Z. Rafiei; S.M. Jafari; M. Alami; M. Khomeiri
Abstract
The aim of the study was to investigate the effect of extraction through two methods of maceration and microwave-assisted extraction on phenolic compounds of olive leaves (Mishen cultivar) with solvents of water, 80% methanol and acetone. The highest total phenolic content (211.385±0.13 mg tannic ...
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The aim of the study was to investigate the effect of extraction through two methods of maceration and microwave-assisted extraction on phenolic compounds of olive leaves (Mishen cultivar) with solvents of water, 80% methanol and acetone. The highest total phenolic content (211.385±0.13 mg tannic acid/g extract) was related to the methanol extract produced by microwave-assisted extraction but acetone extracts gave the lowest amount for both methods. Comparing the extraction methods showed that MAE had higher extraction efficiency in all three tested solvents. Regarding antimicrobial activity of olive leaf extracts, we evaluated the bactericidal effects of different solvent extracts on Staphilococcus aureus, Salmonella typhi and Escherishia coli. In terms of S. aureus, the lowest minimum inhibitory concentration (MIC= 315 µg/ml) and. minimum bactericidal concentration (MBC= 2500 µg/ml) were observed with acetone extract in MAE and methanol extracts in both methods, respectively. As for E.coli the lowest MIC was 625 µg/ml and the lowest MBC (5000 µg/ml) was associated with water and methanol extracts in microwave-assisted extraction. In terms of S. typhi, the lowest MIC and MBC were 315 and 10000 µg/ml, respectively. To conclude, it was found that S. typhi was the most resistant bacteria against the extracts; in most cases MAE-produced extracts showed more antimicrobial activity compared to traditional-produced extracts.
M. Ghaderi Ghahfarokhi; M Alami; A.R Sadeghi Mahoonak; M.H. Azizi; M. Ghorbani
Abstract
The species of oak, the Quercus genus, is classified into Fagaceae family. Acorns (Quercus branti var persica Lindl.) have been traditionally used for treatment of many diseases such as diarrhea, collywobbles, hemorrhoid, rickets, anemia, eczema and varix. The objective of this research was extraction ...
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The species of oak, the Quercus genus, is classified into Fagaceae family. Acorns (Quercus branti var persica Lindl.) have been traditionally used for treatment of many diseases such as diarrhea, collywobbles, hemorrhoid, rickets, anemia, eczema and varix. The objective of this research was extraction of phenolic compounds with various solvents and determination of antioxidant activity of the extracts in oxidative stability of sunflower oil. Phenolic compounds were extracted with methanol (80%), ethanol (70%) and water and total phenolic content was measured by Folin-Ciocalteu method. Extracts of acorns at three different concentrations (250, 500 and 1000 ppm), BHA and BHT at two concentrations of 100 and 200 ppm and TBHQ at 200 ppm were added to the sunflower oil and all samples were kept at 70°c for 12 days. Protective effects of the extracts in stabilizing sunflower oil were tested by measuring peroxide and thiobarbituric acid values at definite time intervals. Total phenolic content of water, ethanolic and methanolic extracts were 79.38, 138.49 and 183.96 (mg tannic acid equivalent/gr dry extract), respectively. During the experimental period, the peroxide and thiobarbitoric acid values of the control samples were raised from 26.23 to 328.88 (meq peroxide/ kg oil) and 0.073 to 0.58 (mg malon aldehyde/kg oil) respectively. TBHQ showed the highest oxidative stability at all days of the experiment. Methanolic extracts (at 500 and 1000ppm concentration) was the best among other extracts and stronger than BHT. Also, other extracts at various concentrations were comparable with BHA and BHT at different levels.
