Chemical composition, antioxidant and anticholinesterase activities of Algerian <i>Inula conyza</i> DC

Abstract

The phytochemical study of the chloroform and ethyl acetate extracts of <i>Inula conyza</i> DC. identified key constituents such as graveolide, illicic acid, axillarine, axillaroside and 1,5-di-<i>O</i>-caffeoylquinic acid <i>via</i> NMR analysis. The total polyphenol and flavonoid contents were quantified, with the ethyl acetate extract showing the highest polyphenolic (693.29 ± 5.00 mg GAE/g extract) and flavonoid content (280.17 ± 3.18 mg QE/g extract). The antioxidant capacity of chloroform, ethyl acetate and n-butanol extracts was evaluated using five complementary methods (DPPH, ABTS, β-Carotene, CUPRAC and reducing power) and compared to four standards (BHT, BHA, α-tocopherol and ascorbic acid). Additionally, the anticholinesterase activity was assessed against AChE and BChE enzymes. The ethyl acetate extract demonstrated excellent antioxidant activity in DPPH (IC50: 19.74 ± 0.39 μg/mL), ABTS (IC50: 5.94 ± 0.03 μg/mL), β-Carotene assays (IC₅₀: 1.17 ± 0.01 μg/mL), and excellent reducing capacities in CUPRAC (8.59 ± 0.17 μg/mL) and reducing power assays (11.20 ± 0.69 μg/mL). Additionally, moderate anticholinesterase activity was observed in the chloroform extract, which inhibited BChE with an IC50 of 140.20 ± 1.11 μg/mL. This study highlights the therapeutic potential of <i>Inula conyza</i> as a source of natural antioxidants and neuroprotective agents.