Antibacterial and Antiproliferative Activities of Azadirachta indica Leaf Extract and Its Effect on Oil-in-Water Food Emulsion Stability.

The present study aims to identify and quantify the phenolic compounds of Azadirachta indica leaf extract using HPLC-MS and to evaluate the antioxidant, antibacterial (against different Gram-positive and negative bacteria) and in vitro anti-proliferative activities of this extract (against breast, human liver and cervix adenocarcinoma-derived cells). The application of this extract as a natural antioxidant for food preservation was also tested on oil-in-water food emulsions for the first time in the present work in order to determine the use of Azadirachta indica leaves as a natural additive to preserve the food against lipid oxidation and rancidity. The results obtained revealed that 50%-aqueous ethanol leaf extract showed the best extraction yield (25.14%), which was characterized by a high content in phenolic compounds and strong antioxidant activity. Moreover, this leaf extract inhibited the growth of the bacterial strains tested (Staphylococcus aureus, Escherichia coli, Salmonella paratyphi and Micrococcus luteus) and showed better anti-proliferative activity against breast and cervix adenocarcinoma-derived cells than human liver cancer cells after 48 h of treatment. Additionally, Azadirachta indica leaf extract showed almost similar effects as gallic acid solutions (0.25% and 0.5%) in preserving the oxidation of oil-in-water food emulsions and prevented the formation of secondary oxidation products (malondialdehyde) as well. The results obtained suggested that extracts of Azadirachta indica leaves are a potential source of antioxidant and antibacterial compounds and pointed to the potential of these natural extracts as therapeutic agents.

Phenolic Profile, EPR Determination, and Antiproliferative Activity against Human Cancer Cell Lines of Anthyllis vulneraria Extracts.

In the current work, the leaf and flower extracts of Anthyllis vulneraria were evaluated for their chemical characterization using HPLC-MS and for their radical scavenging capacity toward methoxy radicals produced by a Fenton-type reaction using an electron paramagnetic resonance (EPR) spectroscopy assay. The in vitro antiproliferative activity of these extracts against several human-derived cancer cells (breast: MCF-7; cervical: HeLa; hepatocellular: HepG2) was also evaluated. The results showed that the Anthyllis vulneraria leaf extract was characterized by 17 different phenolic compounds, among which phenolic acids were the most abundant, while its flower extract exhibited higher contents of flavonoids. Furthermore, Anthyllis vulneraria extracts demonstrated a potent radical scavenging activity against methoxy radicals. Both extracts also significantly reduced the viability of the different cancer cell lines. The results of the current study suggested that Anthyllis vulneraria extracts are a promising source of antioxidant compounds with health benefits and pointed to their potential use for treating cancer and developing novel therapeutic agents.

The Effects of Pecan Shell, Roselle Flower and Red Pepper on the Quality of Beef Patties during Chilled Storage.

The antioxidant and antimicrobial effects of pecan shell (PSW), combined with roselle flower (RS) and red pepper (CA) were analyzed in beef patties by several methods during chilled storage for 13 days. Additionally, the antioxidant and antimicrobial activities of PSW, RS and CA extracts were determined. The PSW extract exhibited a higher radical scavenging activity (by the DPPH method) and more total phenolic compounds than RS and CA. RS presented the best antimicrobial capacity. Nine formulations of beef patties were prepared, including a control (CM), a synthetic preservative (CAMPA N.3 (A)) and different combinations of PSW, RS and CA. The bacterial counts of the beef patties with RS (4-5 log colony-forming units (CFU)/g meat) were significantly lower than those of the control sample (CM) (6-7 CFU/g meat) at day 6. The thiobarbituric acid-reactive substance (TBARS) values at day 7 of all treatments were similar to the values of samples containing the synthetic antioxidant and significantly lower than the CM group. The order of stability assessed by the TBARS values were in agreement with the hexanal content. Thus, these results support the hypothesis that the combination of PWS, RS and CA could represent a good natural food preservative.

The conservative effects of lipopeptides from Bacillus methylotrophicus DCS1 on sunflower oil-in-water emulsion and raw beef patties quality.

Lipid oxidation was considered as a problem in food conservation. The present study aims to investigate the effect of lipopeptides DCS1 on the conservation of food models against lipid oxidation by determining the primary and the secondary oxidation products. Lipopeptides DCS1 are able to preserve the nutritional properties of the emulsion during 23 days of storage, at a concentration of 0.0125% (w/w of emulsion), by slowing down the formation of hydroperoxides and malondialdehyde (MDA) compounds. The direct incorporation of lipopeptides in ground beef patties at a concentration of 0.5% (w/w of meat) was found to be more effective than gelatin film enriched with lipopeptides (2.5%, w/w of gelatin) as a coating, in inhibiting lipid oxidation. Furthermore, lipopeptides DCS1 are not toxic to human kidney cells HEK293 up to a concentration of 250 µg/ml. The results indicate that lipopeptides DCS1 are effective for the preservation of fatty foods against lipid oxidation.

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 ones.

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 industries.