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:

cholesterol

Physiology
Since cholesterol is essential for all animal life, each cell synthesizes it from simpler molecules, a complex 37-step process which starts with the intracellular protein enzyme HMG-CoA reductase . However, normal and especially high levels of fats (including cholesterol) within the blood circulation, depending on how it is transported within lipoproteins , are strongly associated with progression of atherosclerosis .
For a man of about 68 kg (150 pounds), typical total body-cholesterol synthesis is about 1 g (1,000 mg) per day, and total body content is about 35 g, primarily located within all the membranes of all the cells of the body. Typical daily dietary intake of additional cholesterol, in the United States, is 200–300 mg.
However, most ingested cholesterol is esterified and esterified cholesterol is poorly absorbed. The body also compensates for any absorption of additional cholesterol by reducing cholesterol synthesis. For these reasons, cholesterol intake in food has little, if any, effect on total body cholesterol content or concentrations of cholesterol in the blood.
Cholesterol is recycled. The liver excretes it in a non-esterified form (via bile) into the digestive tract. Typically about 50% of the excreted cholesterol is reabsorbed by the small bowel back into the bloodstream.
Some plants make cholesterol in very small amounts. Plants manufacture phytosterols (substances chemically similar to cholesterol produced within plants), which can compete with cholesterol for reabsorption in the intestinal tract, thus potentially reducing cholesterol reabsorption. However, phytosterols are foreign to animal cells and, if absorbed, accelerate the progression of atherosclerosis . [ citation needed ] When intestinal lining cells absorb phytosterols, in place of cholesterol, they usually excrete the phytosterol molecules back into the GI tract, an important protective mechanism.
Plasma transport and regulation of absorption
See also: Blood lipids
Cholesterol is only slightly soluble in water ; it can dissolve and travel in the water-based bloodstream at exceedingly small concentrations. Since cholesterol is insoluble in blood, it is transported in the circulatory system within lipoproteins , complex discoidal particles that have an exterior composed of amphiphilic proteins and lipids whose outward-facing surfaces are water-soluble and inward-facing surfaces are lipid-soluble; triglycerides and cholesterol esters are carried internally. Phospholipids and cholesterol, being amphipathic, are transported in the surface monolayer of the lipoprotein particle.
In addition to providing a soluble means for transporting cholesterol through the blood, lipoproteins have cell-targeting signals that direct the lipids they carry to certain tissues. For this reason, there are several types of lipoproteins within blood called, in order of increasing density, chylomicrons , very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL). The more lipid and less protein a lipoprotein has the less dense it is. The cholesterol within all the various lipoproteins is identical, although some cholesterol is carried as the "free" alcohol and some is carried as fatty acyl esters referred to as cholesterol esters. However, the different lipoproteins contain apolipoproteins , which serve as ligands for specific receptors on cell membranes. In this way, the lipoprotein particles are molecular addresses that determine the start- and endpoints for cholesterol transport.
Chylomicrons, the least dense type of cholesterol transport molecules, contain apolipoprotein B-48 , apolipoprotein C , and apolipoprotein E in their shells. Chylomicrons are the transporters that carry fats from the intestine to muscle and other tissues that need fatty acids for energy or fat production. Cholesterol that is not used by muscles remains in more cholesterol-rich chylomicron remnants, which are taken up from here to the bloodstream by the liver.
VLDL molecules are produced by the liver and contain excess triacylglycerol and cholesterol that is not required by the liver for synthesis of bile acids. These molecules contain apolipoprotein B100 and apolipoprotein E in their shells. During transport in the bloodstream, the blood vessels cleave and absorb more triacylglycerol from IDL molecules, which contain an even higher percentage of cholesterol. The IDL molecules have two possible fates: Half are into metabolism by HTGL , taken up by the LDL receptor on the liver cell surfaces, and the other half continue to lose triacylglycerols in the bloodstream until they form LDL molecules, which have the highest percentage of cholesterol within them.
