Judul: Pengaruh Pupuk Bekas Maggot Terhadap Total Fenolik, Flavonoid, dan Aktivitas Antioksidan Tanaman Sirih Merah (Piper crocatum Ruiz & Pav.)
Abstrak: Sirih merah (Piper crocatum Ruiz & Pav.) mengandung banyak senyawa aktif yang berperan dalam pengobatan penyakit degeneratif, seperti fenolik dan flavonoid. Penelitian ini bertujuan menentukan pengaruh pemberian pupuk bekas maggot terhadap pertumbuhan, kadar total fenolik, flavonoid, dan aktivitas antioksidan tanaman sirih merah. Kadar total fenolik dan flavonoid diukur menggunakan metode kolorimetri dengan reagen folin-ciocalteu dan alumunium klorida. Aktivitas antioksidan diukur menggunakan metode DPPH dan FRAP. Hasil penelitian menunjukkan perlakuan dosis 3 (1 pupuk kasgot : 7 media tanam) memiliki kandungan senyawa aktif tertinggi dibandingkan dengan perlakuan lainnya, yaitu sebesar 166,41 ± 4,50 mg GAE/gr untuk fenolik, 47,59 ± 1,33 mg QE/gr untuk flavonoid, 272,39 ± 15,49 ppm untuk nilai IC50, dan 545,27 ± 12,05 µM TE/gr untuk kapasitas antioksidan. Pertumbuhan tinggi tanaman, jumlah daun, bobot basah, dan bobot kering tertinggi diperoleh dari perlakuan kontrol negatif, yaitu sebesar 115,41 cm, 20,08 lembar daun, 19,03 gram bobot basah, dan 3,85 gram bobot kering. Penggunaan pupuk kasgot mampu meningkatkan produksi senyawa aktif berupa fenolik dan flavonoid serta dapat meningkatkan aktivitas antioksidan tanaman sirih merah. Namun, hal tersebut berbanding terbalik dengan pertumbuhan tanamannya yang terhambat ketika ditambahkan pupuk kasgot., Red betel (Piper crocatum Ruiz & Pav.) contained many active compounds that played a role in the treatment of degenerative diseases, such as phenolics and flavonoids. This research aimed to determine the effect of maggot manure application on the growth, total phenolic content, flavonoid content, and antioxidant activity of red betel plants. The total phenolic and flavonoid content were measured using colorimetric methods with Folin-Ciocalteu and aluminum chloride reagents. Antioxidant activity was measured using the DPPH and FRAP methods. The results showed that treatment with Dose 3 (1 maggot manure: 7 planting media) had the highest content of active compounds compared to other treatments, at 166.41 ± 4.50 mg GAE/g for phenolics, 47.59 ± 1.33 mg QE/g for flavonoids, 272.39 ± 15.49 ppm for IC50 value, and 545.27 ± 12.05 µM TE/g for antioxidant capacity. The highest plant growth, leaf count, wet weight, and dry weight were obtained from the negative control treatment, at 115.41 cm, 20.08 leaves, 19.03 grams wet weight, and 3.85 grams dry weight, respectively. The usage of maggot manure can increase the production of active compounds such as phenolics and flavonoids and enhance the antioxidant activity of red betel plants. However, this was in contrast to the growth of the plants when maggot manure was added.
Keyword: Antioxidant, Flavonoid, Phenolics, Maggot, Red Betel, Antioxidant, Flavonoid, Phenolics, Maggot, Red Betel

Judul: Kadar Total Fenolik, Flavonoid, dan Aktivitas Inhibisi Tirosinase dari Fraksi Ekstrak Sirih Merah (Piper crocatum Ruiz  & Pav) Asal Semarang
Abstrak: Sirih merah (Piper crocatum Ruiz & Pav) merupakan tanaman obat potensial yang dapat menyembuhkan berbagai jenis penyakit seperti diabetes mellitus, asam urat, hipertensi, dan kanker. Selain itu, daun sirih merah diketahui dapat mencegah dan menyembuhkan jerawat, dan mencerahkan kulit wajah kusam. Senyawa aktif pada sirih merah seperti fenolik dan flavonoid dapat berperan dalam menangani hiperpigmentasi dengan menghambat enzim tirosinase. Penelitian ini bertujuan menganalisis kadar total fenolik, flavonoid, dan aktivitas inhibisi tirosinase dari hasil fraksinasi ekstrak etanol sirih merah asal Semarang. Ekstraksi dilakukan dengan maserasi menggunakan etanol 70%, dan selanjutnya difraksinasi dengan 3 pelarut, yaitu n-heksana, etil asetat, dan air. Kadar total fenolik dan flavonoid tertinggi terdapat pada fraksi etil asetat yaitu sebesar 80.294 mg GAE/g dan 61.537 mg QE/g. Nilai penghambatan terhadap tirosinase terbesar juga terdapat pada fraksi etil asetat (65.86%). Aktivitas penghambatan tirosinase menunjukkan bahwa fraksi etil asetat memiliki nilai IC50 3470.53 ppm. Fraksi etil asetat daun sirih merah asal Semarang memiliki kemampuan sebagai inhibitor tirosinase lebih baik dibandingkan dengan fraksi n-heksana, fraksi air, dan ekstrak etanol 70%., Red betel (Piper crocatum Ruiz & Pav) is a potential medicinal plant that can cure various types of diseases such as diabetes mellitus, gout, hypertension, and cancer. Furthermore, red betel leaves are known to prevent and cure acne, and able to brighten facial skin. Active compounds in red betel such as phenolics and flavonoids are able to treat hyperpigmentation by inhibiting the tyrosinase. This research aimed to analyze total phenolics contents, flavonoids contents, and tyrosinase inhibitory activity from the fractionated ethanol extract of red betel from Semarang. The extraction was performed using maceration with 70% ethanol, and then fractionated with 3 solvents, n-hexane, ethyl acetate, and water. The highest total phenolics and flavonoids contents were found in the ethyl acetate fraction with values of 80.294 mg GAE/g and 61.537 mg QE/g. The highest inhibition value of tyrosinase was also found in the ethyl acetate fraction (65.86%). Tyrosinase inhibition activity showed that the ethyl acetate fraction has IC50 value of 3470.53 ppm. Therefore, the ethyl acetate fraction of red betel leaves from Semarang is proven to be a better tyrosinase inhibitor compared to the n-hexane fraction, water fraction, and 70% ethanol extract.
Keyword: phenolic, flavonoid, tyrosinase enzyme, red betel

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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