Enhanced permeation, leaf retention, and plant protease inhibitor activity with bicontinuous microemulsions

Towards Effective Antiviral Oral Therapy: Development of a Novel Self-Double Emulsifying Drug Delivery System for Improved Zanamivir Intestinal Permeability

Self-double emulsifying drug delivery systems have the potential to enhance the intestinal permeability of drugs classified under the Biopharmaceutics Classification System (BCS) class III. One such example is the antiviral agent zanamivir, exhibiting suboptimal oral absorption (with a bioavailability range of 1-5%). To address this challenge, we have developed an innovative oral formulation for zanamivir: a self-double nanoemulsifying Winsor delivery system (SDNE-WDS) consisting of the microemulsion, which subsequently yields final double nanoemulsion (W1/O/W2) upon interaction with water. Two distinct formulations were prepared: SDNE-WDS1, classified as a W/O microemulsion, and SDNE-WDS2, discovered to be a bicontinuous microemulsion. The inner microemulsions displayed a consistent radius of gyration, with an average size of 35.1 ± 2.1 nm. Following self-emulsification, the resultant zanamivir-loaded nanoemulsion droplets for zSDNE-WDS1 and zSDNE-WDS2 measured 542.1 ± 36.1 and 174.4 ± 3.4 nm, respectively. Both types of emulsions demonstrated the ability to enhance the transport of zanamivir across a parallel artificial membrane. Additionally, in situ rat intestinal perfusion studies involving drug-loaded SDNE-WDSs revealed a significantly increased permeability of zanamivir through the small intestinal wall. Notably, both SDNE-WDS formulations exhibited effective permeability (Peff) values that were 3.5-5.5-fold higher than those of the low/high permeability boundary marker metoprolol. This research emphasizes the success of SDNE-WDSs in overcoming intestinal permeability barriers and enabling the effective oral administration of zanamivir. These findings hold promise for advancing the development of efficacious oral administration of BCS class III drugs.

Electrochemical transformations catalyzed by cytochrome P450s and peroxidases

Cytochrome P450s (Cyt P450s) and peroxidases are enzymes featuring iron heme cofactors that have wide applicability as biocatalysts in chemical syntheses. Cyt P450s are a family of monooxygenases that oxidize fatty acids, steroids, and xenobiotics, synthesize hormones, and convert drugs and other chemicals to metabolites. Peroxidases are involved in breaking down hydrogen peroxide and can oxidize organic compounds during this process. Both heme-containing enzymes utilize active Fe^IVO intermediates to oxidize reactants. By incorporating these enzymes in stable thin films on electrodes, Cyt P450s and peroxidases can accept electrons from an electrode, albeit by different mechanisms, and catalyze organic transformations in a feasible and cost-effective way. This is an advantageous approach, often called bioelectrocatalysis, compared to their biological pathways in solution that require expensive biochemical reductants such as NADPH or additional enzymes to recycle NADPH for Cyt P450s. Bioelectrocatalysis also serves as an ex situ platform to investigate metabolism of drugs and bio-relevant chemicals. In this paper we review biocatalytic electrochemical reactions using Cyt P450s including C-H activation, S-oxidation, epoxidation, N-hydroxylation, and oxidative N-, and O-dealkylation; as well as reactions catalyzed by peroxidases including synthetically important oxidations of organic compounds. Design aspects of these bioelectrocatalytic reactions are presented and discussed, including enzyme film formation on electrodes, temperature, pH, solvents, and activation of the enzymes. Finally, we discuss challenges and future perspective of these two important bioelectrocatalytic systems.

Pesticide-loaded colloidal nanodelivery systems; preparation, characterization, and applications

The fast developments in pesticide-loaded nanodelivery systems over the last decade have inspired many companies and research organizations to highlight potential applications by employing encapsulation approaches in order to protect the agricultural crops. This approach is being used to retard the indiscriminate application of conventional pesticides, as well as, to make ensure the environmental safety. This article shed light on the potential of colloidal delivery systems, particularly controlled releasing profiles of several pesticides with enhanced stability and improved solubility. Colloidal nanodelivery systems, being efficient nanoformulations, have the ability to boost up the pest-control competence for prolonged intervals thru averting the early degradation of active ingredients under severe ecofriendly circumstances. This work is thus aimed to provide critical information on the meaningful role of nanocarriers for loading of pesticides. The smart art of pesticide-loaded nanocarriers can be more fruitful owing to the use of lower amount of active ingredients with improved efficiency along with minimizing the pesticide loss. Also, the future research gaps regarding nano-pesticide formulations, such as role of nanomaterials as active ingredients are discussed briefly. In addition, this article can deliver valuable information to the readers while establishing novel pesticide-loaded nanocarriers for a wide range of applications in the agriculture sectors.

