MID SEMESTERS EXAM ANSWERS CHEMISTRY OF NATURAL PRODUCTS


Name  : VEBRIA ARDINA
NIM    : RSA1C110020
1.      The way to obtain a preparation containing an active compound from a natural material with an appropriate solvent. Why should it be removed? In order to extract only contains the active compounds contained in the raw ingredients / natural that were penyari the fluid most optimal able to attract the active compound.
Method of extraction
. There are several methods of extraction of crude natural materials, such as maceration, infundasi, digestion, percolation and soxletasi.
Active a pure compound can be administered in the form of repetition, more accurate dose given. This, of course, can be achieved when we managed to get a pure compound plays a role in biokativitasnya and share experimental dilakuakn selnajutnya to find the dose, dose prepared in the right way and the right way to give. The term is no longer gambling here. Everything is scientifically proven.
The compound was isolated can be more developed in the process of finding the most effective compounds. By knowing the chemical structure of the compound will be a "lead compound" in formation so that it can be synthetically on a large scale. O modification of the structure of the compound will be able to withstand the compounds that can be more active.
Pure compounds which have been isolated can also be tested against a variety of bioactivity, not only based on the bioactivity associated with traditional uses. The possibility is always there, that the slogan for researchers.

2.      New drugs found from nature usually find obstacles in the industry because their numbers are very limited, especially when the drug is derived from marine invertebrates or microbes. For it is made ​​of natural materials synthesis memperlajari how to produce compounds of natural materials en masse and clearly this is not easy because of the diversity of natural products is very high and complicated (especially marine natural ingredients). Ingredients sourced from wild plants and animals is not only widely used in traditional medicine, but also increasingly valued as raw material in the manufacture of modern medicine and herbal preparations. Greater demand and increasing human population which leads to an increased level and often unsustainable exploitation of wild sourced ingredients.
Plants and animals have been used as a source of medicines from ancient times, and even in modern times, animal and plant-based systems continue to play an essential role in health care .  Additionally, a significant portion of the currently available non-synthetic and/or semi-synthetic pharmaceuticals in clinical use is comprised of drugs derived from higher plants, followed by microbial, animal and mineral products, in that order.
Over 50% of commercially available drugs are based on bioactive compounds extracted (or patterned) from non-human species, including some lifesaving medicines such as cytarabine, derived from a Caribbean sponge, which is reputed as the single most effective agent for inducing remission in acute myelocytic leukemia. Other examples of drugs from biological sources include: quinidine to treat cardiac arrhythmias, D-tubocurarine to help induce deep muscle relaxation without general anesthetics, vinblastine to fight Hodgkin's disease, vincristine for acute childhood leukemias, combadigitalis to treat heart failure, ranitidine to fight ulcers, levothyroxine for thyroid hormone replacement therapy, digoxin to treat heart disease, enalapril maleate to reduce high blood pressure, and even aspirin.
A great number of these natural products have come to us from the scientific study of remedies traditionally employed by various cultures, most of them being plant-derived.
There has been increasing attention paid to animals, both vertebrates and invertebrates, as sources for new medicines. Animals have been methodically tested by pharmaceutical companies as sources of drugs to the modern medical science, and the current percentage of animal sources for producing essential medicines is quite significant. Of the 252 essential chemicals that have been selected by the World Health Organization, 11.1% come from plants, and 8.7% from animals.
One excellent example of successful drug development from a component of snake venom (Bothrops jararaca [Wied 1824]) is that of the inhibitors of angiotensin-converting enzyme (ACE). This enzyme is responsible for converting an inactive precursor into the locally active hormone angiotensin, which causes blood vessels to constrict and hence raises blood pressure [62]. Other excellent example is the work initially conducted by Daly during the 1960s of the skin secretions of dendrobatid frogs from Ecuador, and of other "poison dart" frog species in Central and South America. This work has led to the identification of a number of alkaloid toxins that bind to multiple receptors in the membranes of nerve and muscle cells. One compound derived from these studies, which binds to nicotinic acid receptors associated with pain pathways, the synthetic ABT 594 (Abbott Laboratories), is in Phase II clinical trials, and has generated a great deal of interest, as it has been shown to be 30–100 times more potent as an analgesic than morphine [10]. The marine environment is a rich source of biologically active natural products of diverse structural types, many of which have not been found in terrestrial sources [63]. The sponge Luffariella variabilis (Poléjaeff, 1884) produces relatively large amounts of a chemical with anti-inflammatory activity known as monoalide. It was found that monoalide inhibits the action of an enzyme called phospholipase A2. The powerful immunosuppressive agent discodermolide originates from another sponge, Discoderma sp. [64].
Ingredients sourced from wild plants and animals are not only widely used in traditional medicines, but are also increasingly valued as raw materials in the preparation of modern medicines and herbal preparations. Greater demand and increased human populations are leading to increased and often unsustainable rates of exploitation of wild sourced ingredients.
3.      Criteria for selection of the solvent:
a.       The solvent dissolves the material easily extract
b.      The solvent does not mix with the juice extracted
c.       Solvent extract impurities that there are little or no
d.      Solute easily separated from the solvent
e.       The solvent does not react with the solute through any means

