Judul: Flavonoid Content and Antioxidant of Gandarusa (Justicia gendarussa Burm. f.) Methanol Extract Cultivated with Manure and NPK
Abstrak: Gandarusa (Justicia gendarussa Burm. f.) merupakan salah satu tanaman obat yang berpotensi sebagai antioksidan karena adanya kandungan metabolit sekunder. Kandungan metabolit sekunder dan antioksidan pada tanaman dapat dipengaruhi oleh kondisi lingkungan tumbuh tanaman tersebut, salah satunya pemberian pupuk. Penelitian ini bertujuan menentukan teknik budidaya yang tepat menggunakan komposisi pupuk kandang dan NPK terhadap tanaman gandarusa, dengan menganalisis kadar flavonoid dan aktivitas antioksidan secara in vitro. Pupuk yang digunakan adalah kombinasi pupuk kandang dan NPK dengan dilakukannya enam perlakuan. Total flavonoid diukur menggunakan metode kuantitatif spektrofotometri, sedangkan aktivitas antioksidan ditentukan menggunakan metode CUPRAC dan ABTS. Hasil menunjukkan pemberian 50% pupuk kandang dan 50% NPK memberikan hasil total flavonoid tertinggi pada daun sebesar 4,5690 mg/g, dan berkorelasi positif serta signifikan terhadap total antioksidan metode ABTS pada daun sebesar 15,089 µmol/g., Gandarusa (Justicia gendarussa Burm. f.) is a medicinal plant that has the potential as an antioxidant due to the presence of secondary metabolites. The content of secondary metabolites and antioxidants in plants can be affected by the environmental conditions where the plants growth, such as application of fertilizers. This research aims to determine the appropriate cultivation technique using the composition of manure and NPK on gandarusa, by analyzing the levels of flavonoids and antioxidant activity with in vitro method. The fertilizers used were a combination of manure and NPK with six treatments. Total flavonoids content was determined quantitative spectrophotometric methods, and the antioxidant activity use CUPRAC and ABTS methods. The results showed the application of 50% manure and 50% NPK gave the highest total flavonoid yields in gandarusa leaves 4,569 mg/g and had a positive and significant correlation with the total antioxidant ABTS method on leaves 15,089 µmol/g.
Keyword: Antioksidan, Flavonoid, Gandarusa, NPK, Pupuk Kandang

Judul: Phenolic Content and Antioxidant Activity of Gendarussa Ethanolic Extract Cultivated with Manure and NPK Fertilizer
Abstrak: Nutrisi dapat mempengaruhi kandungan fenolik tanaman Justicia gendarussa Burm f. (gandarusa). Penelitian ini bertujuan memperoleh informasi komposisi pemupukan gandarusa dengan kadar total fenolik dan aktivitas antioksidan tertinggi, dan menganalisis korelasi antara kadar fenolik dan aktivitas antioksidan yang diperoleh. Pupuk yang digunakan adalah pupuk kandang, NPK, dan kontrol tanpa pemupukan. Laju aplikasi pemupukan 10% dan 50%. Sampel dimaserasi dengan etanol. Kadar total fenolik diukur dengan metode Folin-Ciocalteu. Aktivitas antioksidan diukur dengan metode Ferric Reducing Antioxidant Power (FRAP) dan 2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Korelasi dianalisis dengan uji Pearson’s. Kadar total fenolik daun dan batang tertinggi diperoleh pada perlakuan 50% pupuk kandang dan 50% pupuk NPK sebesar 8 dan 5 mg EAG g-1 bobot kering. Aktivitas antioksidan tertinggi diperoleh pada sampel daun perlakuan 50% pupuk kandang dan 50% pupuk NPK (FRAP) dan perlakuan pupuk NPK (ABTS), serta sampel batang perlakuan pupuk NPK (FRAP) dan kontrol (ABTS), dengan nilai berturut-turut 21, 25, 12 dan 27 µmol KAET g-1 bobot kering. Kadar total fenolik daun dan aktivitas antioksidannya berkorelasi positif, sedangkan korelasi pada batang tidak bersifat signifikan secara statistik., Nutrient can affect gendarussa plant’s phenolic content. The objective of the research is to obtain the fertilizing condition yielding the highest phenolic content and antioxidant activity on gendarussa, and analyze the correlation between the obtained phenolic content and antioxidant activity. Fertilizers used were manure, NPK, and no fertilizer being the control. Fertilizing application rate were 10% and 50%. Sample was macerated with ethanol. Total phenolic content was measured with Folin-Ciocalteu method. Antioxidant activity was measured with FRAP and ABTS assay. Correlation was analyzed with Pearson’s test. The highest phenolic contents were 8 and 5 mg GAE g-1 dry weight obtained from treatment 50% manure and 50% NPK of leaf and stem sample. The highest antioxidant activity were 21, 25, 12 and 27 µmol TEAC g-1 dry weight obtained from leaf 50% manure and 50% NPK (FRAP) and NPK sample (ABTS), and stem’s NPK (FRAP) and control (ABTS) sample. Leaf’s phenolic content and antioxidant activity were positively correlated, while that of the stem were insignificant.
Keyword: Pupuk, Nutrisi tanaman, Gandarusa, Fenolik, Aktivitas antioksidan, Antioxidant activity, Fertilizer, Gendarussa, Phenolic, Plant nutrition

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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