FINAL EXAM

FINAL EXAM  NATURAL MATERIALS CHEMISTRY
NAME: DESI FEBRIANTI
NIM: RSA1C110011

1.    Explain the triterpenoid biosynthetic pathway, identify important factors that determine the quantities produced many triterpenoids.
Answer:
In the third terpenoid biosynthesis basic reactions, namely:
    Formation of active isoprene derived from acetic acid via mevalonic acid.
    Merging head and tail isoprene units to form mono-, seskui-, di-, Sester-, and poly-terpenoids.
    The incorporation of the tail and the tail unit C-15 or C-20 produces triterpenoids and steroids.

     Acetic acid which has been activated by coenzyme A did Claisen type condensation resulting asetoaseta acid, and these compounds did produce aldol type condensation of carbon branched chain amino mevanolat same. The next reaction is phosphorylation, elimination of phosphoric acid and subsequent decarboxylation produces IPP into DMAPP berisomerisasi, the isomerase enzyme. IPP as active isoprene units joined by the tail with DMAPP and this merger is the first step of the polymerization of isoprene to produce terpenoids, this happens because electrons attack the double bond carbon atoms of IPP to DMAPP electron deficient ison followed by removal of pyrophosphate. These attacks result in geranil pyrophosphate (GPP), which is an intermediate for all compounds monoterpenes.

     Subsequent incorporation between the IPP and GPP unit, with the same mechanism as the IPP and DMAPP, produce farnesil pyrophosphate (FPP), which is an intermediate compound for all sesquiterpene compound. Compounds derived diterpene geranil geranil-pyrophosphate (GGPP) derived from the condensation between one unit of IPP and GPP.

     Organic reactions (Figure 2) explored more deeply, it turns out that the synthesis of terpenoids by organisms is very simple in nature. In terms of the theory of organic synthesis reaction is only using a few basic types of reactions. Subsequent reactions of the compounds between GPP, FPP and GGPP to produce terpenoid compounds one by one just involves some kind of secondary reactions. These secondary reactions, ie hydrolysis, cyclization, oxidation, reduction and spontaneous reactions that can take place easily in a neutral atmosphere and at room temperature, such as isomerization, dehydration, decarboxylation, and so on.

From the above equation it can be seen that the formation of compounds monoterpenes and terpenoids compounds derived from the incorporation of 3.3 dimethyl allil pyrophosphate and isopentenyl pyrophosphate.


2.    Describe the structure determination of flavonoids, specificity and intensity of absorption signal by using IR and NMR spectra. Give the example of at least two different structures.
Answer:
-    Spectrum IR of epigenin

Apigenin is a flavone and is being developed for treatment of cardiovascular disease. A sensitive and accurate quantitative detection method using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) for the measurement of apigenin and luteolin levels in rat plasma is described. Analytes were separated on a separation by a Luna C₁₈ (5 μm, 100 mm × 2.0 mm) column with acetonitrile:methanol:water (35:40:60, v/v/v) as a mobile phase. The eluted compounds were detected by tandem mass spectrometry. Good linearity (R² > 0.9997) was observed for both analytes over the range of 2.5–5000 ng/mL in 0.1 mL of rat plasma. The overall accuracy of this method was 93–105% for apigenin and 95–112% for luteolin in rat plasma. Intra-assay and inter-assay variabilities were less than 11% in plasma. The lowest quantitation limit for both apigenin and luteolin was 2.5 ng/mL in 0.1 mL of rat plasma. Practical utility of this new LC/MS/MS method was demonstrated in a pilot pharmacokinetic study in rats following intravenous administration of apigenin. Metabolism of apigenin to luteolin in vivo was established.

http://www.sciencedirect.com/science/article/pii/S1570023207003546

-       Spectrum nmr of epigenin

The enzyme 17β-hydroxysteroid dehydrogenase type 1 (17β-HSD1) has become an important drug target for breast cancer because it catalyzes the interconversion of estrone to the biologically more potent estradiol which also plays a crucial role in the etiology of breast cancer. Patients with an increased expression of the 17β-HSD1 gene have a significantly worse outcome than patients without. Inhibitors for 17β-HSD1 are therefore included in therapy development. Here we have studied binding of 17β-HSD1 to substrates and a number of inhibitors using NMR spectroscopy. Ligand observed NMR spectra show a strong pH dependence for the phytoestrogens luteolin and apigenin but not for the natural ligands estradiol and estrone. Moreover, NMR competition experiments show that the phytoestrogens do not replace the estrogens despite their similar inhibition levels in the in vitro assay. These results strongly support an additional 17β-HSD1 binding site for phytoestrogens which is neither the substrate nor the co-factor binding site. Docking experiments suggest the dimer interface as a possible location. An additional binding site for the phytoestrogens may open new opportunities for the design of inhibitors, not only for 17β-HSD1, but also for other family members of the short chain dehydrogenases.
http://www.sciencedirect.com/science/article/pii/S0960076009002064

