Judul: Aktivitas antibakteri ekstrak daun dan bunga kitolod (laurentia longiflora (L). Peterm) terhadap beberapa bakteri penyebab konjungtivitas
Abstrak: Leaf and flower Kitolod (Laurentia longiflora (L). Peterm) have been used by Indonesian community as a traditional medicine to treat eye disease such as red eye (conjunctivity). The aim of this study was to test antibacterial activity of leaf and flower ethanol extracts of kitolod against Staphylococcus aureus, Streptococcus pneumonia and Pseudomonas aeruginosa, and to identify the compound of those extracts responsible for the antibacterial activity. Preparation of ethanol extract of kitolod leaf and flower was carried out by maceration with 70% ethanol. Antibacterial activity from those extracts was analyzed by agar diffusion methode using paper disc and chloramphenicol 20% as a positive control. The antibacterial compounds of those extracts were identified by GCMS (Gas Chromatography Mass Spectrometer) pyrolisis. The results of this study showed that ethanol extracts of kitolod leaf and flower inhibited Staphylococcus aureus with inhibition zone diameter are 19,33 mm and 15,66 mm respectively. However, the extracts could not inhibit Streptococcus pneumonia and Pseudomonas aeruginosa. The minimum inhibitory concentration (MIC) of the extracts was determined by the dilution methode using paper disc. Minimum inhibitory concentration values of the ethanol extract of kitolod leaf and flower was 25 mg/ml. The compounds of ethanol extract of kitolod leaf showing antibacterial activity were fatty acid and their derivatives (chloro acetic acid, acetic acid, and palmitic acid); acetophenone; benzyl alcohol; 6 methyl-5-hepten-2-ol; 2,3-dehydrobenzofuran; flavonoid (aesculetin and 4 ethenyl 2 methoxy phenol) and Heptanal. While compounds responsible for antibacterial activity of ethanol extract of kitolod flower were fatty acid and its derivatives (stearic acid, palmitic acid, methyl palmitate, myristic acid, lauric acid, acetic acid, and heptadecane-(8) carbonic); Nitroform; acetophenone; 4 ethenyl 2 methoxy phenol; Levoglucosan; xanthosine; styrene; 2,3-butanediol and 2,3-dihydro benzofuran.
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Judul: Kajian Aktivitas Antibakteri Daun Gatel (Laportea decumana (Roxb.) Wedd.) dan Daun Benalu Cengkeh
Abstrak: Many researches showed that several plants have a good antibacterial activity. The leaves of gatel and clove mistletoe are empirically used to cure several diseases. The aims of this research were: (1) to study the potential of antibacterial activity of gatel and clove mistletoe hexane, ethyl acetate and methanol extracts against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhimurium and Pseudomonas aeruginosa by the well diffusion method; (2) to calculate the minimum inhibitory concentration (MIC) value of the potential extracts; and (3) to study the effect of various pH to antibacterial activity of the extracts. The results showed ethyl acetate and methanol extracts of the studied plants have low antibacterial activity against B. cereus and E. coli. Based on the MIC values, the ethyl acetate extract of gatel leaves showed over 99% percent inhibition against E. coli at a concentration of 3.5%, 4.0%, 4.5% and 5.0%. The same result was obtained by modifying the pH (4, 5 and 6) at the extracts concentration of 5% and 10%. The methanol extract of gatel leaves showed below 60% inhibition of B. cereus at a concentration of extract 4.0%, 4.5%, 5.0%, 5.5% and 6.0%, and more than 90% inhibition at the pH. The ethyl acetate extract of clove mistletoe showed more than 98% inhibition againts E. coli at a concentration of 3.5%, 4.0%, 4.5% and 5.0% and at pH 4, 5 and 6. Percent of inhibition less than 50% occured in the methanol extract of clove mistletoe at 4.0%, 4.5%, 5.0%, 5.5% and 6.0% concentration against B. cereus. For the methanol extract of clove mistletoe, the effect of pH variation (4, 5, 6 and 7) resulted in 92%-97% inhibition. The result may increase the utilization of research plant not only for health purposes but also as a natural food preservative and open new possibilities for the development of natural functional foods.
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Judul: Peramalan Curah Hujan dengan Model ARIMA (Autoregressive Integrated Moving Average) dan VECM (Vector Error Correction Model).
Abstrak: Peramalan curah hujan diperlukan untuk memprediksi curah hujan pada periode berikutnya. Penelitian ini menggunakan 2 (dua) model peramalan yaitu model ARIMA (Autoregressive Integrated Moving Average) dan VECM (Vector Error Correction Model). ARIMA merupakan model peramalan yang berdasarkan pada data deret waktu peubah amatan itu sendiri sebagai pembentuk modelnya. VECM merupakan model peramalan yang melibatkan 1 (satu) atau lebih data deret waktu peubah penjelas sebagai pembentuk modelnya. Berdasarkan model ARIMA, model yang terpilih sebagai model terbaik adalah ARIMA (1, 1, 2). Validasi model dari data pengujian pada model ARIMA (1, 1, 2) berdasarkan MAD dan RMSE sebesar 14.06 dan 17.29. Pada VECM, peubah penjelas yang digunakan yakni suhu, kelembaban, dan lama penyinaran. Berdasarkan VECM (1) yang diperoleh, terdapat dua hubungan terhadap perubahan curah hujan, yakni hubungan jangka panjang dan jangka pendek. Pada hubungan jangka panjang, perubahan curah hujan dipengaruhi oleh curah hujan dan lama penyinaran masing-masing 1 (satu) periode sebelumnya. Pada hubungan jangka pendek, perubahan curah hujan hanya dipengaruhi oleh perubahan lama penyinaran 1 (satu) periode sebelumnya. Validasi VECM (1) dari data pengujian berdasarkan MAD dan RMSE sebesar 13.46 dan 16.81. Sehingga pada penelitian ini, VECM (1) dapat lebih baik meramalkan curah hujan dibanding model ARIMA (1, 1, 2).
Keyword: curah hujan, model ARIMA, VECM