Two major saponins have been isolated from a methanol extract of the seeds of Barringtonia asiatica, and their structures elucidated (mainly by two-dimensional NMR spectroscopy) as 3-O-[[beta-D-galactopyranosyl(1-->3)-beta-D-glucopyranosyl(1-->2)]-beta-D-glucuronopyranosyloxy]-22-O-(2-methylbutyroyloxy)-15,16,28-trihydroxy-(3beta,15alpha,16alpha,22alpha)-olean-12-ene (3) and 3-O-[[beta-D-galactopyranosyl(1-->3)-beta-D-glucopyranosyl(1-->2)]-beta-D-glucuronopyranosyloxy]-22-O-[2(E)-methyl-2-butenyloyloxy]-15,16,28-trihydroxy-(3beta,15alpha,16alpha,22alpha)-olean-12-ene (4). The antifeedant properties of 3 and 4 toward Epilachna larvae are discussed.

A triterpene ester saponin has been isolated from the seed of Barringtonia asiatica and its structure has been established by extensive application of high-resolution FABMS and two dimensional NMR techniques to be 3-O-{[β-D-galactopyranosyl(1→3)-β-D-glucopyranosyl(1→2)]-β-D-glucuronopyranosyloxy}-22-O-[2-methylbutyroyloxy]-15,16,28-trihydroxy-(3β,15α,16α,22α)-olean-12-ene.   Keywords: Barringtonia asiatica, Lecythidaceae, triterpenoid

The red pakoba (Syzygium sp.) is a plant originating from north sulawesi that is often used by local people as a basic ingridient of medicine. This research was conducted to isolate and identify glycoside compounds contained in the n-butanol fraction of red pakoba fruits (Syzygium sp.). The isolation process was carried out using the maceration method, for the separation and purification of compounds using Thin Layer Chromatography (TLC) and Gravity Column Chromatography and obtained F2.4 sub-fraction isolates with a sample weight of 4.5 mg. Identification of compound using Proton Nuclear Magnetic Resonance (NMR-1H) and Carbon Nuclear Magnetic Resonance (NMR-13C) tecniques. The result of identification of isolate F2.4 sub-fraction as flavonoid glycoside compounds with the proposed name 3-O-methyl-butyrate-6,7,3',4' tetrahydroxy-5-methoxy-8-methyl flavan with molecular formula (C22H25O8)

This study aims to determine the effect of the use of Problem Based Learning towards reducing students' misconceptions on acid-base material. The learning model used in this study is the Problem Based Learning (PBL) learning model. The population in this study were all students of class XII IPA in Tomitas Caritas Catholic High School while the sample used was class XII IPA 2. Data collection techniques used a two-tier diagnostic test. Analysis of the data used in this study is the Rasch model and hypothesis testing. The results showed that there were still students who experienced misconceptions even including students who had high abilities, and the average pretest learning outcomes = 48.6 while the average posttest learning outcomes = 86.6. The results of the study for the hypothesis test were analyzed using the T-test statistic at a significant level of 0.05 and the results obtained were obtained at 7.90> 1.684 Ttable so that H0 was rejected and H1 was accepted. Based on these results it can be concluded that the use of Problem Based Learning learning models can reduce student misconceptionsThis study aims to determine the effect of the use of Problem Based Learning towards reducing students' misconceptions on acid-base material. The learning model used in this study is the Problem Based Learning (PBL) learning model. The population in this study were all students of class XII IPA in Tomitas Caritas Catholic High School while the sample used was class XII IPA 2. Data collection techniques used a two-tier diagnostic test. Analysis of the data used in this study is the Rasch model and hypothesis testing. The results showed that there were still students who experienced misconceptions even including students who had high abilities, and the average pretest learning outcomes = 48.6 while the average posttest learning outcomes = 86.6. The results of the study for the hypothesis test were analyzed using the T-test statistic at a significant level of 0.05 and the results obtained were obtained at 7.90> 1.684 Ttable so that H0 was rejected and H1 was accepted. Based on these results it can be concluded that the use of Problem Based Learning learning models can reduce student misconceptions