LDL molecules, therefore, are the major carriers of cholesterol in the blood, and each one contains approximately 1,500 molecules of cholesterol ester. The shell of the LDL molecule contains just one molecule of apolipoprotein B100, which is recognized by the LDL receptor in peripheral tissues. Upon binding of apolipoprotein B100, many LDL receptors become localized in clathrin -coated pits. Both the LDL and its receptor are internalized by endocytosis to form a vesicle within the cell. The vesicle then fuses with a lysosome , which has an enzyme called lysosomal acid lipase that hydrolyzes the cholesterol esters. Now within the cell, the cholesterol can be used for membrane biosynthesis or esterified and stored within the cell, so as to not interfere with cell membranes.
Synthesis of the LDL receptor is regulated by SREBP , the same regulatory protein as was used to control synthesis of cholesterol de novo in response to cholesterol presence in the cell. When the cell has abundant cholesterol, LDL receptor synthesis is blocked so new cholesterol in the form of LDL molecules cannot be taken up. On the converse, more LDL receptors are made when the cell is deficient in cholesterol. When this system is deregulated, many LDL molecules appear in the blood without receptors on the peripheral tissues. These LDL molecules are oxidized and taken up by macrophages , which become engorged and form foam cells. These cells often become trapped in the walls of blood vessels and contribute to atherosclerotic plaque formation. Differences in cholesterol homeostasis affect the development of early atherosclerosis (carotid intima-media thickness). These plaques are the main causes of heart attacks, strokes, and other serious medical problems, leading to the association of so-called LDL cholesterol (actually a lipoprotein ) with "bad" cholesterol.
Also, HDL particles are thought to transport cholesterol back to the liver for excretion or to other tissues that use cholesterol to synthesize hormones in a process known as reverse cholesterol transport (RCT). Having large numbers of large HDL particles correlates with better health outcomes. In contrast, having small numbers of large HDL particles is independently associated with atheromatous disease progression within the arteries.
Metabolism, recycling and excretion
Cholesterol is susceptible to oxidation and easily forms oxygenated derivatives known as oxysterols . Three different mechanisms can form these; autoxidation, secondary oxidation to lipid peroxidation, and cholesterol-metabolizing enzyme oxidation. A great interest in oxysterols arose when they were shown to exert inhibitory actions on cholesterol biosynthesis. This finding became known as the “oxysterol hypothesis”. Additional roles for oxysterols in human physiology include their: participation in bile acid biosynthesis, function as transport forms of cholesterol, and regulation of gene transcription.
In biochemical experiments radiolabelled forms of cholesterol, such as tritiated-cholesterol are used. These derivatives undergo degradation upon storage and it is essential to purify cholesterol prior to use. Cholesterol can be purified using small Sephadex LH-20 columns.
Cholesterol is oxidized by the liver into a variety of bile acids . These, in turn, are conjugated with glycine , taurine , glucuronic acid , or sulfate . A mixture of conjugated and nonconjugated bile acids, along with cholesterol itself, is excreted from the liver into the bile . Approximately 95% of the bile acids are reabsorbed from the intestines, and the remainder are lost in the feces. The excretion and reabsorption of bile acids forms the basis of the enterohepatic circulation , which is essential for the digestion and absorption of dietary fats. Under certain circumstances, when more concentrated, as in the gallbladder , cholesterol crystallises and is the major constituent of most gallstones . Although, lecithin and bilirubin gallstones also occur, but less frequently. Every day, up to 1 g of cholesterol enters the colon. This cholesterol originates from the diet, bile, and desquamated intestinal cells, and can be metabolized by the colonic bacteria. Cholesterol is converted mainly into coprostanol , a nonabsorbable sterol that is excreted in the feces. A cholesterol-reducing bacterium origin has been isolated from human feces.

