Extraction and Application of Rosmarinic Acid and Carnosic Acid from <em>Melissa officinalis</em> and <em>Rosmarinus officinalis</em>, Respectively: Natural Antioxidants for Sustainable Food Preservation and Antimicrobial Therapy (Nutraceutical Application)

Rosmarinic acid (RA) and Carnosic acid (CA), major phenolic antioxidants from Melissa officinalis and Rosmarinus officinalis, respectively, represent promising natural alternatives to synthetic preservatives. In this study, optimized extraction and purification protocols achieved high yields and purity (RA: 75 ± 2.1%, 85 ± 3.2%; CA: 86 ± 1.8%, 92–99.5 ± 2.7%). Structural confirmation was obtained using HPLC, NMR, LC–MS, and ATR-FTIR, as shown in (Figures 17,18,19,20,21,22,23, and 24). Both compounds demonstrated strong antioxidant activity in vitro, with RA showing superior radical scavenging capacity (IC₅₀ = 12.5 µM) and CA exhibiting higher antimicrobial efficacy. Application in food models (cookies, cocoa beverages, and granules) significantly extended shelf life (1.3–5 years) compared to controls (3 months), based on first-order kinetic modeling. Microbiological analysis confirmed compliance with international food safety standards (NIS 554:2015), with CA-treated samples exhibiting a 10-fold lower bacterial load than RA-treated samples. In vivo studies further revealed that RA provided nephroprotection against gentamicin-induced toxicity, reduced oxidative stress biomarkers, and suppressed allergic responses without detectable toxicity at ≤100 mg/kg. Collectively, these results demonstrate that RA and CA are potent, safe, and scalable antioxidants with dual potential as natural food preservatives and nutraceutical agents.