Utilization of dynamic light scattering to evaluate Pterodon emarginatus oleoresin-based nanoemulsion formation by non-heating and solvent-free method

A Perspective on Various Facets of Nanoemulsions and its Commercial Utilities

Nanotechnology is a captivating contemporary technology owing to its extensive range of potential applications. This study emphasizes nanomaterials, substances with a size <100 nm, offering better qualities than coarse particles. Nanoparticles have several advantages compared with conventional drug delivery methods, including enhanced bioavailability and a larger surface area because of their smaller particle size. These characteristics make the nanoparticles a viable clinical candidate. Controlled-release drug delivery systems and targeted drug delivery systems rely heavily on nanoparticles. Because traditional drug delivery methods fail to achieve targeted drug delivery, resulting in toxicity, low bioavailability, poor therapeutic outcomes, and so on, these drug nanoparticles excel in all these areas. Researchers are already interested in developing drug delivery systems such as niosomes, bilosomes, and dendrimers. Nanoemulsion is one of these technologies; nanoemulsions outperform traditional emulsions in terms of pharmacodynamics and pharmacokinetics. Nanoemulsion effectively surpasses the constraints of standard emulsions, primarily by offering enhanced bioavailability, reduced toxicity, improved absorption, and the potential to be used in targeted drug delivery or controlled-release drug delivery systems. This particular work explores several aspects of nanoemulsions, including their constituents, classification, techniques for preparation, criteria for assessment, commercial applications, and future prospects.

Larvicidal Effect of Hyptis suaveolens (L.) Poit. Essential Oil Nanoemulsion on Culex quinquefasciatus (Diptera: Culicidae)

Mosquitoes can be vectors of pathogens and transmit diseases to both animals and humans. Species of the genus Culex are part of the cycle of neglected diseases, especially Culex quinquefasciatus, which is an anthropophilic vector of lymphatic filariasis. Natural products can be an alternative to synthetic insecticides for vector control; however, the main issue is the poor water availability of some compounds from plant origin. In this context, nanoemulsions are kinetic stable delivery systems of great interest for lipophilic substances. The objective of this study was to investigate the larvicidal activity of the Hyptis suaveolens essential oil nanoemulsion on Cx. quinquefasciatus. The essential oil showed a predominance of monoterpenes with retention time (RT) lower than 15 min. The average size diameter of the emulsions (sorbitan monooleate/polysorbate 20) was ≤ 200 nm. The nanoemulsion showed high larvicidal activity in concentrations of 250 and 125 ppm. CL50 values were 102.41 (77.5253−149.14) ppm and 70.8105 (44.5282−109.811) ppm after 24 and 48 h, respectively. The mortality rate in the surfactant control was lower than 9%. Scanning micrograph images showed changes in the larvae’s integument. This study achieved an active nanoemulsion on Cx. quinquefasciatus through a low-energy-input technique and without using potentially toxic organic solvents. Therefore, it expands the scope of possible applications of H. suaveolens essential oil in the production of high-added-value nanosystems for tropical disease vector control.

Recent progress in micro and nano-encapsulation of bioactive derivatives of the Brazilian genus Pterodon

In the last few decades, utilization of medicinal plants by the pharmaceutical industry has led to the identification of many new bioactive compounds. The genus Pterodon, native of the Brazilian Flora, is known for the therapeutic properties attributed to its species, which are widely used in popular medicine for their anti-inflammatory, anti-rheumatic, tonic, and depurative properties. The intrinsic low water solubility of the plant derivatives from the genus, including diterpenes with vouacapane skeletons that are partially associated with the pharmacological activities, impairs the bioavailability of these bioactive compounds. Recent studies have aimed to encapsulate Pterodon products to improve their water solubility, achieve stability, increase their efficacy, and allow clinical applications. The purpose of this paper is to review recent research on the use of nanotechnology for the development of new products from plant derivatives of the Pterodon genus in different types of micro- and nanocarriers. Therapeutic properties of their different products are also presented. Finally, an update about the current and future applications of encapsulated formulations is provided.

Development of nano-emulsions based on Ayapana triplinervis essential oil for the control of Aedes aegypti larvae

Ayapana triplinervis is a plant species used in traditional medicine and in mystical-religious rituals by traditional communities in the Amazon. The aim of this study are to develop a nano-emulsion containing essential oil from A. triplinervis morphotypes, to evaluate larvicidal activity against Aedes aegypti and acute oral toxicity in Swiss albino mice (Mus musculus). The essential oils were extracted by steam dragging, identified by gas chromatography coupled to mass spectrometry, and nano-emulsions were prepared using the low energy method. Phytochemical analyses indicated the major compounds, expressed as area percentage, β-Caryophyllene (45.93%) and Thymohydroquinone Dimethyl Ether (32.93%) in morphotype A; and Thymohydroquinone Dimethyl Ether (84.53%) was found in morphotype B. Morphotype A essential oil nano-emulsion showed a particle size of 101.400 ± 0.971 nm (polydispersity index = 0.124 ± 0.009 and zeta potential = -19.300 ± 0.787 mV). Morphotype B essential oil nano-emulsion had a particle size of 104.567 ± 0.416 nm (polydispersity index = 0.168 ± 0.016 and zeta potential = -27.700 ± 1.307 mV). Histomorphological analyses showed the presence of inflammatory cells in the liver of animals treated with morphotype A essential oil nano-emulsion (MAEON) and morphotype B essential oil nano-emulsion (MBEON). Congestion and the presence of transudate with leukocyte infiltration in the lung of animals treated with MAEON were observed. The nano-emulsions containing essential oils of A. triplinervis morphotypes showed an effective nanobiotechnological product in the chemical control of A. aegypti larvae with minimal toxicological action for non-target mammals.