nicotine

            Nicotine is an alkaloid compound found in tobacco plants as a natural insecticide and potential replacement for synthetic insecticides. Nicotine has biodegradable properties by natural factors so that does not leave a residue on the host plant. Isolation of nicotine can be done by maceration technique and followed by solvent extraction using chloroform. Isolation technique is quite simple and can produce isolates that contain nicotine in concentrations large enough and relatively unspoiled. The purpose of this study was to determine the time and the optimum volume for isolate maceration nicotine than 50 grams of dried tobacco leaves and to know pengruh rough isolates nicotine as natural insecticides against armyworms (Spodoptera litura).

NICOTINE

Tobacco production are abundant in Indonesia only useful as the tobacco industry are extremely negative impact on human health. Tobacco contains the alkaloid nicotine is bad for human health is also highly toxic to insects that nicotine can be used by humans As with the rice stem borer insecticide.

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.

MID SEMESTERS EXAM ANSWERS CHEMISTRY OF NATURAL PRODUCTS

NAME : DESI FEBRIANTI

NIM : RSA1C110011

1.    how to convert a compound of natural ingredients that do not have the potential (inactive) can be made into a superior compound that has the potential of high biological activity that is the way the sample determination, preparation and extraction, phytochemical screening test, test taksisitas, antioxidant test, column chromatography, and the determination molecular structure.
For example: the ant nest
The results of the study on the color reaction test showed that the extract contains phenols, polyphenols, tannins and flavonoids. TLC test showed positive extract contains tannins and flavonoids. Antibacterial test method used in this study by measuring the clear zone pitting caused by the ethanol extract of tubers anthill with a concentration of 10%, 20%, 30%, 40%, and 50%. Positive controls used were ciprofloxacin 50ppm and negative controls were: DMSO. The results showed that the average diameter of clear zone obtained from the concentration of 10% to 50% is 1.540 cm, 1.752 cm, 1.945 cm, 2.033 cm and 2.076 cm. Research data obtained was analyzed by using the non-parametric Anova test krusskal-wallis test and Mann-Whitney test. The results of this study concluded that ethanol extract of tuber anthill has antibacterial activity against Staphylococcus aureus ATCC 25923 growth and there is a power difference between the concentration of antibacterial extract given.

2.    In nature there are many chemical compounds that have benefits for humans, especially as drugs but sometimes the presence of these compounds is very limited so the chemist and pharmacy trying to make a clone of the compound in the laboratory in which we are familiar with the term synthesis. One example is the compound kalkon:
Kalkon is one of a group of flavonoids that are very limited distribution in nature and is found only in a few groups of plants in small amounts. On the other hand, this kalkon compounds have useful biological activities, such as antioxidant, anti-inflammatory and antibacterial properties, so it needs an effort to get kalkon compounds by synthesis. From several studies suggest that group-containing compound kalkon methylenedioxy (-O-CH2-O-) have activity as an antibacterial, so in this study will be the synthesis of compounds derived kalkon with piperonal and Acetophenone. Synthesis of 3,4-metilendioksikalkon through Claisen-Schmidt condensation reaction between piperonal and Acetophenone using NaOH catalyst with various Concentrations of NaOH catalyst is added at 40%, 50%, 60%, 70% and 80%. Results extracted using methylene chloride and then the solvent is evaporated using a rotary evaporator. The next stage characterization of physical properties of synthetic products and their structures analyzed using a spectrophotometer UV-Vis and FT-IR. After that tested the antibacterial activity against bacteria E. coli and S. aureus. Compounds synthesized solid form, is yellow and has a melting point of 80-85 ° C. UV-Vis Data converting the presence of two peaks, namely at λ 264 nm roomates is the absorption of benzoyl and λ 358 nm is the absorption sinamoil roomates. Data shows IR absorption spectra of the carbonyl group (C = O) at wavenumber 1658.7 cm-1, C = C aromatic absorption at wavenumber 1589.2 cm-1 and absorption at wavenumber 2923.9 cm-1 shows vibrational Csp3-H of methylene group (CH2 ). From these data it can be concluded that the compound 3,4-metilendioksikalkon been formed. Highest Yield of 72.58% was obtained at a concentration of 70% NaOH. From the results of the antibacterial test, the greatest inhibition zone Occurs at Concentrations of 3% roomates is 3 mm against E. coli and 2.5 mm against S. aureus.

