Med Chem 1 Flashcards
Define Pharmacognosy
The study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drug substances of natural origin. As well as the search for new drugs from natural sources
Name different ‘pools’ natural drugs can be extracted from and give examples of drugs
- Plant kingdom (Morphine, Salicin, Quinine, Taxol, Reserpine)
- Microbial world (Penicillin and Statins)
- Marine world (curacin A; obtained from a marine cyanobacterium)
- Animals (Epibatidine; from the skin of Ecuadorian poison frog)
- Toxins/Venoms (Teprotide; a peptide isolated from venom of Brazilian pit viper)
The plant kingdom is a ‘plentiful, rich supply of complex and varied chemical compounds’. TRUE or FALSE
TRUE
Many plant species in the rainforest are ‘untapped sources still wanting to be discovered’. TRUE or FALSE
TRUE
Plants evolved for the purpose of producing medicines. TRUE or FALSE
FALSE. Plants did not evolve for the purpose of producing medicines.
All plant chemicals are good chemicals. TRUE or FALSE
FALSE. Many are irritant/toxic and provide defense against predators (herbivores and omnivores)
Herbal remedies involve experimentation with berries, leaves and roots. TRUE or FALSE
TRUE
Herbal remedies are often useless and dangerous. TRUE or FALSE
TRUE
Herbal remedies are an example of placebo effects -state of mind and no real differences. TRUE or FALSE
TRUE
State 5 facts about herbal remedies
1) 80% OF THE WORLD’S POPULATION use herbal drugs as part of their normal health care routine
2) In the USA, herbal remedies are the FASTEST GROWING SEGMENT of pharmacy trade
3) Tend to be LESS EXPENSIVE than prescription drugs
4) They’re NOT PURE substances (contain many constituents)
5) They’re NOT STANDARDISED OR ANALYSED for content of active principle
Define the term ‘Herb’
A crude material, containing multiple pharmacologically active compounds
What method can be used to verify the composition and quality of herbal remedies?
HPLC (High performance liquid chromatography)
Herbal remedies may contain some compounds that reinforce others. TRUE or FALSE
TRUE
Herbal remedies may work through SYNERGY. TRUE or FALSE
TRUE. The mixture acts together to generate beneficial effect
Why should pharmacists be aware of patients taking herbal preparations?
Any prescribed medication may be inhibited or show response consistent with an overdose
State an example of a drug and a herbal remedy that may cause an overdose ?
Drug = Coumadin (Warfarin)
Herbal remedy = Gingko biloba extracts (from chinese kew tree)
Gingko inhibits platelet-activating factor, PAF causing an overdose effect of coumadin. This leads to increased bleeding as a result of excessive blood thinning.
Gingko biloba extracts include ginkgolide A and B. TRUE or FALSE
TRUE
How does gingko affect the arterial and venous circulation ?
It produces VASODILATORY EFFECTS on the arterial and venous circulation (increasing peripheral and cerebral blood flow)
Why are natural products usually hard to synthesise in the lab ?
They usually have complex structures, for example ARTEMISININ (contains a Trioxane ring)
What is ARTEMISININ ?l
An antimalarial agent (Chinese herbal medicine)
Draw Morphine structure
C17H19NO3
Where is the natural drug Reserpine extracted from ?
Indian Snakeroot plant
Reserpine breaks down in the presence of light (especially in clear glass containers). TRUE or FALSE
TRUE
Describe the structure of Reserpine
- Light yellow crystalline alkaloid
- Indole nucleus
What is the role of Reserpine
Reduces blood pressure (anti-hypertensive)
‘Salicin’ is a glycoside. TRUE or FALSE
TRUE
When in the body, Salicin is converted to?
Salicyclic acid
What was Quinine initially used as ?
A muscle relaxant (stopping the shivering brought on by cold weather)
What is Quinine extracted from?
The bark of the Cinchona tree
What is Quinine now used to treat?
Malaria (arrests patient fevers)
Morphine is extracted from ?
