Identification of previously unreported pigments among carotenoids and anthocyanins in floral petals of Delonix regia (Hook.) Raf.

Abstract

Carotenoids and anthocyanins from floral petals of Delonix regia (Fabaceae) were isolated and characterized. Astaxanthin, a ketocarotenoid and anthocyanins — Peonidin-3-O-glucoside and Petunidin-3-o-acetyl-glucoside were newly identified by HPLC-MS. On 100g dry weight basis, anthocyanin content was 830mg in fresh and 580mg in oven dried petals and 30mg of β-carotene content in a total of 69mg of carotenoids. This study has demonstrated that floral petals of D. regia are rich in unusual combination of biologically active carotenoids and anthocyanins, particularly cyanidin-3-O-rutinoside (800mg/100g DW), holding a great promise for food and pharmaceutical applications. Since astaxanthin is rarely found in higher plants, D. regia appears interesting for gene discovery for understanding of ketocarotenoid biosynthesis in higher plants.