Judul: Profile Metabolite and Antioxidant Capacity of Kejibeling Leaf Extract (Strobilanthes crispa (L.) Blume) Based on Different Extractor Solvents
Abstrak: Kejibeling (Strobilanthes crispa (L.) Blume) merupakan salah satu tanaman yang berpotensi sebagai antioksidan karena metabolit di dalamnya. Penelitian ini bertujuan mengidentifikasi metabolit ekstrak etanol 99%, etanol 50%, dan akuades menggunakan liquid chromatography-high resolution mass spectrometry (LC-HRMS), serta menentukan kapasitas antioksidan dengan metode cupric ion reducing antioxidant capacity (CUPRAC) berdasarkan perbedaan pelarut pengekstraksi pada ekstrak daun kejibeling. Total sebanyak 44 metabolit berhasil teridentifikasi pada ekstrak daun kejibeling, dengan masing-masing ekstrak etanol 99%, etanol 50%, dan akuades teridentifikasi sebanyak 34, 30, dan 18 metabolit. Ekstrak tiap pelarut berhasil terbedakan pada principal component analysis (PCA) dengan total PC1 dan PC2 sebesar 99%. Kapasitas antioksidan pada ekstrak etanol 99%, etanol 50%, dan akuades sebesar 3,47; 1,57; dan 0,69 mmol trolox ekuivalen/gram ekstrak (mmol TE/g ekstrak). Analisis partial least square (PLS) menunjukkan adanya korelasi antara metabolit yang terdeteksi dengan kapasitas antioksidan. Penelitian ini menunjukan senyawa yang teridentifikasi paling banyak dan kapasitas antioksidan paling tinggi pada etanol 99% dibandingkan pelarut lain., Kejibeling (Strobilanthes crispa (L.) Blume) is one of the plants that possesses antioxidant potensial by virtue of its metabolites. This study aims to identify metabolites of ethanol 99%, ethanol 50%, and aquades extracts using liquid chromatography-high resolution mass spectrometry (LC-HRMS), and to determine antioxidant capacity by cupric ion reducing antioxidant capacity method (CUPRAC) based on difference extraction solvents in kejibeling leaf extracts. A total of 44 metabolites were identified in kejibeling leaf extracts, ethanol 99%, ethanol 50%, and aquades extracts were identified 34, 30, and 18 metabolites. The extract of each solvent was successfully distinguished in the principal component analysis (PCA) with a total of PC1 and PC2 of 99%. The antioxidant capacity of ethanol 99%, ethanol 50%, and aquades extracts were 3.47, 1.57, and 0.69 mmoles of trolox equivalent/gram extract (mmol TE/g extract). Partial least square (PLS) analysis showed a correlation between detected metabolites and antioxidant capacity. This study showed the most identified compund and the highest antioxidant capacity in ethanol 99% compared to other solvents.
Keyword: antioxidant capacity, kejibeling, LC-HRMS, metabolites

Judul: Total Phenol and Flavonoid Contents and Antioxidant Capacity of Centella asiatica Extract with Various Extraction Solvents
Abstrak: Pegagan (Centella asiatica) merupakan tanaman yang dapat tumbuh liar di wilayah subtropis atau tropis. Spesies ini diketahui memiliki metabolit yang dapat berperan sebagai antioksidan. Oleh karena itu, penelitian ini bertujuan mengevaluasi pengaruh ragam pelarut pengekstraksi pada rendemen, kadar fenol dan flavonoid total, serta kapasitas antioksidan ekstrak daun pegagan asal Lembang, Jawa Barat. Pelarut pengekstraksi yang digunakan ialah etanol 70%, etil asetat, dan diklorometana. Kapasitas antioksidan ditentukan menggunakan metode 2,2-difenil-1-pikrilhidrazil (DPPH) dan ferric reducing antioxidant power (FRAP). Hasilnya menunjukkan ekstrak etanol 70% memberikan hasil tertinggi pada semua parameter yang diuji, yakni rendemen 31,31%, kadar fenol total sebesar 114,241 mg ekuivalen asam galat/g ekstrak, kadar flavonoid total 42,271 mg ekuivalen kuersetin/g ekstrak, serta kapasitas antioksidan dengan metode DPPH dan FRAP secara berturut-turut 34,299 dan 41,635 µmol Trolox/g ekstrak. Berdasarkan hasil tersebut, ragam pelarut pengekstraksi memengaruhi semua parameter yang diuji dan etanol 70% merupakan pelarut pengekstraksi terbaik pada penelitian ini., Pegagan (Centella asiatica) is a plant that can grow wildly in subtropical and tropical regions and is known to have a metabolite that can act as an antioxidant. Therefore, the study aims to evaluate the influence of extraction solvent variations on yield, total phenol and flavonoid content, and the antioxidant capacity of C. asiatica leaf extract from Lembang, West Java. The extraction solvents were 70% ethanol, ethyl acetate, and dichloromethane. Antioxidant capacity is determined using the 2,2-diphenyl-1-picrylhydrazil (DPPH) and ferric-reducing antioxidant power (FRAP) methods. The results of this study showed that 70% ethanol C. asiatica extract had the highest results on all parameters tested, including yields of 31.31%, total phenol of 114.241 mg gallic acid equivalent/g extract, total flavonoid of 42.271 mg quercetin equivalent/g extract, as well as antioxidant capacities with DPPH and FRAP methods of 34.299 and 41.635 µmol Trolox/g extract, respectively. Based on the results, the extraction solvent variations influenced all the parameters tested, and 70% ethanol was the best extraction solvent in this study.
Keyword: antioxidant capacity, Centella asiatica, total flavonoid, total phenol

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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