Assessment of Antioxidant Potential of Lutein, a Retinol Equivalent Carotenoid in Medicinal Landrace of Rice ‘Kavuni’

Background: Indigenous traditional coloured rices are rich in dietary fibre, resistant starch, minerals, bioactive compounds and antioxidants like anthocyanins, luteins and phenols. Kavuni is one such brownish black medical landrace of rice considered as nutrition supplement since 400BC as it cures gastritis, peptic ulcer and also enhances blood circulation and known for its anti diabetic and anti-inflammatory properties. Lutein is the only dietary oxycarotenoid found in both the macula and lens of the human eye, and acts as blocker of blue light damage, quench reactive oxygen species, prevent age related macular degeneration, cataracts, cardiovascular disease and lung cancer. Aim: The objective of the present investigation was to characterize the lutein content and antioxidant potential of Kavuni and released mega varieties of rice (ASD 16, Swarna Sub1) and its derivatives obtained from crosses ASD 16 and Kavuni; Swarna Sub1 and Kavuni. Methodology & Results: It was found that lutein (quantified by HPLC) was much higher in Kavuni (225 µg/100 g) compared with white rice varieties (ASD 16-15 µg/100g and Swarna Sub1-21 µg/100 g) and the DPPH (2, 2-diphenyl-1-picrylhydrazyl) scavenging ability (for quantification of antioxidant potential) were in the order (Kavuni >>ASD16, Swarna Sub1. Pigmented grain genotypes having higher lutein content had higher percentage of free radical scavenging activity of DPPH and lower IC50 values compared to non pigmented genotypes. Conclusion: It is conceivable that the medicinal landraces of rice could be exploited as one of the potential sources for plant - based pharmaceutical products.