Medicinal Ingredients + Proteins

Solvent extraction

- separation process that involves a liquid and a solid
- solid object (such as a plant) is placed in contact with a liquid (solvent), and the plant components of interest are transferred into the solvent

Variants to improve solvent extraction

- Grinding or blending the leaves to break up the plant structure
- Adjusting solvent to match polarity of the extract (solvent blends for low polarity molecules)
- Adjusting temperature. If the desired extracts are thermally stable, prolonged heating will help extraction.

Thermally Stable

can withstand heating without decomposing or undergoing an unwanted chemical reaction.

Steam distillation

- boiler used to produce a flow of steam which is then passed through the leaves
- hot steam breaks down the plant cells and carries plant oils with it
- steam and the oils are then condensed
- non-polar oils separate from the water by forming a layer on top

When is steam distillation used?

- When the desired compounds are volatile and thermally stable.
- Commonly used to extract essential oils, such as tea-tree oil and eucalyptus oil. The extracted plant oils are mixtures, not pure substances.

Secondary structure of proteins

- From coiling and pleating of sections of protein molecule
- Forms hydrogen bonds between amide linkages
- Hydrogen bond between H of -NH group in one peptide link and O of C=O group in another peptide link
- called an a-helix or b-pleated sheet

a-helix

B-pleated sheet

zwitterion

- dipolar ion
- NH2 group acts as a base, accepting a proton to become a -NH3+ group
- COOH group act as an acid, donating a proton to become a -COO- group

Tertiary proteins

- produced by the three-dimensional folding of its secondary structures (a-helices and B-pleated sheets) between side chains

5 types of bonding in the Tertiary Protein Structure of the R groups

- Hydrogen Bonds
- Dipole Dipole Interactions
- Ionic Interactions
- Covalent Cross Links
- Dispersion Forces

Hydrogen Bonds Tertiary Proteins

- contains O-H, N-H or C=O

Dipole Dipole Interactions Tertiary Proteins

- any polar group such as those containing -S-H, -O-H or -N-H

Ionic interactions Tertiary Proteins

- contains -NH3+ and another group that contains -COO- (NH3+ bonds with COO-

Covalent cross-links Tertiary Proteins

- cysteine side groups react to form a disulfide bridge (-S-S-)

Dispersion forces

- any non-polar group

Quaternary Structure of Proteins

- composed of two or more polypeptide chains
- may even interact with non-protein molecules to produce a larger, more complex functional unit