A Low Energy Approach for the Preparation of Nano-Emulsions with a High Citral-Content Essential Oil

Pectis elongata is found in the northern and northeastern regions of Brazil. It is considered a lemongrass due to its citric scent. The remarkable citral content and the wide antimicrobial properties and bioactive features of this terpene make this essential oil (EO) eligible for several industrial purposes, especially in cosmetics and phytotherapics. However, to address the problems regarding citral solubility, nano-emulsification is considered a promising strategy thanks to its improved dispersability. Thus, in this paper we propose a low-energy approach for the development of citral-based nano-emulsions prepared with P. elongata EO. The plant was hydrodistillated to produce the EO, which was characterized with a gas chromatograph coupled to mass spectrometry. The nano-emulsion prepared by a non-heated water titrating (low-energy) method was composed of 5% (w/w) EO, 5% (w/w) non-ionic surfactants and 90% (w/w) deionized water and was analyzed by dynamic light scattering. Levels of citral of around 90% (neral:geranial—4:5) were detected in the EO and no major alteration in the ratio of citral was observed after the nano-emulsification. The nano-emulsion was stable until the 14th day (size around 115 nm and polydispersity index around 0.2) and no major alteration in droplet size was observed within 30 days of storage. Understanding the droplet size distribution as a function of time and correlating it to concepts of compositional ripening, as opposing forces to the conventional Ostwald ripening destabilization mechanism, may open interesting approaches for further industrial application of novel, low-energy, ecofriendly approaches to high citral essential oil-based nano-emulsions based on lemongrass plants.

Efficacy of nanoemulsion with Pterodon emarginatus Vogel oleoresin for topical treatment of cutaneous leishmaniasis

Cutaneous leishmaniasis (CL) is a neglected tropical skin disease caused by the protozoan genus Leishmania. The treatment is restricted to a handful number of drugs that exhibit toxic effects, limited efficacy, and drug resistance. Additionally, developing an effective topical treatment is still an enormous unmet medical challenge. Natural oils, e.g. the oleoresin from P. emarginatus fruits (SO), contain various bioactive molecules, especially terpenoid compounds such as diterpenes and sesquiterpenes. However, its use in topical formulations can be impaired due to the natural barrier of the skin for low water solubility compounds. Nanoemulsions (NE) are drug delivery systems able to increase penetration of lipophilic compounds throughout the skin, improving their topical effect. In this context, we propose the use of SO-containing NE (SO-NE) for CL treatment. The SO-NE was produced by a low energy method and presented suitable physicochemical characteristic: average diameter and polydispersity index lower than 180 nm and 0.2, respectively. Leishmania (Leishmania) amazonensis-infected BALB/c mice were given topical doses of SO or SO-NE. The topical use of a combination of SO-NE and intraperitoneal meglumine antimoniate reduced lesion size by 41 % and tissue regeneration was proven by histopathological analyses. In addition, a reduction in the parasitic load and decreased in the level of IFN-γ in the lesion may be associated, as well as a lower level of the cytokine IL-10 may be associated with a less intense inflammatory process. The present study suggests that SO-NE in combination meglumine antimoniate represents a promising alternative for the topical treatment of CL caused by L. (L.) amazonensis.

Nanoemulsion as a feasible and biocompatible carrier for ocular delivery of travoprost: Improved pharmacokinetic/pharmacodynamic properties

Travoprost is a synthetic prostaglandin F2α analogue used in treatment of glaucoma. Due to its water insolubility and oily nature, novel delivery systems need to be developed to enhance its bioavailability, and sustain its release. In the current work, travoprost nanoemulsion was explored as a novel carrier prepared using low energy technique. Results showed that travoprost nanoemulsions exhibited suitable nanodroplet size, zeta potential, pH, refractive index, controlled release, as well as sufficient stability under accelerated conditions. In vivo studies delineated the enhanced absorption of travoprost nanoemulsion compared to the marketed eye drops Travatan®, as proven by the higher C_max and AUC of the former, and its prolonged intraocular pressure reduction time. Moreover, the nanoemulsion formulation was proven safe and non-irritant to ocular surfaces. Therefore, it can be suggested that travoprost nanoemulsion is a promising ocular delivery system for glaucoma treatment.

Interferon-gamma carrying nanoemulsion with immunomodulatory and anti-tumor activities

The therapeutic administration of cytokines has been introduced aiming to modulate the immune response system, seeking for different approaches to face pathologies such as cancer, auto immune and infectious diseases. The objective of this study was to investigate the effects of a stable oil-in-water (O/W) nanoemulsion system carrying the cytokine Interferon gamma (IFN-γ) on the activity of phagocytes and MCF-7 human breast cancer cells. Nanoemulsions were prepared through ultra-homogenization, and they consisted of distilled water, triglycerides of capric acid/caprylic, sorbitan-oleate, polysorbate 80, and 1-butanol. IFN-γ (100 ng ml^-1 ) was incorporated into two O/W nanoemulsion formulations, and these formulations were characterized in terms of their preliminary and accelerated physicochemical stability, rheological properties, droplet size, polydispersity and surface charge. We identified the most optimal IFN-γ nanoemulsion (IFN-γNE2), which remained stable under extreme temperature variations for 90 days, contained an average dose of 97 ng ml^-1 of IFN-γ and exhibited a biocompatible pH and a relative stable rheological profile. Cell viability and intracellular Ca²⁺ release assays conducted showed that IFN-γNE2 reduced the cell viability of MCF-7 cells without affecting the cell viability of phagocytes. Furthermore, IFN-γNE2 was able to induce cellular activity of phagocytes as evidenced by increased intracellular Ca²⁺ release in these cells. Our findings on this IFN-γ nanoemulsion suggest that it can be a promising therapeutic agent for immunostimulation and cancer treatment.