Responses of Medicinal and Aromatic Plants to Engineered Nanoparticles

Biological roles of soil microbial consortium on promoting safe crop production in heavy metal(loid) contaminated soil: A systematic review

Heavy metal(loid) (HM) pollution of agricultural soils is a growing global environmental concern that affects planetary health. Numerous studies have shown that soil microbial consortia can inhibit the accumulation of HMs in crops. However, our current understanding of the effects and mechanisms of inhibition is fragmented. In this review, we summarise extant studies and knowledge to provide a comprehensive view of HM toxicity on crop growth and development at the biological, cellular and the molecular levels. In a meta-analysis, we find that microbial consortia can improve crop resistance and reduce HM uptake, which in turn promotes healthy crop growth, demonstrating that microbial consortia are more effective than single microorganisms. We then review three main mechanisms by which microbial consortia reduce the toxicity of HMs to crops and inhibit HMs accumulation in crops: 1) reducing the bioavailability of HMs in soil (e.g. biosorption, bioaccumulation and biotransformation); 2) improving crop resistance to HMs (e.g. facilitating the absorption of nutrients); and 3) synergistic effects between microorganisms. Finally, we discuss the prospects of microbial consortium applications in simultaneous crop safety production and soil remediation, indicating that they play a key role in sustainable agricultural development, and conclude by identifying research challenges and future directions for the microbial consortium to promote safe crop production.

Transport of Nanoparticles into Plants and Their Detection Methods

Nanoparticle transport into plants is an evolving field of research with diverse applications in agriculture and biotechnology. This article provides an overview of the challenges and prospects associated with the transport of nanoparticles in plants, focusing on delivery methods and the detection of nanoparticles within plant tissues. Passive and assisted delivery methods, including the use of roots and leaves as introduction sites, are discussed, along with their respective advantages and limitations. The barriers encountered in nanoparticle delivery to plants are highlighted, emphasizing the need for innovative approaches (e.g., the stem as a new recognition site) to optimize transport efficiency. In recent years, research efforts have intensified, leading to an evendeeper understanding of the intricate mechanisms governing the interaction of nanomaterials with plant tissues and cells. Investigations into the uptake pathways and translocation mechanisms within plants have revealed nuanced responses to different types of nanoparticles. Additionally, this article delves into the importance of detection methods for studying nanoparticle localization and quantification within plant tissues. Various techniques are presented as valuable tools for comprehensively understanding nanoparticle-plant interactions. The reliance on multiple detection methods for data validation is emphasized to enhance the reliability of the research findings. The future outlooks of this field are explored, including the potential use of alternative introduction sites, such as stems, and the continued development of nanoparticle formulations that improve adhesion and penetration. By addressing these challenges and fostering multidisciplinary research, the field of nanoparticle transport in plants is poised to make significant contributions to sustainable agriculture and environmental management.

Nanoparticles as novel elicitors in plant tissue culture applications: Current status and future outlook

Plant tissue culture is the primary, fundamental, and applied aspect of plant biology. It is an indispensable and valuable technique for investigating morphogenesis, embryogenesis, clonal propagation, crop improvements, generation of pathogen-free plants, gene transfer and expression, and the production of secondary metabolites. The extensive use of various nanoparticles (NPs) in fields such as cosmetics, energy, medicine, pharmaceuticals, electronics, agriculture, and biotechnology have demonstrated positive impacts in microbial decontamination, callus differentiation, organogenesis, somatic variations, biotransformation, cryopreservation, and enhanced synthesis of bioactive compounds. This review summarizes the current state of knowledge with regard to the use of nanoparticles in plant tissue culture, with a particular focus on the beneficial outcomes. The positive (beneficial) and negative (toxic) effects of engineered NPs in tissue culture medium, delivery of transgenes, NPs toxicity concerns, safety issues, and potential hazards arising from utilization of nanomaterials in agriculture through plant tissue culture are discussed in detail, along with the future prospects for these applications. In addition, the potential use of novel nanomaterials such as graphene, graphite, dendrimers, quantum dots, and carbon nanotubes as well as unique metal or metalloid NPs are proposed. Further, the potential mechanisms underlying NPs elicitation of tissue culture response in different applications are critically evaluated. The potential of these approaches in plant nanobiotechnology is only now becoming understood and it is clear that the role of these strategies in sustainably increasing crop production to combat global food security and safety in a changing climate will be significant.

