pharmacognsy

Question 1

what is pharmacognosy

Answer 1

the study of medicinal drugs derived from plants or other natural sources. it includes analysis of their biological , chemical , biochemical and physical properties

Question 2

example of medicinal plants

Answer 2

atropine , ephedrine , taxol , salicylic acid and caffeine

Question 3

botany

Answer 3

the identification , genetics and cultivation of plants

Question 4

chemical characterisation

Answer 4

includes the isolation , identification and quantification of constituents in plant materials

Question 5

pharmacology

Answer 5

the study of the biological effects that the chemicals in medicinal plants have on cell cultures , animals and humans

Question 6

crude drugs

Answer 6

it is used for those natural products such as plants or part of plants , extracts and exudates which are not pure compounds

Question 7

Phytochemicals

Answer 7

plants produce chemical compounds as part of their normal metabolic activities .
these phytochemicals are divided into
1) primary metabolites - examples include sugar and fats , these are found in all plants
2) secondary metabolites - compounds which are found In a smaller range of plants , serving a more specific function. examples of these are detergents used to get rid of predation . these secondary metabolites can have therapeutic actions in humans and can be refined to produce drugs. examples include quinine from the cinchona for malaria and morphine and codeine from the poppy

Question 8

plants synthesise a bewildering variety of phytochemicals but more are derivatives of a few biochemical groups :

Answer 8

alkaloids
polyphenols
glycosides
terpenes

Question 9

Alkaloids

Answer 9

contain a nitrogen ring
produced by a large variety of organisms including bacteria , fungi , plants and animals .
many alkaloids are toxic to other organisms
they often have pharmacological effects and are used in medications , recreational drugs and entheogenic rituals
they often invoke a bitter taste

Question 10

drugs alkaloids produce

Answer 10

local anaesthetic and stimulant cocaine
psychedelic psilocin
stimulant caffeine
analgesic morphine
anticancer compound vincristine
vasodilator vincamine
anti-arrythmia compound quinidine
antimalarial drug quinine

Question 11

polyphenols

Answer 11

the compounds that contain phenol rings

Question 12

examples of polyphenols

Answer 12

anthocyanins that give grapes their purple colour
the isoflavones
the phytoestrogens from soy
tannins that give tea its astringency

Question 13

glycosides

Answer 13

are molecules in which a sugar is bound to a non-carbohydrate moiety , usually a small organic molecule
many plants store chemicals in the form of inactive glycosides
these can be activated by enzyme hydrolysis , which causes the sugar part to be broken off , making the chemical available for use .

Question 14

example of a glycoside

Answer 14

Digoxin . it is a purified cardiac glycoside that is extracted from the foxglove plant , digitalis lanata .
digoxin is widely used in the treatment of various heart conditions , namely atrial fibrillation , atrial flutter and sometimes heart failure

Question 15

terpenes

Answer 15

large and diverse class of organic compounds , produced by a variety of plants particularly conifers which are often strong smelling and have a protective function.
they are major components in resin and of turpentine produced from resin.
terpenes are major biosynthetic building blocks within nearly ever living creature.

Question 16

examples of terpenes

Answer 16

steroids derived from triterpene squalene
essential oils - natural flavour additives for food
vitamin A
fragrance of rose and lavender is due to monoterpenes
carotenoids produce reds , yellow and oranges of pumpkins , corn and tomatoes

Question 17

the microbial world

Answer 17

microorganisms such as bacteria and fungi are rich for leaf compounds eg antimicrobial drugs : penicillins , cephalosporins , tetracyclines, ahminoglycosides , chloramphenicol , rifamycins

Question 18

the marine world

Answer 18

coral ,sponges , fish and marine microorganisms have biological potent chemicals , with interesting anti-inflammatory , antiviral and anticancer activity e.g. curacin A (anti-tumour )

Question 19

animal sources

Answer 19

antibiotic peptides were extracted from the skin of African clawed frog .

Question 20

the microbial world - anticancer - antibiotics - anthracyclines

Answer 20

daunorubicin was isolated from streptomycin coeruleorubidus and s.peucetius . this significant discovery was made independently in France and Italy in 1963. the most important member of the anthracycline , doxorubicin was isolated from s.peucetius var.caesius in 1969 in Italy

Question 21

Doxorubicin hydrochloride- mechanism of action

Answer 21

anthracyclines inhibit DNA and RNA synthesis by intercalating between base pairs of the DNA/RNA strand , thus preventing the replication of rapidly-growing cancer cells. they also create iron-mediated free oxygen radicals that damage the DNA and cell membranes which also cause toxic side-effects

Question 22

the marine world - the cone snail

Answer 22

cone snail has a toxin packed venom that shocks and paralyses prey. one of these poisons is a painkiller 1,000 times more powerful than morphine . the snail derived drug jams nerve transmission in the spinal cord and blocks certain pain signals from reaching the brain.