Electronic Theses and Dissertation

Penelitian dilakukan untuk mengetahui aktivitas antioksidan dari ekstrak metanol, n-heksana, etil asetat, dan residu metanol, fraksi gabungan serta sub fraksi gabungan dari hasil pemisahan bunga Calotropis gigantea. Pengujian aktivitas antioksidan dilakukan menggunakan metode 1 diphenyl-2-Pycrilhidrazil (DPPH). Nilai inhibitory concentration (IC50) yang diperoleh adalah sebesar 81,81; 168 ; 92,004 ; dan 104,4 ppm untuk ekstrak metanol, n-heksana, etil asetat dan residu metanol secara berturut-turut. Ekstrak etil asetat bunga biduri kemudian diisolasi menggunakan kromatografi cair vakum sehingga diperoleh 5 fraksi berdasarkan kemiripan pola nodanya. Setiap kelompok fraksi diuji aktivitas antioksidan menggunakan metode yang sama sehingga diperoleh nilai IC50 yaitu 104,716 ; 120,494 ; 123,725 ; 82,56 dan 118, 89 ppm untuk F.A, F.B, F.C, F.D, dan F.E secara berturut-turut. Fraksi D (F.D) sebagai fraksi yang paling aktif selanjutnya diisolasi kembali menggunakan kromatografi kolom gravitasi dan diperoleh 6 kelompok sub-fraksi berdasarkan pola noda. Setiap sub fraksi diuji aktivitas antioksidan menggunakan metode yang sama sehingga diperoleh sub fraksi yang paling aktif yaitu sub fraksi II (F.D.2) dengan nilai IC50 sebesar 49,83 ppm. Sub fraksi F.D.2 dianalisis menggunakan gas chromatography – mass spectrometry dan diperoleh senyawa mayor yaitu hexadecanoic acid, metyl ester dan 9-octadecanoic(z)-, methyl ester dengan persentase 48,91 % dan 25,88 % secara berturut-turut.

Kata kunci : Calotropis gigantea L, antioksidan, 1 diphenyl-2-Pycrilhidrazil (DPPH), inhibitory concentration (IC50), isolasi.

The study was conducted to determine the antioxidant activity of methanol extract, n-hexane, ethyl acetate, and methanol residue, combined fractions and combined sub-fractions from the separation of Calotropis gigantea flowers. Antioxidant activity testing was carried out using the 1 diphenyl-2-pycrylhidrazil (DPPH) method. The inhibitory concentration (IC50) values obtained were 81.81; 168 ; 92,004 ; and 104.4 ppm for methanol extract, n-hexane, ethyl acetate and methanol residue respectively. The ethyl acetate extract of biduri flowers was then isolated using vacuum liquid chromatography to obtain 5 fractions based on the similarity of the stain patterns. Each fraction group was tested for antioxidant activity using the same method so that the IC50 value was 104.716; 120,494 ; 123,725 ; 82.56 and 118.89 ppm for F.A, F.B, F.C, F.D, and F.E respectively. The D (F.D) fraction as the most active fraction was further isolated using gravity column chromatography and 6 groups of sub-fractions were obtained based on the stain pattern. Each sub-fraction was tested for antioxidant activity using the same method so that the most active sub-fraction was obtained, namely sub-fraction II (F.D.2) with an IC50 value of 49.83 ppm. The F.D.2 sub-fraction was analyzed using gas chromatography – mass spectrometry and the major compounds were obtained, namely hexadecanoic acid, methyl ester and 9-octadecanoic(z)-, methyl ester with a percentage of 48.91% and 25.88%, respectively. Key word : Calotropis gigantea L, antioxidant, 1 diphenyl-2-Pycrilhidrazil (DPPH), inhibitory concentration (IC50), isolation.