Pomegranate Peel Extract Stabilized Selenium Nanoparticles Synthesis: Promising Antimicrobial Potential, Antioxidant Activity, Biocompatibility, and Hemocompatibility

The green synthesis of selenium nanoparticles (Se NPs) had been synthesized by pomegranate peel extract (PPE). The antimicrobial, antioxidant, and anticancer activities of the synthesized Se NPs, as well as their hemocompatibility, were investigated. Se NPs were characterized by UV-Vis., SEM, XRD, HR-TEM, DLS, EDX, FTIR, and mapping techniques. HR-TEM image represented the spheroidal forms with moderately monodispersed NPs with a mean diameter 14.5 nm. The SEM image of Se NPs, incorporated with PPE, exhibits uniform NP surfaces, and the appearance was clear. The antimicrobial results confirmed the potential of Se NPs to hinder the growth of some tested pathogenic microbes. Results revealed that Se NPs exhibited promising antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Streptococcus mutans where inhibition zones were 29, 16, 41, 22, and 54 mm, respectively. Likewise, it exhibited antifungal activity where the values of inhibition zones were 41, 40, 38, and 36 mm against Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, and A. niger, respectively. The antioxidant activities of Se NPs at concentrations 250-4000 µg/mL were greater than 90% in all cases. Se NP concentrations of 500 µg/mL or less are safe in usage according to hemocompatibility study. Se NPs had an IC50 of 113.73 µg/mL in a cytotoxicity experiment. Results revealed that Se NPs have promising anticancer activities against MCF7 and Mg63 cancerous cell line, where IC50 was 69.8 and 47.9 μg/mL, respectively. In conclusion, Se NPs were successfully biosynthesized using PPE for the first time; these Se NPs had promising antimicrobial, antioxidant, and anticancer activities.

Multifaceted Role of Nanomaterials in Modulating In Vitro Seed Germination, Plant Morphogenesis, Metabolism and Genetic Engineering

The agricultural practices of breeding, farm management and cultivation have improved production, to a great extent, in order to meet the food demands of a growing population. However, the newer challenges of climate change, global warming, and nutritional quality improvement will have to be addressed under a new scenario. Plant biotechnology has emerged as a reliable tool for enhancing crop yields by protecting plants against insect pests and metabolic engineering through the addition of new genes and, to some extent, nutritional quality improvement. Plant tissue culture techniques have provided ways for the accelerated clonal multiplication of selected varieties with the enhanced production of value-added plant products to increase modern agriculture. The in vitro propagation method has appeared as a pre-eminent approach for the escalated production of healthy plants in relatively shorter durations, also circumventing seasonal effects. However, there are various kinds of factors that directly or indirectly affect the efficiency of in vitro regeneration like the concentration and combination of growth regulators, variety/genotype of the mother plant, explant type, age of seedlings and other nutritional factors, and elicitors. Nanotechnology as one of the latest and most advanced approaches in the material sciences, and can be considered to be very promising for the improvement of crop production. Nanomaterials have various kinds of properties because of their small size, such as an enhanced contact surface area, increased reactivity, stability, chemical composition, etc., which can be employed in plant sciences to alter the potential and performance of plants to improve tissue culture practices. Implementing nanomaterials with in vitro production procedures has been demonstrated to increase the shoot multiplication potential, stress adaptation and yield of plant-based products. However, nanotoxicity and biosafety issues are limitations, but there is evidence that implies the promotion and further exploration of nanoparticles in agriculture production. The incorporation of properly designed nanoparticles with tissue culture programs in a controlled manner can be assumed as a new pathway for sustainable agriculture development. The present review enlists different studies in which treatment with various nanoparticles influenced the growth and biochemical responses of seed germination, as well as the in vitro morphogenesis of many crop species. In addition, many studies suggest that nanoparticles can be useful as elicitors for elevating levels of important secondary metabolites in in vitro cultures. Recent advancements in this field also depict the suitability of nanoparticles as a promising carrier for gene transfer, which show better efficiency than traditional Agrobacterium-mediated delivery. This review comprehensively highlights different in vitro studies that will aid in identifying research gaps and provide future directions for unexplored areas of research in important crop species.

