No abstract

No abstract

No abstract

Marine macroalgae are considered as important sources for bioactive phytochemicals. In this research, two potential marine macroalgae, i.e. Sargassum duplicatum and Palmaria palmata taken from Sepanjang beach, Gunungkidul, Yogyakarta, Indonesia were explored as sources of phenolic compound, and their antioxidant activities were evaluated. Three different solvents, i.e. chloroform, ethyl acetate, and methanol were applied as extraction medium. For each species, its total phenolic content (TPC) and antioxidant activity were determined using Folin-Ciocalteu reagent and DPPH scavenging assay, respectively. The result showed that methanolic extracts exhibited the highest yield in both species. The highest TPC (726.54 mg GAE/g) was obtained from S. duplicatum extracted using ethyl acetate. The antioxidant activity from S. duplicatum and P. palmata have similar value with IC50 values of 790.34 µg/mL and 789.29 µg/mL. The scavenging activities of all extracts related to the total polyphenol content, whereas the polarity of solvent affected the resulted yield and TPC of the extracts. However, our results demonstrated that all extracts were inactive against DPPH radicals (IC50 > 250 μg/mL).

Seven tropical plants were extracted and evaluated for their radical scavenging activity and Total Phenolic Content (TPC). Total phenolic content was determined by Folin-Ciocalteu reagent equivalent to gallic acid. The plant extracts were obtained by sonication using ethanol as the solvent. Four plant extracts were found as active antioxidant in this work. The research revealed that Schleicera oleosa bark extract had the highest DPPH radical scavenging activity with (IC50) with 6.59 ± 0.013 µg/ml, followed by Anacardium occidentale bark extract 8.07 ± 0.12 µg/ml, Anacardium occidentale leaves extract 9.65 ± 0.05 µg/ml, and Muntingia calabura leaves extract 27.12 ± 0.5 µg/ml. Positive correlation between free radical scavenging activities and Total Phenolic Content (TPC) in plant extracts was observed. Schleicera oleosa contained a highest Total Phenolic Content (TPC) 451.071 ± 3.3 mg/gr GAE, followed by Anacardium occidentale bark extract 327.6 ± 2.7 µg/ml, Anacardium occidentale leaves extract 307.08 ± 0.55 µg/ml, and Muntingia calabura leaves extract 288 ± 0.5 µg/ml. The result suggest that these tropical plants can be used as resources for natural antioxidant.