3.    Determination of the principal rules of the solvent compounds is a natural material choice of solvent to be used in the extraction process. Principles underlying the selection of a solvent in the extraction process is a rule of "like dissolve like ', polar compounds roomates means should be analyzed together with polar solvents. Extraction is generally performed for the separation of the laboratories, such as the separation of organic compounds (organic phase) of the aqueous solution (water phase) by using a solvent is not miscible roomates (Harvey 2000).
In the selection of the solvent to be used, be aware of the nature of chemical Constituents (metabolites) to be extracted. Important property is polar and polar groups on the compound to be extracted as an OH group, COOH, as well as other functional groups. By knowing the nature of the metabolites be extracted, it can Easily be selected a suitable solvent by polar metabolites and solvents. Polar compounds dissolve in polar solvents and non-polar compounds dissolve in non-polar solvents. In general, the extraction is done in a row starting with non-polar solvents (hexane or benzene) and a semi-polar solvents (ethyl acetate or diethyl ether), and then with a polar solvent (methanol or ethanol). Would thus obtained crude extract containing consecutive non-polar compounds, semi-polar and polar compounds (Hostetmann et al. 1997). Extraction with non-polar solvents Usually required for the removal of fat before it is extracted with a suitable solvent. Thus, the extracts be obtained free of fat (Harborne 1996).
For example:
1) material flavonoid compounds from plants that are commonly used polar solvents such as ethanol and methanol. Flavonoids are compounds that will dissolve in the polar solvent methanol and ethanol Because it has the same polarity properties. In addition to soluble polar, several flavonoid compounds are also known to be separated by semi-polar solvent. Likely this is due to the nature of polar compounds roomates growing niche to dissolve in polar solvents with higher levels lower
2) alkaloids, caffeine such as coffee powder dissolved in diethyl ether is non-polar Because so as to dissolve the caffeine roomates is also non-polar, but is also due to the low boiling point of chloroform. Because if the high boiling point solvent means possible to approach the boiling point of caffeine can lead to caffeine obtained crystals evaporate so little. With a low boiling point solvent, allowing it to evaporate only kloroformnya.
3) terpenoids soluble organic compounds such as ethers and alcohols.
4) Steroids have semipolar properties can be extracted with chloroform. Moreover, it can also by fat solvents such as ether, benzene, carbontetrachlorida, xylene and alcohol.

4.    Examples of compounds of structural determination of caffeine, can be done with infrared spectroscopy. To produce the following data:


With infrared spectroscopy, the structure of caffeine contained in the sample can be determined, ie the typical absorption data from multiple functional groups, or with menbandingkan with standard IR spectrum of caffeine. From the results, it can spektorskopi diketahhui compound structure through cluster-Sugus functions contained therein.

Cholesterol

Cholesterol, from the Greek chole- (bile) and stereos (solid) followed by the chemical suffix -ol for an alcohol, is an organic chemical substance classified as a waxy steroid of fat. It is an essential structural component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity.
In addition to its importance within cells, cholesterol also serves as a precursor for the biosynthesis of steroid hormones, bile acids, and vitamin D. Cholesterol is the principal sterol synthesized by animals; in vertebrates it is formed predominantly in the liver. Small quantities are synthesized in other cellular organisms (eukaryotes) such as plants and fungi. It is almost completely absent among prokaryotes (i.e., bacteria).
Although cholesterol is important and necessary for human health, high levels of cholesterol in the blood have been linked to damage to arteries and cardiovascular disease.
François Poulletier de la Salle first identified cholesterol in solid form in gallstones, in 1769. However, it was only in 1815 that chemist Eugène Chevreul named the compound "cholesterine"

