Anthocyanins in Basil (Ocimum basilicum L.)

Abstract

The Lamiaceae family, which includes basil, sage, and thyme, has long been recognized as a rich source of diverse and unique anthocyanins. The development of intensely purple pigmented basil in the ornamental and herb trade prompted this examination of eight commercial varieties of purple basils (Ocimum basilicum L.) as a potential new source of anthocyanins. Anthocyanins were isolated and characterized utilizing high-performance liquid chromatography, spectral data, and plasma desorption mass spectrometry. Fourteen different anthocyanins were isolated, consisting of 11 cyanidin-based pigments and 3 peonidin-based pigments. The large-leaf basil varieties, Purple Ruffles, Rubin, and Dark Opal, had an average extractable total anthocyanin content ranging from 16.63 to 18.78 mg/100 g of fresh tissue, while the ornamental small-leaf variety, Purple Bush, had only 6.49 mg/100 g of fresh tissue. The highest concentration of total anthocyanins occurred just prior to flowering, although by day 8 seedlings already had accumulated all 14 anthocyanins. Comparisons were made to other anthocyanin sources, with results showing that purple basils are an abundant source of acylated and glycosylated anthocyanins and could provide a unique source of stable red pigments to the food industry. Keywords: Basil; Ocimum basilicum L.; anthocyanins; HPLC; plasma desorption mass spectrometry