Free Radical Scavenging, Metal Chelating and Singlet Oxygen Quenching Activity of Fractionated Brown Seaweed Sargassum hystrix Extract

The discovery of anticancer agents paradigm has been shifted to natural resources to overcome the toxicity of many synthetic agents at early clinical stages. In the present study, the antimutagenic, anticancer, phytochemistry, and free radical scavenging activities of five extracts ofConyza trilobawere investigated. Extracts II (water : methanol), III (methylene chloride), and IV (methylene chloride : methanol) had the highest chlorophyll content and the highest superoxide scavenging, and metal chelating activities comparable to that of trolox. They also showed DPPH•scavenging activities better than that ofα-tocopherol. Virtually all extracts exerted a strong (>40% reduction) antimutagenic activity against sodium azide and benzopyrene. Extracts II, III, and IV showed a remarkable growth inhibition profile with GI50of 0.07–0.87 μg for Hepa1c1c7 and H4IIE1, A549, HT29, and PC3 cell lines and totally abated the growth of all cell lines, except for the breast cells, at 0.3–7.0 μg. The present study found a strong correlation between the chlorophyll content ofConyzaextracts and their DDPH scavenging, metal chelating, and in vitro cytotoxic and cytostatic activities most probably through triggering apoptosis. This study could offer a platform for future studies and help selecting the vital features that identify the extract with potential anticancer activities.

Download Full-text

Antioxidant Protection from UV- and Light-Stress Related to Carotenoid Structures

Antioxidants ◽

10.3390/antiox8070219 ◽

2019 ◽

Vol 8 (7) ◽

pp. 219 ◽

Cited By ~ 19

Author(s):

Gerhard Sandmann

Keyword(s):

Singlet Oxygen ◽

Antioxidant Activities ◽

Light Stress ◽

Radical Scavenging ◽

Hydroxyl Groups ◽

Minor Importance ◽

Oxygen Quenching ◽

Singlet Oxygen Quenching ◽

Living Organisms

This review summarizes studies of protection against singlet oxygen and radical damage by carotenoids. The main focus is on how substitutions of the carotenoid molecules determine high antioxidant activities such as singlet oxygen quenching and radical scavenging. Applied assays were carried out either in vitro in solvents or with liposomes, and in a few cases with living organisms. In the latter, protection by carotenoids especially of photosynthesis against light- and UV-stress is of major importance, but also heterotrophic organisms suffer from high light and UV exposure which can be alleviated by carotenoids. Carotenoids to be compared include C30, C40 and C50 molecules either acyclic, monocyclic or bicyclic with different substitutions including sugar and fatty acid moieties. Although some studies are difficult to compare, there is a tendency towards mono and bicyclic carotenoids with keto groups at C-4/C-4’ and the longest possible polyene structure functions to act best in singlet oxygen quenching and radical scavenging. Size of the carotenoid and lipophilic substituents such as fatty acids seem to be of minor importance for their activity but hydroxyl groups at an acyclic end and especially glycosylation of these hydroxyl groups enhance carotenoid activity.

Download Full-text

Radical Scavenging and Singlet Oxygen Quenching Activity of Marine Carotenoid Fucoxanthin and Its Metabolites

Journal of Agricultural and Food Chemistry ◽

10.1021/jf071848a ◽

2007 ◽

Vol 55 (21) ◽

pp. 8516-8522 ◽

Cited By ~ 257

Author(s):

Nakkarike M. Sachindra ◽

Emiko Sato ◽

Hayato Maeda ◽

Masashi Hosokawa ◽

Yoshimi Niwano ◽

...

Keyword(s):

Singlet Oxygen ◽

Radical Scavenging ◽

Oxygen Quenching ◽

Singlet Oxygen Quenching

Download Full-text

Radical scavenging and singlet oxygen quenching activity of extracts from Indian seaweeds

Journal of Food Science and Technology ◽

10.1007/s13197-010-0022-4 ◽

2010 ◽

Vol 47 (1) ◽

pp. 94-99 ◽

Cited By ~ 52

Author(s):

N. M. Sachindra ◽

M. K. W. A. Airanthi ◽

M. Hosokawa ◽

K. Miyashita

Keyword(s):

Singlet Oxygen ◽

Radical Scavenging ◽

Oxygen Quenching ◽

Singlet Oxygen Quenching

Download Full-text

Radical Scavenging Activity of Edible Fungal Sporocarp Extracts from the Niger Delta Region of Nigeria

International Journal of Pharmacognosy and Phytochemical Research ◽

10.25258/phyto.v9i4.8119 ◽

2017 ◽

Vol 9 (4) ◽

Author(s):

Ita B. N. ◽

Eduok S. I.

Keyword(s):

Free Radical ◽

Niger Delta ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Reducing Power ◽

Free Radical Scavenging ◽

Scavenging Activity ◽

Aqueous Extracts ◽

Metal Chelating ◽

Niger Delta Region

The radical scavenging activity of acetone, ethanol and aqueous extracts from Agaricus placomyces, Cantharellus cibarius and Pleurotus ostreatus from the Niger Delta region of Nigeria was determined with their metal chelating and reducing power. The extracts exhibited significant free radical scavenging activities in the DPPH assay (IC50 = 2.11 to 4.37 mg/mL) with the aqueous extract from P. ostreatus being the most potent. Also, the aqueous extracts exhibited better metal chelating abilities and reducing power than the ethanol and acetone extracts. In addition, higher content of total phenolics and flavonoids was found in the aqueous extract of A. placomyces (55.63mg GAE/g) and P. ostreatus (15.55 mgQE/g) respectively, whereas ascorbic acid ranged from 0.33 to 1.22 mgAAE/ in all the extracts. Overall, our results indicate that mushrooms particularly Agaricus placomyces, and Pleurotus ostreatus contain high amount of polyphenolic compounds with significant free radical scavenging abilities, notable metal chelating activities and promising reducing power. These properties indicate that the mushrooms are functional foods with the potential to attenuate oxidative stress associated with free radical damage in biological systems.

Download Full-text