Judul: Aktivitas Antioksidan Ekstrak Etanol Daun Serai (Cymbopogon citratus) dan Potensinya Sebagai Pencegah Oksidasi Lipid
Abstrak: Cymbopogon citrates is usually used as spices by Indonesian people. The utilization of lemongrass is only limited on it stem, but the leaf remain as waste. The aim of this research was to analyze phytochemical components and to determine the phnolic content and antioxidant assay with ethanol solvent each 30%, 70% and 96%. The extraction of lemongrass leaf was performed by maceration. The result of phytochemical analysis indicated that the ethanolic extract of lemongrass leaf contains alkaloid, saponin, tannin, flavonoid, phenol and steroid. The phenol content determination was performed by Folin- Ciocalteau method with the highest phenolic content was obtained on ethanolic extract 30% was 50.017 GAE (Gallic Acid Equivalent) mg/g. The ethanol extract of lemongrass leaves through its inhibitory potency as an antioxidant against free radical DPPH (2,2-diphenyl-1-pikrylhydrazyl) with with the highest IC50 on 70% ethanol was 79.444 mg/L. The antioxidant activity on lipid system with rancimat method was obtained on 70% ethanol as 1.19 and the longest induction time was 6.15 hours.
Keyword: Bogor Agricultural University (IPB), DPPH., rancimat, total phenolic, antioxidant, lemongrass leaf

Judul: Aktivitas Antibakteri dan Toksisitas Minyak Serai Dapur (Cymbopogon citratus) dengan Perlakuan Pemekatan pada Suhu Berbeda
Abstrak: Lemongrass (Cymbopogon citratus) is a species of the genus Cymbopogon that produces essential oils with a distinctive fragrance. Lemongrass oil can be an alternative choice of natural antibacterial agents during the Covid-19 pandemic in hand soap and hand sanitizer because it is easy to obtain and the price is affordable. Lemongrass essential oil is reported to contain many chemical compounds that contribute to its activity. Chemical compounds reported in lemongrass essential oil include β-mirsen, 3-undekuna, neral, geranial, nerol, geranil asetat and juniper camphor. Differences in the composition of chemical compounds in essential oils can affect the bioactivity of this essential oils. The differences in the composition of chemical compounds in lemongrass essential oil are influenced by several factors, including the treatment in the distillation process and after the distillation process. Evaluation of the effect of post-distillation temperature on the chemical components in lemongrass oil is an aspect that we need to work on as an effort to ensure its quality and efficacy. In this study, the procedure was started by distillation of lemongrass at a temperature of 100–105ºC for 3,5 hours and then stored in the refrigerator. As a comparison, commercial lemongrass oil was provided and then concentrated using a rotary evaporator at different temperatures, at 30, 40, and 50 ºC. There are five samples of lemongrass oil which are then ready to be analyzed. The toxicity test was carried out using the brine shrimp lethality test (BSLT). The results of the BSLT test showed that the five samples had an LC50 value of <1000 ppm. In addition to BSLT, antibacterial activity tests were carried out on lemongrass oil which included minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Antibacterial test was conducted against S. aureus and S. epidermidis by disc method. The result showed that lemongrass oil has very strong antibacterial properties against S. aureus and is in the strong category against S. epidermidis. Meanwhile, the MIC values of lemongrass oil without evaporation treatment was 1250 ppm and 625 ppm, respectively against S. aureus and S. epidermidis. The MBC values of the sample was 2500 ppm and 10000 ppm against S. aureus and S. epidermidis, respectively. While the MIC values of lemongrass oil concentrated at 40 ºC were 5000 ppm and 2500 ppm against S. aureus and S. epidermidis, respectively. The analysis of chemical composition using GC-MS shows that in lemongrass oil without evaporation treatment there are 13 compounds detected with the abundance of each compound > 1% while in lemongrass oil evaporated at 40 ºC for 11 compounds was detected. The main constituent in lemongrass oil was citral, neral and β-mirsen.
Keyword: antibacterial, BSLT, GC-MS, lemongrass

Judul: Implementation of Spatio-Temporal Change Query in Relational Database.
Abstrak: Geographic object changes in various views. Object changes are recorded using a model of static storage. No historical connection between old version data and new version data has been built. For that, a storage model of spatio-temporal queries that can analyze spatio-temporal changes has been developed. The object changes the geometry are grouped according to the taxonomy of Spatio-Temporal Pattern Change. This research has been able to apply the query patterns change including born, expand, merge, contract, split, normal and die. This query based on geometric (area) changes. The implementation of spatio-temporal change queries represents an object changes continuously with easy, change detection is done by comparing two versions of data. Keyword: spatio-temporal change query, spatio-temporal change pattern.
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