Judul: Total Fenolik dan Kapasitas Antioksidan Tanaman Gandarusa (Justicia gendarussa Burm.f.) Terhadap Perlakuan Waktu Perebusan Daun yang Berbeda
Abstrak: Tanaman gandarusa (Justicia gendarussa Burm. f.) merupakan tumbuhan semak yang umumnya tumbuh liar dan dipelihara sebagai tanaman obat serta berpotensi sebagai antioksidan. Potensi ini dikarenakan adanya kandungan berbagai jenis metabolit sekunder pada tanaman tersebut, salah satunya fenolik. Penelitian ini bertujuan menganalisis pengaruh waktu perebusan daun gandarusa terhadap kadar total fenolik dan kapasitas antioksidan metode Ferric Reducing Antioxidant Power (FRAP) dan 1,1-diphenyl-2-picrylhydrazyl (DPPH). Sampel diekstraksi dengan metode gabungan sonikasi dan maserasi. Daun gandarusa dilakukan perlakuan pemanasan yaitu perebusan menggunakan waterbath. Kadar total fenolik diukur menggunakan metode Folin-Ciocalteu dan kapasitas antioksidan menggunakan metode FRAP dan DPPH. Hasil penelitian menunjukkan ekstrak daun gandarusa dari ketiga perlakuan memiliki kadar total fenolik tertinggi pada perlakuan 1 yaitu sampel yang tidak direbus dibandingkan dengan sampel yang direbus sebesar 4.346 (mg GAE/g BK). Begitu pula dengan hasil kapasitas antioksidan FRAP dan DPPH didapat sampel daun yang tidak rebus memiliki kapasitas antioksidan tertinggi dibandingkan dengan sampel yang rebus sebesar 31.033 (µmol TE/g BK) dan 383.851 (µmol TE/g BK)., Gandarusa plant (Justicia gendarussa Burm. f.) is a shrub that generally grows wild and is maintained as a medicinal plant and has potential as an antioxidant. This potential is due to the content of various types of secondary metabolites in these plants, one of which is phenolic. This study aims to analyze the effect of boiling time for willow leaves on total phenolic content and antioxidant capacity using the Ferric Reducing Antioxidant Power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Samples were extracted by a combined method of sonication and maceration. Gandarusa leaves are subjected to heating treatment, namely boiling using a water bath. Total phenolic content was measured using the Folin-Ciocalteu method and antioxidant capacity using the FRAP and DPPH methods. The results showed that the gandarusa leaf extract from the three treatments had the highest Total phenolic content in treatment 1, namely the unboiled sample compared to the boiled sample, which was 4,346 (mg GAE /g DW). Likewise, with the results of the FRAP and DPPH antioxidant capacity, it was found that unboiled leaf samples had the highest antioxidant capacity compared to boiled samples, namely 31,033 (µmol TE/gDW) and 383,851 (µmol TE/g DW).
Keyword: Antioxidants, phenolics, boiling, gandarusa

Judul: Total Fenolik, Flavonoid, dan Kapasitas Antioksidan Ekstrak Air Dari Tiga Aksesi Tanaman Gandarusa (Justicia gendarussa Burm.F).
Abstrak: Kadar fenolik dan flavonoid total serta kapasitas antioksidan pada tanaman obat seperti gandarusa (Justicia gendarussa Burm.F) dipengaruhi oleh banyak faktor, salah satunya perbedaan aksesi. Penelitian ini bertujuan menentukan nilai kadar fenolik dan flavonoid total serta kapasitas antioksidan dari tiga aksesi gandarusa yaitu aksesi Langkat, Malang dan Bekasi menggunakan air sebagai pelarut pengekstraksi. Penentuan kadar fenolik dilakukan dengan metode Follin- Ciocalteu, kadar flavonoid total ditentukan dengan metode AlCl3, dan kapasitas antioksidan dilakukan dengan metode FRAP (Ferric Reducing Antioxidant Power) dan DPPH (2,2’-difenil-1-pikrilhidrazil). Kadar fenolik total tertinggi sebesar 12,31 mg GAE g-1 bobot kering dan flavonoid total tertinggi sebesar 9,75 mg QE g-1 bobot kering serta kapasitas antioksidan (DPPH) tertinggi sebesar 8,04 μmol/g TEAC bobot kering ditemukan pada gandarusa aksesi Langkat. Sementara kapasitas antioksidan tertinggi dengan metode FRAP ditemukan pada gandarusa aksesi Bekasi sebesar 19,95 μmol TE g-1 bobot kering. Kadar fenolik dan flavonoid total memiliki korelasi signifikan dan sangat kuat terhadap kapasitas antioksidan secara statistika pada metode DPPH. Sementara kadar fenolik dan flavonoid total memiliki korelasi yang tidak signifikan terhadap kapasitas antioksidan pada metode FRAP. Simpulan hasil penelitian ini ditemukan bahwa aksesi gandarusa terbaik yaitu aksesi Langkat karena memiliki kadar nilai fenolik dan flavonoid total tertinggi serta nilai kapasitas antioksidan tertinggi menggunakan metode DPPH. Kata kunci: Aksesi, antioksidan, fenolik, flavonoid, gandarusa., Total phenolic and flavonoid levels as well as antioxidant capacity in medical plants such as gandarusa (Justicia gendarussa Burm. F) are influenced by many factors, one of which is accession differences. This study’s purpose is to determine the total phenolic and flavonoid levels and antioxidant capacity of three gandarusa accessions, namely the Langkat, Malang, and Bekasi using water as an extracting solvent. The phenolic content was determined by the Follin-Ciocalteu method, the total flavonoid content was determined by the AlCl3 method, and the antioxidant capacity was determined by the FRAP (Ferric Reducing Antioxidant Power) and DPPH (2,2’-diphenyl-1-pikrilhidrazyl) methods. Total phenolic content of 12.31 mg GAE g-1 dry weight and total flavonoids of 9.75 mg QE g-1 dry weight and the highest antioxidant capacity (DPPH) of 8.04 μmol TEAC g-1 dry weight were found in gandarusa accession Langkat. While the highest antioxidant capacity using the FRAP method was found in the gandarusa of the Bekasi highest antioxidant capacity using the FRAP method was found in the gandarusa of the Bekasi accession of 19.95 μmol TEAC g-1 dry weight. The levels of total phenolic and total flavonoids have a statistically significant and very strong correlation to antioxidant capacity in the DPPH method. Meanwhile, total phenolic and flavonoids level had no significant correlation to antioxidant capacity in the FRAP method. In conclusion, the result of this study found that the best gandarusa accession was the Langkat accession because it had the highest levels of total phenolic and flavonoid values and the highest antioxidant capacity values using the DPPH method. Keywords: Accession, antioxidant, flavonoid, gendarussa, phenolic.
Keyword: Accession, Antioxidant, Flavonoid, Gendarussa, Phenolic

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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