PINIR: a comprehensive information resource for Pin-II type protease inhibitors

BACKGROUND

Serine protease inhibitors belonging to the Potato type-II Inhibitor family Protease Inhibitors (Pin-II type PIs) are essential plant defense molecules. They are characterized by multiple inhibitory repeat domains, conserved disulfide bond pattern, and a tripeptide reactive center loop. These features of Pin-II type PIs make them potential molecules for protein engineering and designing inhibitors for agricultural and therapeutic applications. However, the diversity in these PIs remains unexplored due to the lack of annotated protein sequences and their functional attributes in the available databases.

RESULTS

We have developed a database, PINIR (Pin-II type PIs Information Resource), by systematic collection and manual annotation of 415 Pin-II type PI protein sequences. For each PI, the number and position for signature sequences are specified: 695 domains, 75 linkers, 63 reactive center loops, and 10 disulfide bond patterns are identified and mapped. Database analysis revealed novel subcategories of PIs, species-correlated occurrence of inhibitory domains, reactive center loops, and disulfide bond patterns. By analyzing linker regions, we predict that alternative processing at linker regions could generate PI variants in the Solanaceae family.

CONCLUSION

PINIR ( https://pinir.ncl.res.in ) provides a web interface for browsing and analyzing the protein sequences of Pin-II type PIs. Information about signature sequences, spatio-temporal expression, biochemical properties, gene sequences, and literature references are provided. Analysis of PINIR depicts conserved species-specific features of Pin-II type PI protein sequences. Diversity in the sequence of inhibitory domains and reactive loops directs potential applications to engineer Pin-II type PIs. The PINIR database will serve as a comprehensive information resource for further research into Pin-II type PIs.

Tank-mixing adjuvants enhanced the efficacy of fludioxonil on cucumber anthracnose by ameliorating the penetration ability of active ingredients on target interface

In this study, pot and field experiments showed that S903, Hasten and Gemini-31511 can significantly enhanced the control efficacy of fludioxonil on cucumber anthracnose. Then by studying the deposition and penetration interaction between active ingredients and cucumber leaves to revealed how the adjuvants influence the interaction process between pesticide active ingredients and target plants to improve the control efficacy. By analysis the effect of fludioxonil deposition to synergism of adjuvants, indicated that fludioxonil active ingredient deposition caused by adjuvants was not the main factor for the adjuvants synergistic effect. Fludioxonil + S903 yielded the lowest surface tension and contact angle, which also implying the best wetting ability. The mean diameters in Hasten + fludioxonil group were much smaller than those in only fludioxonil group (5.39 μm-90 g a.i. ha^-1, 5.50 μm-180 g a.i. ha^-1), the average particle size only had 3.45 μm (90 g a.i. ha^-1) and 3.94 μm (180 g a.i. ha^-1). And the result of spray droplets was consistent with the particles of fludioxonil crystals observed on glass slides and cucumber leaves. Therefore, S903 improved the penetrability of fludioxonil in the target plants by improving the wetting and dispersion of active ingredients on the target interface. Meantime, Hasten improved the penetrability of fludioxonil in the target plants by decreasing the particle size of active ingredients.

Evaluation of silica nanoparticle mediated delivery of protease inhibitor in tomato plants and its effect on insect pest Helicoverpa armigera

The inert and surface tunable nature of silica nanoparticles (SiNPs) makes them suitable for different applications. We have evaluated the potential of SiNPs for delivering proteins in tomato (Lycopersicon esculentum) plants. SiNPs of 20 and 100 nm (Si20 and Si100) were functionalized with (3-aminopropyl) triethoxysilane (APTES) to obtain Si20APT and Si100APT, respectively, that were non-toxic toward plants. The functionalized nanoparticles were taken up by plants through roots as well as leaf surfaces. They were seen to be localized near the vasculature, particularly around the xylem. Si20APT and Si100APT nanoparticles were conjugated with soybean trypsin inhibitor (STI) to yield Si20APT-STI and Si100APT-STI, respectively. Based on the trypsin inhibitory activity of loaded nanoparticles, optimum loading was obtained for 0.4 mg of STI per 0.8 mg of NPs. Si20APT nanoparticles retained higher contents of STI than Si100APT. Exposure of STI-conjugated nanoparticles to 25°C or pH 8.0 aided release of the inhibitor. The particle bound STI inhibited bovine trypsin by 80% and Helicoverpa armigera gut proteinase (HGP) activity by 50%. Second instar H. armigera larvae ingesting STI-loaded particles (incorporated in artificial diet or leaves) showed significant retardation in growth. In choice assays, Si20APT-STI applied leaf discs were strikingly avoided by insect larvae. On the basis of the results obtained in this investigation, we recommend the use of Si20 nanoparticles for developing plant delivery vehicles in the future.

