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.
Keyword: 

Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm