In vitro antimalarial activity of synthesized TiO₂ nanoparticles using Momordica charantia leaf extract against Plasmodium falciparum

Nanotherapeutics against malaria: A decade of advancements in experimental models

Malaria, caused by different species of protists of the genus Plasmodium, remains among the most common causes of death due to parasitic diseases worldwide, mainly for children aged under 5. One of the main obstacles to malaria eradication is the speed with which the pathogen evolves resistance to the drug schemes developed against it. For this reason, it remains urgent to find innovative therapeutic strategies offering sufficient specificity against the parasite to minimize resistance evolution and drug side effects. In this context, nanotechnology-based approaches are now being explored for their use as antimalarial drug delivery platforms due to the wide range of advantages and tuneable properties that they offer. However, major challenges remain to be addressed to provide a cost-efficient and targeted therapeutic strategy contributing to malaria eradication. The present work contains a systematic review of nanotechnology-based antimalarial drug delivery systems generated during the last 10 years. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.

Biofabrication of Titanium Dioxide Nanoparticles Catalyzed by Solanum surattense: Characterization and Evaluation of their Antiepileptic and Cytotoxic Activities

The green synthesis of nanoparticles using plant extract is a new method that can be used in various biomedical applications. Therefore, the green approach was an aspect of ongoing research for the synthesis titanium dioxide nanoparticles (TiO₂ NP) using the Solanum surattense aqueous plant extract, which acts as a stabilizing and reducing agent. The synthesis of TiO₂ NPs was confirmed by energy dispersive X-ray (EDX), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and UV-visible spectroscopy (UV-vis) analyses. The excitation energy to synthesize TiO₂ NPs was identified through the UV-vis spectrophotometric analysis at a wavelength of 244 nm. Further, the FT-IR spectroscopy visualized different biomolecules like OH, C=O, C-H, and C-O that were present in an aqueous extract of the plant and were responsible for the stabilization of TiO₂ NPs. The crystallinity and phase purity of TiO₂ NPs were illustrated by the sharp peaks of the XRD pattern. The spherical morphology with sizes ranging from 10 to 80 nm was examined using SEM images. The elemental composition of TiO₂ NPs was revealed by the intensity and narrow widths of titanium and oxygen using EDX analysis. This report also explains the antiepileptic activity of TiO₂ NPs in a maximal electroshock-induced epileptic (MESE) and pentylenetetrazol (PTZ) model. The synthesized TiO₂ NPs showed maximum antiepileptic activity in the PTZ model, significantly decreasing the convulsions (65.0 ± 5.50 s) at 180 mg/kg in contrast to standard drug phenytoin, whereas the MESE model was characterized by the appearance of extensor, clonus, and flexion. The results showed that synthesized TiO₂ NPs significantly reduced the time spent in each stage (15.3 ± 0.20, 16.8 ± 0.25, and 20.5 ± 0.14 s) at 180 mg/kg as compared to control groups. Furthermore, the cytotoxicity of synthesized produced TiO₂ NPs demonstrated that concentrations ≤80 μg/mL were biologically compatible.

Photodegradation of Methylene Blue with Aid of Green Synthesis of CuO/TiO2 Nanoparticles from Extract of Citrus Aurantium Juice

Green synthesis methods using plants have many advantages such as time-saving, chemical-free, and negative effects on the environment. So, extracted Citrus aurantium juice was used to synthesize green CuO/TiO2 and(G- CuO/TiO2) nanocatalyst which was characterized by XRD, SEM, EDX, FTIR, BET, and ZP and utilized in the degradation of methylene blue (MB) under UV lamps and dark environments. The ANOVA program was used to maximize the photodegradation efficiency (%) of (G-CuO/TiO2) on the MB dye. The four independent variables: Initial dye concentration (10-50 mg/L), pH (3-9), adsorbent dose (200-1000 mg/L), and contact time (30-90 min) served to the model of the photodegradation efficiency (%). The ANOVA results confirmed the high significance of the regression model while the predicted values of the photodegradation efficiency (%) of MB were in good agreement with the corresponding experimental ones. Optimized conditions for the maximum photodegradation efficiency (98.6%) by (G- CuO/TiO2) NPs were the initial dye concentration (10.93 mg/L), pH (8.87), adsorbent mass (986.43 mg/L), and contact time (89.08 min). The validity of the quadratic model was examined, and found in good agreement with the experimental values. Results demonstrated that (G-CuO/TiO2) could be a promising photocatalyst in the degradation of MB dye. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Mosquito-Borne Diseases and Their Control Strategies: An Overview Focused on Green Synthesized Plant-Based Metallic Nanoparticles

