Judul: Identification of Metabolites and Grouping of Sidaguri (Sida rhombifolia L.) from Different Growing Locations Using LC-MS/MS
Abstrak: Tumbuhan obat telah banyak digunakan untuk berbagai macam tujuan, baik untuk mencegah maupun mengobati penyakit. Salah satu spesies tanaman yang digunakan sebagai ramuan obat tradisional di Indonesia ialah sidaguri (Sida rhombifolia). Penelitian ini bertujuan mengidentifikasi kandungan senyawa ekstrak metanol herba spesies tersebut dari lokasi tumbuh berbeda. Analisis ekstrak metanol herba sidaguri diklasifikasikan berdasarkan lokasi tumbuh di Malang, Solo, Sukabumi, Tawangmangu, dan Yogyakarta menggunakan kromatografi cair- spektrometri massa dan dikelompokan menggunakan principal component analysis. Sebanyak 17 senyawa berhasil teridentifikasi dalam ekstrak. Senyawa tersebut termasuk dalam golongan fenolik, alkaloid, steroid, flavonoid, monoterpena lakton, dan golongan asam amino dan asam lemak. Didapatkan pola fragmentasi untuk 17 senyawa dengan cara fragmentasi spektrum massa berdasarkan kelompok senyawa masing-masing. Senyawa yang terdapat pada sampel terkelompok sesuai dengan lokasi tumbuhnya masing-masing dengan total varians 66%., Medicinal plants have been widely used for various purposes, both to prevent and treat diseases. One of the plant species used as traditional medicinal ingredients in Indonesia is sidaguri (Sida rhombifolia). This study aims to identify the compound content of the herbal methanol extract of these species from different growing locations. Analysis of sidaguri herb methanol extracts were classified based on growing locations in Malang, Solo, Sukabumi, Tawangmangu, and Yogyakarta using liquid chromatography-mass spectrometry and grouped using principal component analysis. A total of 17 compounds were identified in the extract. These compounds are included in the phenolic group, alkaloids, steroids, flavonoids, monoterpene lactones, and amino acids and fatty acids. Fragmentation patterns were obtained for 17 compounds by means of mass spectrum fragmentation based on each compound group. The compounds contained in the samples were grouped according to their respective growth locations with a total variance of 66%.
Keyword: LC-MS, sidaguri, Sida rhombifolia, PCA, pola fragmentasi

Judul: Classification of Sidaguri’s Stem (Sida rhombifolia) Based on Different Cultivation Ages using LC-MS/MS Combined with Chemometrics
Abstrak: Sidaguri (Sida rhombifolia) merupakan jenis tanaman yang telah banyak dimanfaatkan sebagai obat tradisional karena kandungan metabolit bioaktif di dalamnya. Kandungan metabolit di dalam batang tanaman tersebut dipengaruhi oleh beberapa faktor, salah satunya adalah usia tanam. Penelitian ini bertujuan mengidentifikasi kandungan metabolit ekstrak batang spesies tersebut dengan usia tanam berbeda menggunakan LC-MS/MS dan dikelompokkan menggunakan principal component analysis (PCA). Sampel diekstraksi menggunakan metanol (LC-MS grade) dengan sonikasi. Sebanyak 21 senyawa teridentifikasi secara putatif pada ekstrak batang sidaguri dengan usia tanam 3, 4, dan 5 bulan. Senyawasenyawa tersebut termasuk ke dalam golongan asam fenolat, fenolik aldehida, alkaloid, steroid, flavonoid, kumarin, asam amino dan asam lemak. Berdasarkan hasil pengelompokan dengan PCA menggunakan variabel luas pita 21 metabolit yang teridentifikasi, ekstrak sidaguri mengelompok sesuai dengan usia tanam masing-masing dengan total plot skor sebesar 78%., Sidaguri (Sida rhombifolia) is a plant widely used as a traditional medicine because of its bioactive metabolite content. The metabolites in sidaguri were affected by some factors, such as cultivation age. This study aimed to identify metabolites based on diferrent cultivation ages and classify them using principal component analysis (PCA). Samples from 3, 4, and 5 months post planting were extracted using methanol (LC-MS grade) using sonication. Twenty-one metabolites were putatively identified from all extracts. These metabolites belong to phenolic acids, phenolic aldehydes, alkaloids, steroids, flavonoids, coumarins, amino acids and fatty acids. Based on clustering result by PCA using 21 identified metabolites peak area, each extract was grouped according to cultivation ages with a total score plot of 70%.
Keyword: Sida rhombifolia, LC-MS/MS, metabolite profiling, PCA

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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