# The Antimicrobial Potential of Hexane Oils and Polyphenols-Rich Extracts from _Pistacia vera_ [PERSON].
## 4 Discussion  
This research highlighted the inhibitory effect of polyphenol-rich fractions of pistachio and pistachio oil against _E. fuccium_ DSZM 17050, _L. monocytogenes_ ATCC 13932 and food isolates strains of _L. monocytogenes_. In particular, the polyphenol-rich fractions of NRRE extracted with _n_-hexane (extraction method 1) were active against all the food isolate strains of _L. monocytogenes_. All NRRE extracts and the RURE extracts obtained with the extraction method 2 were active against _L. monocytogenes_ ATCC 13932. These results are in line with previous studies, which reported on the antimicrobial activity of polyphenol pistachio extracts against Gram-positive bacteria. These strains are more susceptible than Gram-negative ones [4, 12]. Compared with our previous report [4], the polyphenol-rich extracts were not active against _E. fuccium_ and _S. aureus_. This could be due to different strains being used in the present study, as well as a different phytochemical composition (both qualitatively and quantitatively) compared with the previous report. The hexane oil fractions from both NPs and RPs were reported to be active against _L. monocytogenes_ ATCC 13932 and _E. fuccium_ DSZM 17050. The NP oil fractions were active against three food isolate strains. Although both NP and RP polyphenic extracts and oil fractions were effective against _L. monocytogenes_ ATCC 13932, NP was more active than RP. This effect could be justified not only by the higher polyphenol amount of NP extracts compared with RP extracts, but also by their qualitative composition. These results are in line with previous studies which report this trend [4, 5]. It is known that the drying process highly influence the phenolic and polyphenonic content, causing the loss of high amount of some compounds. As previously reported, the stability of the various phenolic and polyphenonic compounds is different and the roasting process can be responsible of their lower content in RPs [2, 7, 13]. We have previously reported higher amounts of phenolic acids and flavonoids in NPs compared with RPs, except for hydroxybenzoic acids and luteolin, whereas daidzein and chlorogenic acid \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Strain**} & **Hexane Oil Fraction** & **Hexane Oil Fraction** \\  & **from NPs** & **from RPs** \\ \hline _E. fuccium_ DSZM 17050 & 0.250 & 0.500 \\ _St. aureus_ ATCC 6538 & \textgreater{}2.000 & \textgreater{}2.000 \\ _P. aeruginosa_ ATCC 9027 & \textgreater{}2.000 & \textgreater{}2.000 \\ _E. coli_ ATCC 10536 & \textgreater{}2.000 & \textgreater{}2.000 \\ _C. albicans_ ATCC 10231 & \textgreater{}2.000 & \textgreater{}2.000 \\ _C. albicans_ strain 16 & \textgreater{}2.000 & \textgreater{}2.000 \\ _L. monocytogenes_ ATCC 13932 & 0.031-0.125 & 0.125-0.250 \\ _L. monocytogenes_ (food isolate) & 0.250-1.000 & \textgreater{}2.000 \\ _L. monocytogenes_ (food isolate) & \textgreater{}2.000 & \textgreater{}2.000 \\ _L. monocytogenes_ (food isolate) & \textgreater{}2.000 & \textgreater{}2.000 \\ _L. monocytogenes_ (food isolate) & 0.250 & \textgreater{}2.000 \\ _L. monocytogenes_ (food isolate) & 0.500 & \textgreater{}2.000 \\ _L. monocytogenes_ (food isolate) & \textgreater{}2.000 & \textgreater{}2.000 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: MICs of Hexane Pistachio Oil Fractions (expressed as % _v/v_) against Gram-positive bacteria, Gram-negative bacteria and yeasts. NP: natural raw pistachios; RP: roasted unsalted pistachios. were detected in RPs only [7]. [PERSON] and coauthors reported that the drying process negatively affected the content of the following compounds: anthocyanins, with a loss of about 60%, naringenin with a loss of 50%, eriodyctiol daidzein, luteolin and genistein, with a loss of about 36%, and quercetin recorded a loss of about 22%, whereas no loss was detected after the drying process for genistin, which was the most stable flavonoid [13].