Mosquitoes act as vectors of pathogens that cause most life-threatening diseases, such as malaria, Dengue, Chikungunya, Yellow fever, Zika, West Nile, Lymphatic filariasis, etc. To reduce the transmission of these mosquito-borne diseases in humans, several chemical, biological, mechanical, and pharmaceutical methods of control are used. However, these different strategies are facing important and timely challenges that include the rapid spread of highly invasive mosquitoes worldwide, the development of resistance in several mosquito species, and the recent outbreaks of novel arthropod-borne viruses (e.g., Dengue, Rift Valley fever, tick-borne encephalitis, West Nile, yellow fever, etc.). Therefore, the development of novel and effective methods of control is urgently needed to manage mosquito vectors. Adapting the principles of nanobiotechnology to mosquito vector control is one of the current approaches. As a single-step, eco-friendly, and biodegradable method that does not require the use of toxic chemicals, the green synthesis of nanoparticles using active toxic agents from plant extracts available since ancient times exhibits antagonistic responses and broad-spectrum target-specific activities against different species of vector mosquitoes. In this article, the current state of knowledge on the different mosquito control strategies in general, and on repellent and mosquitocidal plant-mediated synthesis of nanoparticles in particular, has been reviewed. By doing so, this review may open new doors for research on mosquito-borne diseases.

The Use of Medicinal Plant-Derived Metallic Nanoparticles in Theranostics

In the quest to effectively diagnose and treat the diseases that afflict mankind, the development of a tool capable of simultaneous detection and treatment would provide a significant cornerstone for the survival and control of these diseases. Theranostics denotes a portmanteau of therapeutics and diagnostics which simultaneously detect and treat ailments. Research advances have initiated the advent of theranostics in modern medicine. Overall, theranostics are drug delivery systems with molecular or targeted imaging agents integrated into their structure. The application of theranostics is rising exponentially due to the urgent need for treatments that can be utilized for diagnostic imaging as an aid in precision and personalised medicine. Subsequently, the emergence of nanobiotechnology and the green synthesis of metallic nanoparticles (MNPs) has provided one such avenue for nanoscale development and research. Of interest is the drastic rise in the use of medicinal plants in the synthesis of MNPs which have been reported to be potentially effective in the diagnosis and treatment of diseases. At present, medicinal plant-derived MNPs have been cited to have broad pharmacological applications and have been studied for their potential use in the treatment and management of cancer, malaria, microbial and cardiovascular diseases. The subject of this article regards the role of medicinal plants in the synthesis of MNPs and the potential role of MNPs in the field of theranostics.

Current challenges and nanotechnology-based pharmaceutical strategies for the treatment and control of malaria

Malaria is one of the prevalent tropical diseases caused by the parasitic protozoan of the genus Plasmodium spp. With an estimated 228 million cases, it is a major public health concern with high incidence of morbidity and mortality worldwide. The emergence of drug-resistant parasites, inadequate vector control measures, and the non-availability of effective vaccine(s) against malaria pose a serious challenge to malaria eradication especially in underdeveloped and developing countries. Malaria treatment and control comprehensively relies on chemical compounds, which encompass various complications, including severe toxic effects, emergence of drug resistance, and high cost of therapy. To overcome the clinical failures of anti-malarial chemotherapy, a new drug development is of an immediate need. However, the drug discovery and development process is expensive and time consuming. In such a scenario, nanotechnological strategies may offer promising alternative approach for the treatment and control of malaria, with improved efficacy and safety. Nanotechnology based formulations of existing anti-malarial chemotherapeutic agents prove to exceed the limitations of existing therapies in relation to optimum therapeutic benefits, safety, and cost effectiveness, which indeed advances the patient's compliance in treatment. In this review, the shortcomings of malaria therapeutics and necessity of nanotechnological strategies for treating malaria were discussed.

