Electronic Theses and Dissertation

Tingginya prevalensi diabetes melitus mendorong eksplorasi bahan alam sebagai alternatif terapi. kulit buah kopi robusta (coffea canephora pierre ex a.frohner) diketahui mengandung metabolit sekunder seperti flavonoid dan polifenol yang berpotensi menghambat enzim α-amilase sehingga memperlambat pemecahan karbohidrat menjadi glukosa. penelitian ini bertujuan mengidentifikasi kandungan fitokimia serta mengevaluasi aktivitas antidiabetes ekstrak etanol dan fraksi etil asetat kulit buah kopi robusta melalui metode inhibisi enzim α-amilase. penapisan fitokimia dilakukan secara kualitatif, sedangkan uji inhibisi diukur menggunakan spektrofotometri uv-vis pada panjang gelombang 617 nm. hasil menunjukkan bahwa ekstrak etanol mengandung alkaloid, flavonoid, tanin, saponin, dan steroid, sedangkan fraksi etil asetat hanya mengandung tanin dan triterpenoid. uji aktivitas inhibisi menunjukkan kedua sampel bersifat dose-dependent. nilai ic₅₀ ekstrak etanol sebesar 603,491 ppm lebih rendah dibandingkan fraksi etil asetat sebesar 846,214 ppm, sementara acarbose sebagai kontrol positif memiliki ic₅₀ sebesar 14,18 ppm. hasil ini menunjukkan bahwa ekstrak etanol lebih efektif dalam menghambat enzim α-amilase dibandingkan fraksi etil asetat, diduga karena efek sinergisme dari kandungan metabolit sekunder yang lebih lengkap dibandingkan hasil fraksinasinya. kata kunci: coffea canephora, antidiabetes, kulit buah kopi, α-amilase, ic₅₀ .

The high prevalence of diabetes mellitus has driven the exploration of natural products as alternative therapies. Robusta coffee (Coffea canephora Pierre ex A.Frohner) fruit peel is known to contain secondary metabolites, such as flavonoids and polyphenols, which potentially inhibit the α-amylase enzyme, thereby slowing the breakdown of carbohydrates into glucose. This study aims to identify the phytochemical content and evaluate the antidiabetic activity of the ethanol extract and ethyl acetate fraction of robusta coffee fruit peel using the α-amylase inhibition method. Phytochemical screening was conducted qualitatively, while the enzyme inhibition assay was measured using UV-Vis spectrophotometry at a wavelength of 617 nm. The screening results revealed that the ethanol extract contained alkaloids, flavonoids, tannins, saponins, and steroids, whereas the ethyl acetate fraction only contained tannins and triterpenoids. The inhibition activity test showed that both samples exhibited dosedependent activity. The IC₅₀ value of the ethanol extract was 603.491 ppm, which is lower than that of the ethyl acetate fraction at 846.214 ppm. Meanwhile, acarbose, as a positive control, showed a much stronger IC₅₀ of 14.18 ppm. These results indicate that the ethanol extract is more effective in inhibiting the α-amylase enzyme compared to the ethyl acetate fraction. This higher efficacy is likely due to the synergistic effects of a more comprehensive range of secondary metabolites present in the total ethanol extract compared to its fractionated form. Keywords: Coffea canephora, Antidiabetic, Coffee Fruit Peel, α-Amylase, IC₅₀ .