Optimasi Pelarut dan Kondisi Ekstraksi terhadap Kandungan Total Fenolik dan Kapasitas Antioksidan Tertinggi pada Miana (Coleus scutellaroides)

Abstract

Daun Coleus scutellarioides (miana) merupakan sumber antioksidan alami yang kaya senyawa fenolik, namun pemanfaatannya masih terbatas karena belum ada metode ekstraksi yang teroptimasi. Eksperimen dengan desain yang menyeluruh kurang efisien karena membutuhkan banyak percobaan dan bahan, sehingga diperlukan pendekatan desain eksperimen. Penelitian ini bertujuan untuk mengoptimalkan kombinasi pelarut dan kondisi ekstraksi guna meningkatkan kandungan total fenolik (TPC) serta aktivitas antioksidan (DPPH dan FRAP) dari daun miana. Tahap pertama dilakukan optimasi pelarut menggunakan I-optimal mixture design dengan komposisi air, etanol, dan metanol. Kondisi optimum diperoleh pada 26,02% air dan 73,98% metanol dengan desirability 0,938, menghasilkan TPC 26,00 mg GAE/g DW, DPPH 4,81 µmol TE/g DW, dan FRAP 210,93 µmol TE/g DW. Tahap kedua dilakukan optimasi enam faktor ekstraksi dengan two-level fractional factorial design (FFD), meliputi pelarut, pH, rasio cairan-padatan, suhu, waktu, dan ukuran partikel. Kondisi optimum diperoleh pada 74% metanol, pH 4, rasio 30 mL/g, suhu 10 °C, waktu 45 menit, dan ukuran partikel 80 mesh dengan desirability 0,632, menghasilkan TPC 21,55 mg GAE/g DW, DPPH 11,22 µmol TE/g DW, dan FRAP 241,89 µmol TE/g DW. Nilai %RSE seluruh respon <10% menunjukkan model valid. Hasil ini membuktikan bahwa pemilihan pelarut dan optimasi kondisi ekstraksi mampu meningkatkan perolehan senyawa fenolik dan kapasitas antioksidan dari daun miana.

Coleus scutellarioides (miana) leaves are a natural antioxidant source rich in phenolic compounds, but their utilization remains limited due to the absence of an optimized extraction method. Full experimental designs are often inefficient because they require numerous trials and large amounts of materials, thus an experimental design approach is necessary. This study aimed to optimize solvent combinations and extraction conditions to enhance the total phenolic content (TPC) and antioxidant activities (DPPH and FRAP) of C. scutellarioides leaves. In the first stage, solvent optimization was performed using an I-optimal mixture design with water, ethanol, and methanol as components. The optimum condition was achieved with 26.02% water and 73.98% methanol, yielding a desirability of 0.938, TPC of 26.00 mg GAE/g DW, DPPH of 4.81 µmol TE/g DW, and FRAP of 210.93 µmol TE/g DW. In the second stage, optimization of six extraction factors was conducted using a two-level fractional factorial design (FFD), including solvent, pH, solid-to-liquid ratio, temperature, extraction time, and particle size. The optimum condition was obtained with 74% methanol, pH 4, a solid-to-liquid ratio of 30 mL/g, temperature of 10 °C, extraction time of 45 minutes, and particle size of 80 mesh, with a desirability of 0.632, yielding TPC of 21.55 mg GAE/g DW, DPPH of 11.22 µmol TE/g DW, and FRAP of 241.89 µmol TE/g DW. The %RSE values for all responses were <10%, indicating model validity. These findings demonstrate that proper solvent selection and extraction optimization significantly enhance the recovery of phenolic compounds and antioxidant capacity from C. scutellarioides leaves.