Judul: Potensi Lindur (Bruguiera Gymnorrhiza) Dari Mangrove Sebagai Antioksidan Dan Inhibitor Α-Glukosidase
Abstrak: Antioksidan merupakan senyawa yang dapat menghambat atau mencegah terjadinya oksidasi pada substrat yang mudah teroksidasi. Inhibitor α-glukosidase merupakan penghambat enzim α-glukosidase yang berperan dalam pencernaan karbohidrat yang bekerja di dalam usus. Tanaman lindur (B. gymnorrhiza) menjadi salah satu tanaman mangrove yang berpotensi sebagai sumber senyawa bioaktif untuk antioksidan dan inhibitor α-glukosidase. Penelitian ini bertujuan untuk menentukan bagian dari tanaman lindur (daun, kulit batang dan akar) yang paling baik dalam menghasilkan senyawa bioaktif yang berfungsi sebagai antioksidan dengan metode 1,1-diphenyl-2-picrylhydrazyl (DPPH) serta aktivitasnya sebagai inhibitor enzim α-glukosidase secara in vitro. Penelitian ini diawali dengan pengambilan dan preparasi sampel, uji proksimat, ekstraksi bertingkat, uji fitokimia, dan uji aktivitas antioksidan dengan metode DPPH, pengujian inhibitor α-glukosidase dari ekstrak kasar tanaman lindur, fraksinasi dari ekstrak aktif tanaman lindur menggunakan Kromatografi Lapis Tipis (KLT) & Kromatografi Lapis Tipis Preparatif (KLTP), pengujian hasil fraksinasi terhadap aktivitas inhibitor α-glukosidase, dan mengidentifikasi struktur senyawa bioaktif dari fraksi aktif. Nilai rendemen tertinggi dihasilkan dari ekstrak etanol daun yaitu 12.85% dan yang terendah dihasilkan dari ekstrak n-heksana akar yaitu 0.18%. Daun mengandung protein (2.16%), lemak (1.12%), dan air (74.72%) yang paling tinggi dibandingkan dengan kulit batang dan akar. Kulit batang mengandung kadar abu (4.12%) dan kadar karbohidrat (46.02%) yang paling tinggi dibandingkan dengan daun dan akar. Ekstrak etanol kulit batang, etil asetat kulit batang dan etanol akar memiliki komponen bioaktif flavonoid, tanin, fenol, saponin, dan triterpenoid, sedangkan ekstrak etil asetat akar hanya memiliki komponen bioaktif flavonoid, fenol, saponin, dan triterpenoid. Ekstrak etanol kulit batang mengandung flavonoid dan tanin yaitu 0.42% dan 4.10%. Ekstrak etil asetat daun mengandung fenol yaitu 3.48%. Ekstrak etanol akar mengandung saponin dan triterpenoid 0.32% dan 0.10%. Aktivitas antioksidan yang potensial adalah ekstrak etil asetat kulit batang lindur dengan nilai IC50 14.21 ppm. Metode kromatografi dengan KLT menghasilkan eluen terbaik, yaitu metanol:DCM:n-heksana (2:3:1) dan menghasilkan 5 fraksi. Fraksi 1 dari ekstrak etanol akar memiliki potensi sebagai inhibitor α-glukosidase dengan nilai IC50 yaitu 161.05 ppm. Senyawa yang terdapat pada fraksi 1 dengan kemiripan >90% adalah hexadecanoic acid dan fenol, 2,2 methylenebis.
Keyword: akar, antioksidan, Bruguiera gymnorrhiza, mangrove, inhibitor α- glukosidase

Judul: Ekstraksi Komponen Bioaktif dan Aktivitas Antioksidan Daun Lindur (Bruguiera gymnorrhiza)
Abstrak: Lindur are mangrove plants that has been widely used as drug, yet informations on potential drug compounds and antioxidants contained in lindur were still limited. This study aimed to determine of bioactive compound and antioxidant activity of lindur leave. The result showed that lindur fresh leaves had a moisture content 54.91%, ash 4.49%, fat 1.87%, protein 4.45%, and crude fiber 8.67%. Lindur dried leaves had moisture content 9.78%, ash 8.19%, fat 3.90%, protein 9.78%, and crude fiber content 18.05%. The methanol extract had the highest yield (15.79%) compared to the ethyl acetate extract (2.85%), and n-hexane (1.53%). Bioactive compound found in lindur lindur leave extract was flavonoid, phenol hidroquinon, tannin, saponin, dan streoid. Methanol extract showed the highest antioxidant activity with IC50 values of 81.11 ppm, while the n-hexane extract showed the lowest activity with IC50 values of 815.67 ppm. Total phenolic extracts of n-hexane 12.41 mg GAE/g extract, ethyl acetate 97.57 mg GAE/g extract, and methanol 30.07 mg GAE/g extract.
Keyword: leave., Bruguierra gymnorrhiza, bioactive, antioxidant

Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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