Aktivitas Antioksidan Ekstrak Rumput Laut Cokelat (Sargassum polycystum) - Kun Cahyaningrum; Amir Husni; Siti Ari Budhiyanti (Faculty of Agricultural Technology, Universitas Gadjah Mada, Yogyakarta, Indonesia, 2016)
The purpose of this study was to determine antioxidant activity of polyphenol and phlorotannin extracts from brown algae Sargassum polycystum. Polyphenol was extracted with ethanol 96% then tested total phenolic content, while phlorotannin was extracted with methanol, chloroform, aquabidest, and ethyl acetate then tested total phlorotannin content. After crude polyphenol and crude phlorotannin extracts were obtained, the studied compounds were extracted using column chromatography. The extracts were then analyzed with HPLC (High Performance Liquid Chromatograpys). Antioxidant activity was analyzed by radical scavenging activity (RSA) and ferrous ion chelating ability (FIC) for four samples, crude polyphenol, crude phlorotannin, polyphenol, and phlorotannin. The result of total phenolic content was 1.18±0.67 mg GAE/g dry sample and total phlorotannin content was 0.61±0.27 mg PGE/g dry sample. Based on RSA and FIC analysis, phlorotannin (IC50 1.12±0.02 mg/mL and 1.34±0.01 mg/mL) showed the highest activity followed by crude phlorotannin (IC50 1.20±0.01 mg/mL and 1.47±0.10 mg/mL), polyphenol (IC50 1.23±0.01 and 1.55±0.02 mg/mL), and crude polyphenol (IC50 1.27±0.01 mg/mL and 1.63±0.02 mg/mL). The results of chromatographic analysis showed that S. polycystum extract contains phenolic compounds similar to the phloroglucinol.ABSTRAKPenelitian ini bertujuan untuk menentukan aktivitas antioksidan ekstrak polifenol dan florotanin dari rumput laut cokelat Sargassum polycystum. Polifenol diekstrak menggunakan pelarut etanol 96% kemudian diuji kandungan total fenolik, sedangkan florotanin diekstrak dengan menggunakan pelarut metanol, kloroform, akuades, dan etil asetat kemudian diuji kandungan total florotanin. Setelah memperoleh ekstrak polifenol dan florotanin, kedua senyawa tersebut dipurifikasi dengan kromatografi kolom. Hasil kromatografi kolom dianalisis menggunakan HPLC (High Performance Liquid Chromatography). Uji aktivitas antioksidan dilakukan dengan metode radical scavenging activity (RSA) dan ferrous ion chelating ability (FIC) terhadap empat sampel, yaitu ekstrak polifenol, ekstrak florotanin, polifenol, dan florotanin. Kandungan total fenolik yang diperoleh adalah 1,18±0,67 mg GAE/g ekstrak kering, sedangkan kandungan total florotanin diperoleh 0,61±0,27 mg PGE/g ekstrak kering. Berdasarkan uji RSA dan FIC, florotanin (IC50 1,12±0,02 mg/ mL dan 1,34±0,01 mg/mL) memiliki aktivitas tertinggi diikuti ekstrak florotanin (IC50 1,20±0,01 mg/mL dan 1,47±0,10 mg/mL), polifenol (IC50 1,23±0,01 dan 1,55±0,02 mg/mL), dan ekstrak polifenol (IC50 1,27±0,01 mg/mL dan 1,63±0,02 mg/mL). Hasil analisis kromatografi menunjukkan ekstrak S. polycystum mengandung senyawa fenolik relatif seperti senyawa floroglusinol.