Effective Antiplasmodial and Cytotoxic Activities of Synthesized Zinc Oxide Nanoparticles Using Rhazya stricta Leaf Extract

In the present study, zinc oxide (ZnO) nanoparticles were prepared using ZnCl₂.2H₂O as a precursor, via green route using leaf extract of Rhazya stricta as capping and reducing agent. The prepared ZnO nanoparticles were examined using UV-visible spectrophotometer (UV-Vis), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction spectrometer (XRD), and scanning electron microscope (SEM). The UV-Vis absorption spectrum at 355 nm showed an absorption peak, which indicates the formation of ZnO NPs. The FT-IR spectra analysis was performed to identify the potential biomolecule of the as-prepared ZnO NPs. The FT-IR spectra showed peaks at 3455, 1438, 883, and 671 cm⁻¹ in the region of 4000–500 cm⁻¹, which indicates –OH, NH, C-H, and M-O groups, respectively. The SEM images showed aggregation of ZnO nanoparticles with an average size of 70–90 nm. The XRD study indicated that the ZnO NPs were crystalline in nature with hexagonal wurtzite structure and broad peaks were observed at 2 theta positions 31.8°, 34.44°, 36.29°, 47.57°, 56.61°, 67.96°, and 69.07°. The synthesized ZnO NPs were found to be good antiplasmodial with a 50% inhibitory concentration (IC₅₀) value of 3.41 μg/mL. It is concluded from the current study that the ZnO NPs exhibited noble antiplasmodial activity, and for the improvement of antiplasmodial medications, it might be used after further in vivo studies.

Green-synthesized metal nanoparticles for mosquito control: A systematic review about their toxicity on non-target organisms

Studies capturing the high efficiency of green-synthesized metal nanoparticles (NPs) in targeting mosquito vectors of the world's main infectious diseases suggest the NPs' possible utilization as bio-insecticides. However, it is necessary to confirm that these potential bio-insecticides are not harmful to non-target organisms that are often sympatric and natural enemies of the vectors of these diseases. In this systematic review, we comprehensively analyse the content of 56 publications focused on the potentially deleterious effects of NPs on these non-target organisms. Current research on biosynthesised NPs, characterization, and impact on mosquito vectors and non-target larvivorous organisms is reviewed and critically discussed. Finally, we pinpoint some major challenges that merit future investigation. Plants (87.5%) were mainly used for synthesizing NPs in the studies. NPs were found to be spherical or mainly spherical in shape with a large distribution size. In most of the included studies, NPs showed interesting mosquitocidal activity (LC₅₀ < 50 ppm). Some plant families (e.g., Meliaceae, Poaceae, Lamiaceae) have produced NPs with a particularly high larvicidal and pupicidal activity (LC₅₀ < 10 ppm). Regarding non-target organisms, most of the studies concluded that NPs were safe to them, with boosted predatory activity in NP-treated milieu. In contrast, some studies reported NP-elicited adverse effects (i.e., genotoxic, nuclear, and enzymatic effects) on these non-target organisms. This review outlines the promising mosquitocidal effects of biosynthesized NPs, recognizing that NPs' potential usage is currently limited by the harm NPs are thought pose to non-target organism. It is of utmost importance to investigate green NPs to determine whether laboratory findings have applications in the real world.

A systematic review on anti-malarial drug discovery and antiplasmodial potential of green synthesis mediated metal nanoparticles: overview, challenges and future perspectives

BACKGROUND

The recent emergence in Southeast Asia of artemisinin resistance poses major threats to malaria control and elimination globally. Green nanotechnologies can constitute interesting tools for discovering anti-malarial medicines. This systematic review focused on the green synthesis of metal nanoparticles as potential source of new antiplasmodial drugs.

