Judul: Potensi Buah Makasar (Brucea javanica (L.) Merr) sebagai Inhibitor Enzim α-Glukosidase
Abstrak: Buah makasar merupakan salah satu tanaman obat Indonesia yang kaya akan manfaat. Secara empiris buah makasar dapat menurunkan kadar gula darah pada penderita diabetes melitus. Ekstrak buah makasar fraksi air dan heksana diteliti untuk mengetahui potensinya sebagai antidiabetes pada konsentrasi 1% dan dibandingkan dengan acarbose 1% sebagai kontrol positif. Uji antidiabetes dengan ekstrak buah makasar fraksi air ini dilakukan dengan metode inhibisi enzim á-glukosidase. Aktivitas antidiabetes diukur berdasarkan terbentuknya produk berupa p-nitrofenol dari reaksi enzim á-glukosidase dan substratnya pnitrofenil- á-D-glukopiranosida (p-NPG) yang diukur dengan spektrofotometer pada panjang gelombang 400 nm. Uji fitokimia menunjukkan bahwa fraksi air mengandung senyawa alkaloid dan flavonoid, sedangkan fraksi heksana mengandung senyawa alkaloid. Hasil penelitian menunjukkan bahwa fraksi air dan heksana ekstrak buah makasar pada konsentrasi 1% (b/v) dapat menghambat aktivitas enzim á-glukosidase sebesar 14.32% dan 12.76%, lebih rendah dari kontrol positif (Acarbose) dengan hambatan terhadap aktivitas enzim á- glukosidase sebesar 81.15%.
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Judul: Aktivitas Fraksi Kloroform Buah Makasar (Brucea javanica [L.] Merr.) sebagai Inhibitor Enzim α-Glukosidase
Abstrak: Brucea fruit (Brucea javanica (L.) Merr) is a plant used in traditional medicine and proven pre-clinically for antimalaria, antipyretic, anticancer and homeostatic effects. However, the antidiabetic mechanism of this plant has not been elucidated. This research was done to determine the potential of chloroform fraction of brucea fruit at 1, 1.5, 2% as α-glucosidase inhibitor and compared their activities with acarbose 1% as a positive control. Brucea fruits were extracted with ethanol solution of 95% using maceration dan fractination solution method. Chloroform fraction of brucea fruits were used for phytochemical assay and used for α-glucosidase inhibition method. The α-glucosidase activity was determined by measuring the p-nitrophenol release from the reaction of the enzyme and substrate p-nitrophenyl-α-D-glukopiranosida (p-NPG) at wavelength 400 nm. The phytochemical analysis indicates that the chloroform fraction of brucea fruit contain alkaloid, saponin, and tannin. The fraction at concentration 1, 1.5, and 2% (b/v) and acarbose 1% can inhibit α-glucosidase enzyme activity respectively 16.48%, 17.96%, 19.68%, and 81.16%.
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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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