This research was aimed to optimize the extraction conditions of three phenolic compounds: total phenolics, flavonoids and condensed tannins, from White Horehound’s leaves (Marrubium vulgare L.). Distilled water and ...This research was aimed to optimize the extraction conditions of three phenolic compounds: total phenolics, flavonoids and condensed tannins, from White Horehound’s leaves (Marrubium vulgare L.). Distilled water and different organic solvents such as: methanol, ethanol and acetone, were used, with various concentrations (20% - 80%, v/v), temperatures (20°C - 60°C) and extraction times (30 - 450 min). Results showed that the maximum total phenolics amounts (293.34 ± 14.60 mg gallic acid equivalent/g dry weigh), were obtained with 60% aqueous methanol at 25°C for 180 min;total flavonoids (79.52 ± 0.55 mg catechin equivalent/g dry weigh) with 80% aqueous methanol at 20°C for 450 min, and condensed tannins (28.15 ± 0.80 mg catechin equivalent/g dry weigh) with 60% aqueous acetone at 50°C and for 180 min. ANOVA test showed the significant effect (***P < 0.001) of the extraction conditions tested on phenolic compounds. The Principal Component Analysis (PCA) exhibited the positive effect of low temperatures on total phenolics and flavonoids extraction, and the effect of high temperatures on the condensed tannins extraction. The Response Surface Methodology (RSM) provided predicted values of extraction conditions and maximum polyphenols amounts similar to those obtained experimentally.展开更多
Our work consists in inventorying and analyzing the phytodiversity along an altitudinal gradient of the southern slope of the mount of Tessala (north-western Algeria). For this purpose, we choose seven stations, insid...Our work consists in inventorying and analyzing the phytodiversity along an altitudinal gradient of the southern slope of the mount of Tessala (north-western Algeria). For this purpose, we choose seven stations, inside each one of them floristic statements are realized. The inventory carries out on the whole of the stations made it possible to draw up a floristic list represented by 103 species, distributed on 39 botanical families dominated by Asteraceae, Poaceae, Lamiaceae and Brasicasseae. The biological spectrum of these species reveals the predominance of the hemicryptophytes and the therophytes, and on the physiognomical level, the vegetation of our stations allows distinguishing from the tree, shrubby, bushy and herbaceous formations. The processing data obtained by the factorial analysis of correspondences (AFC) and by ascending hierarchical classification (CHA) emphasize the existence of two groups of stations. A first group of stations are located in altitude, less degraded, more diversified and where in particular the phanerophyts dominate. A second group of stations are located in low altitude, little diversified and where the degradation of vegetable cover is important, resulting in the installation of the hemicryptophyts and the therophyts.展开更多
文摘This research was aimed to optimize the extraction conditions of three phenolic compounds: total phenolics, flavonoids and condensed tannins, from White Horehound’s leaves (Marrubium vulgare L.). Distilled water and different organic solvents such as: methanol, ethanol and acetone, were used, with various concentrations (20% - 80%, v/v), temperatures (20°C - 60°C) and extraction times (30 - 450 min). Results showed that the maximum total phenolics amounts (293.34 ± 14.60 mg gallic acid equivalent/g dry weigh), were obtained with 60% aqueous methanol at 25°C for 180 min;total flavonoids (79.52 ± 0.55 mg catechin equivalent/g dry weigh) with 80% aqueous methanol at 20°C for 450 min, and condensed tannins (28.15 ± 0.80 mg catechin equivalent/g dry weigh) with 60% aqueous acetone at 50°C and for 180 min. ANOVA test showed the significant effect (***P < 0.001) of the extraction conditions tested on phenolic compounds. The Principal Component Analysis (PCA) exhibited the positive effect of low temperatures on total phenolics and flavonoids extraction, and the effect of high temperatures on the condensed tannins extraction. The Response Surface Methodology (RSM) provided predicted values of extraction conditions and maximum polyphenols amounts similar to those obtained experimentally.
文摘Our work consists in inventorying and analyzing the phytodiversity along an altitudinal gradient of the southern slope of the mount of Tessala (north-western Algeria). For this purpose, we choose seven stations, inside each one of them floristic statements are realized. The inventory carries out on the whole of the stations made it possible to draw up a floristic list represented by 103 species, distributed on 39 botanical families dominated by Asteraceae, Poaceae, Lamiaceae and Brasicasseae. The biological spectrum of these species reveals the predominance of the hemicryptophytes and the therophytes, and on the physiognomical level, the vegetation of our stations allows distinguishing from the tree, shrubby, bushy and herbaceous formations. The processing data obtained by the factorial analysis of correspondences (AFC) and by ascending hierarchical classification (CHA) emphasize the existence of two groups of stations. A first group of stations are located in altitude, less degraded, more diversified and where in particular the phanerophyts dominate. A second group of stations are located in low altitude, little diversified and where the degradation of vegetable cover is important, resulting in the installation of the hemicryptophyts and the therophyts.
