vii

DAFTAR ISI

HALAMAN JUDUL........................................................................................ i

HALAMAN PENGESAHAN.......................................................................... ii

SURAT PERNYATAAN................................................................................. iii

PERNYATAAN PERSETUJUAN PUBLIKASI KARYA ILMIAH ............. iv

PRAKATA....................................................................................................... v

DAFTAR ISI.................................................................................................... vii

DAFTAR SINGKATAN ................................................................................. xi

DAFTAR TABEL............................................................................................ xiii

DAFTAR GAMBAR ....................................................................................... xiv

DAFTAR LAMPIRAN.................................................................................... xv

INTISARI......................................................................................................... xvi

BAB I PENDAHULUAN........................................................................... 1

1.1. Latar Belakang ....................................................................... 1

1.2. Rumusan Masalah .................................................................. 3

1.3. Tujuan Penelitian ................................................................... 3

1.4. Manfaat Penelitian ................................................................. 3

BAB II TINJAUAN PUSTAKA.................................................................. 5

2.1. Antioksidan ............................................................................ 5

2.3. Fraksinasi ............................................................................... 9

2.3.1. Larutan Penyari .......................................................... 9

viii

2.4. Nanas...................................................................................... 11

2.4.1. Definisi ....................................................................... 11

2.4.2. Taksonomi.................................................................. 12

2.4.3. Tempat tumbuh dan morfologi................................... 12

2.4.4. Jenis-jenis nanas ......................................................... 12

2.4.5. Kandungan kulit nanas ............................................... 13

2.5. Radikal Bebas......................................................................... 14

2.6. DPPH (2,2-difenil-1 pikrilhidrazil)........................................ 15

2.7. Kerangka Teori....................................................................... 18

2.8. Kerangka Konsep ................................................................... 18

2.9. Hipotesis................................................................................. 19

BAB III METODE PENELITIAN ................................................................ 20

3.1. Jenis Penelitian dan Rancangan Penelitian ............................ 20

3.2. Variabel dan Definisi Operasional ......................................... 20

3.2.1. Variabel bebas ............................................................ 20

3.2.2. Variabel tergantung .................................................... 20

3.2.3. Variabel terkendali ..................................................... 20

3.2.4. Definisi operasional.................................................... 20

3.3. Populasi dan Sampel .............................................................. 21

3.3.1. Populasi ...................................................................... 21

3.3.2. Sampel ........................................................................ 21

3.4. Instrumen dan Bahan Penelitian............................................. 22

3.4.1. Instrumen.................................................................... 22

ix

3.4.2. Bahan.......................................................................... 22

3.5. Cara Penelitian ....................................................................... 22

3.5.1.Determinasi tanaman.............................................................. 22

3.5.2. Preparasi sampel......................................................... 23

3.5.3. Pembuatan ekstrak etanolik kulit buah nanas ............ 23

3.5.4. Pembuatan fraksi n-heksana dan fraksi etanol ........... 23

3.5.5. Pembuatan pereaksi.................................................... 24

3.5.6. Penentuan aktivitas antioksidan dengan metode

DPPH.......................................................................... 24

3.6 Tempat dan Waktu ................................................................. 29

3.6.1. Tempat........................................................................ 29

3.6.2. Waktu ......................................................................... 30

3.6.3. Alur Penelitian............................................................ 30

3.6. Analisis Hasil ......................................................................... 31

BAB IV HASIL PENELITIAN DAN PEMBAHASAN............................... 32

4.1 Hasil penelitian....................................................................... 32

4.1.1. Determinasi tanaman.................................................. 32

4.1.2. Ekstrak kulit buah nanas ............................................ 33

4.1.3. Fraksi kulit buah nanas............................................... 33

4.1.4. Screening Fitokimia ................................................... 33

4.1.5. Penentuan Panjang Gelombang Maksimum dan

Operating Time .......................................................... 34

x

4.1.6. Penentuan nilai IC50 fraksi n-heksana kulit buah

nanas........................................................................... 34

4.1.7. Penentuan Nilai IC50 Fraksi Etanol Kulit Buah

Nanas .......................................................................... 36

