Skin damage from ultraviolet (UV) radiation is a significant concern, leading to photoaging, sunburn, and wrinkles. Conventional sunscreens often contain synthetic compounds, prompting a search for alternatives. Calendula arvensis (field marigold) has shown promising antioxidant, antibacterial, and enzyme-inhibiting properties, making it a candidate for a sunscreen. This study investigates the potential of C. arvensis capitula extracts in sunscreen formulations, focusing on their photoprotective and anti-aging properties.
Methods
The C. arvensis capitula were subjected to three different extraction methods: maceration, sonication, and infusion, using solvents of varying polarities such as ethanol, a mixture of ethanol and water, and water. The resulting extracts underwent analysis for their phenolic content, antioxidant activities using DPPH, CAT, and FRAP assays, and enzyme inhibition capabilities against tyrosinase, elastase, and collagenase. The sun protection factor (SPF) against UVB radiation was measured using ultraviolet spectrophotometry and surface and interfacial tensions were assessed using a tensiometer.
Key Findings
● Phytochemical Analysis: Phenolic content ranged from 8 to 27 mg GAE/g, flavonoid concentrations were 7–13 mg QE/g, and tannin levels were 1.15–1.68 mg/mL.
● Antioxidant Activity: The sonicated hydroethanolic extract (S-EtOH-H2O) showed the highest antioxidant potential, with low IC50 values in DPPH and ABTS assays.
● Enzyme Inhibition: The hydroethanolic extract demonstrated low IC50 values for tyrosinase, elastase, and collagenase, indicating anti-aging properties.
● Surface Tension: The ethanol maceration extract reduced the interfacial tension to 2.15 mN/m in 600s, outperforming the conventional emulsifier polysorbate 2018.
● UVB Protection: The sonicated hydroethanolic extract had an SPF of 193.65 ± 0.02, significantly higher than zinc oxide (11.88 ± 0.03).
● Formulation: O/W emulsions were developed, incorporating C. arvensis extracts, with the S-EtOH-H2O extract at 0.2% achieving the highest SPF (194.49 ± 0.18)910. The final formulations met COSMOS standards for biological content, with 87.5% biological ingredients and a 100% organic content of the C. arvensis extract.
● Stability: Stability tests over 90 days showed minimal changes in pH, conductivity, and viscosity for the formulations containing C. arvensis extracts, especially at concentrations of 0.1% and 0.2%.
The study’s novelty lies in its demonstration of the superior photoprotective capabilities of C. arvensis extracts compared to conventional sunscreens like zinc oxide and its effective use as a natural emulsifier. Future research should focus on in-vivo studies to validate the efficacy and safety of the developed formulations for commercial use and confirm the specific active compounds responsible for the biological activities.
Link to the study: https://www.mdpi.com/2079-9284/11/6/216
