Phenolic content, antioxidant and antimicrobial activities of Egyptian date palm (Phoenix dactylifera L.) fruits

Abstract

Date palm fruits are one of the most popular fruits packed with an impressive list of essential nutrients, vitamins, and minerals that are required for normal growth, development and overall well-being. They contain health benefiting polyphenolic antioxidants. This work is aimed to determine the phenolic profile and phenolic content of date palm fruits (Tamr stage) and evaluate their functional properties like antioxidant and antimicrobial activities to confirm the date palm health benefits. Water extract of Tamr stage showed a higher content (14.80 mg GAE/g sample) of phenolic compounds than ethanol extract (10.31mg GAE/g sample). HPLC analysis showed the extracts contain the high concentration in esculetin (15.11 and 17.30mg/100g) and tannic acid (2.85 and 1.79 mg/100g). On the other hand, protocatechuic acid, catechol, Pyrogallol and cinnamic acid didn’t detect in both extracts. Moderate concentrations of gallic acid (7.51 and 5.28 mg/100g), itaconic acid (6.40 and 5.91 mg/100g) and traces of ferulic acid (0.15 and 0.22 mg/100g) were detected. DPPH assay revealed a good antioxidant capacity of water extract, which was higher than of ethanol extract. Antimicrobial data exhibited an impressive antibacterial activity for date extract. Date extract showed a strong antibacterial activity (for water and ethanol extracts) against E. coli (20 ±0.57 and 16 ±0.57 mm), Salmonella enterica (20 ±0.54 and 14 ±0.52 mm) and Bacillus sabtilis (18±0.32, 15±0.23 mm) and moderate inhibition against staphylococcus areues (8 ±0.48 and 5 ±0.52 mm) and Enterococcus faecalis (5 ±0.36 and 2 ±0.57mm). These findings may enhance our knowledge for the value and importance of using the dates in our daily diet; and can be used as natural antioxidants and antimicrobial agents for various food products.