Phytochemical Profile and Cosmeceutical Potential of Lotus germanicus: Antioxidant, Anti-Tyrosinase, Anti-Elastase and Antibacterial Activities of Parent Plant and In Vitro Cultures

Lotus germanicus (syn. Dorycnium germanicum; Fabaceae) is a rare and regionally threatened European species that remains poorly investigated phytochemically and biologically. This study provides a comprehensive characterization of its phytochemical profile and biological activity and, to our knowledge, the first evaluation of in vitro cultures within the genus Lotus (formerly classified under Dorycnium). Extracts from leaf, herb, and microshoot cultures were analyzed by HPLC-DAD and biological assays. Phenolic acids, flavonoids, sterol-related compounds, and triterpenoids were identified. Isoquercitrin was the predominant flavonoid (5860.00 mg/100 g DW), while hydrocaffeic acid was the major phenolic acid (575.53 mg/100 g DW). In microshoot cultures, β-sitosterol and ursolic acid reached 152.94 and 146.30 mg/100 g DW, respectively. Parent-plant extracts contained higher total phenolic and flavonoid levels and generally showed stronger antioxidant, anti-tyrosinase, and anti-elastase activities. All extracts exhibited antioxidant activity and selective antibacterial activity, mainly against Gram-positive bacteria, with MIC values ranging from 5 to 20 mg/mL for susceptible strains. Despite lower metabolite levels, microshoot cultures retained measurable biological activity. These findings suggest that L. germanicus may represent a potential source of bioactive compounds for further investigation in cosmetic and dermatological applications and highlight the potential of Lotus sect. Dorycnium in vitro cultures as an alternative source of plant-derived metabolites. However, further studies using skin-relevant biological models and formulated cosmetic products are required to confirm the efficacy and safety of these extracts before their practical application.