Judul: Antioxidant Activity of Apis cerana Multiflora  Honey Fraction and its Potential as Facial Serum
Abstrak: Apis cerana merupakan salah satu lebah penghasil madu asal Asia yang banyak dibudidayakan di Indonesia. Madu Apis cerana telah banyak diteliti memiliki aktivitas antioksidan. Penelitian ini bertujuan menganalisis aktivitas antioksidan sediaan serum wajah dari fraksi madu multiflora Apis cerana. Madu difraksinasi dengan corong pisah menggunakan pelarut akuades, n-heksana, dan etil asetat. Fraksi kemudian dilakukan pengukuran total fenolik, flavonoid, antioksidan DPPH (2,2-difenil-1-pikrilhidrazil), AEAC (Ascorbic acid Equivalent Antioxidant Capacity), dan PFRAP (Potassium Ferric Reducing Power). Hasil penelitian menunjukkan fraksi etil asetat merupakan sampel terbaik berdasarkan total fenolik (1972 ± 62,8 mg GAE/kg sampel), total flavonoid (1904,8 ± 9,2 mg QE/kg sampel), antioksidan DPPH IC50 (49204,1 ± 2763,6 mg/mL), AEAC (251,50 ± 8,83 mg AEAC/kg sampel) dan PFRAP (2445,6 ± 82,8 mg AAE/kg sampel). Fraksi etil asetat dipilih untuk diformulasikan menjadi serum wajah berdasarkan IC50. Serum wajah berhasil diformulasikan dan memiliki aktivitas antioksidan DPPH %inhibisi 15,84 ±1,27% serta antioksidan PFRAP 0,697 ± 0,049 AU., Apis cerana is one of the honey-producing bee from Asia that widely cultivated in Indonesia. Apis cerana honey has been researched for its antioxidant activity. This study aims to analyze the antioxidant activity of facial serum made from fraction of Apis cerana multiflora honey. Honey was fractionated using distilled water, n-hexane, and ethyl acetate in a split funnel. The fractions were then evaluated for total phenolic content, flavonoid content, DPPH antioxidant activity (2,2-diphenyl-1-picrylhydrazyl), AEAC antioxidant (Ascorbic Acid Equivalent Antioxidant Capacity), and PFRAP antioxidant (Potassium Ferric Reducing Ability of Plasma). The results indicated that the ethyl acetate fraction was the most effective based on total phenolic content (1972 ± 62,8 mg GAE/kg sample), total flavonoid content (1904,8 ± 9,2 mg QE/kg sample), DPPH antioxidant IC50 (49204,1 ± 2763,6 mg/mL), AEAC (251,50 ± 8,83 mg AEAC/kg sample), and PFRAP (2445,6 ± 82,8 mg AAE/kg sample). The ethyl acetate fraction was selected for formulating the facial serum based on its IC50 value. The facial serum was successfully formulated and demonstrated DPPH antioxidant 15,84 ± 1,27% inhibition and PFRAP antioxidant activity 0,697 ± 0,049 AU.
Keyword: antioxidant, honey, serum, fractionation, formulation

Judul: Antioxidant Activity of Facial Serum Mixture from Apis cerana Calliandra Honey Fraction from Bandung, West Java
Abstrak: Madu banyak dimanfaatkan sebagai produk olahan pangan, kesehatan, bahkan kecantikan, karena dapat berperan sebagai antioksidan. Apis cerana merupakan salah satu lebah penghasil madu asli dari wilayah Asia. Penelitian ini bertujuan mengidentifikasi aktivitas antioksidan sediaan serum wajah dari fraksi madu kaliandra Apis cerana. Madu difraksinasi menggunakan perlarut air, n-heksana, dan etil asetat. Selanjutnya dilakukan analisis kadar total fenolik, flavonoid, aktivitas antioksidan 2,2-diphenyl-1,1-picrylhidrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP), dan Ascorbic Acid Equivalent Antioxidant Capacity (AEAC). Fraksi etil asetat (FEA) merupakan fraksi terbaik dengan hasil pengukuran total fenolik dan flavonoid sebesar 5262,7 mg GAE/kg dan 1952,0 mg QE/kg, nilai IC50 DPPH sebesar 3,034 mg/mL, kapasitas antioksidan FRAP dan AEAC sebesar 3932,9 AAE/kg dan 3503,9 mg AEAC/kg. Sediaan serum diformulasikan menggunakan konsentrasi FEA 0,3% (F1) dan 0,6% (F2). Seluruh sediaan serum bersifat homogen, dengan daya sebar sebesar 6,5 cm dan rentang pH antara 5,8 – 6,8. F2 merupakan sediaan serum terbaik dengan nilai % inhibisi DPPH dan nilai absorbansi FRAP tertingi yakni sebesar 68,39% dan 0,110 pada 700 nm., Honey is widely utilized as a processed food, health, even beauty products, due to its antioxidant properties. Apis cerana is one of the native Asian bees that produce honey. This research aims to identify the antioxidant activity of facial serum mixture from calliandra honey fractions of Apis cerana. The honey was fractionated using water, n-hexane, and ethyl acetate solvents. Subsequent analyses included total phenolic content, flavonoid content, and antioxidant activity of DPPH, FRAP, and AEAC. Ethyl acetate fraction (FEA) proved to be the most potent fraction with total phenolic and flavonoid contents of 5262.7 mg GAE/kg and 1952.0 mg QE/kg, IC50 DPPH value of 3.034 mg/mL, also antioxidant capacity of FRAP 3932.9 AAE/kg and AEAC 3503.9 mg AEAC/kg. Serum mixtures were formulated using 0.3% (F1) and 0.6% (F2) concentrations of FEA. Both serum mixtures were homogeneous, with a spreadability of 6.5 cm and a pH range between 5.8 – 6.8. F2 was the best serum mixture with the highest DPPH inhibition percentage and FRAP absorbance values of 68.39% and 0.110 at 700 nm.
Keyword: antioxidant, fractionation, Apis cerana, calliandra honey, facial serum

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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