Preclinical Safety Evaluation of Allicin on Topical Application
Further evaluation of skin irritability and irritation induced by allicin was performed to assess the suitability and safety of allicin for topical applications. Skin changes were observed after allicin treatment daily, including erythema and edema. As shown in Figures 2A and 2B, no allergic reactions were observed in the allicin administration group. After four months of continuous application, compared with the blank solvent control group, allicin led to slight skin irritation in the first three months and yielded no irritation in the fourth month due to gradual development of skin tolerance (figure 2C). Next, we inspected the toxicity of allicin for long-term application, and there was no significant influence on weight (Figure 2D). The organ index was calculated after the major organs were resected and weighed, using the formula Organ index = organ weight (mg) / body weight (kg) ×100%. The heart, liver, spleen, and thymus indexes showed that allicin yielded no significant difference in body weight and major organs compared with the control group (Figure 2E). Hematology (Figure 2F, Table S2) and biochemistry (Table S3) indicators were analyzed before and after continuous topical application of allicin, with no significant changes. Our data demonstrated that allicin was safe and well-tolerated for long-term external use.