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Pomegranate ( Punica granatum L.) peel is a rich source of polyphenols, especially tannins, and concentrations of these compounds may be influenced by extraction processes. This study was aimed to examine phenolic composition and biological activities of pomegranate peel 70% ethanolic extract and its fractions (petroleum ether, ethyl acetate, butanol and water) obtained by liquid/liquid extractions. Fractions were analyzed for polyphenolic content and the highest total phenolic content was obtained in ethyl acetate fraction (200.9 mg gallic acid equivalent/g). This fraction had the highest amounts of gallic acid and ellagic acid, while water fraction contained the highest contents of punicalin and punicalagin. Antioxidant activity was evaluated by four different methods, and butanol and ethyl acetate fractions were the most active in 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) assays, whereas water fraction showed the strongest activity in ferric reducing antioxidant power (FRAP) and β-carotene tests. All fractions showed better inhibitory effect on α-glucosidase, with inhibition concentration IC 50  = 0.26–4.57 μg/mL, than α-amylase (IC 50  = 23.6–284.3 μg/mL), and the most active was ethyl acetate fraction. Antineurodegenerative activity was tested using acetylcholinesterase (AChE) and tyrosinase (TYR) inhibitory activity assays, and the most effective inhibitor of both enzymes was 70% ethanolic extract. Pomegranate peel could be considered as a valuable agro-industrial waste product which could be used as low-cost natural source of biologically active compounds. [ABSTRACT FROM AUTHOR]

Brönsted acidic ionic liquid and microwave energy are introduced for catalytic hydrolysis of hydrolysable tannins into ellagic acid and gallic acid and simultaneous extraction bioactive substances in the present study. Brönsted acidic ionic liquid-based microwave-assisted simultaneous hydrolysis and extraction (BMSHE) method was employed in obtaining ellagic acid, gallic acid and essential oil from Eucalyptus globulus leaves. [HO 3 S(CH 2 ) 4 mim]HSO 4 was used as a dual hydrolysis catalyst and extraction solvent in the proposal approach. The optimized parameters were obtained as follows: [HO 3 S(CH 2 ) 4 mim]HSO 4 concentration of 1.0 M, liquid–solid ratio of 30 mL/g, microwave irradiation time of 20 min and microwave irradiation power of 385 W. Yields of ellagic acid, gallic acid and essential oil under these conditions are 3.32 ± 0.08 mg/g, 3.83 ± 0.11 mg/g and 4.82 ± 0.18 mg/g, respectively. Compared with the reference solvent, [HO 3 S(CH 2 ) 4 mim]HSO 4 shows excellent solvent effect and catalytic activity. Comparison between BMSHE and hydrodistillation indicated the proposed approach is a high efficient, time-saving, low energy consumption and eco-benign methodology. Method validation studies also evidenced that BMSHE is credible for the preparation of ellagic acid and gallic acid. It is reasonable to assume that this method would become a new potential candidate for the preparation of some other kinds of bioactive substances from plant materials. [ABSTRACT FROM AUTHOR]

In this paper, we quantified the impact of an instant controlled pressure drop (DIC) pre-treatment prior to conventional solvent processes on the yields of six phenolic compounds extracted from grape stalk powder of the Monastrell variety ( Vitis vinifera L.). Results indicate that DIC treatment had a positive and significant effect in the concentration of these compounds. Mainly, the DIC treatment increased the availability of gallic acid, quercetin, ellagic acid and resveratrol in 50% (v/v) aqueous ethanol, ethyl acetate or propanol extracts. It had a much greater effect than the solvent used in the extraction process. More polar solvents (ethanol and propanol) were efficient to extract phenolic acids (gallic, caffeic and ellagic acids) and stilbenes (resveratrol), while a moderately polar solvent (ethyl acetate) did for flavonoids [(+)-catechin and quercetin]. The classic process of extraction could be intensified varying different DIC operative parameters such as steam pressure, water content of plant material and duration of treatment. [ABSTRACT FROM AUTHOR]

Abstract: Bioactive compounds extracted from plants or agro-industrial residues have great potential as novel fungicide sources for controlling pathogenic fungi. In this study antifungal activity of polyphenolic extracts from Larrea tridentata leaves, Carya illinoensis shells and Punica granatum husk were evaluated in vitro against eight different plant pathogenic fungi and ten isolates of Fusarium oxysporum. Phenolic solutions of gallic and ellagic acids were also tested at different concentrations. The polyphenolic extracts tested have a high efficiency to inhibit the mycelial growth of Pythium sp., Colletotrichum truncatum, Colletotrichum coccodes, Alternaria alternata, Fusarium verticillioides, Fusarium solani, Fusarium sambucinum, and Rhizoctonia solani. L. tridentata polyphenolic extracts also efficiently inhibited the mycelial growth of eight out of ten F. oxysporum isolates. These results showed that the polyphenolic extracts tested possess antifungal activities against a broad spectrum of plant pathogenic fungi and could be used as potential antifungal agents for the control of fungal plant diseases. [Copyright &y& Elsevier]