Abstract

In the last decades, the interest in anthocyanin pigments has enhanced due to their possible use as natural food colorants and
mostly as antioxidant agents. Anthocyanins in flowers of Odontonema strictum (Nees) Kuntze were characterized by high-
performance liquid chromatography combined with electrospray ionization quadrupole-time-of-flight mass spectrometry. A total
of five anthocyanins were identified. They were reported from O. strictum flowers for the 1st time. O. strictum flowers extracts
were also investigated for their total phenolic, flavonoid, anthocyanin contents, and antioxidant activities using the 2,2-diphenyl-
1-picrylhydrazyl radical scavenging capacity assay. Using the Folin-Ciocalteu’s reagent, the highest total phenolic content from
flowers was obtained with methanol extract (84.0 ± 3.0 mg AGE/g dry weight). The total anthocyanin content (TAC) showed a
similar trend (0.3 ± 0.03 mg cyanidin-3-glucoside/g dry weight) for methanol extract. In line with the total phenolic and TAC,
the methanol extract of O. strictum flowers presents the highest antioxidant capacity (IC50 = 0.28 ± 0.03 mg/mL). The highest
total flavonoid content was observed with ethyl acetate extract (29.0 ± 0.6 mg rutin equivalent/g dry weight). This study provides
useful information for the production of valuable nutraceuticals from flowers of O. strictum (Nees) Kuntze.