MID SEMESTER EXAM

Name          : yulia

Nim            : RSA1C110015

1.     

      1. Put forward your ideas how to convert a compound of natural ingredients that do not have the potential (inactive) can be made into superior compounds that have a high potential for biological activity. Give the example.

Answer:             For example in the biosynthesis of terpenoids, acetic acid is activated by coenzyme A did Claisen type condensation produces asetoasetat.Senyawa acid produced by acetyl coenzyme A did aldol type condensation produces branched carbon chains as found in mevalinat acid, subsequent reactions are fosforialsi, elimination of phosphoric acid and decarboxylation produces isopentenyl (IPP), which later became dimethyl allyl berisomerisasi piropospat (DMAPP) by the enzyme isomerisation. IPP is an active isopropene Uniti. Where to active isoprene formation from acetic acid via mevalonic acid. IPP as active isoprene unti joined head to tail with DMAPP and this merger is the first step of the polymerization of isoprene to produce terpenoids.

Another example when the flavonol quercetin reacts with free radicals, quercetin proton donating compound and a radical, but the unpaired electrons generated by resonance delocalizated, it makes the compound quercetin radical has a very low energy to a reactive radical.
 

    2. Explain how the idea of ​​a compound of natural ingredients that have a high biological potency and     prospective for the benefit of sentient beings can be synthesized laboratory.

Answer:        In this study, bioassay (biological activity test) was performed on the plants that contain high levels of Triterpenoid lot (+ + +) and very much (+ + + +). The reason for the selection of the plant that contains Triterpenoid many and for bioassay is that once the plant is extracted, it is expected that most of the content of the crude extract was Triterpenoid, so when bioassy expected compounds having biological activity is the Triterpenoid compounds. However, allegations must still be proven by way of isolating Triterpenoid contained in the plant extracts are then performed bioassays on pure Triterpenoid generated. Parts of plants that contain many and Triterpenoid compounds are extracted with a solvent extraction using methanol sokhlet. The choice sochlet extraction tool because the tool has several advantages can extract samples in large quantities (gram scale), the search can be done repeatedly so that all extracts can be drawn, and the solvents used can be reused because it does not evaporate.

In this study to determine the biological activity of plant extracts containing Brine Shrimp Triterpenoid test was used. This method was chosen because it can be used to investigate the cytotoxic effects as well as to animal testing easier, it's cheap, the eggs can withstand several years when stored in dry, do it simpler and faster. Besides, this method has been tested and has a positive correlation with the methods that have been used for screening of anti-cancer compounds. If the plant extracts tested have LC50 <1000 ppm, the extract is stated to have biological activity that contains compounds that are cytotoxic [2]. Bioassay results of this study showed that of the 8 samples containing many and Triterpenoid prices have analyzed all LC 50 <1000. Means the concentration it contains 50% of individuals Artemia salina Leach (Brine shrimp) were dead. This translates into 8 parts of the plant extracts have biological activity against Arthemia salina Leach or contain compounds that are cytotoxic. However, to determine whether the compounds that have activity is Triterpenoid, further research needs to be done, by isolating Triterpenoid contained in the extract. After the resulting pure Triterpenoid then tested again with Brine shrimp test. There should also be extracted using a solvent other than methanol as chloroform or carbon tetra chloride to determine the possibility of a Triterpenoid compounds that are soluble in nonpolar solvents or less polar. With the discovery of a biological activity on the part of the plant that contain many compounds Triterpenoid the use of the plant as a traditional medicine needs to be encouraged.

·           Isolation of triterpenoid

A total of ± 1000 g dried leaf powder billowing extracted with maceration technique using n-hexane solvent. n-heksana extracts obtained were separated from the solvent by using a rotary vacuum evaporator in order to get thick n-hexane extract. Thick n-hexane extracts derived activated carbon is added to the ratio of 1:1 and dissolved in n-hexane solvent, then heated with a hot plate and filtered. The extract obtained was concentrated using a rotary vacuum evaporator. Extracts were tested phytochemical thick with Liebermmann-Burchard reagent to determine the presence or absence of triterpenoids. Extract positive viscous triterpenoid separated by column chromatography. Prior to separation by column chromatography, eluent first election by TLC technique. The results of the separation column chromatography (silica gel 60, n-hexane: chloroform (1: 3)) of the same group were combined and divided into fractions. Each group was tested triterpenoid fraction. Positive fractions containing triterpenoid with a single stain followed by TLC purity test with some mixed eluent. If that produces a fraction of the stain can be considered as relatively pure isolates TLC. Relatively pure isolates were then analyzed by Ultra violet-visible spectrophotometer and IR, and tested antiradical activities freely.

3    3. Explain the basic rules in choosing a solvent for the isolation and purification of a compound of natural   ingredients. Give the example for 4 classes of compounds of natural products: terpenoids, alkaloids, flavonoids, and steroids.

Answer: The choice of solvent is generally influenced by the following factors:

1.          Selectivity

Solvents may only dissolve extract desired, not the other components of the material extraction.

2. Solubility

The solvent dissolves the components as possible have a large extract (needs less solvent).

3. Reactivity

In general, the solvent should not cause chemical changes in the components of materials extraction.

            4.          Boiling point

 Because solvent extracts and usually must be separated by evaporation, distillation or rectification, the boiling point of the two materials must not be too close. In terms of economics, it is advantageous if the extraction process is not very high boiling point.

            5.          Other criteria

Solvents where possible it should be cheap, available in large quantities, non-toxic, nonflammable, not explosive, not mixed with air, non-corrosive, does not form the emulsion, has a low viscosity and chemical and thermal stable.

