Chemistry
of Natural Products
Name : Lina Purwanti
Student number : RSA1C110009
Study Program : Chemistry Education of ISSTE
3. Jelaskan kaidah-kaidah pokok dalam memilih
pelarut untuk isolasi dan purifikasi
suatu senyawa bahan alam. Berikan dengan contoh untuk 4 golongan senyawa bahan
alam : terpenoid, alkaloid, flavonoid dan steroid !
Answer : The solvent
selected for the extraction seen by the ability of interesting secondary
metabolites from plants. As the fluid used to perform the extraction of water,
ether, or a mixture of ethanol and water. Alcohol, however, is a versatile
solvent for extraction.
Methods of isolation steroid
Procedures for
isolation of steroids differ according to the chemical nature of the steroids
and the scale and purpose of the isolation. Steroids are isolated from natural
sources by extraction with organic solvents, in which they usually dissolve
more readily than in the aqueous fluids of tissues. The source material often
is treated initially with an alcoholic solvent, which dehydrates it, denatures
(renders insoluble) proteins associated with the steroids, and dissolves many
steroids. Saponification either of whole tissues or of substances extracted
from them by alcohol splits the molecules of sterol esters, triglycerides, and
other fatty esters and permits the extraction of the sterols by means of
water-immiscible solvents, such as hexane or ether, with considerable
purification. Intact sterol esters or hormonal steroids and their metabolites
(compounds produced by biological transformation) that are sensitive to strong
acids or alkalies, however, require essentially neutral conditions for
isolation, and, although some procedures for analysis of urinary steroids
employ acid treatment, milder hydrolysis, as by enzymes, is preferred. The
acidity of some steroids allows them to be held in alkaline solution, while
nonacidic impurities are extracted with organic solvents.
Commercially,
abundant steroids usually are purified by repeated crystallization from
solvents. Small-scale laboratory isolations for investigative or assay purposes
usually exploit differing polarities of the steroid and of its impurities,
which may be separated by partitioning between solvents differing in polarity
or by chromatography. Occasionally, special reagents may selectively
precipitate or otherwise sequester the desired steroid. A classical example is
the precipitation of 3β-hydroxy sterols such as cholesterol by the natural
steroid derivative digitonin. New steroids of great physiological interest
often are isolated from tissue only with extreme difficulty, because they are
usually trace constituents. In one example, 500 kg (1,100 pounds) of silkworm
pupae yielded 25 mg (0.0008 ounce) of pure molting hormone, the steroid
ecdysone (i.e., 20 × 106-fold purification). In such cases each isolation step
is followed by an assay for the relevant physiological activity to ensure that
the desired material is being purified. The percentage recovery of known
steroid hormones during their assay in small biological samples usually is
assessed by adding a trace of the same steroid in radioactive form to the
initial sample, followed by radioassay (analysis based on radioactivity) after
purification is complete. The efficiency of recovery of the radioactive steroid
is assumed to be the same as that of the natural substance.
extraction of Flavonoids
Flavonoid
metabolites (mainly glycosides) can be degraded by the activity of enzymes in
plant material has not been dried or fresh ingredients. Thus it is recommended
to use dried, lyophilized or frozen samples. The use of dried botanicals
commonly milled into powder first. In the solvent extraction process should
choose the appropriate type of flavonoid required so should consider the
polarity of the solvent. Types of non-polar flavonoids (eg, isoflavones,
flavanones, flavones and flavonols alcohol) was extracted using chloroform,
dichloromethane, diethyl ether, or ethyl acetate, while the flavonoid glycoside
and aglycone would be more appropriate extracted with alcohol or alcohol-water
mixture. To glycosides increased solubility if the water or alcohol-water
mixture. Generally most of the extraction process materials containing
flavonoids is done simply with the addition of direct solvent extraction.
Powdered plant material
can also be extracted using a Soxhlet, initially with hexan, to remove lipids
and then with ethyl acetate or ethanol to obtain phenolic compounds. This
method is unsuitable for the content of compounds that are not heat resistant.
