Nanoparticles-Cow Dung Combination Disrupts Physiology, Enzyme Activities with Corresponding Increased Oxidative Stress and Heavy Metal Accumulation in Abelmoschus esculentus.

The effects of a silver nanoparticles (AgNPs)-cow-dung combination on Abelmoschus esculentus physiology, enzyme activities, heavy metal bioaccumulation, and micronutrients were investigated. A. esculentus seedlings were nurtured with foliar application of water, 0.75 mg/L each of AgNPs, cow-dung and AgNPs-cow dung till maturity. AgNPs-cow dung inhibited root and shoot lengths by 12.9% and 24.8%, respectively as opposed to elongation recorded for individual application compared to the control. In contrast to the promotion of photosynthesis, enzyme and antioxidant activities by individual applications, AgNPs-cow dung suppressed more than 50% of these parameters. Implied toxicities of AgNPs-cow dung on A. esculentus manifested in increased malondialdehyde contents with concomitant higher bioaccumulation factor of heavy metals. Cow-dung and AgNPs each stimulated A. esculentus activities in different ways, but their combination was inhibitory, which may be ascribed to the transformed AgNPs in cow-dung and relative availability of toxic metals.

Phytomediated stress modulates antioxidant status, induces overexpression of CYP6M2, Hsp70, α-esterase, and suppresses the ABC transporter in Anopheles gambiae (sensu stricto) exposed to Ocimum tenuiflorum extracts.

The incorporation of phytoactive compounds in the management of malarial vectors holds promise for the development of innovative and efficient alternatives. Nevertheless, the molecular and physiological responses that these bioactive substances induce remain underexplored. This present study investigated the toxicity of different concentrations of aqueous and methanol extracts of Ocimum tenuiflorum against larvae of Anopheles gambiae (sensu stricto) and unraveled the possible underlying molecular pathways responsible for the observed physiological effects. FTIR and GCMS analyses of phytoactive compounds in aqueous and methanol crude extracts of O. tenuiflorum showed the presence of OH stretching vibration, C = C stretching modes of aromatics and methylene rocking vibration; ring deformation mode with high levels of trans-ß-ocimene, 3,7-dimethyl-1,3,6-octatriene in aqueous extract and 4-methoxy-benzaldehyde, 1,3,5-trimethyl-cyclohexane and o-cymene in methanol extract. The percentage mortality upon exposure to methanol and aqueous extracts of O. tenuiflorum were 21.1% and 26.1% at 24 h, 27.8% and 36.1% at 48 h and 36.1% and 45% at 72 h respectively. Using reverse transcription quantitative polymerase chain reaction (RT-qPCR), down-regulation of ABC transporter, overexpression of CYP6M2, Hsp70, and α-esterase, coupled with significantly increased levels of SOD, CAT, and GSH, were observed in An. gambiae (s.s.) exposed to aqueous and methanol extracts of O. tenuiflorum as compared to the control. Findings from this study have significant implications for our understanding of how An. gambiae (s.s.) larvae detoxify phytoactive compounds.

Assessment of larvicidal and genotoxic potentials of extracts of Hyptis suaveolens against Culex quinquefasciatus based on enzyme profile and RAPD-PCR assay.

Vector control strategies have focused on the development of effective and ecofriendly alternatives. In the present study, investigation of larvicidal and genotoxic effects of leaves of Hyptis suaveolens from four different extraction solvents (aqueous, hexane, methanol and acetone) on fourth instar larvae of Culex quinquefasciatus was carried out. Extraction was done using soxhlet apparatus and the characteristics functional group of active constituents were identified using Fourier Transform Infrared spectrophotometer. Larvicidal activities were screened using three different concentrations (50, 150 and 250 mg/mL) following WHO standard protocol and mortality was recorded after 24, 48 and 72 hr. Hexane extract showed the highest mortality (27.92, 38.75, 90.42 %; LC50: 272.5, 191.3, 114.8 mg/mL), followed by aqueous extract (20.83, 34.58, 59.58 %; LC50: 496.6, 392.9, 208.1 mg/mL) and acetone extract (20.83, 32.08, 59.58 %; LC50: 1111.2, 393.6, 266.1 mg/mL) and methanol extract (17.92, 29.17, 52.92 %; LC50: 466.0, 400.1, 272.3 mg/mL). Enzyme profile such as superoxide dismutase (SOD), glutathione-S-transferase (GST), catalase (CAT), glutathione (GSH) and alkaline phosphatase (ALP) were significantly altered in the larvae exposed to the four extracts. Phytochemical screening of all solvents extract revealed the presence of saponins, flavonoids, terpenoids and alkaloids as common constituents. Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) profile implied hexane and aqueous extracts altered the DNA of larvae. Furthermore, FTIR Spectroscopic analysis revealed phenols, alcohols, aliphatic primary amines and saponins as the major groups in the extracts. Conclusively, this study established the lethal potential of extracts of H. suaveolens as alternative plant-based and eco-friendly larvicide against Cx. quinquefasciatus.

