MEDICINAL CHEMISTRY Flashcards
1
Q
medicinal plants
A
medicinal plants: plant extracts that have a biological impact on the body
2
Q
extraction and purification of active ingredients
A
- extract the molecules of interest from the plant
- separate the molecules from each other
- determine the structure of each component
3
Q
solvent extraction
A
- transfer all the molecules of interest from plant into a solvent
- extract- molecules of interest in a solvent
- solvent extraction is a separation process that involves a liquid and solid
- plant - solid is placed into contact with the solvent - liquid → allow extract to go into solvent
- plant is often ground or blended to break up plant structure
- solvent is selected to ensure that the polarity of the solvent matches the polarity of the molecules of interest
- water for extracting polar molecules
- temp may be adjusted to help w extraction
4
Q
steam distillation
A
- used when active ingredients are volatile and thermally stable
- doesn’t break down or easily degrade when heat is applied
- boiler is used to porduce a flow of steam - passes through the leaves
- the hot steam breaks down the plant cells and carries plant oils with it
- steam and oils are then condensed
- oils - non-polar form a layer on top and can be separated from water layer at the bottom
- plant oils produced this way are not pure substances and are a mixture of many components
5
Q
separating the molecules in plant extract and determining their structure
A
- using chromatographic techniques
- extracts obtained often contain many diff compounds
- chromatographic techniques such as HPLC can be used to separate these mixtures into individual components
- can be determined using mass spectroscopy, NMR, and infrared spectroscopy
6
Q
structure of protein
A
- function of protein depends on the 3d shape of the protein
- proteins are directional molecules
- order - sequence of amino acids guides how a protein bends and folds
- the amino acid side chain within the sequence bond with another to hold a length of a protein in a certain shape or conformation - determines its unique 3d shape
- shape of protein: primary, secondary, tertiary and quaternary structures
- using higher order structure phrase may be beneficial
7
Q
primary structure of proteins
A
- the linear sequence of amino acids that make up a protein
- tells us the number, type and sequence of the amino acid units in a protein
- entire shape pf protein is determined by the precise orderin which the amino acids are joined together
8
Q
secondary structure of proteins
A
- describes the coiling or pleating of sections of the chain
- hydrogen bonds can occur between the -NH group in one peptide link and the C=O group in another peptide link
- these hydrogen bonds can form at regular intervals creating coils (alpha helices) or parallel sections (beta pleated sheets)
- highly ordered segments and stabilised by hydrogen bonds
- most proteins contain multiple helices and sheet
9
Q
alpha helices
A
- hydrogen bonds make the long molecule coil around into a shape called an alpha helic
- hydrogen bonds link four amino acid units along the chain
10
Q
beta pleated sheets
A
- can form between peptide links when two or more parts of the chain line up parallel to each other
- the repeating structure of the backbone of the protein chain (N-C-C-N-C-C-N) ALLOWS HYDROGEN BONDS to form at regular intervals which stabilises the protein structure
- silk - protein with Beta pleated sheets
- every second R group is a H atom
- small side chains enable section of the protein molecule in silk to line up closely
- enable hydrogen bonds to form between these adjacent sections to produce beta pleated sheets
- form a regular pattern giving silk its strength and texture
11
Q
tertiary structure of proteins
A
- overall 3d shape of a protein
- produced by further folding of its secondary structures (α-helices or β-pleated sheets).
- overall 3d shape is influenced by side chains - R group of the amino acid units
- some side chains
- very large/small
- polar
- hydrophobic (non-polar)
- charged (dependent on pH)
12
Q
5 type of attractions in tertiary structures
A
- hydrogen bonds
- dipole-dipole interactions
- ionic interactions -> between NH3+ AND COO-
- covalent crosslinks -> disulfide bridges - cysteins R-groups
- dispersion forces
- note - although ionic bonds are very strong in ionic solids - in a protein structure they are disrupted before the covalent primary structure
- covalent bonds are stronger than ionic in proteins
13
Q
quaternary structure of proteins
A
- made up of more than one polypeptide chain
- some proteins may even interact with non-protein molecules to produce large, complex functional units
14
Q
denaturation of proteins
A
- protein is highly dependent on 3d structure - when denatured, proteins loses its function
- denaturation is a process in which proteins lose their quaternary, tertiary and secondary structures
- bonds that give the proteins specific 3d shape are disrupted or broken
- protein become unfolded
- can be reversible or non-reversible
- proteins can be denatured when it is subjected to any treatment that breaks its hydrogen bonds, ionic bonds or hydrophobic bondsby changing temperature, pH, or adding a reductant
- when a protein is denatures, the tertiary and quaternary structures are disrupted first, then the secondary structure
- in tertiary structures, dispersion forces are the weakest
- hydrogen bonds are stronger than normal dipole bonds and covalent bonds are stronger than ionic bonds
15
Q
enzymes
A
- biological catalysts that accelerate the rate of chemical reactions in cells
- only needed in small amounts
- not used up or changed
- provide an alternative pathway - lower activation energy
- increase rate of reaction
- doesn’t change equilibrium constant
- compared to inorganic catalysts - enzymes are more sensitive to changes in reaction conditions
- catalysts only work under a narrow temp range and are sensitive to changes in the pH
- enzymes are very specific for a single reaction or type of reaction