The procedure is safe and commonly used sequential solvent extraction. The
first phase, with dichloromethane, to extract flavonoid aglycone and content of
non-polar. The next stage of the alcohol will extract and flavonoid glycoside
content of polar compounds.
Chalcone glycosides
specific flavanones and difficult to soluble in methanol, ethanol, or a mixture
of alcohol and water. Flavanones solubility depends on the pH of the water as a
solvent. Flavan-3-ol (like catechin, proanthocyanidin, and condensed tannins)
can generally be extracted directly with water. However, the content of the
compounds in the extract is not much different, either using water, methanol,
ethanol, acetone, or ethyl acetate. In this case, can not be claimed that
methanol is the best solvent for catechins and procyanidin acetone 70%, and so
on.
Anthocyanins can be
extracted with cold acidified methanol. The acid used is usually acetic acid
(approximately 7%) or trifluoroacetic acid (TFA) (about 3%).
Anthocyanin extraction (include in flavonoid)
Using solvent
extraction based on the solubility of the component to other components in the
mixture. stating that polar solvents will dissolve polar solutes and non-polar
solvents will dissolve the non-polar solute or so-called "like dissolve
like".
In the fruit or
vegetable, anthocyanin pigments are generally located in the cells near the
surface. Extraction of anthocyanin pigments from plant materials commonly used
solvent extractors HCl in ethanol. HCl in ethanol plants will denaturation of
the cell membrane and then dissolving the pigment anthocyanin out of the cell.
Anthocyanin pigments soluble in ethanol because both polar.
In research for the
extraction of anthocyanins from flowers girlfriend water, the best solvent used
is ethanol 95%. So is the research on the extraction of pigment from the skin
of the fruit rambutan. This is due to the level of anthocyanin polarity similar
to the 95% ethanol that can dissolve well in ethanol 95%. In addition to the
solvent, the factors that can affect the outcome of anthocyanin extraction is
the extraction time, pH and temperature extraction.
Methods Isolation of Compounds Alkaloids
(Nicotine)
Alkaloids are
usually isolated from the plant by using the method of extraction. 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
alkalinize alkaloid-containing plant material by adding sodium carbonate. Bases
are formed can then extraction by organic solvents such as chloroform or ether
For alkaloids that
are not heat resistant, insulation can be done using techniques alkalinize the
solution concentration by first. By using this technique the alkaloid will
evaporate and then be purified by steam distillation method.
Each compound in
the extract (extraction) based on the level of polarity (solubility)
Extraction is
usually performed in stages ranging from non-polar compounds >>
semi-polar polar >>
Polar compounds
will tersari with polar solvents (eg, ethanol, methanol, water) as did so.
examples of semi-polar solvent (ethyl acetate), an example of a non-polar
solvent (n-hexane)
Compounds tersari
with non-polar solvents >> Lipids, Steroids, Tannins
Compounds tersari
the semi-polar solvents >> Alkaloids, Flavonoids, Glycosides
Compounds with a
polar solvent tersari >> flavonoid Glycosides
Extractions are
often used to separate organic compounds are liquid extraction, the separation
of substances based on the comparison of the distribution of substances
dissolved in the two solvents are not mutually dissolve.
It's best in a
solvent in which the solubility is one greater than the concentration of
solutes in the other solvents, the price of K should be larger or smaller than
the short-term extraction process called pengorokan, whereas in the long-term
use and the heating soxhlot.
Solvent selection
criteria:
- Solvents dissolve
easily extracted material
- The solvent does
not mix with the juices extracted
- Solvent extract
little or no impurities that exist
- Solvent easily
separated from the solute
- The solvent does
not react with the solute through any means
4. jelaskan dasar titik tolak penentuan struktur
suatu senyawa organic. Bila senyawa bahan alam tersebut adalah kafein misalnya.
Kemukakan gagasan anda tentang hal-hal pokok apa saja yang diperlukan untuk
menentukan struktur secara keseluruhan !
Answer : I chose the
determination structure of tobacco (nicotine).
To know the strycture we should have
solvent like methanol, and the tools for identification the structure.
We can identification
structure based on some method like Using Column Chromatography, Using TLC, Infrared
Spectrophotometer (IR), UV spectrophotometer, GC-MS.
