Antioxidant and antimicrobial phenolic compounds from extracts of cultivated and wild-grown Tunisian Ruta chalepensis

The antioxidant and antibacterial activities of phenolic compounds from cultivated and wild Tunisian Ruta chalepensis L. leaves, stems, and flowers were assessed. The leaves and the flowers exhibited high but similar total polyphenol, flavonoid, and tannin content. Moreover, two organs showed strong, although not significantly different, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl scavenging ability, and reducing power. Investigation of the phenolic composition showed that vanillic acid and coumarin were the major compounds in the two organs, with higher percentages in the cultivated organs than in the spontaneous organs. Furthermore, R. chalepensis extracts showed marked antibacterial properties against human pathogen strains, and the activity was organ- and origin-dependent. Spontaneous stems had the strongest activity against Pseudomonas aeruginosa. From these results, it was concluded that domestication of Ruta did not significantly affect its chemical composition and consequently the possibility of using R. chalpensis organs as a potential source of natural antioxidants and as an antimicrobial agent in the food industry

Comparison of the volatile antioxidant contents in the aqueous and methanolic extracts of a set of commercial spices and condiments

Spices are of great interest because their aromatic properties and to preserve food, with no or low nutritional value, and also as components of a healthy diet. The composition of the methanolic and aqueous extracts of commercial samples of Basil, Cinnamon powder, Cinnamon sticks, Clove, Cumin, Turmeric, Ginger, Nutmeg, Oregano, Rosemary and Thyme was studied as a first step in the relation of their antioxidant activities with the composition. Methods used were Gas Chromatography coupled with Mass Spectrometry (GC-MS) and High Performance Liquid Chromatography (HPLC). Extracts were prepared with an amount of the sample suspended in ultrapure water preheated at 100 oC or methanol at 60 ºC, stirring at room temperature and filtering; for GC-MS the extracts were dried and re-dissolved in methanol. To solve the problem in GC-MS with the flash-points of some compounds, both techniques have been combined. The contents in antioxidants of the different species are compared finding spices having much higher antioxidant contents in the methanolic extract than in water, other with aqueous extracts much rich in antioxidants than the alcoholic extracts, and spices with low antioxidant content in both extracts. For Clove, Turmeric, Ginger, Cinnamon, Rosemary and Cumin, it is recommended the use of lipid and/or alcoholic fractions for the food preparation. For Basil, Oregano, Thyme and Nutmeg, to extract most of their antioxidant content only water must be used. Knowledge of the composition in antioxidants can aid the food industry in the design of healthy foods and food preparations