Judul: Pengoptimuman Ekstraksi dan Pemurnian Asiatikosida dari Pegagan (Centella asiatica)
Abstrak: Extraction of asiaticoside from Centella asiatica has already reported but the effective extraction method should be continuously developed. This study was developed to find an effective extraction and purification method of asiaticoside from this species. Extraction parameter such as temperature, time, and solvent were varied and extraction was conducted using ultrasonic. Asiaticoside content from crude extract was determined using ultraviolet-visible spectrophotometer. Asiaticoside from the extract was further isolated by column chromatography with chloroform: methanol as using step gradient elution. The concentration and purity of asiaticoside fraction from preparative TLC was determined using high performance liquid chromatography analysis. The optimum extraction conditions was that using ethanol as solvent at 30 °C for 15 min. The result showed that the best eluent to separate asiaticoside fraction was chloroform: methanol in 6:4, 5:5, and 4:6 ratios. The asiaticoside contents of fraction 1 and 2 was 23:14 mg/g preparative TLC fraction and 193.75 mg/g preparative TLC fraction with purity less than 50%.
Keyword: extraction, Centella asiatica, asiaticoside

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: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular