Composés phénoliques et capacité antioxydante des extraits méthanoliques du Tripodion (Anthyllis tetraphylla L.)

Le stress oxydant, causant plusieurs maladies, suscite la recherche de nouveaux remèdes antioxydants. Dans cette optique, l’étude de l’activité antioxydante des extraits méthanoliques du Tripodion (Anthyllis tetraphylla L.) a été étudiée. Cette plante est issue de la région semi-aride de la Tunisie, précisément du Parc National de Boukornine, et appartient à la famille des Fabacées. Les extraits foliaires et floraux sont obtenus après macération dans le méthanol pendant 24h. Le tri phytochimique, l’activité antioxydante par les tests ORAC et TEAC et l’inhibition de la peroxydation lipidique dans le model d’émulsion huile/eau ont été réalisés. Le tri phytochimique a permis de révéler que ces extraits contiennent des teneurs importantes en polyphénols et flavonoïdes surtout au niveau de l’extrait floral (75.93 mg EAG/g MS et 87.86 EQ mM/L d’extrait, respectivement) qui présente aussi les activités antioxydantes (ORAC et TEAC) les plus élevées (92.36 mM TE /g MS et 0.13 µM TE/ g MS, respectivement). En ce qui concerne la capacité antioxydante de la poudre lyophilisée des feuilles et des fleurs testée dans l’émulsion, formée par l’huile de tournesol dans l’eau, les fleurs ont présenté la valeur la plus faible de l’indice de peroxyde, c’est à dire la meilleure activité antioxydante, tandis que les feuilles n’ont présenté un effet antioxydant puissant qu’au début du processus d’oxydation.Postprint (published version

Radical scavenging and antioxidant activity of anthyllis vulneraria leaves and flowers

The main targets of this work were to determine the phenolic content of Anthyllis vulneraria (A. vulneraria) leaves and flowers and to evaluate their antioxidant activity. Total polyphenols and flavonoid content (TPC and TFC, respectively) were determined. Antioxidant capacity was evaluated by the Ferric Reducing Antioxidant Power (FRAP), the Oxygen Radical Absorbance Capacity (ORAC), the Trolox Equivalent Antioxidant Capacity (TEAC) and the diphenyl picrylhydrazyl (DPPH) assays, and by the analysis of primary and secondary oxidation products in oil-in-water emulsions and in raw beef patties during storage. The results revealed that the flowers of the A. vulneraria contained the highest content of total polyphenols and flavonoids and extracts from these tissues exhibited the strongest antioxidant activity, as they were more effective at retarding lipid oxidation in oil-in-water emulsions and raw beef patties than extracts from the leaves which had a potent antioxidant effect only at the beginning of the oxidation process. The results of this study allowed us to obtain a deep knowledge about the properties of A. vulneraria and confirmed the possibility of using its biologically active extracts in the food, cosmetic and pharmaceutical industriesPeer ReviewedPostprint (published version

Effect of Neem (Azadirachta indica L.) on lipid oxidation in raw chilled beef patties

The aim of this study was to determine the total polyphenol content, radical scavenging and antimicrobial activities of Azadirachta indica (A. indica) and to evaluate their effect on shelf-life stability of raw beef patties during refrigerated storage at 4 ± 1 °C. During 11 days of storage, the antioxidant effect of A. indica on ground beef meat was investigated by the determination of lipid oxidation, pH, anti-radical activity, color, hexanal content, and microbial growth. The results obtained showed that fresh A. indica leaves and synthetic conservative behaved in the same way and retarded the lipid oxidation of chilled beef patties while increasing their pH (5.40 and 5.45, respectively). It can also be said that A. indica limited the loss of color, reduced the metmyoglobin formation (36.70%) and had a significant effect on bacterial growth and hexanal content. In addition, the results obtained through anti-radical and antimicrobial properties showed proportional values of total polyphenol content and radical scavenging activity of leaf extracts as they showed their antimicrobial effect against some bacteria such as Staphylococcus aureus and Micrococcus luteus, among others. These results support the involvement of A. indica in the food industry as a natural antioxidant that could replace synthetic onesPeer ReviewedPostprint (published version

Phytochemical screening and evaluation of the antioxidant and anti-bacterial activity of Woundwort (Anthyllis vulneraria L.)

For millennia, medicinal plants have been used to prevent and cure diseases. Up to now there is a growing interest in their use in several areas as conducted for Anthyllis in our investigation. Actually the present research aims to investigate the biochemical characterisation of a medicinal plant collected from Tunisia named Woundwort [Anthyllis vulneraria L. (Jones and Turrill 1933)] by determining the mineral content, phenolic compound contents and biological activities of its leaf and flower extracts. On the one hand, the results obtained showed that A. vulneraria accumulated minerals at different amounts with significant differences between leaves and flowers extracts. On the other hand, the data revealed that the hydroethanolic flower extract contained the highest content of total polyphenols, flavonoids and condensed tannin, as it exhibited the strongest antioxidant activity. The flower extract also showed better antibacterial effect than leaf extract. These results support the exploitation of active compounds extracted from the leaves and especially the flowers of A. vulneraria, which can provide new alternatives to the use of certain drugs, additives, among others, as they can be used as structure–activity models for the development of new products.Peer ReviewedPostprint (published version

Radical scavenging and antioxidant activity of anthyllis vulneraria leaves and flowers

The main targets of this work were to determine the phenolic content of Anthyllis vulneraria (A. vulneraria) leaves and flowers and to evaluate their antioxidant activity. Total polyphenols and flavonoid content (TPC and TFC, respectively) were determined. Antioxidant capacity was evaluated by the Ferric Reducing Antioxidant Power (FRAP), the Oxygen Radical Absorbance Capacity (ORAC), the Trolox Equivalent Antioxidant Capacity (TEAC) and the diphenyl picrylhydrazyl (DPPH) assays, and by the analysis of primary and secondary oxidation products in oil-in-water emulsions and in raw beef patties during storage. The results revealed that the flowers of the A. vulneraria contained the highest content of total polyphenols and flavonoids and extracts from these tissues exhibited the strongest antioxidant activity, as they were more effective at retarding lipid oxidation in oil-in-water emulsions and raw beef patties than extracts from the leaves which had a potent antioxidant effect only at the beginning of the oxidation process. The results of this study allowed us to obtain a deep knowledge about the properties of A. vulneraria and confirmed the possibility of using its biologically active extracts in the food, cosmetic and pharmaceutical industriesPeer Reviewe