Phytochemical Profile of Main Antioxidants in Different Fractions of Chnoospora Minima and Gracillaria Edulis
Posted: 5 Dec 2019
Date Written: December 3, 2019
Natural bioactive compounds are abundant in seaweeds with potentials therapeutic activities. As Sri Lankan marine algae are underexploited, here we aimed to investigate the total phenolic, flavonoid contents and antioxidant activities of the methanol extract of Chnoospora minima and Gracillaria edulis and its fractions. De-polysaccharide methanol extracts of C.minima and G.edulis were partitioned with hexane, chloroform, ethyl acetate and phytochemicals, antioxidant activities were determined in the crude methanol extract (ME), hexane (HF), chloroform (CF), ethyl acetate (EAF) and aqueous (AF) fractions. Total phenolic (TPC) and flavonoid contents (TFC) were determined using Folin–Ciocalteu and aluminium chloride methods. Total alkaloid content was determined using the standard method. Antioxidant potentials were determined using ferric reducing antioxidant power (FRAP), ferrous iron chelating activity (FICA), 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 2,-2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The highest TPC and TFC were recorded in the ME (59.01± 1.86 mg GAE/g) and EAF (5.14±0.43 mg QE/g) of C.minima whereas the highest alkaloid content was reported in ME (7.17±0.06 mg PE/g) of G.edulis. The highest DPPH activity was recorded in ME (IC50: 0.48± 0.01 mg/ml) of C.minima compared to the standard trolox (IC50: 0.011 mg/ml). However, most potent ABTS scavenging activity was detected in EAF (IC50: 0.06±0.001 mg/ml) of C.minima while the lowest was recorded in ME (IC50:0.56 ± 0.01 mg/ml) of G.edulis compared to the standard Trolox (IC50: 0.008 mg/ml). Compared to the chelation capacity, the highest FICA was found in EAF (IC50: 0.38±0.01 mg/ml) of C.minima while the lowest was in the ME (IC50: 9.23 ± 0.19 mg/ml) of G.edulis compared to the standard EDTA (IC50-0.019 mg/ml). Similarly, EAF (20.34±1.72 mg TE/g) of C.minima showed highest reducing power, whereas in ME of G.edulis recorded the lowest reducing power (0.26 ± 0.03 (mg TE/g). In conclusion, ME and EAF of C.minima possess marked antioxidant activities, which can be used for management of oxidative stress-associated chronic diseases.
Keywords: gracillaria edulis, choonospora minima, phytochemicals, antioxidants
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