The Impact of Gold Nanoparticles on Somatic Embryogenesis Using the Example of Arabidopsis thaliana

Although the influence of nanoparticles (NPs) on developmental processes is better understood, little is known about their impact on somatic embryogenesis (SE). This process involves changes in the direction of cell differentiation. Thus, studying the effect of NPs on SE is essential to reveal their impact on cell fate. This study aimed to examine the influence of gold nanoparticles (Au NPs) with different surface charges on the SE of 35S:BBM Arabidopsis thaliana, with particular emphasis on the spatiotemporal localization of pectic arabinogalactan proteins (AGPs) and extensin epitopes in cells changing the direction of their differentiation. The results show that under the influence of nanoparticles, the explant cells of 35S:BBM Arabidopsis thaliana seedling origin did not enter the path of SE. Bulges and the formation of organ-like structures were observed in these explants, in contrast to the control, where somatic embryos developed. Additionally, spatiotemporal changes in the chemical composition of the cell walls during the culture were observed. Under the influence of Au NPs, the following effects were observed: (1) explant cells did not enter the SE pathway, (2) the impacts of Au NPs with different surface charges on the explants were variable, and (3) the compositions of the analyzed pectic AGPs and extensin epitopes were diverse in the cells with different developmental programs: SE (control) and non-SE (treated with Au NPs).

Nanoengineered particles for sustainable crop production: potentials and challenges

Nanoengineered nanoparticles have a significant impact on the morphological, physiology, biochemical, cytogenetic, and reproductive yields of agricultural crops. Metal and metal oxide nanoparticles like Ag, Au, Cu, Zn, Ti, Mg, Mn, Fe, Mo, etc. and ZnO, TiO2, CuO, SiO2, MgO, MnO, Fe2O3 or Fe3O4, etc. that found entry into agricultural land, alter the morphological, biochemical and physiological system of crop plants. And the impacts on these parameters vary based on the type of crop and nanoparticles, doses of nanoparticles and its exposure situation or duration, etc. These nanoparticles have application in agriculture as nanofertilizers, nanopesticides, nanoremediator, nanobiosensor, nanoformulation, phytostress-mediator, etc. The challenges of engineered metal and metal oxide nanoparticles pertaining to soil pollution, phytotoxicity, and safety issue for food chains (human and animal safety) need to be understood in detail. This review provides a general overview of the applications of nanoparticles, their potentials and challenges in agriculture for sustainable crop production.

The comparative effects of manganese nanoparticles and their counterparts (bulk and ionic) in Artemisia annua plants via seed priming and foliar application

The world has experienced an unprecedented boom in nanotechnology. Nanoparticles (NPs) are likely to act as biostimulants in various plants due to having high surface/volume value. However, understanding the actual effect of NPs is essential to discriminate them from other counterparts in terms of being applicable, safe and cost-effective. This study aimed to assay the impact of manganese(III) oxide (Mn₂O₃)-NPs via seed-priming (SP) and a combination of SP and foliar application (SP+F) on Artemisia. annua performance at several times intervals and comparison with other available manganese (Mn) forms. Our findings indicate that SP with MnSO₄ and Mn₂O₃-NPs stimulates the processes that occur prior to germination and thus reduces the time for radicle emergence. In both applications (i.e., SP and +F), none of the Mn treatments did show adverse phytotoxic on A. annua growth at morpho-physio and biochemical levels except for Mn₂O_3, which delayed germination and further plant growth, subsequently. Besides, from physio-biochemical data, it can be inferred that the general mechanism mode of action of Mn is mainly attributed to induce the photosynthetic processes, stimulate the superoxide dismutase (SOD) activity, and up-regulation of proline and phenolic compounds. Therefore, our results showed that both enzymatic and non-enzymatic antioxidants could be influenced by the application of Mn treatments in a type-dependent manner. In general, this study revealed that Mn₂O₃-NPs at the tested condition could be used as biostimulants to improve germination, seedling development and further plant growth. However, they are not as effective as MnSO₄ treatments. Nonetheless, these findings can be used to consider and develop Mn₂O₃-NPs priming in future studies to improve seed germination and seedling quality in plants.

