Antibacterial Properties and Effects of Fruit Chilling and Extract Storage on Antioxidant Activity, Total Phenolic and Anthocyanin Content of Four Date Palm (Phoenix dactylifera) Cultivars

Abstract

Abstract:Phoenix dactylifera or date palm fruits are reported to contain natural compounds that exhibit antioxidant and antibacterial properties. This research aimed to study the effect of fruit chilling at 4˝C for 8 weeks, extract storage at´20˝C for 5 weeks, and extraction solvents (methanol or acetone) on total phenolic content (TPC), antioxidant activity and antibacterial properties of Saudi Arabian P. dactylifera cv Mabroom, Safawi and Ajwa, as well as Iranian P. dactylifera cv Mariami. The storage stability of total anthocyanin content (TAC) was also evaluated, before and after storing the extracts at´20˝C and 4˝C respectively, for 5 weeks. Mariami had the highest TAC (3.18˘1.40 mg cyd 3-glu/100 g DW) while Mabroom had the lowest TAC (0.54˘0.15 mg cyd 3-glu/100 g DW). The TAC of all extracts increased after storage. The chilling of date palm fruits for 8 weeks prior to solvent extraction elevated the TPC of all date fruit extracts, except for methanolic extracts of Mabroom and Mariami. All IC 50 values of all cultivars decreased after the fruit chilling treatment. Methanol was a better solvent compared to acetone for the extraction of phenolic compounds in dates. The TPC of all cultivars extracts decreased after 5 weeks of extract storage. IC 50 values of all cultivars extracts increased after extract storage except for the methanolic extracts of Safawi and Ajwa. Different cultivars exhibited different antibacterial properties. Only the methanolic extract of Ajwa exhibited antibacterial activity against all four bacteria tested: Staphylococcus aureus, Bacillus cereus, Serratia marcescens and Escherichia coli. These results could be useful to the nutraceutical and pharmaceutical industries in the development of natural compound-based products.

Comparison of PrestoBlue® and plating method to evaluate antimicrobial activity of ascorbic acid, boric acid and curcumin in an in vitro gastrointestinal model

“…Moreover, the 1 : 1 mixture of AA and CUR (1% w/w, T16) showed no effect in the different compartments of the digestive model, and hence, an antagonistic effect could have occurred, due to possible interactions or interferences between them, which caused the reduction in their individual activity as has been described previously (Naksuriya and Okonogi 2015). During the oxidation of AA to dehydroascorbic, hydrogen peroxide is produced as a by-product, which negatively affects the phenolic compounds and therefore are produced phenoxy radicals in CUR, which are less reactive (Shrivastava et al 2013;Priyadarsini 2014;Samad et al 2016). On the other hand, when AA and BA are in contact, they react to form two complexes: monoesters of boron and bicyclic diesters of boron (Hunt 2003).…”

“…; Priyadarsini ; Samad et al . ). On the other hand, when AA and BA are in contact, they react to form two complexes: monoesters of boron and bicyclic diesters of boron (Hunt ).…”

“…; Samad et al . ). More recently, another alternative to antibiotics is the use of certain organic acids (Ricke ; Cox and Pavic ; Menconi et al .…”

“…Consequently, several methods to control Salmonella have been implemented, including the use of antibiotics. However, concerns about drug-resistant bacteria and the appearance of antimicrobial residues in animal products have pushed the research of alternative nutraceutical treatments such as probiotics, plant extracts and bacteriophages (Subbiah 2007;Hailu et al 2009;Skj anes et al 2013;Samad et al 2016). More recently, another alternative to antibiotics is the use of certain organic acids (Ricke 2003;Cox and Pavic 2010;Menconi et al 2013).…”

Phenolic profiling and antibacterial potential of Saudi Arabian native date palm (Phoenix dactylifera) cultivars

“…[1] The drive to investigate and discover the antibacterial and antioxidant properties of various indigenous plants are majorly motivated by the consumers' increasing awareness and knowledge of the health benefits of antioxidants as well as the quest for natural antibacterial compounds against the increasing emergence of antibiotic-resistant bacteria. [7][8][9][10] The antibacterial activity of the crude extracts of various date palm against both Gram-positive and Gram-negative bacteria have also been well documented. [10,11] According to the literature, phenolic compounds in dates have the inherent capability to bind with the bacterial cell wall thereby inhibiting the bacterial growth.…”