Aktivitas Antioksidan Ekstrak Metanol Biji Langsat (Lansium domesticum var. pubescens) dan Duku (Lansium domesticum var. domesticum) dengan Metode DPPH
Penelitian ini bertujuan untuk mengetahui kandungan fitokimia dan aktivitas antioksidan ekstrak biji langsat dan duku dengan metode DPPH. Biji buah langsat dan buah duku diekstraksi menggunakan metode maserasi dengan pelarut metanol. Skrining fitokimia yang dilakukan meliputi uji alkaloid, flavonoid, tannin, triterpenoid, steroid dan saponin secara kualitatif dengan metode uji warna. Uji aktivitas antioksidan menggunakan metode DPPH dan vitamin C sebagai pembanding, serapan diukur menggunakan spektrofotometer UV-Vis pada panjang gelombang 517 nm. Skrining fitokimia pada ekstrak metanol biji langsat menunjukkan hasil positif terhadap alkaloid, triterpenoid dan saponin, sementara pada ekstrak metanol biji duku menunjukkan hasil positif terhadap alkaloid, flavonoid, tannin, triterpenoid, steroid dan saponin. Aktivitas antioksidan ekstrak biji langsat dianalisis menggunakan persamaan garis regresi y = 0,2922x + 33,143, diperoleh IC₅₀ 57,69 μg/mL. Sedangkan aktivitas antioksidan ekstrak biji duku dianalisis menggunakan persamaan garis regresi y = 0.6554x + 29.421, diperoleh IC₅₀ 31,40 μg/mL dan pembanding vitamin C diperoleh IC₅₀ 8,03 μg/mL. Hasil penelitian ini dapat disimpulkan bahwa ekstrak metanol biji buah langsat memiliki kandungan alkaloid, triterpenoid dan saponin serta memiliki aktivitas antioksidan yang kuat sedangkan ekstrak metanol biji buah duku memiliki kandungan alkaloid, flavonoid, tannin, triterpenoid dan saponin serta memiliki aktivitas antioksidan yang sangat kuat.Kata Kunci: Antioksidan, biji duku, biji langsat Antioxidant Activity of Methanol Extract of Langsat Seeds (Lansium domesticum var. pubescens) and Duku Seeds (Lansium domesticum var. domesticum) by Using DPPH Method ABSTRACTThis study aimed to determine the phytochemical content and antioxidant activity of langsat seed extract and duku seed extract by using the DPPH method. Langsat seeds and duku seeds were extracted by using maceration method with methanol as the solvent. Phytochemical screening was carried out including a qualitative test of alkaloids, flavonoids, steroids/triterpenoids, saponins, and tannins by using the color test method. Antioxidant activity was tested by using the DPPH method and vitamin C used as comparison, the absorption was measured by using UV-Vis spectrophotometer at 517 nm wavelength. The result of phytocemical screening on methanol extract of langsat seeds showed positive results on alkaloids, triterpenoids, and saponins, meanwhile methanol extract of duku seeds showed positive results on alkaloids, flavonoids, triterpenoids, tannin and saponins. The antioxidant activity of methanol extract of langsat seeds was analyzed by using the equation of the regression line y = 0.2922x + 33.143, which obtained IC₅₀ value of 57.69 μg/mL. Meanwhile, the antioxidant activity of methanol extract of duku seeds was analyzed by using the equation of the regression line y = 0.6554x + 29.421, obtained IC₅₀ 31,40 μg/mL. Vitamin C obtained IC₅₀ 8.03 μg/mL. On the basis of all results, it can be concluded that the methanol extract of langsat seeds contained alkaloids, saponins and triterpenoid and has a strong antioxidant activity. Meanwhile, the methanol extract of duku seeds contained alkaloids, flavonoids, triterpenoids, tannin and saponins and has a very strong antioxidant activity.Keywords: Antioxidants, duku seeds, langsat seeds