4.1.8. Daya Antioksidan Antara Fraksi N-Heksana Dan

Fraksi Etanol Ekstrak Etanolik Kulit Buah Nanas

Terhadap Kontrol Positif ............................................ 37

4.1.9. Analisis Statistik......................................................... 38

4.2 Pembahasan............................................................................ 39

4.2.1 Determinasi tanaman.................................................. 39

4.2.2 Ekstraksi kulit buah nanas.......................................... 39

4.2.3 Fraksinasi Kulit Buah Nanas...................................... 42

4.2.4 Uji screening fitokimia............................................... 42

4.2.5 Aktivitas antioksidan antara Fraksi n-heksana dan

etanol ektrak etanolik kulit buah nanas ...................... 45

BAB V KESIMPULAN DAN SARAN ....................................................... 49

5.1 Kesimpulan ............................................................................ 49

5.2 Saran....................................................................................... 49

DAFTAR PUSTAKA ...................................................................................... 50

xi

DAFTAR SINGKATAN

C : Celcius

Cit : Sitasi

Cm : Sentimeter

Cm3 : Senti meter kubik

cP : Sentipoise

Depkes : Departemen Kesehatan

Dkk : Dan kawan-kawan

DNA : Deoxyribose-nucleic acid

DPPH : 2,2-difenil-1 pikrilhidrazil

FeCl3 : Besi (III)klorida atau ferri klorida

FMIPA : Fakultas Matematika dan Ilmu Pengetahuan Alam

FTC : Ferric Thiocyanate

g : Gram

H2O2 : Hidrogen peroksida

HCl : Hidrogen klorida

IC50 : Inhibitor Concentration 50 %

Kg : Kilogram

Mg : Magnesium

mg : Miligram

mL : Mililiter

mM : Milimol

N : Normalitas

xii

nm : nanometer

NrF2 : Nuclear factor erythroid 2 related factor 2

p.a : Pro analisis

Ppm : part per milion

Rpm : Revolutions per minute

SD : Standar deviasi

SOD : Superoxide dismutase

UNNES : Universitas Negeri Semarang

UV : Ultraviolet

UV : Ultraviolet-Visible

v/V : Volume/volume

μg : Mikrogram

μL : Mikroliter

xiii

DAFTAR TABEL

Tabel 2.1. Sifat Fisika dan Kimia Etanol ....................................................... 10

Tabel 2.2. Sifat Fisika dan Kimia n-Heksana................................................. 10

Tabel 4.1. Hasil pemeriksaan karakteristik ekstrak etanolik kulit buah

nanas.............................................................................................. 33

Tabel 4.2. Uji Screening Fitokimia ................................................................ 33

Tabel 4. 3. Data % inhibisi DPPH pada setiap konsentrasi fraksi n-heksana . 35

Tabel 4. 4. Nilai IC50 fraksi n-heksana ekstrak etanolik kulit buah nanas ...... 36

Tabel 4. 5. Data % inhibisi DPPH pada setiap konsentrasi fraksi etanol........ 36

Tabel 4. 6. Nilai IC50 fraksi etanol ekstrak etanolik kulit buah nanas ............. 37

Tabel 4. 7. % Inhibisi dan nilai IC50 pada vitamin C ...................................... 38

Tabel 4. 8. Daya antioksidan setiap sampel .................................................... 38

Tabel 4. 9. Hasil analisis statistik .................................................................... 39

xiv

DAFTAR GAMBAR

Gambar 2. 1 Buah Nanas .............................................................................. 11

Gambar 2. 2 Kerangka Teori ......................................................................... 18

Gambar 2. 3 Kerangka Konsep ..................................................................... 18

Gambar 4. 1. Hasil penentuan operating time (OT)....................................... 34

Gambar 4. 2. Kurva regresi linear antara konsentrasi fraksi n-heksana

dengan % inhibisi DPPH (replikasi 1)...................................... 35

Gambar 4. 3. Kurva regresi linear antara konsentrasi fraksi etanol dengan

% inhibisi DPPH (replikasi 1) .................................................. 37

xv

DAFTAR LAMPIRAN

Lampiran 1. Hasil determinasi tanaman ....................................................... 56

Lampiran 2. Hasil rendemen ekstrak kental dan kadar air............................ 57

Lampiran 3. Hasil Uji screening Fraksi n-heksana....................................... 59

Lampiran 4. Hasil Uji screening Fraksi etanol ............................................. 60

Lampiran 5. Spektra DPPH pada λ 500-550 nm........................................... 61

Lampiran 6. Data % inhibisi DPPH pada setiap konsentrasi fraksi n-

heksana ..................................................................................... 62

Lampiran 7. Kurva regresi Linier pada fraksi n-heksana.............................. 63

Lampiran 8. Data % inhibisi DPPH pada setiap konsentrasi fraksi etanol ... 64

Lampiran 9. Kurva regresi Linier pada fraksi etanol .................................... 65

Lampiran 10. Perhitungan daya antioksidan setiap sampel ............................ 66

Lampiran 11. Analisa Statistik........................................................................ 67

Lampiran 12. Ethical Clearance...................................................................... 68

Lampiran 13. Surat Keterangan Bebas Laboratorium .................................... 69

Lampiran 14. Dokumentasi Penelitian........................................................... 72