Photochem

Time-resolved (TR) resonance Raman (RR) spectroscopy with continuous-wave excitation is a fundamental technique that has contributed substantially to the understanding of the structure and dynamics of retinal proteins. However, the underlying principles were developed about fifty years ago for instrumentation that is hardly in use anymore. Thus, the adaptation of the technique to the current state-of-the-art equipment is needed to satisfy the increasing demand for the spectroscopic characterization of novel retinal proteins. In this work, we focus on pump–probe TR RR experiments with a confocal spectrometer using a rotating cell. We define the parameters ensuring fresh-sample condition and the photochemical innocence of the probe beam as a prerequisite for studying retinal proteins that undergo a cyclic photoinduced reaction sequence. For the measurements of intermediate states and reaction kinetics, pump–probe experiments are required in which the two laser beams hit the flowing sample with a defined but variable delay time. An appropriate set-up for such two-beam experiments with a confocal spectrometer is proposed and tested in TR experiments of bacteriorhodopsin. The comparison with the results obtained with classical slit spectrometers using a 90-degree scattering illustrates the advantages and disadvantages of the confocal arrangement. It is shown that modern confocal spectrometers substantially decrease the spectra acquisition time but require a more demanding optical set-up. Furthermore, the extent of photoconversion by the pump beam is lower than for the 90-degree-scattering arrangement, which reduces the accuracy of kinetic measurements.

The transition to more sustainable models of production and consumption has encouraged the scientific community to seek innovative solutions that promote environmental responsibility and reduce waste. The cosmetic industry, in particular, has increasingly invested in natural and eco-friendly ingredients as alternatives to synthetic and environmentally harmful components. In this context, plant-derived bioactive compounds with antioxidant and anti-inflammatory potential have gained attention for their ability to enhance photoprotection and reduce the concentration of conventional ultraviolet (UV) filters in sunscreens. Humulus lupulus L. (hop), a plant traditionally used in the brewing industry, generates large amounts of organic waste after the beer production process, especially through the dry-hopping technique. Despite often being discarded, this residual biomass retains important secondary metabolites with high biological value. Our investigation researched the sustainable valorization of hop brewing residues as a source of bioactive compounds for the development of more natural photoprotective products. We performed HLPC-MS/MS analysis and confirmed the presence of α-acids in both pure and reused hop material extracts, while a xanthohumol-like prenylated flavonoid was tentatively detected exclusively in the extract obtained from reused hop extract. In vitro tests demonstrated that sunscreens containing extract obtained from reused material significantly increased the sun protection factor (SPF) without negatively altering the critical wavelength when water was used as the solvent. None of the samples developed higher UVAPF values compared to the control. Our investigation, to the best of our knowledge, constitutes the first successful proof of concept demonstrating the use of both pure (non-reused) and reused hop material extracts as functional photoprotective adjuvants in sunscreen formulations evaluated by a robust, standardized in vitro methodology. This work highlights the dual benefit of reducing industrial waste and developing more sustainable, consumer-friendly cosmetic products.

Sosnovsky’s hogweed (Heracleum sosnowskyi Manden.) is an invasive plant species widely distributed across Eastern Europe and Russia that poses a serious threat to human health due to its pronounced phototoxic properties. Contact with the plant sap followed by exposure to solar ultraviolet (UV) radiation frequently results in phytophotodermatitis, which is characterized by erythema, blistering, ulceration, and persistent hyperpigmentation. The development of these photochemical injuries—most notably furanocoumarins—act as potent photosensitizers and induce cellular and DNA damage upon UV activation. This review provides an integrated overview of the geographical spread and invasiveness of H. sosnowskyi, the chemical composition of its biologically active metabolites, and the molecular mechanisms underlying hogweed-induced skin injury. Particular emphasis is placed on the photochemical transformations of furanocoumarins, including psoralens and their photooxidation products, such as 1,2-dioxetanes, which generate reactive oxygen species and DNA crosslinks. In addition, the review examines other compounds derived from hogweed biomass—including furan derivatives, aromatic compounds, fatty acids, sterols, and their oxidative products—that may contribute to phototoxic and cytotoxic effects. Clinical manifestations of hogweed-induced burns, their classification, symptomatology, and current therapeutic approaches are critically discussed, highlighting the absence of standardized treatment guidelines. Rather than serving as a purely clinical or botanical survey, this review frames Sosnovsky’s hogweed injury as a solar-light-activated photochemical hazard, tracing the sequence from environmental sunlight exposure through molecular photochemistry to biological tissue damage. By integrating chemical, biological, and dermatological perspectives, the review aims to clarify injury mechanisms and support the development of more effective preventive and mitigation strategies under real-world exposure conditions.