Judul: Daun Pelindung Bunga Temu Lawak (Curcuma xanthorriza Roxb.) sebagai Inhibitor Tirosinase dan Antioksidan
Abstrak: The utilization a bract flower of temu lawak (C. xanthorrhiza) as tyrosinase inhibitor and antioxidant was verified by identifying its active compound. Sample of a bract flower of temu lawak was extracted with n-hexane, ethyl acetate, and methanol as well as distillation of its essential oil. Tyrosinase inhibition (monophenolase and diphenolase) and antioxidant (diphenylpicryl hydrazyl (DPPH) method) assays were performed on various extracts and essential oil of the sample. The ethyl acetate extract was the active extract with IC50 1.97 mg/mL on monophenolase, 1.57 mg/mL on diphenolase and 12.68 μg/mL on antioxidant. The ethyl acetate extract that was fractionated with column chromatography (CC) produced 12 fractions. F12 was the most active fraction from fractionation by CC that might contain flavonol-related compound based on infrared spectrophotometer analysis and phytochemical assay. A fraction with the highest yield (F1) continued fractionation by preparative thin layer chromatography (TLC) produced 2 fractions. F1.2 was the more active fraction resulted F1 fractionation using preparative TLC which might contain auron-type compound based on infrared spectrophotometer analysis and phytochemical assay
Keyword: antioxidant, Curcuma xanthorrhiza, tyrosinase inhibitor, fractionation

Judul: Potensi Pelepah Temulawak (Curcuma xanthorriza) sebagai Antikanker dan Antioksidan
Abstrak: The study aimed to evaluate the potency of temulawak (Curcuma xanthorrhiza) stem as anticancer by brine shrimp lethality test (BSLT) and antioxidant by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. The stem of temulawak midrib obtained from Bogor, was extracted by n-hexane, chloroform, ethyl acetate, methanol, and water, and the volatile oil was obtained by water distillation. The chloroform extract and volatile oil showed anticancer potency towards Artemia salina (LC50: 370.69 ± 22.69 μg mL-1 ; 123.05 ± 3.49 μg mL-1, respectively). Ethyl acetate and chloroform extracts had antioxidant activities (IC50: 46.41 ± 15.49 μg mL-1 and 52.72 ± 3.46 μg mL-1) but the activity did not as strong as ascorbic acid (control positive, IC50 1.80 ± 0.33 μg mL-1). The chloroform extract was further fractionated by column chromatography with Silica Gel G60F254-Merck as stationary phase and gradient of n-hexane, chloroform, and methanol as mobile phase. Antioxidant and anticancer potency of fraction which had antioxidant activity qualitatively were tested. The most antioxidant active fraction (F9) had anticancer potency (LC50: 522.95 ± 43.35 μg mL-1) and antioxidant activity (IC50: 79.57 ± 8.96 μg mL-1). In conclusion, F9 is potencial as an anticancer and antioxidant.
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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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