Example in Results Identification of Compounds in Tobacco Leaf
Extract Using TLC. in this method we can use developer solution of methanol.
At this stage the results of the chromatography column (more concentrated
solutions) that have been obtained and identified by thin layer chromatography
using the solvent methanol developers.
From the analysis
of thin-layer chromatography separation obtained only one peak each sample, it
means that it has produced a compound perfectly separated.
Results Infrared Spectrophotometer (IR) in the
Tobacco Leaf Extract Fraction Methanol. In this method we can use methanol as a
solvent. Infrared spectrophotometer was used to analyze the functional group of
chemical compounds found in tobacco leaves with the solvent methanol. results
of Infrared Spectrophotometer (IR) was also determined from the use of solvent
in column chromatography for example in one result of identification structure
using infrared spectrophotometer produce The existence of absorption at 3398.3
wavenumber indicates the-OH group. This is because the use of methanol as
column chromatography. So chromatography column was first performed will affect
the outcome of the determination of the method used for the next.
Test results with a
UV spectrophotometer Tobacco Leaf
Extract Fraction methanol. UV spectrophotometry is used for organic compounds
associated with electronic transitions in electron energy levels given. Usually
measured compounds having conjugated double bonds. Nicotine has a conjugated
double bond in the ring of piridin. Maximum absorption difference may be due to
differences in the solvent used. In this method we can use different solvent
and that will make difference absorption.
The results of GC-MS Fraction Methanol Extracts of
Tobacco Leaves. The end of for
identification is using GC-MS, from the first step until the end step have
relationship like using the same solvent, from one to another will affect
result for the next identification structure.
2. jelaskan bagaimana idenya suatu senyawa bahan
alam yang memiliki potensi biologis tinggi dan prospektif untuk kemaslahatan makhluk
hidup dapat disintesis di labortorium !
Answer : For this question I choose calkon (calkon
synthesis of pyridine compounds as potential drug candidates)
calkon natural
materials including compound flovonoid group, calkon compounds have a wide
range of interesting activities such biolgi antioxidant, antitumor,
anti-inflammatory, and others. calkon content at relatively low in extrack of
plant with limited structural variation, because calkon an intermediate product
in the process of formation of the biosynthesis of other flavonoid compounds.
this is one of the factors to conduct molecular synthesis calkon well to study
the physico-chemical properties and understand the relationship between
structure and activity, and as an effort to find new bioactive compounds of
potential used modern medicine. synthesis of compounds has been carried out in
the presence of pyridine calkon various combinations of functional groups and
pyridine core with several other heterocyclic core. calkon some synthesized
compounds turned out to exhibit strong antibacterial activity.
calkon compound
pyridine synthesis approach with combinatorial chemistry to produce a compound
with a structure that varies in a relatively short time and using a simple
method.
1-
synthesis of pyridine calkon compounds were
calculated using grinding or mixing by using a simpler tool.
2- synthesis of pyridine compounds calkon done by
eliminating or minimizing the use of organic solvents.
3-
synthesis of pyridine calkon compounds can
produce high redeman a relatively short time.
4-
some calkon pyridine compounds showed strong
antibacterial activity.
5-
calkon pyridine compounds potentially have other
activities such as antioxidant and anti-inflammatory.
From synthesis
calkon can obtain potential new drugs and useful for life in the community, in
addition to the method used is also simple, environmentally friendly, and the
compound structure of the new calkon.
1.
kemukakan gagasan anda bagaimana cara mengubah suatu senyawa bahan alam yang
tidak punya potensi (tidak aktif) dapat dibuat menjadi senyawa unggul yang
memiliki potensi aktifitas biologis tinggi. Berikan dengan contoh !
Answer : the way 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 is
activated by using pengaktifasi functional groups.
One example is an important
alkaloid found in mengkudu fruit is
xeronine. Xeronine also produced by the human body in a limited number of
functions to activate enzymes and regulate fungtion of proteins in the cell.
other than that to
activate it can also be reacted with an enzyme that is sensitive to a reaction
that takes place
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