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By understanding all the components of plants, especially medicinal ones, our goal is to discover plant-derived alternatives to antibiotics. This research aims to contribute to the knowledge of the biological activities Mentha spicata (MS) extracts and their effects under different environmental conditions. Hemolysis, analgesic, anti-inflammatory and antimicrobial activities were estimated of aqueous extracts of Mentha spicata. The results showed that MS El Oued extract protected the erythrocytes from hemolysis, while MS El Taref extract showed a lower protection capability. The results showed high levels of anti-inflammatory activity from plants found in the northeastern region (Tebessa and El Taref) compared to the southeast region (El Oued). They showed that MS El Oued extract exhibited higher analgesic activity (32.46%) compared to MS Tebessa, and MS El Taref extracts (19.48 and 12.97%, respectively). The results showed the antimicrobial activity, the inhibition diameter was between 17.4 - 25mm, and the largest diameter of all extracts was recorded against Aspergillus niger from the MS El Taref extract and the lowest against Staphylococcus aureus from the MS El Oued extract. The MS El Taref extract had the highest levels of activity against Aspergillus niger and Staphylococcus aureus and the MS Tebessa extract had the highest levels against Pseudomonas aeruginosa and Escherichia coli. The activity levels against Candida lipolytica, were found to be equal. In conclusion, the environmental conditions had an influence on the bioactive substances present in the plants. These bioactive substances directly influenced the biological activities of the plant extracts.

This work combines experimental and computational modeling studies for the preparation of a composite of metformin and an organoclay, examining the advantages of a Tunisian clay used for drug delivery applications. The clay mineral studied is a montmorillonite-like smectite (Sm-Na), and the organoclay derivative (HDTMA-Sm) was used as a drug carrier for metformin hydrochloride (MET). In order to assess the MET loading into the clays, these materials were characterized by means of cation exchange capacity assessment, specific surface area measurement, and with the techniques of X-ray diffraction (XRD), differential scanning calorimetry, X-ray fluorescence spectroscopy, and Fourier-transformed infrared spectroscopy. Computational molecular modeling studies showed the surface adsorption process, identifying the clay–drug interactions through hydrogen bonds, and assessing electrostatic interactions for the hybrid MET/Sm-Na and hydrophobic interactions and cation exchange for the hybrid MET/HDTMA-Sm. The results show that the clays (Sm-Na and HDTMA-Sm) are capable of adsorbing MET, reaching a maximum load of 12.42 and 21.97 %, respectively. The adsorption isotherms were fitted by the Freundlich model, indicating heterogeneous adsorption of the studied adsorbate–adsorbent system, and they followed pseudo-second-order kinetics. The calculations of ΔGº indicate the spontaneous and reversible nature of the adsorption. The calculation of ΔH° indicates physical adsorption for the purified clay (Sm-Na) and chemical adsorption for the modified clay (HDTMA-Sm). The release of intercalated MET was studied in media simulating gastric and intestinal fluids, revealing that the purified clay (Sm-Na) and the modified organoclay (HDTMA-Sm) can be used as carriers in controlled drug delivery in future clinical applications. The molecular modeling studies confirmed the experimental phenomena, showing that the main adsorption mechanism is the cation exchange process between proton and MET cations into the interlayer space. [ABSTRACT FROM AUTHOR]

This study was aimed at investigating the micro-formulation of capsules using natural biopolymers, such as cactus mucilage (CM), carboxymethyl cellulose sodium salt (CMCNa) and chitosan (Chi) as the wall material, for the transport and supply of sunflower oil. CM samples were extracted from Opuntia ficus indica (OFI) by precipitation at different supernatant pH values (2, 4 and 12). The extracted natural polysaccharide and the resulting microcapsules were characterized by different experimental techniques. Fourier transform infrared spectroscopy analysis of the CM showed the presence of uronic acid units and sugars. Scanning electron microscopy revealed that most particles were adhered together, causing the formation of compact, linked agglomerates, which resulted in different microstructures with irregular shapes. All oil–core microcapsules were characterized, and the results showed that the different shell materials could be used to microencapsulate sunflower oil. Among them, the microcapsule crosslinked with CM and Chi was the most suitable, with the highest encapsulation efficiency (95 %). This coacervation led to the narrowest size distribution of the capsules, with diameters ranging from 1 to 5 μm. Optical microscopy confirmed the deposition of coacervate droplets around oil drops and clearly showed that the formation of coacervated particles and their deposition onto oil droplets were successive events.

In this work, we provide a new investigation on the effect of Sm3+ doping on the sol–gel mixture and stabilization of TiO2 sol. Sm3+ dopant was initially dissolved in dilute ethanol solvent to form Sm-ethanol solvation shells. After hydrolysis, the effect of Sm-modified solvent on the growth and aggregation of TiO2 primary particles was put in evidence. 1H-NMR spectrum of Sm–TiO2 sol shows signals broadening of nBuOH and ethanol molecules without splitting effect, indicating that the two alcohols are located in solvation shells surrounding the Sm3+ cations. The stabilization of TiO2 colloidal sol is induced by the bound Sm3+-solvate species to Ti-oxo-alkoxy polymers, inhibiting the growth of TiO2 particles. In the absence of Sm3+ dopant, the TiO2 colloidal sol shows a high resolution 1H-NMR spectrum with splitting of 1H signals of ethanol and free nBuOH. SEM analysis of TiO2 consists of monodisperse spherical particles, whereas Sm–TiO2 shows a massive monolith with small particle size. These effects were correlated with TG/DTA and XRD results showing that Sm3+ dopant induces a more complex and prolonged thermal decomposition, decreasing the crystallization degree of TiO2 anatase. The effect of Sm3+ doping on UV-absorption region, adsorption capacity, and photocatalytic activity of TiO2 nanoparticles was also investigated. [ABSTRACT FROM AUTHOR]