Anti-obesity Effect of Bioengineered Silver Nanoparticles Synthesized from Persea americana on Obese Albino Rats

BACKGROUND

Obesity is an immoderate or abnormal accretion of fat or adipose tissue in the body that is prone to damage the health of mankind. Persea americana (Avocados) is a nutritious fruit known for its several health benefits. The current research was planned to evaluate the anti-obesity activity of bioengineered Silver Nanoparticles (AgNPs) against a high-fat diet (HFD) treated obese albino rats.

METHODS

AgNPs were synthesized and characterized for the Phytochemical constituents, UV-vis Spectroscopy, FTIR, SEM and XRD. Furthermore, the lipid profile in serum, biochemical parameters and histopathological changes in tissues of albino rats were determined.

RESULTS

The present study revealed the presence of tannins, flavonoids, steroids and saponins, carbohydrates, alkaloids, phenols and glycosides. The peak was disclosed at 402 nm in UV-vis spectroscopy, confirming the synthesis of AgNPs. FTIR analysis showed two peaks at 3332.25 cm-1 which correspond to the O-H stretch of the carboxylic acid band, and 1636.40 cm-1 represents the N-H stretch of the amide of proteins, respectively. This result confirms their contribution to the capping and stabilization of AgNPs. The XRD results confirm the crystalline nature of AgNPs, and SEM results indicated that the synthesized AgNPs were spherical. Further, the results of the current study showed the improved lipid profile and biochemical parameters in rats supplemented with methanolic pulp extract of Persea americana AgNPs when compared with other experimental groups. The histopathological findings displayed improved results with reduced hepatocyte degradation under the influence of AgNPs treatment.

CONCLUSION

All the experimental evidence indicated the possible anti-obesity effect of silver nanoparticles synthesized from the methanolic pulp extract of Persea americana.

Anticancer Applications of Essential Oils Formulated into Lipid-Based Delivery Nanosystems

The use of natural compounds is becoming increasingly popular among patients, and there is a renewed interest among scientists in nature-based bioactive agents. Traditionally, herbal drugs can be taken directly in the form of teas/decoctions/infusions or as standardized extracts. However, the disadvantages of natural compounds, especially essential oils, are their instability, limited bioavailability, volatility, and often irritant/allergenic potential. However, these active substances can be stabilized by encapsulation and administered in the form of nanoparticles. This brief overview summarizes the latest results of the application of nanoemulsions, liposomes, solid lipid nanoparticles, and nanostructured lipid carriers used as drug delivery systems of herbal essential oils or used directly for their individual secondary metabolites applicable in cancer therapy. Although the discussed bioactive agents are not typical compounds used as anticancer agents, after inclusion into the aforesaid formulations improving their stability and bioavailability and/or therapeutic profile, they indicated anti-tumor activity and became interesting agents with cancer treatment potential. In addition, co-encapsulation of essential oils with synthetic anticancer drugs into nanoformulations with the aim to achieve synergistic effect in chemotherapy is discussed.

Alkaloids in Contemporary Drug Discovery to Meet Global Disease Needs

An overview is presented of the well-established role of alkaloids in drug discovery, the application of more sustainable chemicals, and biological approaches, and the implementation of information systems to address the current challenges faced in meeting global disease needs. The necessity for a new international paradigm for natural product discovery and development for the treatment of multidrug resistant organisms, and rare and neglected tropical diseases in the era of the Fourth Industrial Revolution and the Quintuple Helix is discussed.

Trimethoxycinnamates and Their Cholinesterase Inhibitory Activity

A series of twelve nature-inspired 3,4,5-trimethoxycinnamates were prepared and characterized. All compounds, including the starting 3,4,5-trimethoxycinnamic acid, were tested for their ability to inhibit acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in vitro; the selectivity index (SI) was also determined. 2-Fluororophenyl (2E)-3-(3,4,5-trimethoxyphenyl)-prop-2-enoate demonstrated the highest SI (1.71) in favor of BChE inhibition. 2-Chlorophenyl (2E)-3-(3,4,5-trimethoxyphenyl)prop-2-enoate showed the highest AChE-inhibiting (IC50 = 46.18 µM) as well as BChE-inhibiting (IC50 = 32.46 µM) activity with an SI of 1.42. The mechanism of action of the most potent compound was determined by the Lineweaver–Burk plot as a mixed type of inhibition. An in vitro cell viability assay confirmed the insignificant cytotoxicity of the discussed compounds on the two cell lines. Trends between structure, physicochemical properties and activity were discussed.