Mineral contents, Antioxidant and Antimicrobial Activities of Algerian Terfezia claveryi extracts

Abstract

Terfezia species are known for their high nutritional value and diverse biological activities due to their unique chemical composition. The current study aims to evaluate the different extracts of Terfezia claveryi Chatin for their in vitro antioxidant, antibacterial, total phenolic content, total flavonoid content and mineral content. The antioxidant activity was evaluated via 1,1-diphenyl-2-picrylhydrazyl (DPPH), ABTS and phosphomolybdenum assays. While the in vitro antibacterial activity was evaluated via disc diffusion method against Staphylococcus aureusas a Gram-positive bacteria as well as Escherichia coli and Pseudomonas aeruginosa as Gram-negative bacteria. The total phenolic content (TPC) and total flavonoid content (TFC) were evaluated via Folin-Ciocalteu's and AlCl3 assays, respectively. The mineral content was evaluated via using atomic absorption spectrophotometer. In the antioxidant assays, the aqueous extract showed the most potent activity IC50/DPPH equal to 0.09mg/mL, IC50/ABTS equal to 0.24mg/mL and total antioxidant capacity equal to 0.10. Among all the tested extracts, the aqueous extract showed the highest TPC (176.67 mg GAE / g DW) and the highest TFC (14.53 mg ER / g DW). Obviously, the antioxidant activities are exist in a positive correlation with the TPC and TFC. On the other side, the tested extracts exhibited strong to moderate antibacterial activity against tested pathogenic microbial strains. The methanolic and aqueous extracts showed the most potent antibacterial activity against Pseudomonas aeruginosa with inhibition zones 21.91 and 15.79 mm, respectively. The extracts contain macroelements like Na (3293.01 mg‧kg-1dw) and K (21092.19 mg‧kg-1dw). Additionally, they contain micro-elements like Fe (16.45 mg‧kg-1dw), Cu (22.80 mg‧kg-1dw) and Ni (27.88 mg‧kg-1dw). In conclusion, T. claveryi extracts are considered as promising sources of naturally occurring antioxidant and antimicrobial agents as well as their high nutritional values.