Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Oct 30;23(11):2814.
doi: 10.3390/molecules23112814.

Process Optimization for Improved Phenolic Compounds Recovery from Walnut (Juglans regia L.) Septum: Phytochemical Profile and Biological Activities

Marius Emil Rusu  1 , Ana-Maria Gheldiu  2 , Andrei Mocan  3 , Cadmiel Moldovan  4 , Daniela-Saveta Popa  5 , Ioan Tomuta  6 , Laurian Vlase  7
Affiliations

Process Optimization for Improved Phenolic Compounds Recovery from Walnut (Juglans regia L.) Septum: Phytochemical Profile and Biological Activities

Marius Emil Rusu et al. Molecules. .

Abstract

Plant by-products can be valuable sources of polyphenol bioactive compounds. Walnut (Juglans regia L.) is a very important tree nut rich in biologically active molecules, but its septum was scarcely researched. Experimental data indicated a hypoglycemic effect of septum extracts, with almost no details about its phytochemical composition. The main objectives of this study were: (1) to obtain walnut septum (WS) extracts with high content in bioactive compounds and antioxidant activity based on an original experimental design; (2) characterization of the phytochemical profile of the WS extracts using HPLC-MS/MS; (3) evaluation of the biological potential of the richest polyphenolic WS extract. The variables of the experimental design were: extraction method (maceration and Ultra-Turrax extraction), temperature, solvent (acetone and ethanol), and percentage of water in the solvent. The first quantifiable responses were: total phenolic content, total flavonoid content, condensed tannins, and ABTS antioxidant capacity. The phytochemical profile of lyophilized extracts obtained by Ultra-Turrax extraction (UTE), the most efficient method, was further determined by HPLC-MS/MS analysis of individual polyphenolic and phytosterols compounds. It is the first study to assay the detailed composition of WS in hydrophilic and lipophilic compounds. The biological potential of the richest polyphenolic WS extract was also evaluated by FRAP and DPPH antioxidant capacity and the inhibition of tyrosinase, an enzyme involved in the browning in fruits and vegetables, skin wrinkles and aging. Conclusion: The phytochemical profile of the analyzed extracts proves that WS can be a valuable source of biologically active compounds (polyphenols) for food and/or pharmaceutical industry and warrant the continuation of current research in further evaluating its bioactive potential.

Keywords: HPLC-MS/MS; Ultra-Turrax extraction; antioxidant activity; biological activity; experimental design; optimization; phytochemicals; phytosterols; polyphenols; walnut septum.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Total phenolic content (gallic acid equivalents, GAE), total flavonoid content (quercetin equivalents, QE), and condensed tannin content (catechin equivalents, CE) of analyzed walnut septum extracts.
Figure 2
Figure 2
The total antioxidant activity evaluated through ABTS radical cation scavenging activity assay (expressed as Trolox equivalents, TE) of analyzed walnut septum extracts.
Figure 3
Figure 3
Influence of working conditions on the bioactive compounds recovery from walnut septum extracts, presented as scaled and centered coefficient plots. X1—temperature (°C); X2(A)—solvent type (acetone), X2(E)—solvent type (ethanol); X3—water % in mixture with solvent; Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y10, Y11—dependent variables (bioactive compounds) according to Table 5.
Figure 3
Figure 3
Influence of working conditions on the bioactive compounds recovery from walnut septum extracts, presented as scaled and centered coefficient plots. X1—temperature (°C); X2(A)—solvent type (acetone), X2(E)—solvent type (ethanol); X3—water % in mixture with solvent; Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y10, Y11—dependent variables (bioactive compounds) according to Table 5.
Figure 4
Figure 4
Response surface for predicting the bioactive compounds recovery from walnut septum extracts with respect to: X1—temperature (°C); X2(A)—solvent type (acetone), X2(E)—solvent type (ethanol); X3—water % in mixture with solvent (the regions in red represent the domains of working conditions that assure a maximum extraction yield for the evaluated bioactive compounds).
See this image and copyright information in PMC

References

    1. Soccol C.R., da Costa E.S.F., Letti L.A.J., Karp S.G., Woiciechowski A.L., de Souza Vandenberghe L.P. Recent developments and innovations in solid state fermentation. Biotechnol. Res. Innov. 2017;1:52–71. doi: 10.1016/j.biori.2017.01.002. - DOI
    1. Zhang S., Wang S., Huang J., Lai X., Du Y., Liu X., Li B., Feng R., Yang G. High-specificity quantification method for almond-by-products, based on differential proteomic analysis. Food Chem. 2016;194:522–528. doi: 10.1016/j.foodchem.2015.08.056. - DOI - PubMed
    1. Kempf K., Martin S., Döhring C., Dugi K., von Wolmar C.W., Haastert B., Schneider M. The epidemiological Boehringer Ingelheim Employee study-part I: Impact of overweight and obesity on cardiometabolic risk. J. Obes. 2013 doi: 10.1155/2013/159123. - DOI - PMC - PubMed
    1. Murakami K., Livingstone M.B.E. Eating Frequency Is Positively Associated with Overweight and Central Obesity in US Adults. J. Nutr. 2015;145:2715–2724. doi: 10.3945/jn.115.219808. - DOI - PubMed
    1. Franceschi C., Campisi J. Chronic inflammation (Inflammaging) and its potential contribution to age-associated diseases. J. Gerontol. A Biol. Sci. Med. Sci. 2014;69:S4–S9. doi: 10.1093/gerona/glu057. - DOI - PubMed

MeSH terms

LinkOut - more resources