Judul: Interaction of Genotype and Environment on Flavonoid Content, Terpenoid Content, also Antioxidant Activity of Willow-leaved Justicia
Abstrak: Gandarusa (Justicia gendarussa Burm. f.) merupakan tanaman yang sering dimanfaatkan karena kandungan antioksidannya. Gandarusa menghasilkan variasi akumulasi metabolit sekunder jika ditanam pada lingkungan yang berbeda-beda. Penelitian bertujuan mengukur kandungan flavonoid, terpenoid, serta aktivitas antioksidan pada daun gandarusa dan mendapatkan informasi mengenai stabilitas gandarusa terhadap penanaman di tiga lokasi (Bogor, Cianjur, Sukabumi). Tahapan penelitian meliputi pengujian kadar total flavonoid, kadar total terpenoid, dan aktivitas antioksidan dengan metode Cupric Reducing Antioxidant Capacity (CUPRAC) serta 2,20-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) dan adaptasi gandarusa terhadap penanaman multilokasi. Semua parameter uji rata-rata tertinggi pada lokasi Cianjur dan genotipe G2, kecuali kadar total terpenoid pada genotipe G3. Stabilitas genotipe dan lingkungan menunjukkan genotipe G1 spesifik pada lokasi Bogor, genotipe G2 spesifik pada lokasi Cianjur, dan genotipe G3 spesifik pada lokasi Sukabumi pada kadar total flavonoid. Genotipe G1 spesifik pada lokasi Bogor, genotipe G2 spesifik pada lokasi Sukabumi, dan genotipe G3 spesifik pada lokasi Cianjur pada kadar total terpenoid. Aktivitas antioksidan metode CUPRAC menunjukkan genotipe G1 spesifik pada lokasi Cianjur dan genotipe G2 spesifik pada lokasi Sukabumi, dan genotipe G3 spesifik pada lokasi Bogor. Aktivitas antioksidan metode ABTS menunjukkan genotipe G1 spesifik pada lokasi Sukabumi, genotipe G2 spesifik pada lokasi Bogor, dan genotipe G3 spesifik pada lokasi Cianjur., Willow-leaved justicia (Justicia gendarussa Burm. f.) is often used because of its antioxidant content. Differences in environmental conditions could indirectly affect the plant’s antioxidant activity. This research aimed to measure flavonoid, terpenoid, and antioxidant activity, also information about the stability of willow-leaved justicia on cultivation in three locations (Bogor, Cianjur, Sukabumi). This research used four types of parameters which are total flavonoid content, total terpenoid content, and antioxidant activity measured by the CUPRAC assay and ABTS assay. The highest in all parameters was obtained from Cianjur and G2, except total terpenoid content in G3. Genotype and environment stability indicated G1 had good stability at Bogor, G2 had good stability at Cianjur, and G3 had good stability at Sukabumi on total flavonoid content parameter. G1 had good stability at Bogor, G2 had good stability at Sukabumi, and G3 had good stability at Cianjur on total terpenoid content. The CUPRAC assay showed that G1 had good stability at Cianjur and G2 had good stability at Sukabumi, and G3 had good stability at Bogor. The ABTS assay showed that G1 had good stability at Sukabumi, G2 had good stability at Bogor, and G3 had good stability at Cianjur.
Keyword: antioxidant, flavonoids, multilocation, terpenoids, Willow-leave justicia

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: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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