• Isolation class of terpenoids

In the isolation of terpenoid compounds using solvents n-heksane, methanol, and chloroform as the compound is most soluble in the solvent is good and the principal is not containing water molecules. And chloroform also volatile and flammable.

• Isolation of flavonoid

Flavonoids are polar compound because it has a hydroxyl group that is not substituted. Polar solvents such as ethanol, methanol, ethylacetate, or a mixture of the solvent can be used to extract flavonoids from plant tissue. Eluent Analysis best done using TLC. GF254 TLC plates were used as the stationary phase. Eluennya is a wide range of different solvent polarity, ie CHCl3, methanol, ethylacetate, and ether.

For example, the isolation of flavonoids on yellow leaves, extraction is done using sokletasi. Sochletation first using n-hexane solvent and second sokletasi using methanol. And at this stage of extraction by column chromatography using a mixture of n-hexane eluent with ethyl acetate, ethyl acetate: methanol, followed by methanol. Fractions collected from the column with a vial / test tube and monitored by thin layer chromatography (TLC) with the eluent mixture of ethyl acetate and methanol with a ratio of 9: 1.

In isolation this is a widely used solvent methanol as a preliminary test to test and TLC sianidin apparition using UV254 nm light stain on the methanol fraction showed a positive test result. Positive methanol fraction containing flavonoids with sianidin test and also have cytotoxic activity against Arthemia salina indicated by LC 50 <1000 microg / ml, then the fraction of methanol has the potential to be further explored to obtain the pure compound, while n-heksane showed negative test results .
In the isolation of anthocyanin compounds using methanol because methanol is a polar compound that can be easily soluble anthocyanin pigments, in addition to the relatively low boiling point of 65 ° C, making it easier to extract concentration.

• Isolation class of alkaloids

In the isolation of alkaloids using ethanol, methanol and chloroform. Because when these solvents are equally polar and volatile that will facilitate the ongoing isolation.

• Isolation of steroid compounds

In the isolation of steroid use maceration method. The first maceration method using n-hexane solvent while the second maceration process using methanol solvent. And the purification using chloroform and methanol. This is because the solvent can separate polar and nonpolar solvents so that can further simplify the process of separation.

4. Explain the basic starting point for the determination of the structure of an organic compound. When the compounds of natural ingredients such as caffeine tersebuat is. Put forward your ideas subject matter whatever is needed to determine the overall structure.

Answer: The basic starting point for determining the structure of the compound is an organic compound that isolates.

selectivity

From the chromatogram show in fig. 5B it is evident that under the proposed chromatographic conditions amphetamine, methamphetamine, and caffeine are completely separated from each other, roomates indicates the method is selectiveand can be used for their simultaneous idemtification and quantification.
 

Figure of chromatograms obtained from methanol (A) and standards (100 mg mL-1) of amphetamine, methamphetamine, and caffeine (B). (A, amphetamine; M, methamphetamine; C, caffeine.

other example Identification of flavonoids

The results of this preliminary investigation on compound leads flavonol glycosides substituted with OH-3 and OH-4 have ', or flavonoids with OH-5, or flavanones with OH-5 or kalkon without OH on ring B. It is based on the dark purple spots under UV light, and the color changed to yellow after reacted with ammonia vapor. In methanol solution of this compound gives two maximum absorption bands are bands I and II 258.0 358.0 indicating that the compound was flavones or flavanones. The existence of the shoulder on the maximum absorption bands II showed the presence of 2 or more O atoms in the ring B. With the addition of sodium hydroxide maximum absorption bands I to 413.0, a shift batokromik 55 nm and without a decrease in intensity, suggesting the existence of OH-4 'free. The formation of new bands with maximum absorption 333 indicate the presence of OH-7 free. So the compound leading to flavonol not chalcon.

Figure 4. UV spectrum of flavonoids SA-DE-1

In determining the required structures are:

1. Mixed melting point test, the use of derivatives solids, comparison of physical properties and reaction chalitatif.

2. The maximum wavelength

If the spectrum of a given compound shows an absorption band with a very  = 10 100) 270 350 nm region and no other absorptionelow intensity ( bands above 200 nm, it can be expected that the compound contains a chromophore that has no simple conjugated electron- n electrons.  * transitions.pWeak ribbon occurs by n

If the spectrum shows several absorption bands, of which there are in the visible region, the compound is expected to contain long chains of conjugated or aromatic chromophore polisiklis. If a compound is colored, it is likely to have at least four to five and a conjugated chromophore groups auksokhrom (Pengecualaian: some anitrogen-containing compounds, such as nitro, azo, nitroso compounds,  diketon, glioksal and iodoform).

3.   maximum.e

There is a mutual relationship between intersitas main absorption bands, the biggest bands of wavelengths and the length or area (the conjugation) of the chromophore.

.a priced between 10,000 and 20,000 generally represent a simple unsaturated ketone e  diene.b Ribbons priced between 1,000 and 10,000 e, usually indicates the aromatic system. Substitution on the aromatic core by extending chromophore functional groups,  absorption band with greater than 10,000.eproviding   * transitions.p n eThe absorption bands of less than 100 suggests

4. Calculation of maximum absorption of unsaturated compounds
Diene and triena, if the compound is believed conjugated diene or dienes substituted, the wavelength of maximum absorption can be estimated with the help of the table. To be able to use these tables, first must be known in advance types of different diene, conjugation, double bonds and others.