Fungicide Formulations Influence Their Control Efficacy by Mediating Physicochemical Properties of Spray Dilutions and Their Interaction with Target Leaves

In this study, three types of pyraclostrobin formulations (including emulsifiable concentrate (EC), suspension concentrate (SC), and microcapsules (MCs)) were used to control cucumber anthracnose. Pyraclostrobin EC had the highest inhibitory activity against Colletotrichum orbiculare in vitro. Much different from the bioactivity in vitro, pyraclostrobin MCs exhibited the highest control efficacy on cucumber anthracnose both in pot and field experiments. The physicochemical properties (particle size, surface tension) of the spray dilution, their interaction with target leaves (contact angle, adhesional tension, work of adhesion, retention, crystallization) and dissipation dynamic of the active ingredient were found to be highly potential factors that would significantly influence the control efficacy of pesticide formulations. Results showed that the control efficacies of different formulations of pyraclostrobin were determined mainly by the final behavior of the pesticides at the target interface, namely, the retention, crystallization, and dissipation dynamics of active ingredients. This study had revealed crucial factors that would influence the efficacy of different formulations of pyraclostrobin and thus could guide the rational and efficient use of different formulations of pesticides on target crops.

Budding trends in integrated pest management using advanced micro- and nano-materials: Challenges and perspectives

One of the most vital supports to sustain human life on the planet earth is the agriculture system that has been constantly challenged in terms of yield. Crop losses due to insect pest attack even after excessive use of chemical pesticides, are major concerns for humanity and environment protection. By the virtue of unique properties possessed by micro and nano-structures, their implementation in Agri-biotechnology is largely anticipated. Hence, traditional pest management strategies are now forestalling the potential of micro and nanotechnology as an effective and viable approach to alleviate problems pertaining to pest control. These technological innovations hold promise to contribute enhanced productivity by providing novel agrochemical agents and delivery systems. Application of these systems engages to achieve: i) control release of agrochemicals, ii) site-targeted delivery of active ingredients to manage specific pests, iii) reduced pesticide use, iv) detection of chemical residues, v) pesticide degradation, vi) nucleic acid delivery and vii) to mitigate post-harvest damage. Applications of micro and nano-technology are still marginal owing to the perception of low economic returns, stringent regulatory issues involving safety assessment and public awareness over their uses. In this review, we highlight the potential application of micro and nano-materials with a major focus on effective pest management strategies including safe handling of pesticides.

Structural characteristics of oil-poor dilutable fish oil omega-3 microemulsions for ophthalmic applications

Docosahexaenoic acid (DHA) promotes synthesis of anti-inflammatory prostaglandins and relief of dry eye symptoms. However, topical ophthalmic application of DHA is difficult because of its lipophilic property. Therefore, it is important to develop aqueous-based formulation with enhanced capabilities. Novel, unique water-dilutable microemulsions (MEs) were constructed to allow loading of naturally occurring rigid long-chain triglyceride of DHA (TG-DHA). The TG-DHA serves as solubilizate and as the oil phase, therefore preparation is poor in oil. The structural transformations of MEs upon water dilution were studied by SAXS, viscosity, electrical conductivity, self-diffusion NMR, DSC, cryo-TEM, and DLS techniques. At low water content a new type of water-in-oil (W/O) structure is formed. The glycerol/water phase hydrates the headgroups of surfactants, and the oil solvates their tails, forming "ill-defined bicontinuous domains". Upon further water dilution more structured bicontinuous domains of high viscosity are formed. After additional dilution, the mesophases invert to oil-in-water (O/W) droplets of ∼8nm. In the structures composed of up to 25wt% water, the TG-DHA spaces and de-entangles the surfactant tails. Once the bicontinuous structures are formed, the surfactants and TG-DHA content decrease and their interfacial layer shrinks, leading to entanglement and buildup of viscous non-Newtonian mesophase. Above 70wt% water TG-DHA is embedded in the core of the O/W droplets, and its effect on the droplets' structure is minimal. This new dilutable ill-defined microemulsion can be a potential delivery vehicle for ophthalmic TG-DHA transport.

Biocompatible colloidal dispersions as potential formulations of natural pyrethrins: a structural and efficacy study

Biocompatible colloidal dispersions of the micro- and nanoemulsion type based on lemon oil terpenes, polysorbates, water, and glycerol were used for the formulation of pyrethrins, botanical insecticides derived from the white pyrethrum daisy, Tanacetum cinerariifolium. The proposed formulation is based on pyrethrin-containing water-in-oil (W/O) microemulsions that could be diluted in one step with an aqueous phase to obtain kinetically stable oil-in-water (O/W) nanoemulsions. Structural characteristics of the micro- and nanoemulsions were evaluated by electron paramagnetic resonance (EPR) spectroscopy, dynamic light scattering (DLS), small angle X-ray scattering (SAXS), and electrical conductivity. Dynamic properties of the surfactant monolayer as evidenced by EPR measurements were affected by the water content, the surfactant, and also the presence of the biocide. DLS and SAXS experiments of the nanoemulsions indicated the existence of two populations of oil droplets dispersed in the aqueous phase, globular droplets of 36-37 nm in diameter, and also larger droplets with diameters >150 nm. All of the applied techniques for structural determination revealed the participation of the biocide in the nanostructure. The insecticidal effect of the encapsulated natural pyrethrin was evaluated in laboratory bioassays upon a target-insect pest, the cotton aphid Aphis gossypii Glover (Hemiptera: Aphididae) in eggplant, and was found to be increased compared to the commercial pyrethrin formulation.