Systematic HPLC/DAD/MSⁿ study on the extraction efficiency of polyphenols from black goji: Citric and ascorbic acid as alternative acid components in the extraction mixture

Issue title: The Application of Modern Chromatographic and Spectroscopic Techniques for the Analysis of Berry Fruits

Guest editors: Prof. Etsuo Niki, Prof. Esra Capanoglu and Dr. Elwira Sieniawska

Article type: Research Article

Authors: Stanoeva, Jasmina Petreska^{; *} | Stefova, Marina | Bogdanov, Jane

Affiliations: Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje, Macedonia

Correspondence: [*] Corresponding author: Jasmina Petreska Stanoeva, Arhimedova 3, 1000 Skopje, Republic of North Macedonia. Tel.: +389 2 324 9935; Fax: +389 3226 865; E-mail: jasmina.petreska@pmf.ukim.mk and jasmina.petreska@gmail.com.

Abstract: BACKGROUND:The beneficial effects of the fruit of Lycium rhutenicum (black goji) have been linked to their polyphenolic profile. OBJECTIVE:Systematic examination of the extraction efficiency of polyphenols from cultivated black goji from Macedonia was carried out using 25 different solvent mixtures containing methanol, acetone or water combined with different acids (hydrochloric, acetic, citric and ascorbic acid). METHODS:An HPLC/DAD/MSn method was used for identification and quantification of phenolic acids, flavonoids, anthocyanins and also spermines and spermidines. RESULTS:The extraction solvent composition was found to have a significant effect on the yield of total as well as specific polyphenols. Pure methanol was found to be more efficient solvent for extraction of total phenolic compounds than pure water or acetone. Ascorbic acid in methanol (2%, m/v) was found to be the most efficient extraction solvent for total phenolic compounds. Aqueous solutions of citric and ascorbic acid gave the highest yield of phenolic acids, spermidines and flavonoids. The anthocyanin content in these extracts was somewhat lower in comparison with the one obtained with methanol/water/ascorbic acid (70 : 28 : 2). The qualitative analysis of the fruits cultivated in Macedonia showed similar polyphenolic pattern and anthocyanin content to the native plant growing in China. CONCLUSIONS:Citric and ascorbic acid can be used as alternative acid components in the extraction mixture.

Keywords: Lycium rhutenicum, black goji, polyphenols, extraction, phenolic acids, spermine, spermidine, anthocyanins, citric acid, ascorbic acid

DOI: 10.3233/JBR-210717

Journal: Journal of Berry Research, vol. 11, no. 4, pp. 611-630, 2021