Judul: Metabolit Sekunder dari Ranting Pinus Klinki (Araucaria hunsteinii K. Schum.)
Abstrak: Araucaria hunsteinii K. Schum. atau pinus klinki merupakan tumbuhan yang tersebar di kawasan Malesia, salah satunya dapat ditemukan di Kebun Raya Bogor, Indonesia. Metabolit sekunder pada daun tumbuhan ini sudah pernah dilaporkan, yaitu golongan terpenoid dan biflavonoid, tetapi belum ada informasi mengenai bagian rantingnya. Oleh karena itu, penelitian ini bertujuan mengisolasi metabolit sekunder dari ranting pinus tersebut dan menentukan struktur senyawanya. Ekstrak ranting yang merupakan fraksi larut aseton, kemudian difraksionasi dengan kromatografi kolom gravitasi Sephadex LH-20 dan dimurnikan dengan kromatografi lapis tipis preparatif. Isolat dikarakterisasi menggunakan spektrofotometer ultraviolet-sinartampak, spektrometer inframerah, dan spektrometer massa. Biflavonoid berhasil diisolasi pada ranting, yaitu 4',4''',7,7''- tetra-O-metilkupresuflavon. Senyawa tersebut pernah dilaporkan pada bagian daunnya, tetapi baru pertama kali ditemukan pada ranting. Penelitian ini juga menemukan artefak, yaitu di-2-propilpentilftalat, yang diduga berasal dari kontaminan pada pelarut yang digunakan selama proses isolasi., Araucaria hunsteinii K. Schum. or pinus klinki, is a plant spread in the Malesia area, one of which can be found in the Bogor Botanical Garden, Indonesia. Secondary metabolites in the leaves of this plant have been reported, namely the terpenoid and biflavonoid groups, but there is no information about the twigs. Therefore, this study aims to isolate secondary metabolites from the pine twigs and determine the structure of the compound. The twig extract that was a soluble fraction of acetone, was fractionated by Sephadex LH-20 gravity column chromatography and purified by preparative thin-layer chromatography. The isolates were characterized using ultraviolet-visible-light spectrophotometers, infrared spectrometers, and mass spectrometers. Biflavonoids isolated from the twigs is 4',4'',7''-tetra-O-methylcupressuflavone. The compound has been reported on leaves but was first discovered in twigs. The study also found an artifact, di-2- propylpentilphthalate, thought to have come from a contaminant in the solvent used during the isolation process.
Keyword: Araucaria hunsteinii, artifact, biflavonoid, twigs

Judul: Isolation and Characterization of Non-Biflavonoid faction from Araucaria hunsteinii K. Schum Leaves and Their Bioactivity as Antibacterial
Abstrak: Meningkatnya penyakit disebabkan bakteri disertai resistensi terhadap antibiotik menyebabkan permasalahan medis. Pemanfaatan senyawa antibakteri yang bersumber dari tumbuhan merupakan alternatif penyelesaian masalah tersebut. Tumbuhan genus Araucaria memiliki 19 spesies dengan lima spesies telah diuji aktivitas antibakterinya. A. hunsteinii K. Schum merupakan salah satu spesies yang dapat ditemukan di Kebun Raya Bogor. Kandungan biflavonoid dan terpenoid pada tumbuhan ini sudah pernah dilaporkan, tetapi informasi terkait senyawa non-biflavonoid dan aktivitas antibakterinya belum diteliti. Pada penelitian ini, fraksi non-biflavonoid difraksionasi dengan kromatotron dan kromatografi kolom gravitasi Sephadex LH-20 serta dimurnikan dengan kromatografi lapis tipis preparatif. Isolat (T5 dan T6) dikarakterisasi dengan LC-MS dan dalam kedua fraksi tersebut masing-masing teridentifikasi 4 dan 11 senyawa dugaan termasuk seskuiterpena. Uji antibakteri menggunakan bakteri Staphylococcus aureus, Kocuria rhizopila, dan Escherichia coli menunjukkan potensi aktivitas antibakteri., Increased bacterial diseases, accompanied by antibiotic resistance, cause medical problems. Antibacterial compounds from plants are an alternative solution to this problem. Araucaria genus has 19 species, five of which have been tested for antibacterial activity. A. hunsteinii K. Schum is a species that can be found in Bogor Botanical Garden. Biflavonoids and terpenoids in this plant have been reported, but information related to non-biflavonoid compounds and their antibacterial activity has yet to be studied. In this research, the isolation of non-biflavonoids was performed by fractionating it through chromatotron and Sephadex LH-20 column chromatography and purified by preparative thin-layer chromatography. The isolates (T5 and T6) were characterized using LC-MS; in two fractions, 4 and 11 identified compounds were identified, including sesquiterpenes. Antibacterial tests using the bacteria Staphylococcus aureus, Kocuria rhizopila, and Escherichia coli showed potential antibacterial activity.
Keyword: antibakteri, Araucaria hunsteinii, daun, terpenoid

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model