MATA KULIAH :
KIMIA BAHAN ALAM
SKS :
2
DOSEN :
Dr. Syamsurizal, M.Si
WAKTU :
22-29 Desember 2012
PETUNJUK : Ujian ini
open book. Tapi tidak diizinkan mencontek, bilamana ditemukan, maka anda
dinyatakan GAGAL. Jawaban anda diposting di bolg masing-masing.
1.Jelaskan
dalam jalur biosintesis triterpenoid, identifikasilah faktor-faktor penting
yang sangat menentukan dihasilkannya triterpenoid dalam kuantitas yang banyak.
2. Jelaskan dalam penentuan struktur flavonoid,
kekhasan signal dan intensitas serapan dengan menggunakan spektrum IR dan NMR.
Berikan dengan contoh sekurang-kurangnya dua struktur yang berbeda.
3. Dalam
isolasi alkaloid, pada tahap awal dibutuhkan kondisi asam atau basa. Jelaskan
dasar penggunaan reagen tersebut, dan berikan contohnya sekurang-kurangnya tiga
macam alkaloid.
4. Jelaskan
keterkaitan diantara biosintesis, metode isolasi dan penentuan struktur senyawa
bahan alam . Berikan contohnya.
ANSWER
1.
Squalen
Biosynthesis reaction (Making Triterpenoid)
Path begins at biosentesis triterpenoid acetyl coenzyme A
did kodensasi type
aldol produce a
branched carbon chains
which are found in
mevalinat acid and
subsequent reaction such as phosphorylation reactions, elimination of
phosphoric acid and decarboxylation
yield piroposfat isopentenyl
(IPP) which selanjutnyaa
berisomerisasi a dimethyl
allyl pyrophosphate (DMAPP) by enzyme isomerase.
IPP which are the units
of active isopern DMAPP join between
the head and tail of this is caused by the
attack of electrons of the double
bond carbon atoms of IPP to DMAPP a shortage of electrons
followed by the
removal of phosphate ions produced piro geranil.
after it is
formed aqualane triterpenoids
which experience structuring
as shown below:
a.
EC
2.5.1.21 squalene synthase: Reaction: 2 (2E,6E)-farnesyl diphosphate + NAD(P)H
+ H+ = squalene + 2 diphosphate + NAD(P)+ (overall reaction) (1a) 2
(2E,6E)-farnesyl diphosphate = diphosphate + presqualene diphosphate (1b)
presqualene diphosphate + NAD(P)H + H+ = squalene + diphosphate + NAD(P)+
This microsomal
enzyme catalyses the first committed step in the biosynthesis of sterols. The
enzyme from yeast requires either Mg2+ or Mn2+ for activity. In the absence of
NAD(P)H, presqualene diphosphate (PSPP) is accumulated. When NAD(P)H is
present, presqualene diphosphate does not dissociate from the enzyme during the
synthesis of squalene from farnesyl diphosphate (FPP) [8]. High concentrations
of FPP inhibit the production of squalene but not of PSPP
b.
EC
2.5.1.32 : geranylgeranyl diphosphate = 15-cis-phytoene + 2 diphosphate
(overall reaction)
(1a) 2 geranylgeranyl diphosphate =
diphosphate + prephytoene diphosphate
(1b) prephytoene diphosphate =
15-cis-phytoene + diphosphate
Requires Mn2+
for activity. The enzyme produces 15-cis-phytoene. cf. EC 2.5.1.99,
15-trans-phytoene synthase.
Enzymatic cyclization reactions
Enzymatic cyclization with
the Help of Enzymes.
Initiation cyclization by
oxygen Molekuler.Simbol E-O2 * is used to represent oxygen
"activated" by forming a complex with the enzyme.
biosynthesis Lanosterol
Sumber
http://dc314.4shared.com/doc/5KpoKJFS/preview.html
factors that influence the
scope of the results of triterpenoids
is a method of isolation of factor where many existing
methods of isolation. to produce
triterpenoids, which method of isolation is an important factor to generate the numbers or results of triterpenoids
same. one of the many
methods that produce triterpenoids
are Soxhlet extraction
method, which is a method of
immersion and heating causes
pressure differences lead to breakage
of the wall and the cell membrane
of heating causing
evaporation and condensation occurs after passing the
air conditioner so that the steam
is attached to the pipe wall and serkulasi occurred,
repeated movement that causes the result of
extract much triterpenoid.
