Isolation and Structure Elucidation of Bioactive Compounds Chemical as Inhibitors of the Enzyme Α-Glucosidase Raru Bark Ethanol Extract ( Vatica pauciflora Blume )

Inhibitory compound of α-glucosidase bioactivity was isolated from ethanol extract of the stem bark of raru (Vatica pauciflora Blume) which, is a wild plant that grows in Tapanuli state in Indonesia.The ethanol extract of the stem bark of raru was partitioned and was chromatographed on columns with stationare fase silica gel 60 mesh F254 (0.063 mm-0.200 mm). The ethanol extract of isolates showed the enzyme α-glucosidase inhibitor IC50 of 93.46. The next step is the determination of the chemical structure of the Ultraviolet–visible spectroscopy (UV Vis); FT-IR (Fourier Transform Infrared spectroscopy), NMR (Nuclear Magnetic Resonance) namely COSY, Heteronuclear Multiple-Quantum Correlation (HMQC); and Heteronuclear Multiple-Bond Correlation (HMBC). It found of compounds consist of two of methoxy, one of aromatic, and one of carbonil compounds. The isolat is a 3,4,9,Trihidroxy-2-(hydroxymethyl)-8-10-dimethoxy-2-3-4atetrahydropyrano(3,2-c)isochromen-6(10bH)-one acording to International Union of Pure and Applied Chemistry (IUPAC).


Isolation and Structure Elucidation of Bioactive Compounds Chemical as Inhibitors of the Enzyme Α-Glucosidase Raru Bark Ethanol Extract
(Vatica pauciflora Blume)

Introduction
The use of traditional medicine is Indonesian culture that goes back thousands years ago. It is a cultural heritage of Indonesia that need to be explored, researched, and developed (Hedi, 2007). Consumed plant extracts for the treatment, which is made in the form of decoction, herbal remedies and herbal capsule form. Things like this do to treat diabetic mellitus. Diabetic Mellitus (DM) is a condition of the concentration of glucose in the blood is chronically higher than normal value (hyperglycemia). This is caused by a deficiency of insulin or the insulin does not function effectively. Diabetic can lead to various diseases such as hypertension, stroke, coronary heart disease, and kidney failure (Guyton & Hall, 2007).
Measurement of glucose levels can be determined in vitro by enzymatic methods (Lucile, 1997). Spectrophotometer for color intensity is used hereinafter blood glucose levels can be determined.
According to World Health Organization (2005), more than 80% of the population in developing countries consume natural ingredients derived mainly from plants, either as a form of maintaining health and medicine. The use of natural medicine is intended to avoid the side effects of chemical drugs. And plant-based treatments currently has a market share of about 30%.

Fractionation by Column Chromatography Method
Extract ethanol fractionation by chromatography column I, performed by taking as much as 5.0 g of ethanol extract, and further fractionated by column chromatography using silica gel stationary phase 60 mesh. And the mobile phase used was chloroform-methanol (40:1~1:1). The compounds in botanicals, grouped by polarity in the form of fractions. To obtain a more simple fractions, done by combining fractions that have the same pattern of the chromatogram. Results fractions of column 1 are combined into 14 fractions, and then tested the inhibition of the enzyme α-glucosidase. The test results showed inhibition of the enzyme α-glucosidase is the fraction 9.
Extract ethanol fractionation by column chromatography II made to the fraction 9 that the same method as in column I. Results fractions were combined, and obtained six fractions, were then tested for inhibition against α-glucosidase enzyme.
Further separation of fraction VPEt-9 with chromatography columns III conducted in fractions 9-4 with the same method as in column I. Results fractions were combined and gained 5 fractions. Tests conducted on the inhibition of the enzyme α-glucosidase. Provided that fractions 9-4 VPEt-4 of the ethanol extract had α-glucosidase inhibitory activity of the most high, and further separated by column chromatography. This was done to obtain a pure compound.

Results
The yield of extraction results shown in Table 1, where the highest obtained in the extraction of ethanol.  Figure 2 rum of isolates  72 (s). The relationship between carbon and proton in the ethanol extract of the isolates showed no association between the signal and the carbon nucleus on the same proton. Spot spectrum indicates the two are directly related to the bond. Proton signal at δH 3.79 ppm seen (H1-13) and δH 3.99 (H2-13). C-12 at δC 73.26 with δH 4.80 (H-12), C-3 at δC 115.00 with δH 7.32 (H-3).
O O OH OH OH . O activity of the enzyme α-vitro glucosidase by VpEt fraction 9-4-4-1, that is equal to IC50 93.46.
(2) The chemical structure of spectral data based on UV-Vis spectrophotometer, FT-IR and NMR spectrometer and proton carbon Nuclear Magnetic Resonance (COSY, HMQC, and HMBC); HRMS isolates obtained VpEt 9-4-4-1 is bergenin dimethoxy compound. The isolate is a acording to International Union of Pure and Applied Chemistry (IUPAC).