Flavonoid Content During the Growth and Floral Development of Calendula officinalis L

Pot marigold (Calendula officinalis L.) with multiple uses, notably its medicinal applications due to its richness and diversity in secondary metabolites, such as flavonoids, which possess anti-inflammatory and antioxidant properties.This study analyzed plant growth and biomass distribution, as well as total flavonoid concentration in tubular, ligulate flowers, and flower heads throughout floral development. Floral initiation and differentiation occurred five weeks after transplantation, following a sigmoid pattern of biomass accumulation in its organs as well as in plant height. Aerial organs reached a maximum biomass of 76 g/ g/plant on day 69. The maximum absolute growth rate was 2.38 g/day at 62 days, while the highest relative growth rate was recorded in reproductive organs on day 48 (0.137 g/g/day). Flavonoids, expressed as quercetin equivalents, showed higher concentrations during stages ranging from flower buds to fully opened flower heads (145-177 mg/g of dry matter). These findings emphasize the importance of harvesting at optimal stages to maximize flavonoid content and leverage their potential for therapeutic and commercial applications.