Calendula officinalis L. as a Source of Bioactive Compounds for Functional Foods: A Review

Abstract

Calendula officinalis L. (pot marigold) is a medicinal and edible plant used as a source of bioactive compounds with potential applications in functional foods. This review brings together current data on the phytochemical profile, biological activity, agronomic factors, and food applications of C. officinalis, based on 76 publications. More than 500 secondary metabolites have been reported in this species, including flavonoids, carotenoids, terpenoids, polysaccharides, coumarins, and essential-oil components. Reported levels depend strongly on cultivar, growing conditions, plant part, and analytical method. Total flavonoid content in dried flowers ranges from 0.21 to 0.68% across 20 European cultivars, with up to 1.7% in selected Estonian-grown cultivars such as ‘Radio’. Reported total carotenoid values cover almost two orders of magnitude (about 48 to 3510 mg/100 g of dried material), reflecting differences in plant part, colour variant, and method (spectrophotometric sum vs. HPLC). Dried flowers contain up to 62.33 g/100 g of total dietary fibre (mostly insoluble). The associated activities are antioxidant, anti-inflammatory, antimicrobial, regenerative, cytotoxic, and neuroprotective. Recent food-application studies show useful effects in yogurt (0.25 g lyophilized extract/100 g), wheat bread (10–15% of formulation water replaced with aqueous extract), and fresh pasta (5% flower powder substitution), with notable increases in antioxidant capacity and acceptable sensory scores. The number of full food-product trials is still small, and this review identifies the processing variables and the research gaps that determine whether C. officinalis can be used as a standard functional-food ingredient.