METHODS

Seven electronic database were used following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

A total of 17 papers were included in the systematic review. 82.4% of the studies used plant leaves to produce nanoparticles (NPs) while three studies used microorganisms, including bacteria and fungi. Silver was the main metal precursor for the synthesis of NPs. The majority of studies obtained nanoparticles spherical in shape, with sizes ranging between 4 and 65 nm, and reported no or little cytotoxic effect of the NPs. Results based on 50% inhibitory concentration (IC50) varied between studies but, in general, could be divided into three NP categories; (i) those more effective than positive controls, (ii) those more effective than corresponding plant extracts and, (iii) those less effective than the positive controls or plant extracts.

CONCLUSIONS

This study highlights the high antiplasmodial potential of green-synthesized metal nanoparticles thereby underscoring the possibility to find and develop new anti-malarial drugs based on green synthesis approaches. However, the review also highlights the need for extensive in vitro and in vivo studies to confirm their safety in humans and the elucidation of the mechanism of action.

Phytosynthesized metal oxide nanoparticles for pharmaceutical applications

Developments in nanotechnology field, specifically, metal oxide nanoparticles have attracted the attention of researchers due to their unique sensing, electronic, drug delivery, catalysis, optoelectronics, cosmetics, and space applications. Physicochemical methods are used to fabricate nanosized metal oxides; however, drawbacks such as high cost and toxic chemical involvement prevail. Recent researches focus on synthesizing metal oxide nanoparticles through green chemistry which helps in avoiding the involvement of toxic chemicals in the synthesis process. Bacteria, fungi, and plants are the biological sources that are utilized for the green nanoparticle synthesis. Due to drawbacks such as tedious maintenance and the time needed for the nanoparticle formation, plant extracts are widely used in nanoparticle production. In addition, plants are available all over the world and phytosynthesized nanoparticles show comparatively less toxicity towards mammalian cells. Secondary metabolites including flavonoids, terpenoids, and saponins are present in plant extracts, and these are highly responsible for nanoparticle formation and reduction of toxicity. Hence, this article gives an overview of recent developments in the phytosynthesis of metal oxide nanoparticles and their toxic analysis in various cells and animal models. Also, their possible mechanism in normal and cancer cells, pharmaceutical applications, and their efficiency in disease treatment are also discussed.

Fe-TiO2 Nanoparticles Synthesized by Green Chemistry for Potential Application in Waste Water Photocatalytic Treatment

Anatase TiO2 nanoparticles doped with iron ions have been synthesized via the green chemistry method using aqueous extract of lemongrass (Cymbopogon citratus) obtained from Soxhlet extraction and doped by wet impregnation. The TiO2 anatase phase has been doped with Fe3+ (0.05, 0.075, and 0.1 Fe3+ : Ti molar ratio) at 550°C and 350°C, respectively. The scanning electron microscopy with energy-dispersive X-ray (SEM-EDS) shows nanoparticle clusters and efficiencies of impregnations between 66.5 and 58.4% depending on the theoretical dopant amount. The electron transmission microscopy (TEM) reveals final particle sizes ranging between 7 and 26 nm depending on the presence or not of the dopant. The cathodoluminescence (CL) and photoluminescence (PL) studies of the doped and undoped nanoparticles show a luminescence signal attributed to surface oxygen vacancies (visible CL emission 380–700 nm and PL emission 350–800 nm); additionally, a decrease in emission intensity is observed due the inhibition of the recombination of the photogenerated electron-holes pairs; moreover, nanopowders were analyzed by UV-Vis spectrophotometry of diffuse reflectance, and the absorption edge of the Fe-TiO2 in comparison to undoped TiO2 is extended greatly toward the visible light. The six bands (A1g + 2B1g + 3Eg) found by Raman spectroscopy and the x-ray diffraction pattern (XRD) confirm that synthesized TiO2 is only anatase phase, which is commonly used as a catalyst in waste water treatment, specifically in heterogeneous photocatalytic processes.