Algae in general characterized by their rich content of biological compounds. However, few studies were conducted on the soil-inhabiting algae and their antioxidant characteristics. The present study was designed to evaluate the antioxidant activity of four edaphic algae including one on-soil alga (Vaucheria geminata) and three axenic isolated in-soil algae (Pleurochloris pyrenoidosa, Botrydiopsis eriensis, and Scenedesmus obliquus). Total antioxidant activity by Phosphomolybdenum assay ranged from 6.66 to 36.33 mg of Asc/g dwt; meanwhile, the percentage inhibition of DPPH radical was up to 97.37%. Antioxidant activity of each alga was assessed also by measuring their contents of total phenols, flavonoids, and pigments (chlorophyll a and carotenoids). B. eriensis and S. obliquus recorded the highest levels of phenols, flavonoids, and chlorophyll a followed by P. pyrenoidosa and V. geminata, while B. eriensis showed the highest carotenoids content. Moreover, about seven types of each phenol and flavonoid compound were identified by HPLC chromatography in the four algae under investigation. The most common detected phenols were gallic, chlorogenic, caffeic, and ferulic, while rutin, quercetin, apigenin, and quercitrin were the most abundant flavonoids among all algae under investigation. All the tested algae were characterized with high antioxidant activities besides the rich contents of compounds with antioxidant properties which recommend their further potential using in nutritional, pharmaceutical, and medicinal implications.

中文翻译：

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埃及某些土壤藻类的抗氧化活性

藻类的一般特征是它们富含生物化合物。然而，关于土壤栖息藻类及其抗氧化特性的研究很少。本研究旨在评估四种土壤藻类的抗氧化活性，包括一种土壤藻类 (Vaucheria geminata) 和三种无菌分离的土壤藻类 (Pleurochloris pyrenoidosa、Botrydiopsis eriensis 和 Scenedesmusobliquus)。磷钼测定的总抗氧化活性范围为 6.66 至 36.33 毫克 Asc/g dwt；同时，DPPH自由基抑制率高达97.37%。每种藻类的抗氧化活性也通过测量它们的总酚、黄酮类化合物和色素（叶绿素 a 和类胡萝卜素）的含量来评估。B. eriensis 和 S.obliquus 记录了最高水平的酚类、类黄酮、和叶绿素 a 其次是 P. pyrenoidosa 和 V. geminata，而 B. eriensis 的类胡萝卜素含量最高。此外，在所研究的四种藻类中，通过 HPLC 色谱法鉴定了大约七种类型的苯酚和类黄酮化合物。检测到的最常见的酚类是没食子酸、绿原、咖啡酸和阿魏酸，而芦丁、槲皮素、芹菜素和槲皮素是所有被调查藻类中含量最丰富的黄酮类化合物。除了富含具有抗氧化特性的化合物外，所有测试的藻类都具有高抗氧化活性，这表明它们在营养、药物和医学方面的进一步潜力。在所研究的四种藻类中，通过 HPLC 色谱法鉴定了大约 7 种酚类和黄酮类化合物。检测到的最常见的酚类是没食子酸、绿原、咖啡酸和阿魏酸，而芦丁、槲皮素、芹菜素和槲皮素是所有被调查藻类中含量最丰富的黄酮类化合物。除了富含具有抗氧化特性的化合物外，所有测试的藻类都具有高抗氧化活性，这表明它们在营养、制药和医学方面的进一步潜力。在所研究的四种藻类中，通过 HPLC 色谱法鉴定了大约 7 种酚类和黄酮类化合物。检测到的最常见的酚类是没食子酸、绿原、咖啡酸和阿魏酸，而芦丁、槲皮素、芹菜素和槲皮素是所有被调查藻类中含量最丰富的黄酮类化合物。除了富含具有抗氧化特性的化合物外，所有测试的藻类都具有高抗氧化活性，这表明它们在营养、药物和医学方面的进一步潜力。在所有被研究的藻类中，槲皮素和槲皮素是最丰富的黄酮类化合物。除了富含具有抗氧化特性的化合物外，所有测试的藻类都具有高抗氧化活性，这表明它们在营养、药物和医学方面的进一步潜力。在所有被研究的藻类中，槲皮素和槲皮素是最丰富的黄酮类化合物。除了富含具有抗氧化特性的化合物外，所有测试的藻类都具有高抗氧化活性，这表明它们在营养、药物和医学方面的进一步潜力。