Phytomodulatory effects of silver nanoparticles on Corchorus olitorius: Its antiphytopathogenic and hepatoprotective potentials.

This study has reported the effects of biogenic silver nanoparticles (AgNPs) using cocoa pod extract on physiological tolerance indices, antioxidant activity and hepatoprotective potentials of Corchorus olitorius as well as its efficiency for controlling soil phytopathogens. C. olitorius seeds were grown in soil prepared with water (control), 0.05, 0.1, 0.15 and 0.2 mg AgNPs/g soil. C. olitorus grown with AgNPs had significantly (p < 0.05) higher free radical scavenging ability, ferric reducing ability, percentage germination, vigour indices, longer roots and shoots as well as lower moisture content over control. C. olitorius grown with AgNPs attenuated hydrogen peroxide (H2O2)-mediated reduction in catalase concentrations and H2O2-induced malondialdehyde elevations in liver. Efficiency of AgNPs to reduce soil phytopathogens (fungi and nematodes) revealed significant (p < 0.05) reduction in the incidences of soil and shoot Meloidogyne spp., Aspergillus terreus, A. niger, Fusarium spp. and Cladosporium spp. with increase in concentrations of AgNPs. More efficiently, there was complete extermination of A. niger and Fusarium spp. in the leaves of C. olitorius grown with AgNPs. Results in this study have shown the positive influence of AgNPs on C. olitorius by strengthening its resistance against fungi, and nematodes, improvement of its shelf-life, modulation of antioxidant activities and promotion of liver-detoxifying potentials.

Zero-valent silver nanoparticles attenuate Cd and Pb toxicities on Moringa oleifera via immobilization and induction of phytochemicals.

Potentials of zero-valent extract of cocoa pod mediated silver nanoparticles (AgNPs) for heavy metals (cadmium and lead) immobilization, attenuation of induced toxicities and influence on phytochemical contents in Moringa oleifera were investigated. M. oleifera seeds were planted in soil spiked and watered with water (control), 0.2 mg AgNPs, 0.5 mg CdCl2, 0.5 mg PbCl2, 0.2 mg AgNPs + 0.5 mg CdCl2, 0.2 mg AgNPs + 0.5 mg PbCl2, 0.2 mg AgNPs + 0.75 mg CdCl2 and 0.2 mg AgNPs + 0.75 mg PbCl2 per g soil designated as groups A, B, C, D, E, F, G and H respectively. Significant (p < 0.05) repression in shoot and root lengths, percentage germination, number of leaves, vigour and growth tolerance indices, relative water contents with attendant inhibition of photosynthetic pigments, total carotenoid contents, total flavonoid contents and total phenolic contents were obtained for M. oleifera planted on Cd and Pb spiked soil. There were marked decrease in ferric reducing, hydrogen peroxide scavenging and free radical scavenging activities with resultant significant increase in lipid peroxidation (MDA) levels for M. oleifera grown on Cd and Pb treated soil compared to control with Pb having more deleterious effects. Conversely, AgNPs significantly enhanced both physiological and biochemical parameters in M. oleifera over control and considerably attenuated suppressions of these parameters in M. oleifera induced by Cd and Pb. Results in this study have shown AgNPs as excellent immobilizing agents and outstanding modulators of heavy metal induced toxicities.