Search

Purpose: To evaluate the total phenolic and flavonoid contents of Mentha spicata (MS) leaves aqueous extracts obtained from different regions (El-Oued, Tebessa and El-Tarf) of Algeria, as well as their in vitro antioxidant and antidiabetic activities. Methods: Aqueous extracts were obtained from the air-dried leaves of MS by maceration followed by filtration and evaporation using a rotary evaporator. Folin-Ciocalteu and Aluminium chloride colorimetric techniques were used to determine the total phenolic and flavonoid contents, respectively. The radical DPPH, ABTS, and FRAP tests were used to determine their antioxidant activities, while the in vitro inhibition percentages of α-amylase and α-glucosidase enzymes were used to assess the anti-diabetic activity. Results: The El-Oued's extract exhibited the highest total phenolic content (108.94 mg GAE/g dry extract (DE)), while the highest total flavonoid content (0.039 mg QE/g DE) was found in El-Tarf's extract. The radical DPPH and FRAP scavenging activity of the El-Oued extract exhibited the highest inhibition activities (IC50 = 102.5 and 289.5 μg/mL), respectively, while the ABTS inhibition activity of the El-Tarf extract exhibited a maximum IC50 value of 111 ± 2.8 μg/mL. The MS extract of the El-Oued region had the highest α-amylase and α-glucosidase enzyme activities with IC50 values of 121.4 and 216.9 μg/mL, respectively. Conclusion: The leaves of Mentha spicata exhibit high phenolic and flavonoid contents, along with significant antioxidant and antidiabetic properties. This study reveals that Mentha spicata flavonoid and phenolic contents as well as other properties vary by region.

Echinops spinosissimus Turra subsp. roots was investigated, after extraction with two different solvents: ethanol and ethyl acetate, for its phenolic profile as well as biological activities. Echinops spinosissimus Turra subsp. spinosus roots ethanolic extract was characterized by the highest content of total polyphenols (19.3 mg GAE/100 g of DW). In addition, the phenolic profiles of the two studied extracts were analysed using HPLC-UV, where p-coumaric (8.59 mg/kg of DW) and cinnamic acids (4.68 mg/kg of DW) were detected as the most abundant phenolic acids, and kaempferol was the predominant flavonoids (30.37 mg/kg of DM) followed by quercetin and rutin in the ethanolic extract. While, only p-coumaric acid, epicatechin, kaempferol and quercetin were identified and quantified in ethyl acetate roots extract. All tested extracts exhibited an antimicrobial effect against Gram-positive and Gram-negative bacteria. These findings indicate that Echinops spinosissimus Turra subsp. spinosus roots can be regarded as a new source of edible oil having health benefits and nutritional properties.