Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity
Malaysia is ranked as the second largest oil palm producer in the world after Indonesia. This leads to the generation of large quantities of oil palm (<i>Elaeis guineensis</i> Jacq.) leaves (OPLs) annually, considered an underutilized oil palm biomass with low economical value. The prese...
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doaj-a50ae3daa2d8406e9a050b3d660c51232020-11-27T08:07:39ZengMDPI AGProcesses2227-97172020-11-0181540154010.3390/pr8121540Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging ActivityMohamad Shazeli Che Zain0Nurul Azani Jakariah1Jen Xen Yeoh2Soo Yee Lee3Khozirah Shaari4Natural Medicines and Product Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, MalaysiaDepartment of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, MalaysiaDepartment of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, MalaysiaNatural Medicines and Product Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, MalaysiaNatural Medicines and Product Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, Serdang 43400, MalaysiaMalaysia is ranked as the second largest oil palm producer in the world after Indonesia. This leads to the generation of large quantities of oil palm (<i>Elaeis guineensis</i> Jacq.) leaves (OPLs) annually, considered an underutilized oil palm biomass with low economical value. The present study aimed to study the effects of several parameters of ultrasound-assisted extraction (UAE) and the acid hydrolysis of phenolic compounds from OPLs using the single factor experimental approach. The effects of different solvents (hexane, ethyl acetate, 1:1 methanol–ethyl acetate, absolute methanol, and 4:1 methanol–water), solid–liquid ratios (1:20, 1:40, 1:50, 1:60, and 1:70), times (0.5, 1, 2, 3, and 5 h), and temperatures (25, 30, 40, 60, and 70 °C) were investigated for UAE. Moreover, the effects of acid concentration (0.2, 1, 2, 4, 6, and 12 M), incubation time (10, 30, 45, 60, and 90 min), and incubation temperature (65, 75, 85, 90, and 95 °C) on the acid hydrolysis of flavonoid glycosides were also determined. The results revealed that some of the tested parameters had prominent effects on the total phenolic (TPC) and total flavonoid (TFC) contents, as well as the DPPH free radical scavenging activity recovered from the OPLs. The optimal UAE conditions were determined to be 0.5 h at 25 °C using 4:1 methanol–water and 1:50 solid–liquid ratio, producing OPL extracts with TPC and TFC at 335.30 and 60.67 milligrams quercetin equivalents per gram of extract (mg QCE/g extract), respectively, and DPPH free radical scavenging activity at 94.06%. The phenolics present in OPLs were optimally hydrolysed using 6 M hydrochloric acid with an incubation period of 45 min at 95 °C with TPC, TFC, and DPPH free radical scavenging activity at 126.33 milligrams gallic acid equivalents per gram of extract (mg GAE/g extract), 36.08 mg QCE/g, and 54.88%, respectively. Moreover, acid hydrolysis managed to optimally recover the total apigenin content (TAC), total luteolin content (TLC), and total flavonoid <i>C</i>-glycoside content (TFCGC) with values of 79.12 micrograms vitexin equivalents per milligram of extract (µg VE/mg extract), 20.97 micrograms orientin equivalents per milligram of extract (µg OE/mg extract), and 100.09 µg/mg, respectively. Additionally, there were significant correlations between the polyphenolic compounds, flavonoid <i>C</i>-glycosides, and antioxidant activity for all parameters based on the Pearson correlation analysis. This indicates that OPLs have potential as a natural source of phenolic compounds, especially flavonoid <i>C</i>-glycosides, with beneficial free radical scavenging activity that can be incorporated in food and pharmaceutical products.https://www.mdpi.com/2227-9717/8/12/1540oil palm (<i>Elaeis guineensis</i> Jacq.) leavesultrasound-assisted extractionacid hydrolysispolyphenolic contentsflavonoid <i>C</i>-glycosidesfree radical scavenging activity |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Mohamad Shazeli Che Zain Nurul Azani Jakariah Jen Xen Yeoh Soo Yee Lee Khozirah Shaari |
spellingShingle |