Ancient Egyptian opium poppy (found in the opium juice)
Salicin is extracted from ?
Medieval England Willow tree
Quinine is extracted from ?
S.American (Quechua Indians of Peru) Cinchona bark
Name 2 examples of more recent Natural drugs
1) Combretastatin
2) Taxol (Paclitaxel)
What is Combretastatin extracted from ?
The South African ‘combretum caffrum’ tree
What is the role of Combretastatin ?
A potent cytotoxic against a variety of human cancer cells (still in clinical trials but may be the next anticancer choice of drug)
What is the main drawback of Combretastatin ?
Has poor water solubility
In vitro studies shows Taxol had ….. activity ? Fill in the gap
Cytotoxic
Name 4 types of Cancer Taxol can be used to treat ?
1) Ovarian cancer
2) Lung cancer
3) Prostate cancer
4) Metastatic breast cancer
Define Alkaloids
Amines found in plants (in the seeds, roots, bark and leaves)
Is Morphine an Alkaloid ?
Yes, It has a tertiary amine
Name 5 Semi-synthetic drugs
1) Aspirin
2) Taxol
3) Taxotere (docetaxel) - modified from Taxol
4) Galanthamine
5) Heroin
What is a semi-synthetic drug ?
A drug from natural sources that has been modified in the lab
What is the role of Aspirin ?
An analgesic
When was Aspirin marketed ?
After curing toothache (highlighting its Analgesic properties)
Taxol can be extracted from Pacific yew trees ? TRUE or FALSE ?
TRUE
Why do we need to use the Semi-synthetic approach when making Taxol ?
Because we’d need 4 Pacific Yew trees per patient! therefore we need to harvest a bio-synthetic intermediate
Name a bio-synthetic intermediate for making Taxol (Paclitaxel)
10-deacetylbaccatin III (easier to extract from the tree as it is found in the needles of the tree)
How many more steps are required to convert 10-Deacetylbaccatin III to Taxol
4
What is Taxotere (docetaxel) approved to treat ?
Advanced breast cancer
What is Galanthamine extracted from ?
European daffodils and snowdrops
Galanthamine is a tertiary alkaloid ?TRUE or FALSE
TRUE
What is Galanthamine used to treat and why?
Mild Alzheimer’s Disease (as significant improvements in performance and attention have been found)
(-)-galanthamine is prepared by ?
The stereospecific reduction of (-)-narwedine
Synthetic drugs include drugs originating from the screening of …. ?Fill in gap
Dyes
Name a scientist who made an important contribution to synthetic drugs/ the dye industry?
Paul Ehrlich
Describe Paul Ehrlich’s initial work…
Initial work involved the use of natural dyes/analogues in histological staining. (staining microbes and viewing them under microscope)
Paul Ehrlich ‘s thesis was critical of ?
Histologists that failed to base their work on the understanding of how dyes bind to tissue components
Paul Ehrlich suggested that …. and ….. …… are important for the UPTAKE and DISTRIBUTION of dye in cellular and animal models
Size and Chemical structure
Name 3 Synthetic drugs (originating from the screening of dyes)
1) Methylene blue (Ehrlich & Guttman)
2) Antibacterial azodyes (Chrysoidine and Pheazopyridine)
3) Heterocyclic sulfonamides (Sulfapyridine)
What is Methylene blue used to treat ? state strength and dose
Malaria, 5 x100mg capsules per day
Name the first synthetic drug (originated from dye screening) successfully used to treat against a specific disease
Methylene blue
What properties do Chrysoidine possess ?
Powerful antiseptic properties
What is Phenazopyridine used as ?
A Urinary antiseptic (relief for urinary tract pain)
Give an example of a potent antibacterial sulfonamide
Sulfapyridine
- Winston Churchill saved by this in 1943
- Reduced mortarlity in pneumonia patients from 1 in 4 to 1 in 25
Natural products vs Synthetic products. State 3 things that Natural products have more …
1) More protonated amine and free hydroxy functionalities
2) More single bonds
3) More fused rings containing more chiral centres
