Mosquitocidal and Anti-Inflammatory Properties of The Essential Oils Obtained from Monoecious, Male, and Female Inflorescences of Hemp (Cannabis sativa L.) and Their Encapsulation in Nanoemulsions.

Among the various innovative products obtainable from hemp (Cannabis sativa L.) waste biomass originating from different industrial processes, the essential oil (EO) deserves special attention in order to understand its possible application in different fields, such as cosmetics, pharmaceuticals, and botanical insecticides. For the purpose, in the present work, we studied the chemical composition of EOs obtained from different hemp varieties, namely Felina 32 and Carmagnola Selezionata (CS) using monoecious, male, and female inflorescences, and we evaluated their mosquitocidal activities on larvae and pupae of two main malaria vectors, Anopheles gambiae and An. stephensi. Then, in order to evaluate the safe use of hemp EOs for operators, the potential pro- or anti-inflammatory effect of hemp EOs together with their toxicological profile were determined on dermal fibroblasts and keratinocytes. Given the promising results obtained by insecticidal and anti-inflammatory studies, a preliminary evaluation of EOs encapsulation into nanoemulsions (NEs) has been performed with the aim to develop a formulation able to improve their poor physicochemical stability. Felina 32 and CS inflorescences provided EOs with an interesting chemical profile, with monoterpene and sesquiterpene hydrocarbons as the major components. This study highlighted the potential application of male inflorescences, which are usually discharged during hemp product processing. These EOs could be exploited as potential sustainable and eco-friendly insecticides, given their capability to be toxic against mosquitoes and the possibility to use them to prepare stable and safe formulations. The LC50 values found in this study (<80 ppm) are lower, on average, than those of many plant EOs, with the advantage of using an industrial waste product. From MTT assay and gene and protein expression analysis, EOs showed no cytotoxicity at the appropriate doses and exerted an anti-inflammatory effect on the human cell lines tested. These findings encourage further applied research on hemp EOs in order support their industrial exploitation.

Development and characterization of monoterpene loaded microemulsions as novel scolicidal agents.

Cystic echinococcosis (CE) is one of the most important zoonotic diseases. The primary treatment is surgery and chemical sterilization of the parasitic layers by injection of a scolicidal agent. Available scolicidals possess side effects, and may cause postoperative complications. Several studies reported the scolicidal properties of monoterpene phenols and alcohols such as carvacrol, thymol, and geraniol. The present study aimed to develop, characterize, and assess monoterpene loaded microemulsions as novel green scolicidals products. For this purpose, microemulsions composing 0.37%, 0.75%, and 1.5% of monoterpenoid(s), thymol, carvacrol, and geraniol, alone or in binary or ternary mixtures were formulated. Samples were analyzed by visual inspection, polarizing optical microscope, and dynamic light scattering (DLS). The stability of the samples was evaluated up to a 3-month storage. For the scolicidal bioassay, samples at different concentrations of 200, 100, 50, 25, and 10 µg/ml were added to wells containing 104 viable protoscoleces and mortality rates were recorded at 2, 5, 10, and 20 min after exposure. Results of the present study showed that microemulsions formulated with 0.75% of pure carvacrol or the binary mixture of thymol and carvacrol at 0.375% are promising scolicidal agents.

An Overview of Micro- and Nanoemulsions as Vehicles for Essential Oils: Formulation, Preparation and Stability.

The interest around essential oils is constantly increasing thanks to their biological properties exploitable in several fields, from pharmaceuticals to food and agriculture. However, their widespread use and marketing are still restricted due to their poor physico-chemical properties; i.e., high volatility, thermal decomposition, low water solubility, and stability issues. At the moment, the most suitable approach to overcome such limitations is based on the development of proper formulation strategies. One of the approaches suggested to achieve this goal is the so-called encapsulation process through the preparation of aqueous nano-dispersions. Among them, micro- and nanoemulsions are the most studied thanks to the ease of formulation, handling and to their manufacturing costs. In this direction, this review intends to offer an overview of the formulation, preparation and stability parameters of micro- and nanoemulsions. Specifically, recent literature has been examined in order to define the most common practices adopted (materials and fabrication methods), highlighting their suitability and effectiveness. Finally, relevant points related to formulations, such as optimization, characterization, stability and safety, not deeply studied or clarified yet, were discussed.

Developing a Highly Stable Carlina acaulis Essential Oil Nanoemulsion for Managing Lobesia botrana.