Type of solvent used
Related to the type of solvent polarity of the solvent. Things to be considered in the extraction process is a compound that has the same polarity will be easier interested / dissolved by the solvent that has the same polarity. Correlated to the polarity of the solvent, there are three classes of solvents, namely:
a.       polar solvents
It has a high level of polarity, suitable for extracting polar compounds from plants. Polar solvents tend to be used universally because normally if polar, can still cite compounds with lower levels of polarity. An example is the polar solvents: water, methanol, ethanol, acetic acid.
b.      semipolar solvent
Semipolar polarity solvent has a lower rate than the polar solvent. It is a good solvent for semipolar compounds from plants. Examples of these solvents are: acetone, ethyl acetate, chloroform
c.       nonpolar solvents
Non-polar solvents, almost completely polar. It is a good solvent to extract the compounds do not dissolve in polar solvents. The compound is better to extract different types of oils. Example: hexane, ether
The flavonoids possess a less polar, if extracted with a non-polar solvent, then it will not be possible to obtain the compound to be our extraction. To extract flavonoids we use polar or semi-polar solvents. As methanol.
Alkaloids, such as coffee powder caffeine dissolved in diethyl ether is because non-polar so as to dissolve the caffeine which 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 koroformnya.
Terpenoid polar nature so that it can be used semi-polar or polar solvents such as methanol and ethanol.
Steroids have properties that can be used polar solvents polar or semi-polar such as acetone, chloroform.
4.      Covering ultraviolet spectroscopic methods, infrared and nuclear magnetic resonance.
In essence, the explanation structure using spectroscopic methods of UV / Vis, IR, MS and NMR. However, in practice, is in the head NMR, integrated by MS. MS is sometimes become very important in the elucidation especially for long-chain compounds. IR is not so helpful in the elucidation of the structure, while the dereplikasi UV / Vis more useful.
NMR as the primary means of generating NMR spectra for H and C (typical), the data are called 1D NMR. While 2D NMR correlation gives date2 H / C with H / C in the form of HSQC, HMBC, COSY, TOCSY, ADEQUATE, etc.
NMR data obtained through the planar structure of a compound and from here is to determine the stereochemistry (if it contains a chiral atom) whose methods are divided into three: chemical reactions, physical (NMR and circular dichroism), and X-ray chrystallography .
Determination of the stereochemistry of the end of the elucidation of structure-activity.
Throughout the process structure elucidation, there are two important things were done. The first is a test of bioactivity that can be done at the beginning / middle (for screening) or at the end of pure compound (for the determination of the activity) and dereplikasi.
In summary, dereplikasi is a method to quickly identify known compounds. Since the objective laboratory natural materials is usually a new compound, the compound is not new, all the work, must be identified as soon as possible, in order not to lose time (with membuang2 resources of compounds which are no longer new).


0 komentar:

Poskan Komentar

Write here, about you and your blog.
 
Copyright 2009 Chemistry All rights reserved.
Free Blogger Templates by DeluxeTemplates.net
Wordpress Theme by EZwpthemes