The Antimicrobial Potential of Hexane Oils and Polyphenols-Rich Extracts from Pistacia vera L.

Abstract

Pistachio (Pistacia vera L.) nuts contain nutrients and phytochemicals which have been linked to several positive outcomes. The aim of this research was to examine the antimicrobial effect of natural raw and roasted unsalted polyphenols-rich pistachio extracts (NRRE and RURE) and hexane oil fractions. American Type Culture Collection (ATCC), food and clinical isolates of Gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus), Gram-negative bacteria (Pseudomonas aeruginosa, Escherichia coli and Enterococcus faecium) and yeasts (Candida albicans) were used. In addition, the influence of the extraction method was evaluated. Generally, NRRE extracts were richer in polyphenolic compounds compared with RURE extracts. NRRE extracted with n-hexane was the most effective on Listeria monocytogenes food isolates strains (MIC values between 0.25 and 2.0 mg mL−1). All extracts, except for RURE extracted with n-hexane, were active against Listeria monocytogenes ATCC 13932. Both hexane oil fractions were active against Listeria monocytogenes ATCC 13932 and Enterococcus faecium DSZM 17050. The oil obtained from natural pistachio was active against three food isolates of Listeria monocytogenes. In conclusion, the present study indicates an inhibitory effect of pistachio polyphenols against Listeria monocytogenes, one of the most serious pathogens causing foodborne disease.

Mechanistic Understanding of the Antiviral Properties of Pistachios and Zeaxanthin against HSV-1

“…In this paper, we examined the effect of NRRE and RURE pistachio polyphenols-rich extracts against HSV-1 infection obtained by two different extraction methods. Consistent with previous results on the antibacterial activity [ 21 ], here we report a different antiviral effect due to the two extraction methods. Indeed, the polyphenol-rich fractions of NRRE and RURE extracted with n -hexane (extraction method 1) resulted in more activity against HSV-1 replication than NRRE and RURE extracts obtained with extraction method 2 ( Figure 2 ).…”

“…Our choice was supported by the phytochemical characterization ( Table 2 ) in which α, β, and δ tocopherol, β-carotene, and zeaxanthin were amongst the most abundant compounds present in NRRE n -hexane and RURE n -hexane and completely absent in NRRE and RURE. Luteolin was chosen since it was present in greater quantities using extraction method 2 [ 21 ]. Before exploring any antiviral activity, the viability assay was carried out by treating VERO cells with different concentrations of pure compounds to determine the non-toxic concentration for further experiments ( Figure 4 ).…”

“…The drying process also influences the polyphenolic content and could be responsible for the lower content of RPs [ 21 , 32 ]. In line with previous results [ 21 , 33 , 34 ], the natural extracts were more active against HSV-1 compared with the roasted.…”

“…Californian natural shelled (NPs, Pistacchi Sgusciati California Pissgsu01/BSV1, L673-16221262) and roasted (RPs, Pistacchi Sgusciati Tostati California Pissgstu01/BSV1) pistachio kernels were kindly supplied by the American Pistachio Growers (Fresno, CA, USA). Polyphenolic extracts were prepared following two different extraction methods as previously reported [ 21 ]. Briefly, in the first method (extraction method 1), NPs or RPs (10 g) were extracted with n -hexane (100 mL) five times for 2 h, in order to separate the lipid fraction, and the residues were combined with methanol/HCl 0.1% ( v / v ) (100 mL).…”

“…RP-HPLC-DAD identification and quantification of phenolic compounds was performed as previously reported [ 21 , 22 ]. Briefly, a Shimazu system, having an LC-10AD pump system, a vacuum degasser, a quaternary solvent mixing, an SPD-M10A diode array detector, and a Rheodyne 7725i injector, was used for the compound identification.…”