Latar belakang: Diabetes melitus (DM) ditandai dengan kenaikan kadar gula darah. Jumlah penderita DM di Indonesia terus meningkat. Acarbose sebagai obat DM penghambat α-amilase memiliki banyak efek samping, sehingga diperlukan alternatif dari bahan alami lain dengan kemampuan setara. Spirulina platensis dapat diteliti potensi inhibisi α-amilasenya mengingat sumber daya perairan Indonesia yang besar dan manfaat kandungannya dalam kesehatan. Tujuan: Mengidentifikasi jumlah kandungan fenolik dan flavonoid total serta membandingkan aktivitas inhibisi α-amilase secara in vitro pada ekstrak Spirulina platensis yang berasal dari perairan Indonesia dengan acarbose. Metode: Spirulina platensis diekstraksi menggunakan etanol, etil asetat, serta n-heksana kemudian dilakukan uji fenolik, flavonoid total, dan aktivitas inhibisi α-amilase secara in vitro. Hasil: Kandungan fenolik dan flavonoid total pada ekstrak etanol, etil asetat, dan n-heksana Spirulina platensis yang berasal dari perairan Indonesia berturut-turut adalah 0,460 ± 0,018; 25,5 ± 0,012; 19,064 ± 0,007 mg GAE/g ekstrak serta 17,040 ± 0,055; 49,764 ± 0,010; 42,460 ± 0,098 mg QE/g ekstrak. IC50 inhibisi α-amilase adalah 1,17 ± 0,13; 1,09 ± 0,04; 1,24 ± 0,04; dan 0,185 ± 0,008 µg/mL untuk acarbose. Terdapat perbedaan IC50 yang signifikan antara setiap ekstrak Spirulina platensis dengan acarbose. Kesimpulan: Ekstrak Spirulina platensis yang berasal dari perairan Indonesia terbukti memiliki kandungan fenolik dan flavonoid. Aktivitas inhibisi α-amilase secara in vitro pada ekstrak Spirulina platensis tergolong sangat aktif, namun lebih rendah apabila dibandingkan dengan acarbose.

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Background: Diabetes mellitus (DM) is characterized by an elevation of blood sugar levels. The number of DM patients in Indonesia continue to increase. Acarbose as α-amylase inhibitor DM drug has many side effects, so alternatives from other natural ingredients with equivalent capabilities are needed. Spirulina platensis can be investigated for its α-amylase inhibition potential considering Indonesia's large water resources and its health benefits. Objective: To jdentify the total phenolic and flavonoid content and to compare the in vitro α-amylase inhibitory activity of Spirulina platensis extracts from Indonesian waters with acarbose. Method: Spirulina platensis was extracted using ethanol, ethyl acetate, and n-hexane. The extracts were then tested for total phenolic and flavonoid content and their in vitro inhibitory activity against α-amylase. Results: The total phenolic and flavonoid content in the ethanol, ethyl acetate, and n-hexane extracts of Spirulina platensis were 0.460 ± 0.018; 25.5 ± 0.012; 19.064 ± 0.007 mg GAE/g extract and 17.040 ± 0.055; 49.764 ± 0.010; 42.460 ± 0.098 mg QE/g extract, respectively. The IC50 of α-amylase inhibition were respectively 1.17 ± 0.13; 1.09 ± 0.04; 1.24 ± 0.04; and 0.185 ± 0.008 µg/mL for acarbose. There were significant IC50 difference between each extracts of Spirulina platensis with acarbose. Conclusion: Spirulina platensis extracts from Indonesian waters were proven to contain phenolic and flavonoid. The in vitro α-amylase inhibitory activity of extracts were classified as very active, but lower compared to acarbose.