Assessment of the antioxidant and antibacterial activities of different olive processing wastewaters

Abstract

Olive processing wastewaters (OPW), namely olive mill wastewater (OMW) and table-olive wastewaters (TOW) were evaluated for their antibacterial activity against five Gram-positive and two Gram-negative bacteria using the standard disc diffusion and thin layer chromatography (TLC)-bioautography assays. Disc diffusion screening and bioautography of OMW were compared to the phenolic extracts of table-olive brines. Positive activity against S. aureus was demonstrated. The optimization of chromatographic separation revealed that hexane/acetone in the ratio of 4:6 was the most effective for phenolic compounds separation. A HPLC-MS analysis was performed showing that only two compounds, hydroxytyrosol and tyrosol, were the predominant phenolic compounds in all OPW. The phenolic extract of OMW generated by a semi-modern process showed the highest free radical-scavenging activity (DPPH assay) compared to the other phenolic extracts. It is apparent from the present study that OPW are a rich source of antioxidants suitable for use in food, cosmetic or pharmaceutical applications.

Olive mill wastewater as a potential source of antibacterial and anti-inflammatory compounds against the food-borne pathogen Campylobacter

“…These results demonstrate the strong capacity of the fraction F5 to inhibit Campylobacter growth. According to the described results, recent studies have also demonstrated the antibacterial effects of phenolic and secoiridoid enriched fractions obtained from OMW on several bacterial pathogens, including gram positive and gram negative bacteria (Aissa et al, 2017;Belaqziz et al, 2017). Usually, the antibacterial effect is greater in grampositive than gram-negative bacteria, which is consistent with a thicker and more complex cell wall in the case of gram-negative bacteria (Leouifoudi et al, 2015;Obied et al, 2007).…”

Effects of Hydroxytyrosol against Lipopolysaccharide-Induced Inflammation and Oxidative Stress in Bovine Mammary Epithelial Cells: A Natural Therapeutic Tool for Bovine Mastitis

“…Additionally, numerous biologic activities have been ascribed to HT, although in some cases its mechanism of action has not been clarified. Of particular interest are the anti-inflammatory and antimicrobial properties of HT, which have been described in many diseases [ 28 , 31 , 32 , 33 , 34 , 35 , 36 ]. In particular, it has been reported that HT was able to inactivate the staphylococcal enterotoxin A, a key factor in the patho-physiology of animal mastitis [ 37 ].…”

Protective Effect of Hydroxytyrosol on LPS-Induced Inflammation and Oxidative Stress in Bovine Endometrial Epithelial Cell Line

“…Elevated HT concentration has also been detected in olive mill wastewater and leaf extract [ 18 ]. In particular, numerous beneficial activities have been attributed to HT and its application has been described in different diseases [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. From the molecular point of view, HT enhanced the Nrf2 pathway [ 25 , 26 ] and ameliorated the antioxidant activity of several enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) [ 27 ].…”