POTENTIAL BIOREDUCTORS FROM MORINGA (Moringa oleifera, L.) LEAVES EXTRACTS AS MATERIALS FOR THE DEVELOPMENT OF PRACTICUM AND CHEMISTRY LEARNING MODULES

• Main Author: MARIA WOGA NAY (NIM:90516004), DORTHEA
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/26766
• Institution: Institut Teknologi Bandung

Chemistry is one of the main subjects that has been included in the curriculum since the junior secondary level. <br /> <br /> Chemistry learning techniques in general are in form of theoretical exposures causing chemistry subject to be <br /> <br /> considered abstract by students. Therefore, teachers must be more creative in designing chemistry learning by <br /> <br /> implementing practical activities, where students are directly involved in the experimental application of the theory, <br /> <br /> making it easier for students to understand the concepts of science that have been learned. Practical activities can <br /> <br /> be carried out by utilizing plants as one of the potential natural resources in Indonesia. One type of plant that has <br /> <br /> been developed is Moringa plants. The distribution of Moringa plants is very widespread in East of Nusa Tenggara <br /> <br /> and is a profitable local potency. Therefore, it is necessary to study the potential of active compounds in Moringa <br /> <br /> leaves; one of those is the synthesis of silver nanoparticles. Moringa plant leaves were identified qualitatively and <br /> <br /> used in the synthesis of silver nanoparticles using precursors (AgNO3). The results of this potential study are utilized <br /> <br /> in the development of practicum modules as an effort to improve the students understanding regarding the benefits <br /> <br /> of the active compounds in plants as a way to study chemistry. Moringa oleifera, L. leaves used as bioreductors in <br /> <br /> this study contain many active compounds, including flavonoid compounds. Mass spectrum analysis using LC-MS <br /> <br /> (Liquid Chromatography-Mass Spectrometer) on isolates from moringa leaf methanol extract showed quercetin <br /> <br /> compounds with a molecular weight of 301.14 g/mol. In addition there is also methyl ophiopogonanone A with a <br /> <br /> molecular weight of 365.10 g/mol. Moringa leaf extract is used in the synthesis of silver nanoparticles which its <br /> <br /> formation can be monitored by the color change of the solution from green to yellow and becoming increasingly <br /> <br /> concentrated as the increase in contact time and the greater concentration of precursor. Observation of absorbance <br /> <br /> value of silver nanoparticles in UV-Vis spectra showed optimum absorption in the wavelength range of 410-420 nm. <br /> <br /> Silver nanoparticles with the highest absorbance were then characterized using PSA (Particle Size Analyzer) and <br /> <br /> SEM (Scanning Electron Microscope). At 1 hour contact time, silver nanoparticles were formed with particle <br /> <br /> diameter distribution in the range of 33.7-135.7 nm and stable up to 120 hours contact time with a particle diameter <br /> <br /> distribution range of 40.8-151.8 nm. Morphological characterization using SEM showed that the spherical <br /> <br /> synthesized silver nanoparticles with a diameter range of 20-175 nm. Based on UV-Vis spectrophotometry <br /> <br /> measurements, there was a bathochromic shift after the addition of NaOH in methanol solution of Moringa leaf <br /> <br /> extract and isolate solution resulting from the separation of active compounds which showed the presence of <br /> <br /> phenolic hydroxyl groups in flavonoid compounds in the sample. The results of the development and trial of the <br /> <br /> practicum module showed a positive responses from the students of SMA Mutiara Bunda, Bandung, indicated the <br /> <br /> increased of student’s comprehension towards redox and acid-base reactions topics up to 91.7%. The <br /> <br /> comprehension of the introductory section of the practicum module was low so that feedback was then made by <br /> <br /> improving the practicum module by adding some images and shorter theoretical description.