Studies on the Antioxidant Property of Some Weeds Found in Agricultural Fields

The object of the present study was to determine the phenols, flavonoids contents and antioxidant potential of some weeds growing in agriculture fields. Ten common weed species viz. Acalypha indica (kuppi), Amaranthus spinosus (kanta chaulai), Argemone Mexicana (satyanashi), Bacopa monnieri (brahmi), Calotropis procera (aak), Cannabis sativa (bhang), Cuscuta reflexa (amar bel), Mimosa pudica (chui-mui), Tinospora cordifolia (gulbel) and Withania somnifera (Ashwagandha) were assessed for the secondary metabolites content and antioxidant potential in the different parts of these plants. Methanolic extracts were prepared by the maceration method. Total phenolic, flavonoid content, DPPH radical scavenging activity, nitric oxide scavenging activity and reducing power of methanolic extracts of different parts of weeds were performed using UV-Vis spectrophotometer. Maximum content of phenolics were reported in Withania somnifera (295.48±1.9 mg GAE/g) and lowest in Mimosa pudica (7.86±0.6 mg GAE/g). The flavonoid content was also reported to be highest in Withania somnifera (108.43±1.4 mg QE/g) and lowest in Mimosa pudica (9.12±0.2 mg QE/g). All the species of weeds having high phenol and flavonoid content, also have strong antioxidant potential in terms of DPPH radical scavenging activity, nitric oxide scavenging activity and reducing power of different extracts. The DPPH inhibition (%) was reported to be highest in Withania somnifera leaves (89%) and lowest inhibition in DPPH radical was observed by Mimosa pudica leaves (20%). The nitric oxide scavenging activity was also reported to be highest (93%) in Withania somnifera leaves and lowest (25%) in Mimosa pudica leaves. The reducing power of these extracts also exhibited the same pattern with highest reducing power shown by leaves of Withania somnifera (90%) and lowest (10%) in Mimosa pudica leaves. Our results demonstrate that, these weeds could be a potential source of natural antioxidants in future for the pharmaceutical industry.