Antioxidant Activity of Phenolic Compounds Extracted from the Roots and Leaves of Withania somnifera (L.) from Different Geographical Locations in India

摘要

Phenolic compounds and antioxidant activity were determined in the extracts of Withania somnifera root (RE) and leaf (LE) from five different geographical locations like Coimbatore, Gujarat, Kambam, Lucknow and Nagappattinam of India. The highest amount of total phenolic compounds at 29.25 mg/g DW (dry weight) of plant tissue and total flavonoids at 6.3 mg/g DW were found in RE-Lucknow. The maximum amount of kaempferol at 4.472 mg/100 g DW and quercetin at 1.340 mg/100 g DW were found in RE-Lucknow and LE-Lucknow, respectively. Kaempferol was found in all root extracts and LE-Lucknow, while quercetin was found in all leaf extracts and two roots extracts like RE-Coimbatore and RE-Gujarat. RE-Lucknow showed the best radical scavenging activity with the IC_(50) value of 105.06 ± 1.65 ug/mL in the DPPH assay. In addition, RE-Lucknow also showed maximum percentage of ABTS absorption inhibition activity with the IC50 value of 204.03 ± 14.88 ug/mL. Therefore, the present study reveals that the W. somnifera leaf and root extracts from five geographical locations possess different antioxidant capacities due to various amounts of phenolic compounds.