Antioxidant activity of turmeric (Curcuma longa L.) cultivars

Turmeric cultivars exhibit variability with respect to growth and yield attributes, biotic and abiotic stress as well as quality characters. Studies were conducted on methanolic extract of eight turmeric cultivars in three different forms and in eight levels for free radical scavenging activity [DPPH (1, 1-diphenly-2-picrylhydrazyl)]. Among the eight cultivars, Prathibha variety exhibited higher radical scavenging activity of 59.58±2.82 followed by Suvarna, Kedaram, Alleppey supreme, Prabha, Suguna, Local variety and Sudharshana (Prathibha > Suvarna > Kedaram > Alleppeysupreme > Prabha > Suguna > Localvariety > Sudharshana). It is observed that the radical scavenging activity of all varieties are statistically significant. All the extracts notably reduced the concentration of DPPH free radical due to their hydrogen donating ability irrespective of processing methods. The results have clearly established that the variety Prathibha, processed as per the standard curing method displayed significant radical scavenging activity. The higher antioxidant activity of Prathibha variety may be due to the presence of phenolics, flavonoids and natural antioxidants such as Curcuminoids in higher percentage. The effective concentration to quench the DPPH free radical was highest level (100 μg/ml). The findings thus, highlight the importance of the cultivars, method of processing and its antioxidant potential.