Mohamad Shazeli Che Zain Nurul Azani Jakariah Jen Xen Yeoh Soo Yee Lee Khozirah Shaari Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity Processes oil palm (<i>Elaeis guineensis</i> Jacq.) leaves ultrasound-assisted extraction acid hydrolysis polyphenolic contents flavonoid <i>C</i>-glycosides free radical scavenging activity |
author_facet |
Mohamad Shazeli Che Zain Nurul Azani Jakariah Jen Xen Yeoh Soo Yee Lee Khozirah Shaari |
author_sort |
Mohamad Shazeli Che Zain |
title |
Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity |
title_short |
Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity |
title_full |
Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity |
title_fullStr |
Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity |
title_full_unstemmed |
Ultrasound-Assisted Extraction of Polyphenolic Contents and Acid Hydrolysis of Flavonoid Glycosides from Oil Palm (<i>Elaeis guineensis</i> Jacq.) Leaf: Optimization and Correlation with Free Radical Scavenging Activity |
title_sort |
ultrasound-assisted extraction of polyphenolic contents and acid hydrolysis of flavonoid glycosides from oil palm (<i>elaeis guineensis</i> jacq.) leaf: optimization and correlation with free radical scavenging activity |
publisher |
MDPI AG |
series |
Processes |
issn |
2227-9717 |
publishDate |
2020-11-01 |
description |
Malaysia is ranked as the second largest oil palm producer in the world after Indonesia. This leads to the generation of large quantities of oil palm (<i>Elaeis guineensis</i> Jacq.) leaves (OPLs) annually, considered an underutilized oil palm biomass with low economical value. The present study aimed to study the effects of several parameters of ultrasound-assisted extraction (UAE) and the acid hydrolysis of phenolic compounds from OPLs using the single factor experimental approach. The effects of different solvents (hexane, ethyl acetate, 1:1 methanol–ethyl acetate, absolute methanol, and 4:1 methanol–water), solid–liquid ratios (1:20, 1:40, 1:50, 1:60, and 1:70), times (0.5, 1, 2, 3, and 5 h), and temperatures (25, 30, 40, 60, and 70 °C) were investigated for UAE. Moreover, the effects of acid concentration (0.2, 1, 2, 4, 6, and 12 M), incubation time (10, 30, 45, 60, and 90 min), and incubation temperature (65, 75, 85, 90, and 95 °C) on the acid hydrolysis of flavonoid glycosides were also determined. The results revealed that some of the tested parameters had prominent effects on the total phenolic (TPC) and total flavonoid (TFC) contents, as well as the DPPH free radical scavenging activity recovered from the OPLs. The optimal UAE conditions were determined to be 0.5 h at 25 °C using 4:1 methanol–water and 1:50 solid–liquid ratio, producing OPL extracts with TPC and TFC at 335.30 and 60.67 milligrams quercetin equivalents per gram of extract (mg QCE/g extract), respectively, and DPPH free radical scavenging activity at 94.06%. The phenolics present in OPLs were optimally hydrolysed using 6 M hydrochloric acid with an incubation period of 45 min at 95 °C with TPC, TFC, and DPPH free radical scavenging activity at 126.33 milligrams gallic acid equivalents per gram of extract (mg GAE/g extract), 36.08 mg QCE/g, and 54.88%, respectively. Moreover, acid hydrolysis managed to optimally recover the total apigenin content (TAC), total luteolin content (TLC), and total flavonoid <i>C</i>-glycoside content (TFCGC) with values of 79.12 micrograms vitexin equivalents per milligram of extract (µg VE/mg extract), 20.97 micrograms orientin equivalents per milligram of extract (µg OE/mg extract), and 100.09 µg/mg, respectively. Additionally, there were significant correlations between the polyphenolic compounds, flavonoid <i>C</i>-glycosides, and antioxidant activity for all parameters based on the Pearson correlation analysis. This indicates that OPLs have potential as a natural source of phenolic compounds, especially flavonoid <i>C</i>-glycosides, with beneficial free radical scavenging activity that can be incorporated in food and pharmaceutical products. |
topic |
oil palm (<i>Elaeis guineensis</i> Jacq.) leaves ultrasound-assisted extraction acid hydrolysis polyphenolic contents flavonoid <i>C</i>-glycosides free radical scavenging activity |
url |
https://www.mdpi.com/2227-9717/8/12/1540 |
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