# Biocompatibility of Membranes Based on a Mixture of Chitosan and _Lythri herba_ Aqueous Extract
## 4 Discussion
It has been observed that several of these plants harbor chemical compounds that are recognized for their mutagenic and/or carcinogenic properties [82; 83]. In our study, it was observed that neither the aqueous extract of _Lythri herba_ nor the combined solutions of chitosan and extract exhibited any mutagenic processes. One may underscore the observation that the non-activated and metabolically activated samples exhibited the most elevated induction factor (IF) values at a concentration of 1 g/L of _Lythri herba_ extract. Specifically, values of 0.78 (-S9) and 0.46 (+S9) were recorded. However, it is noteworthy that these values fall below the threshold of 1.5, thereby indicating that the _Lythri herba_ extract, sourced from Romania, lacks genotoxic properties at the aforementioned concentration. The plant species studied in vivo has a very low cytotoxic action [55] and a great potential for exploitation. More investigations are needed to decide whether this specific extract or extracts from other medicinal plants can be used without hazards to human health [84; 85]. The hemocompatibility of the new blended membranes (chitosan and _Lythri herba_ aqueous extract) was evaluated using a hemolytic assay, which is a common method for evaluating the blood compatibility of materials [86]. The membranes obtained from the combination of the biopolymer chitosan (CS) with different concentrations of _Lythri herba_ aqueous extract had the weakest hemolyzing effect, comparable with the standard material (medical steel). A possible explanation would be that the presence of the extract induces chemical bonds with the chitosan biopolymer, thus blocking the ability of these positively charged groups to interact with the negatively charged erythrocyte membranes. This evaluation highlighted hemolysis ratio values of all tested samples that were lower than the 5% recommended by the general standard for hemocompatibility materials. According to the ASTM standard F756, a hemoglobin release of 0-2%, 2-5% or >5% of the total release is classified as non-hemolytic, slightly hemolytic or hemolytic, respectively [87]. Chitosan, in blood contact processes, involves erythrocyte aggregation, platelet activation, the contact activation pathway and the formation of the space net structure. Also, the hemostatic effect of chitosan is influenced by factors such as the quantity of protonated amine groups, molecular weight and degree of deacetylation [88]. A slow hemolysis effect was recorded after 1 h and 2 h between the membranes and blood contact; the effect was similar to other chitosan derivates [89] and chitosan oligosaccharides tested [90]. [PERSON] et al. (2016) compared the hemolytic activity of the variants of membranes based on collagen, chitosan and alkaline phosphatase cross-linked with glutaraldehyde and concluded that simple collagen membranes do not show hemolytic activity, but chitosan ones are slightly hemolyzing. When collagen and alkaline phosphatase are added to chitosan membranes, there is a significant decrease in the hemolyzing property,which suggests that the combination of chitosan with other non-interacting red cells' biomaterials reduces the hemolytic effect [91]. An additional significant aspect to consider in the evaluation of biocompatibility for biomaterials [92; 93] pertains to their capacity to engage with specific blood constituents, thereby initiating a series of reactions that promote the process of coagulation. Surfaces that come in contact with plasma have been found to play a significant role in accelerating the activation of FXII through the prekallikrein and high molecular weight kininogen systems [93]. The existence of a significant activity of thrombin generation in the studied CS-Ly membranes compared with medical steel is a result that confirms the information from the local traditional practice of using the plant as an anticoagulant.