In the current context of concern for the improvement and protection of environmental conditions, emphasis is placed on the provision of non-toxic, eco-friendly, renewable biomaterials to replace established chemical substances. Lythri herba is the aerial part of the plant species Lythrum salicaria L., known in the scientific literature especially for its content of tannins and total polyphenols, which highlight its antioxidant, hemostatic, antibacterial and antidiarrheal properties. Chitosan is a biopolymer widely used in industry and medicine due to its abundance in nature, its biodegradability, lack of toxicity and the ease with which it can be transformed into several basic forms (hydrogel, membrane, sponge). The aqueous solutions and membranes obtained in this study by merging these two natural resources were biologically tested in terms of genotoxicity (SOS-Chromo assay), hemolytic activity, thrombin generation activity and bacterial adhesion to reveal outwardly the lack of these properties and their use for medical purposes. The results of the current study attest to the absence of mutagenic and slight hemolyzing properties, thus supporting the possibility of using this extract and membrane in medical and pharmaceutical therapeutic practice. The surface parameters of membranes were examined and important influences at thrombin activity were found. Also, bacterial adhesion results showed a correlation between Lythri herba and chitosan concentrations and membranes’ appearances (swelling, stability). The results show that the membranes could be a promising material for biomedical applications.

The Black Sea offers underutilized marine bioresources with potential for the development of materials intended for wound healing and skin tissue repair. In this study, new composite biomaterials were created using collagen peptides extracted from the jellyfish Rhizostoma pulmo (JPC) and hydroalcoholic extracts from the seaweeds Ulva lactuca (ALGU) and Enteromorpha intestinalis (ALGE). The marine-derived ingredients and resulting biocomposites were physicochemically and rheologically characterized and evaluated for antioxidant, antimicrobial, and biological activities on cell cultures relevant to wound healing. Two hydrogel biocomposites, B1 (JPC–ALGU 20%) and B2 (JPC–ALGE 20%), exhibited antioxidant activity of 65.2% and 63.5%, respectively, in the DPPH assay at a concentration of 400 mg/mL, and values of 1.26 μg/mg AAE and 1.15 μg/mg AAE, respectively, in the reducing power assay at a concentration of 800 µg/mL. Antibacterial activity was investigated against several Gram-positive and Gram-negative bacteria. The strongest effects were observed against Staphylococcus aureus. In vitro tests conducted on fibroblast and keratinocyte cultures revealed concentration-dependent cellular responses, while scratch assays confirmed the formulations’ potential to promote cell migration. These results support further investigation of jellyfish collagen–green algae biocomposites for wound-healing and skin tissue-repair applications, although additional dose optimization and in vivo validation are required.