Judul: Isolasi Komponen Bioaktif Flavonoid dari Tanaman Daun Dewa (Gynura pseudochina (Lour) DC)
Abstrak: This research was including of isolation of flavonoid component from leaf and rhizoma of daun dewa plant, followed by bioassay test of larvae mortality of Artemia salina Leach and antikhamir to Saccharomyces cerevisiae. Extraction process of antocyanin flavonoid was done by maceration using HCl in MeOH solvent, whereas another flavonoid was done maceration too, but with two steps, first, using MeOH – H2O (9:1) and second, using MeOH – H2O (1:1). Filtrate obtained from these steps was collected together and dried using rotavapour. Extract that obtained from this process was partitied using n-hexan, chloroform, diethylether, ethylacetic and n-buthanol solvent, respectively. Its residue was soxhletated using petroleum ether and methanol. The existency of flavonoid was traced by phytochemical test, its bioavailabiolity was traced by toxicity test using A. salina Leach larvae (BSLT test) and antikhamir activity test to Saccharomyces cerevisiae with spectrometer UV-Vis and FTIR, GC-MS and HPLC. The result of phitochemical test of fresh leaf extract of daun dewa plant could not detect the anthocyanin flavonoid group. The result of BSLT test of leaf powder extract showed that buthanol fraction has the highest value of LC50 = 832.12297 ppm, in rhizoma powder extract, the ethylacetic showed the highest value of LC50 was 723.44205 ppm, but in those both extract did not show antikhamir activity to S. cerevisiae khamir. Separation of buthanol fraction was using TLC preparative with silica gel 60 F254 as a stationer phase and BAW as a mobile phase. It was resulted 7 fractions. Fraction 4 and 7 had LC50 value 7.80408 and 208.51563 ppm, respectively. The result of structure identification of fraction 4 and 7 with spectrometer UV-Vis and FTIR gave a clue that fraction 4 and 7 could be presumed contain of flavonoid group compound and these fractions had functional group such as OH, C=O ketone, C=C aromatic and C-O. The results of GC and HPLC showed fraction 4 and 7 obtained was not pure. From the result of HPLC analysis, the content of quercetine in fraction 4 was 2.7458 mg/g.
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Judul: Isolasi dan Identifikasi Golongan Flavonoid daun Dandang  Gendis (Clinacanthus nutans) Berpotensi sebagai Antioksidan
Abstrak: Isolation of flavonoid was carried out by extracting the leaves of Dandang Gendis (Clinacanthus nutans) with 70% ethanol. Maceration was used as a method of extraction. The extract then was concentrated and calculated for its yield, phytochemical test, and flavonoid group test. The extract were hydrolysed and partitioned in ethyl acetate, then fractionated using column chromatography through gradient elusion process between a mixture of methanol:chloroform. Antioxidant test was conducted by FTIR (Fourier Transform Infrared) to analyze the functional groups present in the most active fractions. The 70% ethanol gave 34.58% yield. Phytochemical test was positive for alkaloids, triterpenoids, and flavonoids. Flavonoid group test was positive for flavon and flavonol. The most active fraction was fraction l with IC50 value of 48.42 mg/L, flavonoid group test was positive for flavon and flavonol, and FTIR analysis results showed the functional groups of O-H, C = O, C-O, aromatic C=C, and aliphatic C-H.
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Judul: Rancang Bangun Mekanisme Penggetar Untuk Bajak Subsoil Getar Dengan Dua Bilah Bajak
Abstrak: Bajak subsoil merupakan alat pengolahan tanah pertama yang sering digunakan sebelum pembajakan dengan bajak singkal atau bajak piring untuk memecah lapisan keras di lapisan bawah. Alat ini biasanya digunakan pada tanah yang telah mengalamli pemadatan akibat lalu lintas traktor. Alat ini memiliki tahanan tarik yang tinggi dan biasa ditarik traktor empat roda
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