Judul: Diastase Enzyme Activity and Antibacterial Effectiveness to Gastroenteritis by Apis mellifera Honey from Indonesia
Abstrak: Kualitas madu monoflora (Apis mellifera) sebagai antibakteri dapat dipengaruhi oleh aktivitas enzim diastase dan metabolit sekunder sumber nektar. Penelitian ini bertujuan untuk membandingkan aktivitas enzim diastase dan efektivitas madu monoflora yang berasal dari lebah Apis mellifera sebagai antibakteri alami terhadap bakteri Staphylococcus aureus, Escherichia coli, dan Salmonella typhi. Metode pengambilan sampel madu monoflora dari sembilan sumber nektar yang berbeda (akasia, kaliandra, rambutan, kayu putih, randu, mangga, kopi robusta 1, kopi robusta 2, dan karet) dilakukan dengan menentukan nilai diastase menggunakan spektrofotometri UV-Vis dan zona hambat bakteri menggunakan cakram difusi. Analisis multivariatif kadar brix, aktivitas enzim diastase, dan antibakteri menggunakan Principal Component Analysis (PCA). Hasil penelitian menunjukkan bahwa aktivitas enzim diastase tertinggi sebesar 20,00 DN pada madu mangga, rambutan, dan kopi robusta 2, sedangkan terendah sebesar 4,00 DN pada madu kaliandra. Aktivitas antibakteri terhadap S. aureus tertinggi sebesar 19,47 mm pada madu kopi robusta 2, terhadap E. coli sebesar 27,93 mm pada madu randu, dan terhadap S. typhi sebesar 18,53 mm pada madu kopi robusta 2. Nilai konsentrasi hambat minimum (KHM) tehadap bakteri yang diuji sebesar 8 µg/mL pada madu akasia, kayu putih, randu, kopi robsuta 1, dan kopi robusta 2. Analisis klasterisasi berdasarkan kadar brix, aktivitas enzim diastase, dan antibakteri yaitu klaster 1 (kaliandra); klaster 2 (akasia, kayu putih, randu, kopi robusta 1); klaster 3 (mangga, rambutan, kopi robusta 2); klaster 4 (karet)., The quality of monoflora honey (Apis mellifera) as an antibacterial can be influenced by the activity of the diastase enzyme and the secondary metabolites of the nectar source. This study aims to compare the activity of the diastase enzyme and the effectiveness of monoflora honey derived from Apis mellifera bees as a natural antibacterial agent against Staphylococcus aureus, Escherichia coli, and Salmonella typhi. The sampling method for monoflora honey from nine different nectar sources (acacia, calliandra, rambutan, eucalyptus, randu, mango, robusta coffee 1, robusta coffee 2, and rubber) was carried out by determining the diastase value using UV-Vis spectrophotometry and the bacterial inhibition zone using the diffusion disc. Multivariate analysis of brix content, diastase enzyme and antibacterial activity using Principal Component Analysis (PCA). The results showed that the highest diastase enzyme activity was 20.00 DN in mango, rambutan, and robusta coffee 2 honeys, while the lowest was 4.00 DN in calliandra honey. The highest antibacterial activity against S. aureus was 19.47 mm in robusta coffee 2 honey, against E. coli was 27.93 mm in randu honey, and against S. typhi was 18.53 mm in robusta coffee 2 honey. Minimum inhibitory concentration (MIC) values for the tested bacteria were 8 g/mL on acacia honey, eucalyptus, randu, robsuta coffee 1, and robsuta coffee 2. Clusterization analysis was based on brix content, diastase enzyme activity, and antibacterial activity, namely cluster 1 (calliandra); cluster 2 (acacia, eucalyptus, randu, robusta coffee 1); cluster 3 (mango, rambutan, robusta coffee 2); and cluster 4 (rubber).
Keyword: antibakteri, enzim diastase, madu Apis mellifera, antibacterial, diastase enzyme, Apis mellifera honey

Judul: Physicochemical property and inhibition activity of Indonesian Honeys toward β-Secrtease Enzymes
Abstrak: Indonesia memiliki berbagai jenis madu lokal dengan karakteristik dan kualitas yang beragam. Madu-madu lokal tersebut bisa mengandung senyawa bioaktif yang bisa menghambat aktivitas enzim β-sekretase. Penelitian ini bertujuan untuk mengevaluasi karakteristik fisikokimia beberapa jenis madu lokal Indonesia dan menguji kemampuannya dalam menghambat aktivitas enzim β-sekretase. Tiga jenis madu lokal yang digunakan dalam penelitian ini adalah madu rambutan, kelengkeng dan multiflora. Kadar air dan viskositas ketiga madu tersebut secara statistic berbeda (P < 0.05). Kadar air madu rambutan (20,75%) lebih tinggi dibandingkan dengan kadar air madu kelengkeng (19,27%) dan madu multiflora (19,18%). Sementara itu, madu multiflora memiliki tingkat kekentalan paling tinggi (24,00 pascal second) dibandingkan dengan madu rambutan (18,33 pascal second) dan madu kelengkeng (19,67 pascal second). Di sisi lain, tingkat keasaman ketiga madu tersebut tidak berbeda secara signifikan dengan rentang 31,48 – 45,16 mL NaOH. Analisis penghambatan enzim β-sekretase dengan uji fluorometri menunjukan bahwa aktivitas enzim tersebut secara signifikan lebih rendah dengan penambahan salah satu madu lokal tersebut (P<0.05). Madu multiflora memiliki aktivitas penghambatan lebih tinggi (243,63 RFU) dibandingkan dengan madu rambutan (394,45 RFU) dan kelengkeng (401,17). Meskipin demikian, daya hambat tersebut masih lebih rendah dibandingkan dengan inhibitor komersial (132,82 RFU). Penelitian ini menunjukan ketiga madu tersebut sudah memenuhi standar SNI dan menunjukan bahwa ketiga madu tersebut mampu menghambat enzim β- sekretase., Indonesia is rich with the local honeys with different characteristics and qualities. The local honeys may contain various bioactive compounds exhibiting inhibitory properties against β-secretase enzyme. This enzyme is known to be the culprit behinds various neurodegenartive diseases, which is found to be one of publich health issue in Indonesia. This study aims to evaluate the physicochemical properties of several Indonesian local honeys and investigate their inhibitory properties against β-secretase. To address, three local honeys were used, including rambutan, kelengkeng and raw multifloral honey. Water content and viscosity of these honeys were found to be statistically different (P<0.05). Rambutan honey has the highest water content (20.75%) than the kelengkeng (19.27%) and raw multifloral (19.18%). Meanwhile, the raw multifloral honey was found to have the highest viscosity (24.00 pascal second) compared to rambutan (18.33 pascal second) and kelengkeng (19.67 pascal second). On the other hand, the acidity of those honey were statistically comparable (P>0.05), with the values ranging from 31.48 to 45.16 mL NaOH. Interestingly, inhibitory assay against β-secretase enzyme showed that the three madu were able to reduce the enzymatic activity (P<0.05). The raw multifloral honey exhibited highest inhibiton activity (243,63 RFU) than the rambutan (394,45 RFU) or the kelengkeng (401,17). Nevertheless, these activities were remarkably lower than the inhibition activity of the commercially available inhibitor for β-secretase enzyme (132.82 RFU). Altogether, this study showed that three honeys met the SNI standard and showed that the three honeys were able to inhibit the -secretase enzyme.
Keyword: madu, β-sekretase, fisikokimia madu, beta amyloid

Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition