Total phenolic content and antioxidant activity of six wild Mentha species (Lamiaceae) from northeast of Algeria

Objective: To investigate the total phenolics, flavonoids and tannins content and the in vitro antioxidant activities of methanolic extracts of six wild Mentha species which are Mentha aquatica, Mentha arvensis, Mentha piperita, Mentha pulegium, Mentha rotun-difolia and Mentha villosa. Methods: The Folin–Ciocalteu method was used to determine the total phenols content while flavonoids were estimated according to the aluminum chloride colorimetric method. To evaluate tannins content, vanillin and HCl were added to methanolic extracts. The antioxidant potential was measured by 1,1-diphenyl-2-picrylhydrazyl radical scavenging, ferrous ion chelating and the inhibition ofβ-carotene bleaching assays. Results: The methanol extracts of Algerian mints were rich in phenolic compounds and exhibited powerful antioxidant activity ranging from 7.5μg/mL to 44.66μg/mL, which varied significantly among species. Mentha aquatica stood out with efficient antioxidant ability which was correlated to the high total phenolics content, followed by Mentha arvensis and Mentha piperita with very close values, comparing to Mentha pulegium, Mentha rotundifolia and Mentha villosa with lowest values. Conclusions: These results show that methanolic extracts of Mentha species from Algeria have a great potential of polyphenols which can be used as a natural food pre-servative and antioxidant source.

Evaluation of antioxidant activities of the edible and medicinal Acacia albida organs related to phenolic compounds.

This study compared phenolic contents and antioxidant activity in different organs of Acacia albida (leaves and bark) and focuses on identification of phenolic compounds of leaves by HPLC-DAD. The analysed organs exhibited differences in total polyphenol contents (100 and 59.5 mg GAE g(-1) DW). Phenolic contents of leaves were two times higher than those in bark. Ethanolic extracts exhibited good antioxidant activities with IC50 = 26 µg mL(-1) for DPPH and EC50 = 50 µg mL(-1) for FRAP. Identification by HPLC-DAD revealed the presence of nine phenolic compounds known for their high antioxidant activity. The results suggested that this species can be used as source of natural antioxidants.