Pressurized liquid extraction of bioactive extracts with antioxidant and antibacterial activity from green, red and brown Algerian algae

In this work, the protein, sugar, phenolic and phlorotannin contents, as well as the antioxidant and antibacterial activity of hydroethanolic extracts of six algae species from the west cost of Algeria (Padina pavonica, Halopteris scoparia, Cystoseira mediterranea, Ulva lactuca, Ulva intestinalis, and Ceramium virgatum), obtained by pressurized liquid extraction (PLE) were investigated. Ceramium virgatum PLE extracts showed the highest content of protein (4.36 ± 0.13 %), while the total sugar content was maximum in U. lactuca extract (23.89 ± 0.21 %). Likewise, P. pavonica PLE extract presented a relevant total phenolic content (49.82 ± 1.40 mg GAE/g extract). On the other hand, phlorotannins were only found in brown algae in a range of 1.84–2.93 mg PGE/g. Furthermore, P. Pavonica extract presented considerably higher antioxidant capacity of inhibiting ABTS radical (1.16 ± 0.023 mmol TE/g) and 50 % of DPPH (1,1-diphenyl-2-picryl hydrazyl) (IC50 = 57.03 ± 1.28 μg/mL) in comparison with the other studied algae. Regarding to the potential antimicrobial activity, the results showed that Cystoseira Mediterranea produced the lowest minimal inhibitory concentration on Salmonella typhi (0.83 ± 0.14 mg/mL), Escherichia coli (4.66 ± 0.57 mg/mL), Vibrio cholera (1.08 ± 0.14 mg/mL), and Candida albicans (2.16 ± 0.28 mg/mL). Besides, different carotenoids and phenolic compounds were tentatively identified by LC-DAD in the algae extracts which could be the responsible of the tested bioactivities. These findings show the potential of using PLE as green solvent extraction technique and the prolific bioactivities of Algerian seaweeds.Peer reviewe

Olive oils from Algeria: Phenolic compounds, antioxidant and antibacterial activities

The phenolic compositions, antioxidant and antimicrobial activities against six bacteria of phenolic extracts of olive oil varieties from eleven Algerian varieties were investigated. The antioxidant activity was assessed by determining the scavenging effect on the DPPH and ABTS^.+ radicals. The antimicrobial activity was measured as a zone of inhibition and minimum inhibitory concentration (MIC) on human harmful and foodborne pathogens. The results show that total phenols was significantly (p < 0.05) correlated with DPPH (r = 0.72) and ABTS^.+ radicals (r = 0.76). Among the bacteria tested, <em>S. aureus</em> and to a lesser extent <em>B. subtilis</em> showed the highest sensitivity; the MIC varied from 0.6 to 1.6 mg·mL^-1 and 1.2 to 1.8 mg·mL^-1, respectively. The results reveal that Algerian olive oils may constitute a good source of antioxidant and antimicrobial agents.<br><br>Se ha estudiado la composición fenólica y las actividades antioxidante y antimicrobiana, contra seis bacterias, de extractos de aceites de oliva de once variedades argelinas. La actividad antioxidante se evaluó mediante la determinación del efecto captador de radicales de DPPH y ABTS^.+. La actividad antimicrobiana se midió como zona de inhibición y como concentración inhibitoria mínima (MIC) sobre bacterias perjudiciales humanas y agentes patógenos transmitidos por los alimentos. Los resultados mostraron que los fenoles totales está significativamente (p < 0,05) correlacionados con DPPH (r = 0,72) y los radicales ABTS^.+ (r= 0,76). Entre las bacterias ensayadas, <em>S. aureus</em> y, en menor grado <em>B. subtilis</em> mostraron la mayor sensibilidad; el MIC varió de 0,6 a 1,6 mg·mL^-1 y 1,2 a 1,8 mg·mL^-1 respectivamente. Los resultados muestran que los aceites de oliva argelinos pueden constituir una buena fuente de antioxidantes y agentes antimicrobianos

Characterization of monovarietal extra virgin olive oils from the province of Béjaïa (Algeria)

Olive fruits from 19 varieties and different areas of Béjaïa province (Algeria) were used to produce monovarietal olive oils in laboratory. The olive oils were analyzed using both traditional chemical analyses and nuclear magnetic resonance (NMR) methodology. The investigation involved pigment content determination, tocopherol analysis, fatty acid composition, and chromatographic determination of phenolic compounds. Chlorophyll, carotenoids, tocopherols and the content of oleic acid turned out to be variety dependent. The extra-virgin olive oils (EVOOs) were analyzed as a whole and as phenolic extract by NMR. The study gave general indication on olive oil quality and information about geographical origin of the samples. Overall, the results obtained in the present work reveal that Algerian monovarietal olive oils produced in Béjaïa province have the potential to produce blends that may compete with other Mediterranean products