Assessment of Ocimum gratissimum L. Leaf Extracts as Potent Anti-Aging and Skin-Lightening Agents for Food Supplement and Cosmeceutical Applications

Ocimum gratissimum L. (OGL) is a medicinal plant known for various therapeutic properties, yet its potential in genetic-level skin anti-aging remains underexplored. This study aimed to evaluate the phytochemical profiles, antioxidant activities, and anti-aging potential of OGL leaf extracts obtained via aqueous boiling (OGL-B) and ethanolic maceration (OGL-M). Total phenolic and flavonoid contents were quantified using colorimetric assays, while rutin, catechin, and quercetin were analyzed using HPLC. Biological activities were assessed using antioxidant models, tyrosinase inhibition, and B16F10 anti-melanogenesis assays, while skin regenerative potential was evaluated through collagen biosynthesis and expression of longevity-related genes (SIRT1, FOXO1, TERT, and KLOTHO) in human skin fibroblasts. OGL-B provided a significantly higher extraction yield (14.70%) and superior multifunctional antioxidant capacity than OGL-M. OGL-M showed higher phenolic content and cell-free tyrosinase inhibition, whereas OGL-B demonstrated greater cellular anti-melanogenic efficacy and more than twofold higher collagen stimulatory effects than L-ascorbic acid. OGL-B significantly upregulated mRNA expression (271.25 ± 0.21%), exceeding the reference activator resveratrol, and enhanced fibroblast viability to 121.53 ± 3.85% at 1 mg/mL, indicating high biocompatibility. These findings suggest that OGL-B is a multifunctional extract capable of modulating longevity-related pathways, with potential for advanced anti-aging food supplement and cosmeceutical applications.