Oligosakarida alginat (OSA) adalah produk hasil depolimerisasi polimer alginat yang biasanya terdiri dari 2-25 monomer. Produksi OSA dapat dilakukan melalui proses enzimatis, fisik maupun kimiawi. Tujuan penelitian ini adalah mengetahui karakteristik dan bioaktivitas OSA sebagai antioksidan dan inhibitor α-glukosidase. Proses produksi OSA dilakukan secara enzimatis dengan 3 cara penambahan alginat liase yaitu ditambahkan satu kali di awal reaksi (E1), ditambahkan 4 kali dengan interval 2 jam (E2) dan 2 kali interval 4 jam (E3) dengan total volume sama, yaitu 0,15 mL dan aktivitas enzim (1 unit/mL). Total waktu inkubasi adalah 8 jam. Karakterisasi OSA yang dilakukan adalah perhitungan rendemen, analisis profil TLC dan FTIR serta kadar gula pereduksi. Metode DPPH (1,1-diphenyl-2-picrylhydrazyl) digunakan untuk menguji aktivitas antioksidan OSA, sedangkan pengamatan terhadap aktivitas inhibitor α-glukosidase dilakukan dengan melihat aktivitas α-glukosidase dalam mengubah substrat yang diberikan. Hasil penelitian menunjukkan bahwa rendemen OSA dan kadar gula pereduksi tidak berbeda nyata antar perlakuan dengan rendemen OSA berkisar antara 77,29±1,97% hingga 85,46±9,15% dan kadar gula pereduksi OSA berkisar antara 290,32±20,42 µg/mL hingga 312,76±4,74 µg/mL. Aktivitas antioksidan tertinggi diperlihatkan oleh OSA E1 dengan penghambatan terhadap DPPH sebagai radikal bebas sebesar 41,22±2,03% pada konsentrasi 1,2 mg/mL. Aktivitas inhibitor α-glukosidase OSA E1 lebih kecil dibandingkan dengan alginat dengan nilai IC50 masing-masing sebesar 11,23±4,17 ppm dan 5,27±0,29 ppm. Proses depolimerisasi alginat meningkatkan aktivitas alginat sebagai antioksidan namun tidak meningkatkan aktivitasnya sebagai inhibitor α-glukosidase. AbstractAlginate oligosaccharides (AOS) is depolymerization of alginate polymer product that consist of 2-25 monomers. Alginate oligosaccharides can be produced by enzymatic, physical and chemical processes. This research was conducted to find out the characteristics and bioactivity of AOS as an antioxidant and α-glucosidase inhibitor. AOS was produced by enzymatic process with 3 procedures of the addition of the alginate lyase that was added once at the beginning reaction (E1), 4 times every 2 hours (E2) and 2 times every 4 hours (E3) with the same addition of enzyme volume (0.15 mL) and enzyme activity (1 unit/mL). Total incubation times was 8 hours. Alginate oligosaccharides was then characterized their yield, TLC, FTIR profiles and reducing sugar content. DPPH (1,1-diphenyl-2-picrylhydrazyl) method was used to determine antioxidant activity of AOS while observation of α-glucosidase activity in changing the substrate was used to determine inhibitor α-glucosidase activity of AOS. The results showed that yields and reducing sugar level of AOS were not significantly different between treatments. The AOS yields ranged from 77.29±1.97% to 85.46±9.15% and the reducing sugar levels ranged from 290.32±20.42 µg/mL to 312.76±4.74 µg/mL. The highest antioxidant activity was shown by AOS E1 with free radical (DPPH) inhibition of 41.22±2.03%. AOS E1 α-glucosidase inhibitor activity was lower than that of alginate, with the IC50 values of 5.27±0.29 ppm for alginate and 11.23±4.17 ppm for AOS. Depolymerization process of alginates increased antioxidant activity but did not enhance its activity as α-glucosidase inhibitor.
α-GLUCOSIDASE INHIBITOR AND ANTIOXIDANT ACTIVITY ASSAYS OF GUAVA LEAF, CASHEW LEAF AND THE COMBINATIONS AS ANTIDIABETIC AGENT