The growing interest in the development of green pest management strategies is leading to the exploitation of essential oils (EOs) as promising botanical pesticides. In this respect, nanotechnology could efficiently support the use of EOs through their encapsulation into stable nanoformulations, such as nanoemulsions (NEs), to improve their stability and efficacy. This technology assures the improvement of the chemical stability, hydrophilicity, and environmental persistence of EOs, giving an added value for the fabrication of natural insecticides effective against a wide spectrum of insect vectors and pests of public and agronomical importance. Carlina acaulis (Asteraceae) root EO has been recently proposed as a promising ingredient of a new generation of botanical insecticides. In the present study, a highly stable C. acaulis-based NE was developed. Interestingly, such a nanosystem was able to encapsulate 6% (w/w) of C. acaulis EO, showing a mean diameter of around 140 nm and a SOR (surfactant-to-oil ratio) of 0.6. Its stability was evaluated in a storage period of six months and corroborated by an accelerated stability study. Therefore, the C. acaulis EO and C. acaulis-based NE were evaluated for their toxicity against 1st instar larvae of the European grapevine moth (EGVM), Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera: Tortricidae), a major vineyard pest. The chemical composition of C. acaulis EO was investigated by gas chromatography-mass spectrometry (GC-MS) revealing carlina oxide, a polyacetylene, as the main constituent. In toxicity assays, both the C. acaulis EO and the C. acaulis-based NE were highly toxic to L. botrana larvae, with LC50 values of 7.299 and 9.044 µL/mL for C. acaulis EO and NE, respectively. The C. acaulis-based NE represents a promising option to develop highly stable botanical insecticides for pest management. To date, this study represents the first evidence about the insecticidal toxicity of EOs and EO-based NEs against this major grapevine pest.

Green Micro- and Nanoemulsions for Managing Parasites, Vectors and Pests.

The management of parasites, insect pests and vectors requests development of novel, effective and eco-friendly tools. The development of resistance towards many drugs and pesticides pushed scientists to look for novel bioactive compounds endowed with multiple modes of action, and with no risk to human health and environment. Several natural products are used as alternative/complementary approaches to manage parasites, insect pests and vectors due to their high efficacy and often limited non-target toxicity. Their encapsulation into nanosystems helps overcome some hurdles related to their physicochemical properties, for instance limited stability and handling, enhancing the overall efficacy. Among different nanosystems, micro- and nanoemulsions are easy-to-use systems in terms of preparation and industrial scale-up. Different reports support their efficacy against parasites of medical importance, including Leishmania, Plasmodium and Trypanosoma as well as agricultural and stored product insect pests and vectors of human diseases, such as Aedes and Culex mosquitoes. Overall, micro- and nanoemulsions are valid options for developing promising eco-friendly tools in pest and vector management, pending proper field validation. Future research on the improvement of technical aspects as well as chronic toxicity experiments on non-target species is needed.

Linear Viscoelastic Properties of Selected Polysaccharide Gums as Function of Concentration, pH, and Temperature.

Hydrocolloids have been intensively investigated due to their ability to modify the rheology of the system where they are employed. They find application as thickening and gelling agents in many food, cosmetic, and pharmaceutical preparations, due to their biocompatibility and biodegradability. The present study aims to provide an exhaustive and comprehensive viscoelastic characterization of a series of hydrocolloid formulations, as function of concentration, pH, and temperature. Glucomannan, xanthan gum, tara gum, guar gum, konjac gum, and gellan gum have been analyzed at two concentrations (0.5% w/w and 1.5% w/w), using three different pH conditions (pH 1.2, 5.5, and 6.8). Their viscoelastic properties have been monitored measuring the main rheological parameters, namely, storage modulus G' and loss modulus G'' as function of frequency, time, and temperature. The results obtained show a clear dependence of the linear viscoelastic properties of the systems on concentration and pH, while the temperature was not a critical factor. Glucomannan, xanthan gum, tara gum, and guar gum samples prepared in phosphate buffer (pH 6.8) at the final concentration of 1.5% (w/w) have been selected as the most promising systems for further investigations, exploring the possibility of combinations to improve the rheological properties. PRACTICAL APPLICATION: Glucomannan, xanthan gum, tara gum, guar gum, konjac gum, and gellan gum have been chosen among the most common thickening agents derived from plants to perform a systematic investigation of the influence of pH, concentration, and temperature on the rheological properties of their water dispersions. The data obtained may be useful for further application of these hydrogels in the nutraceutical field as thickeners, texture modifiers, emulsifiers, stabilizers, and gelling agents.

A Simple and Inexpensive Image Analysis Technique to Study the Effect of Disintegrants Concentration and Diluents Type on Disintegration.

Tablets disintegration is often the result of a size expansion of the tablets. In this study, we quantified the extent and direction of size expansion of tablets during disintegration, using readily available techniques, that is, a digital camera and public domain image analysis software. After validating the method, the influence of disintegrants concentration and diluents type on kinetics and mechanisms of disintegration were studied. Tablets containing diluent, disintegrant (sodium starch glycolate, crospovidone, or croscarmellose sodium), and lubricant were prepared by direct compression. Projected area and aspect ratio of the tablets were monitored using image analysis techniques. The developed method could describe the kinetics and mechanisms of disintegration qualitatively and quantitatively. Sodium starch glycolate and crospovidone acted purely by swelling and shape recovery mechanisms. Instead, croscarmellose sodium worked by a combination of both mechanisms, the extent of which changed depending on its concentration and the diluent type. We anticipate that the method described here could provide a framework for the routine screening of tablets disintegration using readily available equipment.