Effect of extraction solvents/techniques on polyphenolic contents and antioxidant potential of the aerial parts of Nepeta leucophylla and the analysis of their phytoconstituents using RP-HPLC-DAD and GC-MS

Abstract

In the present study, evaluation of antioxidant potential, percentage yield, phytochemical and polyphenolic composition of methanol, chloroform and hexane extracts obtained from the aerial parts (leaves and flowers) of Nepeta leucophylla using different extraction techniques (ultrasound, Soxhlet, and maceration) was carried out. The antioxidant potential of different extracts was measured using DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging), NOS (nitric oxide scavenging), FRAP (ferric reducing antioxidant power) and TAC (total antioxidant capacity) assays. The results of percentage yield, TPC (total polyphenolic content), TFC (total flavonoids content), FRAP, TAC, percentage inhibition of DPPH and NO scavenging for different extracts varied from 3.66 to 17.66%, 0.98 ± 0.47 to 141.9 ± 3.86 mg GAE per g DPE, 6.21 ± 0.49 to 394.48 ± 15.45 mg RE per g DPE, 4.64 ± 0.71 to 196.38 ± 0.31 mg Fe(II) E per g DPE, 10.98 ± 1.36 to 74.72 ± 1.1 mg AAE per g DPE, 8.93 ± 2.09 to 92.57 ± 0.11% and 6.13 ± 0.41 to 64.03 ± 2.29%, respectively. RP-HPLC-DAD and GC-MS analysis of bioactive extracts was also carried out to determine their chemical composition.