Optimization of ultrasound-assisted extraction of phenolic compounds and antioxidant activity from Argel (Solenostemma argel Hayne) leaves using response surface methodology (RSM).

In this study, phenolic compounds were extracted from Argel leaves using an ultrasound-assisted extraction (UAE) method. The extraction parameters (sonication temperature, time, and ethanol concentration) were optimized using a response surface methodology (Box-Behnken design), in order to maximize the total phenolic content (TPC) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity of Argel leaf extracts (ALEs). The phenolic compounds of the ALEs obtained under optimized conditions were also identified. The optimum UAE conditions for achieving maximum TPC (72.27 g gallic acid equivalents kg-1 DW) and DPPH scavenging activity (86.15%) were a 60 °C temperature, a 37.07 min duration, and a 39.14% ethanol concentration. Under these conditions, the experimental values of TPC and DPPH scavenging activity were 73.02 g GAE kg-1 and 85.56%, respectively, which agreed with the predicted values. In addition, the major phenolic acids found in ALEs under the optimized extraction conditions were sinapic, p-coumaric, and ferulic acid. Overall, the findings of this study demonstrated the suitability of UAE and the success of RSM in optimizing the extraction conditions of bioactive compounds from ALEs.

Colonic Bacteria-Transformed Catechin Metabolite Response to Cytokine Production by Human Peripheral Blood Mononuclear Cells.

Human gut microbes are a profitable tool for the modification of food compounds into biologically active metabolites. The biological properties of catechins have been extensively investigated. However, the bioavailability of catechin in human blood plasma is very low. This study aimed to determine the biotransformed catechin metabolites and their bioactive potentials for modulating the immune response of human peripheral blood mononuclear cells (PBMCs). Biotransformation of catechin was carried out using in-vitro gut microbial biotransformation method, the transformed metabolites were identified and confirmed by gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-mass spectrometry (HPLC-MS). Present observations confirmed that the catechin was biotransformed into 11 metabolites upon microbial dehydroxylation and C ring cleavage. Further, immunomodulatory potential of catechin metabolites was analyzed in peripheral blood mononuclear cells (PBMCs). We found up-regulation of anti-inflammatory cytokine (IL-4, IL-10) and down-regulation of pro-inflammatory (IL-16, IL-12B) cytokine may be due to Th2 immune response. In conclusion, biotransformed catechin metabolites enhance anti-inflammatory cytokines which is beneficial for overcoming inflammatory disorders.

The effect of Acacia nilotica seed extract on the physicochemical, microbiological and oxidative stability of chicken patties.

The present study investigates the effect of Acacia seed water extract (ASWE) at four levels (0, 50, 100, 150 mg/100 mL) in triplicate batch on the shelf-life and quality of chicken patties. Flavones, mainly (+)-catechin, were the predominant phenolic compounds in ASWE with high antioxidant activity. ASWE showed greater inhibition effects against gram-positive bacteria than gram-negative bacteria. ASWE incorporation had no significant effects on the chemical composition of chicken patties. The microbial load, and thiobarbituric acid reactive substances of chicken patties significantly decreased (P ≤ 0.05) and reached minimum values at 150 mg/100 mL but the pH decreased slightly. The cooking properties were significantly improved (P ≤ 0.05) at 150 mg/100 mL. Moreover, ASWE at high level (150 mg/100 mL) significantly (P ≤ 0.05) enhanced total phenolic content and free radical scavenging activity of chicken patties. The results showed that chicken patties with ASWE had better quality attributes compared to the unformulated. Shelf-life of chicken patties can therefore be prolonged for 15 days in refrigerated storage using ASWE especially at high concentration (150 mg/100 mL).

Antimicrobial activity of nanoemulsion on drug-resistant bacterial pathogens.

The appearance of drug-resistant (DR) bacteria in the community is a crucial development, and is associated with increased morbidity, mortality, healthcare costs, and antibiotic use. Natural oil nanoemulsions (NEs) have potential for antimicrobial applications. In the present study, we determined the antimicrobial activity of an NE against DR bacterial pathogens in vitro. The NE comprised Cleome viscosa essential oil, Tween 80 nonionic surfactant, and water. We found that an NE with a droplet size of 7 nm and an oil:surfactant (v/v) ratio of 1:3 was effective against methicillin-resistant Staphylococcus aureus (MRSA), DR Streptococcus pyogenes, and DR extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Fourier-transform infrared (FTIR) spectroscopy revealed that NE treatment modified the functional groups of lipids, proteins, and nucleic acids in DR bacterial cells. Scanning electron microscopy (SEM) showed damage to the cell membranes and walls of NE-treated DR bacteria. These alterations were caused by bioactive compounds with wide-spectrum enzyme-inhibiting activity in the NE, such as ß-sitosterol, demecolcine, campesterol, and heneicosyl formate. The results suggest that the nanoemulsion is effective against DR bacteria, and acts by inhibiting the drug efflux mechanism of DR strains.