Physiology

Since cholesterol is essential for all animal life, each cell synthesizes it from simpler molecules, a complex 37-step process which starts with the intracellular protein enzyme HMG-CoA reductase. However, normal and especially high levels of fats (including cholesterol) within the blood circulation, depending on how it is transported within lipoproteins, are strongly associated with progression of atherosclerosis.
For a person of about 68 kg (150 pounds), typical total body-cholesterol synthesis is about 1 g (1,000 mg) per day, and total body content is about 35 g, primarily located within all the membranes of all the cells of the body. Typical daily dietary intake of additional cholesterol, in the United States, is 200–300 mg.
However, most ingested cholesterol is esterified and esterified cholesterol is poorly absorbed. The body also compensates for any absorption of additional cholesterol by reducing cholesterol synthesis.  For these reasons, cholesterol intake in food has little, if any, effect on total body cholesterol content or concentrations of cholesterol in the blood.
Cholesterol is recycled. The liver excretes it in a non-esterified form (via bile) into the digestive tract. Typically about 50% of the excreted cholesterol is reabsorbed by the small bowel back into the bloodstream.
Some plants make cholesterol in very small amounts.  Plants manufacture phytosterols (substances chemically similar to cholesterol produced within plants), which can compete with cholesterol for reabsorption in the intestinal tract, thus potentially reducing cholesterol reabsorption.  However, phytosterols are foreign to animal cells and, if absorbed, accelerate the progression of atherosclerosis. When intestinal lining cells absorb phytosterols, in place of cholesterol, they usually excrete the phytosterol molecules back into the GI tract, an important protective mechanism.

Biosynthesis

All animal cells manufacture cholesterol with relative production rates varying by cell type and organ function. About 20–25% of total daily cholesterol production occurs in the liver; other sites of higher synthesis rates include the intestines, adrenal glands, and reproductive organs. Synthesis within the body starts with one molecule of acetyl CoA and one molecule of acetoacetyl-CoA, which are hydrated to form 3-hydroxy-3-methylglutaryl CoA (HMG-CoA). This molecule is then reduced to mevalonate by the enzyme HMG-CoA reductase. This step is the regulated, rate-limiting and irreversible step in cholesterol synthesis and is the site of action for the statin drugs (HMG-CoA reductase competitive inhibitors).
Mevalonate is then converted to 3-isopentenyl pyrophosphate in three reactions that require ATP. Mevalonate is decarboxylated to isopentenyl pyrophosphate, which is a key metabolite for various biological reactions. Three molecules of isopentenyl pyrophosphate condense to form farnesyl pyrophosphate through the action of geranyl transferase. Two molecules of farnesyl pyrophosphate then condense to form squalene by the action of squalene synthase in the endoplasmic reticulum. Oxidosqualene cyclase then cyclizes squalene to form lanosterol. Finally, lanosterol is then converted to cholesterol.
Konrad Bloch and Feodor Lynen shared the Nobel Prize in Physiology or Medicine in 1964 for their discoveries concerning the mechanism and regulation of cholesterol and fatty acid metabolism.

biosynthesis of flavonoids

Abstract

Kalkon is one of a group of flavonoids that are very limited distribution in nature and is found only in a few groups of plants in small amounts. On the other hand, this kalkon compounds have useful biological activities, such as antioxidant, anti-inflammatory and antibacterial properties, so it needs an effort to get kalkon compounds by synthesis. From several studies suggest that group-containing compound kalkon methylenedioxy (-O-CH2-O-) have activity as an antibacterial, so in this study will be the synthesis of compounds derived kalkon with piperonal and acetophenone. Synthesis of 3,4-metilendioksikalkon through Claisen-Schmidt condensation reaction between piperonal and acetophenone using NaOH catalyst with various concentrations of NaOH catalyst is added at 40%, 50%, 60%, 70% and 80%. Results extracted using methylene chloride and then the solvent is evaporated using a rotary evaporator. The next stage characterization of physical properties of synthetic products and their structures analyzed using a spectrophotometer UV-Vis and FT-IR. After that tested antibacterial activity against bacteria E. coli and S. aureus. Compounds synthesized solid form, is yellow and has a melting point of 80-85 ° C. UV-Vis data converting the presence of two peaks, namely at λ 264 nm which is the absorption of benzoyl and λ 358 nm which is the absorption sinamoil. Data shows IR absorption spectra of the carbonyl group (C = O) at wavenumber 1658.7 cm-1, absorption C = C aromatic at wavenumber 1589.2 cm-1 and absorption at wavenumber 2923.9 cm-1 shows vibrational Csp3-H of methylene group (CH2). From these data it can be concluded that the compound 3,4-metilendioksikalkon been formed. Highest Yield of 72.58% was obtained at a concentration of 70% NaOH. From the results of the antibacterial test, the greatest inhibition zone occurs at concentrations of 3% which is 3 mm against E. coli and 2.5 mm against S. aureus.