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Showing 2 results for Phenols
G. Diba, Sh. Jamili, E. Ramezani Fard,
Volume 25, Issue 4 (1-2017)
Abstract
Sea cucumber is a valuable resource containing several materials that can be used as natural products and pharmaceutical industries. In this study, proximate composition and the amount of total phenols, flavonoids and antioxidant activity of fresh and rehydrated (after drying) sea cucumber, Holothuria parva, were examined. The samples were collected from Bandar Lengeh in the Persian Gulf during low tide and kept frozen. The samples were freeze-dried and the moisture content was calculated. The protein, lipid, ash and carbohydrate contents were then measured. The amounts of antioxidant activity (DPPH), phenol and flavonoid contents were also measured. All results have possibility (p<0.05). In fresh sample, the moisture, protein, lipid, ash and carbohydrate contents were ±81.20, ± 12.00, ± 0.34, ±5.50 and ±0.95%, respectively, while they were ±92.50, ± 3.76, ±0.36, ±1.00 and ±2.07% in rehydrated sample. The antioxidant activity in fresh and rehydrated samples were equal to ±0.063 and ±0.060 mg vitamin C/g dry sample, respectively. The IC50 in fresh sample was ±5.26 while in the rehydrated sample was ±4.14. Total phenol content of fresh and rehydrated samples were equal to ±0.22 and ±0.19 mg gallic acid/g dry sample, repectively. The flavonoid contents in fresh and rehydrated samples were equal to ±3.86 and ±5.02 mg Quercetin/g dry sample, respectively. The amounts of protein and ash in fresh sample were significantly higher than rehydrated sample with significant difference (p<0.05). Moisture in rehydrated sample was significantly higher than fresh sample with significant difference (p<0.05). There were no significant difference between fresh and rehydrated samples in terms of their phenon and flavonoid contents. The DPPH radical scavenging capacity was significantly higher in the fresh sample compared to the rehydrated sample with significant difference (p<0.05). It can be concluded that this species of fresh sea cucumber has more antioxidant activity than rehydrated (after drying) sea cucumber and more beneficial to be used in pharmaceutical and food industries.
Salim Sharifian, Melika Nazemi,
Volume 33, Issue 6 (2-2025)
Abstract
Introduction
Among all marine organisms, seaweeds are considered as one of the sources of bioactive compounds. The most important compounds found in brown seaweed include phenolic compounds, polysaccharides, polyunsaturated fatty acids, proteins, peptides, pigments, vitamins, terpenoids and sterols (Sadeghi et al., 2023). Phlorotannins are compounds containing a benzene ring with one or more hydroxyl group substitutions, which are found only in brown seaweeds. So far, more than 150 algal polyphenol structures have been reported (Asaduzzaman et al., 2020). Reports indicate that these compounds have several medicinal properties such as antimicrobial and antioxidant (Milledge et al., 2015). Phycocolloids or hydrocolloids are another group of bioactive compounds found in brown seaweeds. The most important hydrocolloids found in seaweeds include alginate, agar, and carrageenan (Cmikova et al., 2022). Sargassum cristaefolium and Nizimudinia zanardinii are brown seaweeds species with good distribution on the southern coasts of Iran that can be considered as potential options for investigating the presence of compounds with antioxidant and functional properties. Therefore, the objectives of the present study included 1) extraction of bioactive compounds (including phenolic compounds and alginate) using different solvents and 2) investigation of the extraction efficiency and antioxidant properties of the extracted compounds.
Methodology
Brown seaweeds S. cristaefolium and N. zanardinii were collected from the Chabahar coast, washed and dried in the shade. Extraction was performed using methanol (100%, 70%, 30%), ethyl acetate (100%, 70%, 30%) and water (100%) and the extraction yield, phlorotannins content, DPPH free radical scavenging activity and copper chelating ability of different extracts were measured. To purify phenolic compounds in N. zanardinii, the methanol extract was fractionated using chloroform, dichloromethane and ethyl acetate solvents. Alginate was extracted using distilled water and the residue obtained from the extraction in the previous section was used for extraction. Total phenol content was measured based on the standard phloroglucinol (PHG) and using the Folin-Ciocalteu indicator. DPPH free radical scavenging activity was measured according to the method of Shimada et al. (1992). Cupric chelating ability of different extracts was measured according to the method mentioned by Wong et al. (2006).
Results
In S. cristaefolium, among the different treatments, the highest extraction yield was obtained in 70% methanol solvent (5.50 g/100 g), while in N. zanardinii the highest yield was in 100% methanol solvent and equal to 43.6 g/100 g seaweed. The extract yield in N. zanardinii was higher than S. cristaefolium in most treatments. In both seaweeds, the highest phlorotannins content was observed in 100% ethyl acetate treatment and the lowest in 100% water treatment. The highest DPPH scavenging activity was obtained in 100% ethyl acetate treatment of N. zanardinii at 84.38%. The lowest DPPH scavenging activity was observed in 100% water extract. Among the different fractions, the highest extraction yield by weight was associated with the ethyl acetate fraction (2.54 g). The highest amount of phlorotannins, i.e. 19.14 mg phloroglucinol/g extract, was found in the ethyl acetate fraction, while the lowest amount (1.35 mg PHG/g) was found in the chloroform fraction. The highest radical scavenging activity, 98.95%, was found in the ethyl acetate fraction. When comparing the fractions with the first extract, only the cupric chelation rate in the ethyl acetate fraction (73.44%) was higher than in the first extract (43.45%), and lower chelating ability was observed in the other fractions.
Discussion and Conclusion
In the present study, organic solvents in pure form were more effective than those mixed with water in both S. cristaefolium and N. zanardinii. These results are in agreement with the study of El-Sheekh et al. (2023) who reported that the extraction yield and antioxidant properties varied depending on the type of solvent and ...
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