scholarly journals Subcritical water extraction of horse chestnut (Aesculus hippocastanum) tree parts

2021 ◽  
Vol 86 (6) ◽  
pp. 603-613
Author(s):  
Tanja Gagic ◽  
Zeljko Knez ◽  
Mojca Skerget

Subcritical water extraction of horse chestnut (Aesculus hippocastanum) parts, such as seeds, seed shell, bark and leaves has been performed in a batch reactor at temperatures of 150, 200 and 250?C and extraction times of 5, 15 and 30 min. The obtained extracts were analyzed by spectrophotometric methods to determine the total phenols, total carbohydrates and antioxidant activity. Furthermore, the compounds detected in the extracts, such as triterpene saponins (escins), coumarin glycosides (esculin and fraxin), phenolic compounds (chlorogenic, neochlorogenic and gallic acids) and furfurals (5-hydroxymethyfurfural, furfural, and 5-methylfufrual) were quantified using HPLC. High amount of escins was obtained in the seed extracts, while the highest amounts of esculin and fraxin were obtained in bark extracts. The total phenol content was the highest in shell and bark extracts, which implies that these extracts gave the highest antioxidant activity.

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2774 ◽  
Author(s):  
Tanja Gagić ◽  
Željko Knez ◽  
Mojca Škerget

The aim of the work was the optimization of the subcritical water extraction process of chestnut bark using Box–Behnken response surface methodology. The influence of process parameters, such as temperature, extraction time and solvent-solid ratio, on extraction yield, yield of the main compounds, total phenol content, total tannin content and antioxidant activity has been investigated. The identified compounds were ellagic and gallic acids, ellagitannins (vescalagin, castalagin, 1-o-galloyl castalagin, vescalin and castalin), sugars (maltose, glucose, fructose and arabinose) and sugar derivatives (5-HMF, furfural and levulinic acid). Finally, the optimal process conditions for obtaining the bark extract highly rich in ellagic acid and with satisfactory levels of total phenols and total tannins have been determined.


2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Hongyi Sun ◽  
Xi Yuan ◽  
Zhenya Zhang ◽  
Xin Su ◽  
Min Shi

Subcritical water extraction (SWE) has been employed for the extraction of bioactive compounds from plant materials with cost-effectiveness, less consuming time, and environmental sustainability. To explore the effects of thermal processing during SWE, total organic content (TOC), total sugar, polysaccharides, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity (ABTS and DPPH assays) of eight aqueous extracts have been quantitatively investigated. The results indicated that elevated temperatures indeed resulted in significant changes in the constituents and antioxidant activities of okara extracts. Among them, the extract obtained at 220°C exhibited the highest total phenolic, flavonoid content, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical-scavenging activity, and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)] radical-scavenging activity. However, phenolic compounds were destroyed after the treatment above 230°C, suggesting that any polymer processing is improper to undertake at higher than this value to achieve the high antioxidant activity. Moreover, a significant positive correlation between TPC or TFC and antioxidant capacity (DPPH and ABTS) values was detected.


2019 ◽  
Vol 4 (2) ◽  
pp. 101-106
Author(s):  
Zohreh Didar

Abstract Objectives Subcritical water extraction technique is considered as an environmentally extraction technique. The aim of this study was to compare the different characteristics of water extract and subcritical water extract of Helicteres isora L. Materials and Methods Water extraction was performed under the following conditions: 25°C, 24 h, and solid-to-water ratio 1:30. Subcritical water extract was carried out under specific conditions (pressure = 10 bar, temperature = 160°C, solid-to-water ratio = 1: 30, time = 30 min). Chemical composition analysis was performed using GC–Mass chromatography. Anti-biofilm activity in the terms of anti-attach and removal of biofilm were assessed using the ELISA reader method and reading absorbance at 570 nm. Anti-microbial activity against Bacillus cereus, Staphylococcus aureus, Staphylococcus saprophyticus, and Bacillus subtilis was investigated by measurement of inhibitory zone diameter. Anti-enzymatic and antioxidant properties were also assessed. Results The results of GC–Mass analysis showed some components extracted in subcritical method which were absent in water extract such as octadecanoic acid, hexadecanoic acid, and berberin. Antioxidant activity of the two tested extracts revealed that subcritical water extract had more antioxidant capacity than water extract (P ≤ 0.05). The two tested extracts exhibited anti-enzymatic activity against polyphenol oxidase enzyme with better performance of subcritical water extract. Anti-biofilm activity of the two extracts implies that, in the case of preventing biofilm formation, both extracts had similar efficiency but in the removal of biofilm, subcritical water extract showed better performance. Both extracts had anti-microbial activity against B. cereus, S. aureus, S. saprophyticus, and B. subtilis with better performance of subcritical water extract. Anti-enzymatic assay also showed similar results. Conclusions Subcritical water extract of H. isora showed more antioxidant activity as well as anti-biofilm, anti-bacterial, and anti-enzymatic activity rather than ordinary water extract.


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