AKTIVITAS ANTIOKSIDAN DARI EKSTRAK ETANOL DAUN UNGU (Graptophyllum pictum L. Griff) - Ni Luh Rustini; Ni Komang Ariati (CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry), 2017)
ABSTRAK: Penelitian ini dilakukan untuk mengetahui kandungan total fenol, total flavonoid, dan aktivitas antioksidan berbagai fraksi dan ekstrak etanol daun ungu (Graptophyllum pictum L. Griff) secara in vitro. Penentuan total fenol menggunakan metode Manian dengan pereaksi Folin Ciocalteu dan total flavonoid dengan metode Aluminium Klorida. Penentuan aktivitas antioksidan menggunakan metode penangkapan radikal bebas 2,2-difenil-1-pikrilhidrazil (DPPH). Hasil ekstraksi 700 g serbuk kering daun ungu dengan 6000 mL etanol 96% menghasilkan 31 g ekstrak kental yang berwarna ungu kehijauan. Hasil partisi 15 g ekstrak kental etanol dengan pelarut kloroform, etik asetat dan n-butanol menghasilkan 12,5 g ekstrak pekat kloroform, 1,4 g ekstrak pekat etil asetat dan 1,0 g ekstrak pekat n-butanol yang semuanya berwarna ungu. Kandungan total fenol ekstrak etanol, kloroform, etil asetat dan n-butanol berturut-turut sebesar 3870,75 ; 2851,63 ; 7540,12 dan 18455,30 mg/100 g GAE. Kandungan total flavonoid ekstrak etanol, kloroform, etil asetat dan n-butanol berturut-turut sebesar 402,88 ; 98,14 ; 374,45 dan 345,95 mg/100 g QE. Hasil uji aktivitas antioksidan menunjukkan bahwa ekstrak etanol, etil asetat dan n-butanol daun ungu mempunyai kemampuan menangkap radikal bebas DPPH dengan nilai IC50 berturut-turut sebesar 83,25 ppm ; 271,04 ppm dan 385,82 ppm. Ekstrak kloroform daun ungu tidak memiliki kemampuan menangkap radikal bebas DPPH karena memiliki nilai IC50 lebih dari 500 ppm, yaitu sebesar 1365,73 ppm. ABSTRACT: This research has been done to determine the content of total phenol, total flavonoids and antioxidant activity in vitro of various fractions and ethanol extract of ungu leaves (Graptophyllum pictum L. Griff). Determination of total phenols using Manian method with Folin Ciocalteau reagent and total flavonoids using Aluminium chloride methode. Determination of antioxidant activity using DPPH method. The extraction of 700 g of dry powder ungu leaves with 6000 mL ethanol of 96 % produces 31 g of concentrated extract greenish purple. The partition of 15 g concentrated ethanol extract with chloroform, ethyl acetate and n-butanol to yield of 12.5 g concentrated chloroform extract, 1.4 g concentrated extract of ethyl acetate and 1.0 g of n-butanol concentrated extracts of which were purple. The content of total phenol of ethanol, chloroform, ethyl acetate and n-butanol extract in a row amounted to 3870.75; 2851.63; 7540.12 and 18455.30 mg/100 g GAE. The content of total flavonoid of ethanol, chloroform, ethyl acetate and n-butanol extract in a row amounted to 402.88; 98.14; 374.45 and 345.95 mg / 100 g QE. The result of antioxidant activity of ethanol, ethyl acetate and n-butanol extract of ungu leaf have the potent scavenger of free radicals DPPH with IC50 values were 83.25 ppm; 271.04 ppm and 385.82 ppm. Ungu leaf chloroform extract does not have potent scavenger of free radicals DPPH because it has IC50 values was 1365,73 ppm ??, more than 500 ppm,