The emergence of bacterial resistance has motivated researchers to discover new antibacterial agents. Nowadays, fluoroquinolones keep their status as one of the essential classes of antibacterial agents. The new generations of fluoroquinolones are valuable therapeutic tools with a spectrum of activity, including Gram-positive, Gram-negative, and atypical bacteria. This review article surveys the design of fluoroquinolone hybrids with other antibacterial agents or active compounds and underlines the new hybrids’ antibacterial properties. Antibiotic fluoroquinolone hybrids have several advantages over combined antibiotic therapy. Thus, some challenges related to joining two different molecules are under study. Structurally, the obtained hybrids may contain a cleavable or non-cleavable linker, an essential element for their pharmacokinetic properties and mechanism of action. The design of hybrids seems to provide promising antibacterial agents helpful in the fight against more virulent and resistant strains. These hybrid structures have proven superior antibacterial activity and less susceptibility to bacterial resistance than the component molecules. In addition, fluoroquinolone hybrids have demonstrated other biological effects such as anti-HIV, antifungal, antiplasmodic/antimalarial, and antitumor activity. Many fluoroquinolone hybrids are in various phases of clinical trials, raising hopes that new antibacterial agents will be approved shortly.

The evolution of the class of antibacterial quinolones includes the introduction in therapy of highly successful compounds. Although many representatives were withdrawn due to severe adverse reactions, a few representatives have proven their therapeutical value over time. The classification of antibacterial quinolones into generations is a valuable tool for physicians, pharmacists, and researchers. In addition, the transition from one generation to another has brought new representatives with improved properties. In the last two decades, several representatives of antibacterial quinolones received approval for therapy. This review sets out to chronologically outline the group of approved antibacterial quinolones since 2000. Special attention is given to eight representatives: besifloxacin, delafoxacin, finafloxacin, lascufloxacin, nadifloxacin and levonadifloxacin, nemonoxacin, and zabofloxacin. These compounds have been characterized regarding physicochemical properties, formulations, antibacterial activity spectrum and advantageous structural characteristics related to antibacterial efficiency. At present these new compounds (with the exception of nadifloxacin) are reported differently, most often in the fourth generation and less frequently in a new generation (the fifth). Although these new compounds’ mechanism does not contain essential new elements, the question of shaping a new generation (the fifth) arises, based on higher potency and broad spectrum of activity, including resistant bacterial strains. The functional groups that ensured the biological activity, good pharmacokinetic properties and a safety profile were highlighted. In addition, these new representatives have a low risk of determining bacterial resistance. Several positive aspects are added to the fourth fluoroquinolones generation, characteristics that can be the basis of the fifth generation. Antibacterial quinolones class continues to acquire new compounds with antibacterial potential, among other effects. Numerous derivatives, hybrids or conjugates are currently in various stages of research.

Nitrogen heterocycles are valuable structural elements in the molecules of antibacterial drugs approved and used to treat bacterial infections. Pyrrole is a five-atom heterocycle found in many natural compounds with biological activity, including antibacterial activity. Numerous compounds are being develop based on the pyrrole heterocycle as new potential antibacterial drugs. Due to the phenomenon of antibacterial resistance, there is a continuous need to create new effective antibacterials. In the scientific literature, we have identified the most relevant studies that aim to develop new compounds, such as pyrrole derivatives, that are proven to have antibacterial activity. Nature is an endless reservoir of inspiration for designing new compounds based on the structure of pyrrole heterocycles such as calcimycin, lynamycins, marinopyrroles, nargenicines, phallusialides, and others. However, many other synthetic compounds based on the pyrrole heterocycle have been developed and can be optimized in the future. The identified compounds were classified according to the type of chemical structure. The chemical structure–activity relationships, mechanisms of action, and antibacterial effectiveness of the most valuable compounds were highlighted. This review highlights scientific progress in designing new pyrrole-containing compounds and provides examples of lead compounds that can be successfully optimized further.

Glutamic acid is a non-essential amino acid involved in multiple metabolic pathways. Of high importance is its relationship with glutamine, an essential fuel for cancer cell development. Compounds that can modify glutamine or glutamic acid behaviour in cancer cells have resulted in attractive anticancer therapeutic alternatives. Based on this idea, we theoretically formulated 123 glutamic acid derivatives using Biovia Draw. Suitable candidates for our research were selected among them. For this, online platforms and programs were used to describe specific properties and their behaviour in the human organism. Nine compounds proved to have suitable or easy to optimise properties. The selected compounds showed cytotoxicity against breast adenocarcinoma, lung cancer cell lines, colon carcinoma, and T cells from acute leukaemia. Compound 2Ba5 exhibited the lowest toxicity, and derivative 4Db6 exhibited the most intense bioactivity. Molecular docking studies were also performed. The binding site of the 4Db6 compound in the glutamine synthetase structure was determined, with the D subunit and cluster 1 being the most promising. In conclusion, glutamic acid is an amino acid that can be manipulated very easily. Therefore, molecules derived from its structure have great potential to become innovative drugs, and further research on these will be conducted.

Cannabidiol (CBD), a non-psychoactive phytocannabinoid derived from Cannabis sativa L., has emerged as a promising multifunctional agent in dermatology and cosmetic science. The review provides an updated synthesis of CBD’s topical therapeutic potential, challenges, and evolving regulatory frameworks. CBD exhibits diverse biological effects, including anti-inflammatory, antioxidant, antibacterial, analgesic, lipostatic, antiproliferative, moisturising, and anti-ageing properties through interactions with the skin’s endocannabinoid system (ECS), modulating CB1, CB2, TRPV channels, and PPARs. Preclinical and clinical evidence support its efficacy in managing acne, psoriasis (including scalp psoriasis), atopic and seborrheic dermatitis, and allergic contact dermatitis. CBD also relieves pruritus through neuroimmune modulation and promotes wound healing in conditions such as pyoderma gangrenosum and epidermolysis bullosa. In hair disorders such as androgenetic alopecia, it aids follicular regeneration. CBD shows promise in managing skin cancers (melanoma, squamous cell carcinoma, Kaposi sarcoma) and pigmentation disorders such as melasma and vitiligo. It enhances skin rejuvenation by reducing oxidative stress and boosting collagen and hydration. However, there are challenges regarding CBD’s physicochemical stability, skin penetration, and regulatory standardisation. As consumer demand for natural, multifunctional skincare grows, further research is essential to validate its long-term safety, efficacy, and optimal formulation strategies.