Bioactive Phenolic Metabolites from Adriatic Brown Algae Dictyota dichotoma and Padina pavonica (Dictyotaceae) (original) (raw)
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Journal of Applied Phycology, 2019
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Polyphenol Content and Antioxidant Activities of Crude Extract from Brown Algae by Various Solvents
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International Journal of Food Science and Technology, 860-869, 48(4), 2013
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Bioactive Phenolic Compounds from Algae
Phenolics, sometimes called polyphenolic compounds, are present in a variety of terrestrial and marine plants. They are utilized as important components of both human and animal diets for their antioxidant capacity. More than 8000 phenolic structures are currently known (Bravo 1998). To date, most polyphenols isolated from marine sources and referenced in the literature are of macroalgal origin (Li et al. 2011). The structures of natural polyphenols vary from simple molecules, such as phenolic acids and other simple polyphenolic compounds, to the more complex phlorotannins, which consist of polymeric structures made up of units of phloroglucinol (1,3,5-trihydroxybenzene), typically isolated from marine brown algae or Phaeophyceae (Harborne 1980; Ragan & Glombitza 1986). Polyphenols exhibit a wide range of biological effects as a consequence of their antioxidant properties. The relatively high concentration of phenolic compounds in marine algae species contributes to their antioxidant properties, which can be of benefit in reducing oxidative reactions deleterious to health. Oxidative stress in the human cell occurs during disease conditions or when optimal nutrition is lacking. Under these circumstances, the so-called “reactive oxygen species” (ROS) are available to initiate lipid peroxidation and damage to other biomolecules. Current evidence strongly supports the contribution of phenolic compounds to the prevention of cardiovascular diseases (CVDs) and cancers, and suggests their role in the prevention of neurodegenerative diseases and diabetes mellitus (Urquiaga & Leighton 2000). This chapter reviews some of the chemical and biological properties of marine algae phenolics as natural antioxidants and discusses their protective effects in biological systems and their potential activities in food products.
Marine Drugs
This study aims to explore novel extraction technologies (ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), ultrasound–microwave-assisted extraction (UMAE), hydrothermal-assisted extraction (HAE) and high-pressure-assisted extraction (HPAE)) and extraction time post-treatment (0 and 24 h) for the recovery of phytochemicals and associated antioxidant properties from Fucus vesiculosus and Pelvetia canaliculata. When using fixed extraction conditions (solvent: 50% ethanol; extraction time: 10 min; algae/solvent ratio: 1/10) for all the novel technologies, UAE generated extracts with the highest phytochemical contents from both macroalgae. The highest yields of compounds extracted from F. vesiculosus using UAE were: total phenolic content (445.0 ± 4.6 mg gallic acid equivalents/g), total phlorotannin content (362.9 ± 3.7 mg phloroglucinol equivalents/g), total flavonoid content (286.3 ± 7.8 mg quercetin equivalents/g) and total tannin content (189.1 ± 4.4 mg cat...
Tropical Journal of Pharmaceutical Research, 2015
To determine the antioxidant activity of methanol extract (ME) and solvent fractions of Avrainvillea erecta as well as their total phenolic and flavonoid contents. Methods: The antioxidant activities of ME as well as its chloroform, butanol, and aqueous fractions (CF, BF and WF, respectively) of A. erecta were evaluated via 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and hydrogen peroxide (H2O2) scavenging assays as well as ferric reducing antioxidant power (FRAP) assay. Total phenolic and flavonoid contents were determined spectrophotometrically. Results: CF and BF possessed equally high DPPH scavenging activity with half-maximal effective concentration (EC50) of 535 and 532 mg/ml, respectively. CF had stronger NO scavenging activity (EC50 743 µg/mL) than ME and BF, although weaker compared with quercetin (EC50 279 µg/ml). CF also produced the highest FRAP value (451 µmol Fe 2+ /g) among all samples examined. Notably, H2O2 scavenging activity was only found in CF (EC50 387 µg/ml), which was as strong (p > 0.05) as that of gallic acid (EC50 456 µg/mL). BF had the highest total phenolic content while CF had the highest total flavonoid content. Conclusion: CF of A. erecta, which has the highest flavonoid content of all the extracts evaluated, is a potential source of natural antioxidants, especially hydrogen peroxide scavengers.