Judul: Fingerprint, Antioxidant, and Anti-tyrosinase Activity of Fungus Comb Extract
Abstrak: Fungus comb merupakan suatu struktur yang dibuat oleh koloni rayap Macrotermitinae dengan banyak potensi karena mengandung metabolit sekunder seperti steroid, terpenoid, dan saponin, serta senyawa yang memiliki sifat antioksidan dan anti-tirosinase. Tujuan penelitian ini adalah menemukan pola sidik jari serta menentukan kapasitas antioksidan dan aktivitas anti-tirosinase ekstrak fungus comb. Kromatografi lapis tipis (KLT) digunakan untuk menggambarkan pola sidik jari. Pola KLT yang dihasilkan diolah dengan ImageJ dan diubah menjadi densitogram. Fungus comb diekstraksi dengan pelarut n-heksana dan etil asetat. Hasil KLT menunjukkan ekstrak mengandung steroid dan terpenoid serta memiliki sifat antioksidan. Kapasitas antioksidan diuji dengan pereaksi 2,2-difenil-1-pikrihidrazil. Ekstrak n-heksana memiliki nilai kapasitas antioksidan 9,07 mg asam askorbat ekuivalen (AAE)/g ekstrak sedangkan ekstrak etil asetat memiliki nilai 6,04 mg AAE/g ekstrak. Aktivitas anti-tirosinase diuji dengan substrat L-tirosina dan L-3,4-dihidroksifenilalanin (L-DOPA). Ekstrak n-heksana memiliki aktivitas anti-tirosinase lebih baik dengan nilai IC50 1804 µg/mL untuk L-tirosina dan 6784 µg/mL untuk L-DOPA., Fungus comb is a structure made by termite colony Macrotermitinae with lots of potential because it contains secondary metabolites such as steroids, terpenoids, and saponins and compounds containing antioxidant and anti-tyrosinase properties. This study aimed to determine fungus comb extracts' fingerprint pattern, antioxidant capacity, and anti-tyrosinase activity. Thin layer chromatography (TLC) was used to determine fingerprint patterns. The resulting TLC pattern was processed with ImageJ and converted into a densitogram. The fungus comb was extracted with n-hexane and ethyl acetate. TLC results showed that fungus comb extracts contain steroids and terpenoids and have antioxidant properties. The antioxidant capacity assay was carried out with 2,2-diphenyl-1-picrylhydrazyl reagent. N-hexane extract had an antioxidant capacity value of 9,07 mg ascorbic acid equivalent (AAE)/g extract, while ethyl acetate extract had 6,04 mg AAE/g extract. Anti-tyrosinase activity assay was carried out with L-tyrosine and L-3,4-dihydroxyphenylalanine (L-DOPA) as substrates. N-hexane extract had a better anti-tyrosinase activity with IC50 of 1804 µg/mL for L-tyrosine and 6784 µg/mL for L-DOPA.
Keyword: analisis sidik jari, antioksidan, anti-tirosinase, ImageJ, KLT

Judul: Potential Inhibition of Alpha-Glucosidase of Fungus Comb Extract from Macrotermitinae Subfamily
Abstrak: Subfamily Macotermitinae termite nests have a unique structure, namely fungus comb which contains bioactive compounds that can be used as antidiabetic and anticancer agents. The aim of this research was to determine the toxicity and bioactivity of α-glucosidase inhibition from fungus comb fractions and extracts. Toxicity of fungus comb extract was tested using the brine shrimp lethality test (BSLT) method. Fungus comb extract is classified as a toxic extract because it has an LC50 value of 656,75 ppm which the third fraction is the most active fraction with an LC50 value of 96,16 ppm. Antidiabetic bioactivity of fungus comb extract was tested using the inhibition of α-glucosidase activity to hydrolyze p-nitrophenylα-D-glucopyranoside. Fungus comb extract has an IC50 value of 979,58 ppm which the third fraction is the most active fraction with an IC50 value of 423,74 ppm. Fungus comb fractions and extract do not hace antidiabetic bioactivity as well as acarbose with an IC50 value of 0,24 ppm, Sarang rayap subfamili Macrotermitinae memiliki struktur yang unik yakni fungus comb yang mengandung senyawa-senyawa bioaktif yang dapat dimanfaatkan sebagai antidiabetes dan antikanker. Tujuan dari penelitian ini menentukan toksisitas dan bioaktivitas inhibisi enzim α-glukosidase dari fraksi dan ekstrak fungus comb. Toksisitas ekstrak dan fraksi fungus comb diuji dengan metode brine shrimp lethality test (BSLT). Ekstrak fungus comb tergolong sebagai ekstrak yang toksik karena memiliki nilai LC50 sebesar 656,75 ppm dengan fraksi ketiga sebagai fraksi teraktif dengan nilai LC50 sebesar 96,16 ppm. Bioaktivitas antidiabetes ekstrak fungus comb diuji dengan menggunakan metode inhibisi aktivitas enzim α-glukosidase untuk menghidrolisis p-nitrofenil-α-D glukopiranosida. Ekstrak fungus comb memiliki nilai IC50 sebesar 979,58 ppm dengan fraksi ketiga menjadi fraksi teraktif dengan nilai IC50 sebesar 423,74 ppm. Fraksi dan ekstrak fungus comb belum memiliki bioaktivitas antidiabetes sebaik akarbosa dengan nilai IC50 sebesar 0,24 ppm
Keyword: α-Glucosidase, Antidiabetic, Acarbose, Fungus Comb, Macrotermitinae

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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