2. Determination of flavonol Substituents at the core is done by measuring the
spectrum at a wavelength of 200-600 nm. Flavonoids shows typical spectra in the
region, consists of two peaks, which is in the range of 240-285 nm (bands II) and
300-550 nm (tape I).
IR spectrum of quercetrin demonstrate functional groups OH (3294 cm-1), CC aliphatic
(2931 cm-1), C = O (1728 cm-1), C = C aromatic (1504 and 1604 cm-1) and COC ether
(1064 cm-1). 13C NMR spectra showed 14 carbon aromatic, one carbonyl, and six aliphatic
carbon. Then the identification of the 1 H NMR spectra showed the presence of
five aromatic protons, hydroxyl proton, five aliphatic protons and 3 methyl protons.
Based on these data showed a compound of flavonoids (quercetin), which binds to
a sugar group is rhamnosil. Based on data from HMBC, rhamnosil bound to C-3 of quercetin.
These compounds are known as quercetrin (quercetin-3-O-rhamnosida).
Isoflavon |
Antosianin |
3. In the acid extraction, the
plant material is processed by
the solution of a weak acid
(eg acetic acid
in water, ethanol, methanol, or). Bases is then
added to convert alkaloids to
basic forms are extracted with an organic solvent (if
the extraction is done by alcohol, will be removed
first, and the remainder is
dissolved in water).
Solvents are used when
extracting the compound mixture is acidified
water molecules. This solvent will be able to dissolve the alkaloid salts.
It also can basify alkaloid-containing
plant material by adding sodium carbonate. Bases
are formed can
then extract with organic solvents such as
chloroform or ether
As
for the solution
of the alkaloid in the acidic water then
the solution must basified beforehand. Further
alkaloids can be extracted
using organic solvents. Another way to get the alkaloids from the alkaline solution
is the method using
a reagent penjerapan Lloyd. Alkaloid that
is obtained is then eluted and precipitated using
reagents Meyer. After
that, the precipitate formed is
separated by ion exchange chromatography method.
Grinding done to break
down the cell walls of secondary metabolites botanicals
that, in this case aalah alkaloids, can
come out. Chloroform is used to pull the alkaloid
bases. Dragendorff reagent and Mayer's
reagent is a
common reagent used for the identification of alkaloids. Acid HCl
(1:10) in water is
used to turn into salt alkaloid base is drawn
back into alkaloid
HCl chloroform. Due
to attract alkaloid bases used chloroform
is semipolar, it
can be concluded that the alkaloid
compounds is semipolar.
Example:
a) Purification Nicotine compounds, to alkaloids that are not heat resistant, insulation can be done using the technique of concentration by basify the solution first. By using this technique the alkaloid will evaporate and then be purified by steam distillation method.
b) Purification of morphine, an alkaloid morphine binds organicmisal acid binds with acetic acid to form acetic acid. Because it's time to identify, ammonia is used to free the alkaloid from organic acids and alkaloids make alkaline soluble in chloroform.
c) sample extract caffeine drip in holes 1 plate was tested by adding 1-2 drops of reagent meyer and allowed to settle. After that, the observed precipitation and its color. Sample extract caffeine in the 2 hole plate drops tested by adding 1-2 drops of reagent dragendroff and allowed to settle. After that, the observed precipitation and its color.
a) Purification Nicotine compounds, to alkaloids that are not heat resistant, insulation can be done using the technique of concentration by basify the solution first. By using this technique the alkaloid will evaporate and then be purified by steam distillation method.
b) Purification of morphine, an alkaloid morphine binds organicmisal acid binds with acetic acid to form acetic acid. Because it's time to identify, ammonia is used to free the alkaloid from organic acids and alkaloids make alkaline soluble in chloroform.
c) sample extract caffeine drip in holes 1 plate was tested by adding 1-2 drops of reagent meyer and allowed to settle. After that, the observed precipitation and its color. Sample extract caffeine in the 2 hole plate drops tested by adding 1-2 drops of reagent dragendroff and allowed to settle. After that, the observed precipitation and its color.
4. Relationship between the biosynthesis, isolation
and structural determination of compounds of natural ingredients are: Isolation role in
the process by which we can get the pure compound (natural materials) of
plants. then identified the elements of the pure
compounds obtained by spectroscopic methods, followed by testing the biological activity of either crude extract
or pure compound. Once known molecular structure
is usually followed by a modification of the structure through the process of biosynthesis to obtain compounds
with the desired activity and
stability.