Judul: Profil Metabolit Volatil Rimpang Temulawak (Curcuma xanthorrhiza Roxb.) yang Dipanen pada Waktu Berbeda.
Abstrak: Yield and composition of secondary metabolites in plants can be affected in many factors, such as harvesting time in a day. Metabolite profiling necessary to explain the influence of harvesting time in a day in volatile metabolites composition of temulawak essential oil. GC-MS analysis used to distinguish the changes in volatile metabolites of temulawak essential oil at different harvesting time. The aims of this research is to explain the influence of harvesting time in composition volatile metabolites temulawak essential oil and their correlation with their bioactivity as antioxidant. A total of 25 volatile compound were identified by GC-MS analysis. The major volatile component in both harvesting time are α- cedrene, α-curcumene, and xanthorrhizol with m/z 204, 202, and 218. The in vitro antioxidant activity was investigated with radical DPPH scavenging assay, ascorbic acid was employed as positive control. The result showed that temulawak essential oil has an antioxidant property, with the IC50 of 3.24x109 ppm in morning and 1.15x1013 ppm in afternoon harvesting time. The essential oil showed radical scavenging, but lower than ascorbic acid. There is no significant different in composition of volatile metabolite and radical scavenging activity of temulawak essential oil with different harvesting time in α=0,05.
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Judul: Pengaruh Nisbah Bahan Baku – Pelarut dan Suhu Ekstraksi terhadap Kandungan Xanthorrhizol dalam Oleoresin Temulawak (Curcuma xanthorhiza roxb.).
Abstrak: Temulawak (Curcuma xanthorrhiza Roxb.) belongs to the plant family Zingiberaceae which have various benefits. Sidik et al (1995) described that temulawak can be used as anti-inflammatory, anti-cancer, medicine for many disease like hipokolesterolemia, disorders of liver function, improved gastrointestinal function, for anti-bacterial and anti-fungal, and as anti-acne. Those benefits are related to active components of temulawak rhizhome. Curcuminoids and xanthorrhizol are predicted as components that provides pharmacological effects of temulawak rhizomes. Curcuminoids is the pigment that gives yellow color to temulawak, while xanthorrhizol is one component of the essential oil of temulawak. Temulawak is usually prepared as rhizome slices, powder, oleoresin, and essential oil. Temulawak in form of rhizome slices or powder has some weaknesses, such as bulky, easily to have color and flavor defect caused by climate change, easily contaminated by foreign material and microorganism, slowly produce of active component in the stage application and not completely extracted, and the final product have spots or strain that caused by the rhizome particles (Ravindran et al, 2007). To avoid these weaknesses, temulawak can be processed into temulawak oleoresin. Oleoresin is defined as a mixture of resin and volatile oil extracted from various kinds of herbs, either from the fruit, seeds, leaves, bark, and rhizomes by using organic solvents (Glibertson, 1971). In the process of extraction using this solvent, there are several factors that can affect the extraction efficiency and effectiveness. These factors include the type and concentration of solvent, solvent volume, extraction temperature, and size of the extracted material In this research, extraction temperature and solvent volume were observed to determine their effect on xanthorrhizol content of temulawak oleoresin. The effects of these factors were measured on yield of oleoresin, curcumin content, volatile oil content, solvent residu and the refractive index of the oleoresin. Extraction temperature applied in the experiments were three levels, 30 oC, 40 oC and 50 oC. The solvent volume factor is indicated by the ratio of raw materials to solvent. This study observed three levels of ratio, 1:4, 1:6, and 1:8 using 100 grams of temulawak powder as the ratio basis. Preparation prior to extraction process includes rhizome slicing, drying, and grinding to the size of 60 mesh. Temulawak powder was extracted by stirred maceration using ethanol 96% for four hours, followed by conditioning in room temperature for 24 hours. Temulawak extract was then separated from the solid waste by filtration. The evaporation to remove the solvent from the oleoresin finally conducted using a rotary vacuum evaporator at temperature of 50oC. The yields of temulawak oleoresin are in the range of 9.40% - 17.77% (w / w). The curcumin content is 1.11 to 3.88%, the essential oil content is 3,64 - 11.43%, the xanthorrhizol content equal to peak percentage area of 1.26 - 42.82%, the solvent residu in the oleoresin is 40.950 – 63.750 ppm, and the refractive index value (20/20oC) is ranged from 1.4817 to 1.5198. Statistical analysis of variance at 95% confidence level was used to determine the influence of extraction temperature and raw material-solvent ratio on yield and other experiments parameters. The result showed that
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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