The natural polymer chitosan is the second most abundant biopolymer on earth after chitin and has been extensively explored for preparation of versatile drug delivery systems. The presence of two distinct reactive functional groups (an amino group at C2, and a primary and secondary hydroxyl group at C3 and C6) of chitosan are involved in the transformation of expedient derivatives such as acylated, alkylated, carboxylated, quaternized and esterified chitosan. Amongst these, quaternized chitosan is preferred in pharmaceutical industries owing to its prominent features including superior water solubility, augmented antimicrobial actions, modified wound healing, pH-sensitive targeting, biocompatibility, and biodegradability. It has been explored in a large realm of pharmaceuticals, cosmeceuticals, and the biomedical arena. Immense classy drug delivery systems containing quaternized chitosan have been intended for tissue engineering, wound healing, gene, and vaccine delivery. This review article outlines synthetic techniques, basic characteristics, inherent properties, biomedical applications, and ubiquitous challenges associated to quaternized chitosan.

In addition to the benefits, increasing the constant need for antibiotics has resulted in the development of antibiotic bacterial resistance over time. Antibiotic tolerance mainly evolves in these bacteria through efflux pumps and biofilms. Leading to its modern and profitable uses, emerging nanotechnology is a significant field of research that is considered as the most important scientific breakthrough in recent years. Metal nanoparticles as nanocarriers are currently attracting a lot of interest from scientists, because of their wide range of applications and higher compatibility with bioactive components. As a consequence of their ability to inhibit the growth of bacteria, nanoparticles have been shown to have significant antibacterial, antifungal, antiviral, and antiparasitic efficacy in the battle against antibiotic resistance in microorganisms. As a result, this study covers bacterial tolerance to antibiotics, the antibacterial properties of various metal nanoparticles, their mechanisms, and the use of various metal and metal oxide nanoparticles as novel antibiotic carriers for direct antibiotic delivery.

The antimicrobial properties of essential oil from Lavandula sp. raise hopes related to its use in phytotherapy. This study aimed to evaluate the antimicrobial activity of essential oils from cultivars of L. angustifolia (‘Hidcote Blue Strain’, ‘Hidcote Blue’) and L. × intermedia (‘Phenomenal’, ‘Grosso’) grown in central-eastern Poland, that is, at the border of the northern lavender cultivation range. The chemical composition of the essential oils was determined by GC/MS. Essential oil concentrations (20, 10, 5, 2.5, 1.25, 0.6, 0.3, 0.16, 0.08, and 0.04 mg/mL) were tested to determine the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) or minimum fungicidal concentration (MFC) towards ten strains of Gram-positive bacteria, five Gram-negative bacteria, and eight yeasts in vitro culture. Essential oils from the Lavendula cultivars showed antimicrobial activity against all microorganisms analysed. The yeasts were characterised by higher sensitivity to lavender oil compared to bacteria, while Gram-positive bacteria were more sensitive than Gram-negative bacteria. The lowest MIC values for bacteria and fungi were obtained for ‘Grosso’. Furthermore, the ‘Grosso’ oil showed the highest fungicidal activity, while the highest bactericidal activity was found in ‘Hidcote Blue’ and ‘Grosso’. Using Staphylococcus aureus as an example, it was shown that different bacterial strains of the same species show varying sensitivity to the essential oil. A higher oil content was noted for the cultivars L. × intermedia, especially for the ‘Phenomenal’. Linalyl acetate and linalool were the main components of the essential oil in all cultivars. However, in the ‘Grosso’ oil, a high content of terpinen-4-ol (18.08%) was also recorded. An analysis of the relationships between the content of the main components in the analysed essential oils and the antimicrobial activity of essential oils suggested that linalool and terpinen-4-ol were compounds potentially responsible for antimicrobial activity. The obtained results allow us to conclude that essential oil with significant antimicrobial activity can be obtained from Lavandula sp. plants harvested in the northern part of the cultivation range.

Dog rose (Rosa canina L.) is a beautiful ornamental plant that provides fruit with high biological value. To be available throughout the year, rose hips need to be conserved, such as dried and canned. For this reason, a study was undertaken to investigate the effects of drying as the most common method for preservation. Therefore, the influence of variation drying temperature (20, 35 and 68 °C) on the content of flavonoids, total polyphenols, ascorbic acid, carotenoids and antioxidant activity - determined using the free radical source DPPH (2,2-diphenyl-1-picrylhydrazyl) and a test measuring the measuring of compounds to reduce ferric ions Fe3+ (FRAP) - of rose hips was the main topic in this study. Drying decreased total polyphenols (from 38.06 mg g–1 by fresh fruits to 9.41 mg g–1 drying to 20 °C), ascorbic acid (from 2000.5 mg 100 g–1 by fresh fruits to 1308.2 mg 100 g–1 drying to 68 °C) and flavonoids, the latter only in those dried at 35 °C (0.54 mg g–1), but did not affect the antioxidant activity of DPPH (84.21–85.73%) and FRAP (2.99–3.41 mgTr g–1). The study also showed that the extraction time influenced the antioxidant activity level of fruit infusions for the first time. The antioxidant potential FRAP value increased systematically with extraction time, but the DPPH values of extracts obtained from dried rose hips were not affected by the extraction time. These results indicate that changes in the antioxidant activity of extracts may not be linear and that the choice of the time of evaluation of this activity may determine the results.

Proline is an amino acid that increases plant tolerance to abiotic and biotic stresses, but the effects of its application can be influenced by many factors. The present study investigated the effects of time and the number of applications of this amino acid on the yield of root parsley in field conditions. The experimental material comprised of two parsley cultivars (Petroselinum crispum (Mill.) Nyman ex A.W. Hill), ‘Halblange’ and ‘Sonata’. The parsley plants were sprayed with proline (1000 mg L⁻¹) at growth stages determined according to the BBCH scale: BBCH 15–16 (I: 5–6 leaf phase), BBCH 41 (II: roots start to widen, diameter > 0.5 cm), and BBCH scale 42–43 (III: roots are 20–30% of the typical diameter), including I + II, II + III, and I + II + III. The time and number of proline applications affected the weight of leaves and the total and marketable yield. The amino acid spraying increased the average number of plants during harvest in the ‘Halblange’ but decreased the number in the ‘Sonata’ in all applications. Using proline twice or three times reduced the total essential oil content and modified its composition. The most beneficial effect in terms of the composition was achieved by using proline twice at stages II + III, even in ‘Sonata’, where the values were lower in the other treatments than in the control. Spraying three times did not give better results in terms of the composition and content of the essential oil. However, the use of this amino acid did not affect the total and marketable yield of the roots or the leaf weight of the parsley compared to the control. Our study showed that the time of the proline application may be more important than the number of applications, and the results may be cultivar-dependent.