Phytochemical Profile, Antioxidant Capacity, and Photoprotective Potential of Brazilian Humulus Lupulus

Background and Objectives: The cultivation of Humulus lupulus has been encouraged in Brazil, despite the country's climate generally being unfavorable for its development. This study aimed to evaluate the chemical composition, antioxidant activity, and photoprotective potential of four H. lupulus varieties, Cascade, Columbus, Comet, and Nugget, cultivated in the northwestern region of Paraná State, Brazil. Methods: The varieties were grown in experimental plots. Crude extracts (CEs) of cones and leaves were obtained through dynamic maceration with solvent renewal (96% ethanol), followed by concentration in a rotary evaporator. Assays for sun protection factor (SPF), total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), 2.2-diphenyl-1-picrylhydrazyl (DPPH^•) radical scavenging activity, and 2.2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS^•⁺) were performed to assess antioxidant activity. Chemical profiling was performed using UHPLC-MS/MS. Results: UHPLC-MS/MS analysis revealed the presence of phenolic and organic acids, flavonoids, phenolic aldehydes, alkaloids, and α-benzopyrone-type lactones, with high concentrations of rutin (>500 µg/g) in both cones and leaves. Total phenolic content ranged from 69.70 to 95.95 µg gallic acid equivalent/mg CE; flavonoids from 170.53 to 696.67 µg quercetin equivalent/mg CE; DPPH^• EC₅₀ values ranged from 1.34 to 3.13 mg/mL; FRAP from 1.19 to 2.52 µM ferrous sulfate/mg; ABTS^•⁺ from 5.11 to 22.60 mM Trolox/mg CE; and SPF ranged from 16.02 to 39.48 in the CE of H. lupulus cones and leaves. Conclusions: These findings demonstrate that the cultivated varieties possess antioxidant and photoprotective properties, encouraging further studies to explore their potential applications.