- Spectrum IR of catechin

The role of short-range order (SRO) metal oxides, which are common in acid soils and associated environments, in influencing the abiotic transformations of catechin, which is common in the soil of tea plantations, still remains poorly understood. The aim of this study was to investigate the catalytic power of SRO Mn(IV)-, Fe(III)- and Al-oxides in influencing the abiotic transformations of catechin. At the end of a 90-h reaction period, the release of CO2 in all the oxide-catechin systems is higher than that for the system with only catechin. Polymerization of catechin is catalyzed and enhanced by SRO-oxides, as is indicated by the absorbance values of the supernatants, which were obtained via visible adsorption spectroscopy, and the yields of humic polymers. The sequence of the oxides that increased the yield of total humic polymers in these systems under ambient atmosphere is: Fe(III)-oxide > Mn(IV)-oxide > Al-oxide ≫ no catalyst (catechin). The electron spin resonance (ESR) and Fourier transformation infrared absorption spectrometry (FT-IR) of humic polymers formed in the oxide-catechin systems were similar to the spectra obtained from the humic polymers extracted from the soil. The catalytic power of SRO-oxides in promoting the oxidative polymerization of catechin, the resultant formation of humic substances, and C turnover in acid soils thus merit attention.
http://www.sciencedirect.com/science/article/pii/S0927776510003760




-    Spectrum NMR of catechin

Separation of the water-soluble fraction of peanut skins led to the isolation of five proanthocyanidins. Based on the spectroscopic investigation and partial acid catalyzed degradation, their structures were determined to be epicatechin-(2β → O → 7, 4β → 6)-[epicatechin-(4β → 8)]-catechin (1), epicatechin-(2β → O → 7, 4β → 8) epicatechin-(4β → 8)-catechin-(4α → 8)-epicatechin (2), and procyanidins B2 (3), B3 (4) and B4 (5). The absolute configuration of the new compounds was determined from their circular dichroism curves and the 1H NMR spectra of analysis of flavan-3-ols formed by thiolytic degradation of 1 and 2 in the presence of a chiral dirhodium complex (dirhodium tetra-(R)–(trifluoromethyl) phenyl acetate).

http://www.sciencedirect.com/science/article/pii/S0031942204002870

3.    In the isolation of alkaloids, in the early stages of acid or base required conditions. Explain the basis of the use of reagents, and give examples of at least three kinds of alkaloids.
Answer:

Amino acids are organic compounds that are very important, these compounds are composed of amino (NH2) and carboxyl (COOH). there are 20 kinds of essential amino acid which is the standard, also known as alpha amino acid alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, fenilalanine, proline, serine, treonine, triptopan, tirosine, and valine. the use of amino acid reagent is intended as both providers and other basic nitrogen atom allkaloid framework.
Example:

-    isolation of piperine from black pepper powder
1. black pepper cleaned, milled to a powder, and put into a Soxhlet extraction apparatus
2.  in extraction for ± 5jam using absosut solvent.
3.  ektarak was screened by solvent evaporation to separate absolute ethanol.
4.  enter 30 mL solution of 10% KOH-ethanol into rsidu. And perform filtering. in alkaline ethanol solution let stand for one night, to form crystals
5.  separate crystals formed from sediment. Be obtained crystals are yellow. do recrystallized with 95% ethanol, lakukan melting point test and identify structures with IR and H1 NMR

-    isolation of nicotine
In this research, isolation of nicotine from tobacco leaves dried soxhletasi by using methanol and then do the salting with acid and alkaline extraction of alkaloids with. The extract obtained was then purified by TLC, and column chromatography. After it was analyzed using IR, UV, and GC-MS. Other tobacco extracts tested for its effectiveness as an insecticide rice stem borers by spraying the rice seedbed with various concentrations.

From the results of TLC analysis using prices obtained methanol solution developers Rf = 0.725. IR spectra analysis results indicate a tertiary aromatic amine, methyl, tertiary amine alifatis and aromatic CH bonds. The results of GC-MS chromatograms showed nicotine compounds appear at the top of the retention time = 9.245 s and 63% similarity index, this suggests that the tobacco alkaloid nicotine contained. Results from UV spectrophotometers generate maximum wavelength 206 nm indicating kearomatisan of pyridine ring in nicotine. Tobacco extracts are used to test the effectiveness of the rice stem borer, rice plants by spraying in which there is the rice stem borer, obtained Fhitung = 19,061 and F table = 3.48. Because Ftabel <Fhitung then Ho is rejected and Ha accepted, the concentration of tobacco leaf extracts affect its effectiveness as an insecticide rice stem borer.

4.    Describe the relationship between biosynthesis, methods of isolation and structural determination of compounds of natural ingredients. Give an example.
Answer:
a compound of natural ingredients can be obtained through the process of biosynthesis. Once the information is known about the natural ingredient compounds, we can perform a suitable method used for isolasi.kemudian as proof that the compound material are studied alkaloids or other compounds test requires the IR and NMR spectra. Based on these test results, we can know what.
Example: