Effects of Combined Leonurus japonicus and Trichosanthes kirilowii Extracts on Anti-Inflammatory, Antimicrobial, and Skin Thermoregulatory Activities

Purpose: This study aimed to evaluate the potential of a complex extract containing <i>Leonurus japonicus</i> (LS) and <i>Trichosanthes kirilowii</i> (TKR) as a natural functional cosmetic ingredient by investigating its effects on inflammatory responses in macrophages, the proliferation of skin resident bacteria, and variations in skin temperature.Methods: The anti-inflammatory efficacy was analyzed by measuring NO production and the expression of pro-inflammatory cytokines, specifically TNF-α and IL-1β, in LPS-stimulated RAW 264.7 macrophages. Antibacterial activity was assessed against <i>Staphylococcus epidermidis</i>, a prominent skin resident and opportunistic pathogen. Additionally, clinical evaluations were conducted to monitor changes in skin temperature immediately and at specific intervals following topical application.Results: The complex extract effectively inhibited NO production and suppressed the expression of TNF-α and IL-1β in a dose-dependent manner, confirming its ability to block inflammatory mediators. In the antibacterial assays, the growth of <i>S. epidermidis</i> was significantly inhibited in proportion to the concentration, with both LS and the LS+TKR complex exhibiting a potent inhibition rate of over 90% at a concentration of 100 ㎍/㎖. These results indicate a superior antibacterial synergy compared to single treatments. Furthermore, clinical measurements demonstrated a significant reduction in skin temperature post-application. This thermal reduction is consistent with the scientific mechanism wherein decreased skin temperature leads to reduced sebum secretion and microbial metabolic rates, thereby enhancing overall antibacterial efficacy and stabilizing skin exposed to thermal stress.Conclusion: In conclusion, the complex extract of <i>Leonurus japonicus</i> and <i>Trichosanthes kirilowii</i> demonstrated a functional synergy exceeding that of individual components. By simultaneously providing macrophage-based anti-inflammatory action, skin temperature regulation, and robust antibacterial activity, this complex extract holds significant promise as a multifunctional natural material for improving acne-prone and sensitive skin conditions.