secondary metabolites from plants

Question 1

how can plants be useful as secondary metabolites?

Answer 1

useful drug precursors,

although they are not necessarily pharmacologically active in their original naturally occurring forms.

Question 2

where was the anti tumor
drug paclitaxel originally sourced from?

Answer 2

Cropping of the bark of the slow-growing Pacific yew tree, Taxus brevifolia Nutt.,

Question 3

what was the issue with this?

Answer 3

is not a feasible method to provide sufficient amounts to meet the market demand

Question 4

what was the solution?

Answer 4

semi-synthetic route
10-deacetylbaccatin III can be isolated in relatively large amounts from the
needles of other related yew species, such as Taxus baccata L. (a renewable resource), and can be converted chemically in several steps into paclitaxel

Question 5

how is paclitaxel produced now?

Answer 5

through plant cell culture

Question 6

what is Oseltamivir phosphate (7, Tamiflu) used for?

Answer 6

is an orally active neuraminidase inhibitor developed for the treatment and prophylaxis of influenza viruses A and B

Question 7

what plant secondary metabolite is important for the synthesis of this drug?

Answer 7

starting material for the oseltamivir synthesis is (−)-shikimic acid, an important biochemical intermediate in plants and microorganisms

Question 8

where was it originally taken from?

Answer 8

extracted solely from the fruits of the shikimi tree (Illicium verum Hook.f.), also known as star anise

Question 9

what other method was produced to be more cost effective?

Answer 9

obtained from the fermentation of genetically engineered Escherichia coli strains, which are deficient in the shikimate kinase gene

Question 10

what is used now?

Answer 10

still relies on both extraction and fermentation methods to obtain ton
quantities of shikimic acid. not better alternative yet

Question 11

define a drug prototype

Answer 11

as “the first compound discovered in a
series of chemically related therapeutic agents”

Question 12

What is Guanidine used for?

Answer 12

a natural product with good hypoglycemic activity isolated
from Galega officinalis L., but is too toxic for clinical use

Question 13

so how is it useful?

Answer 13

Many derivatives of guanidine have been synthesized, and metformin (dimethylbiguanide)
was later found to be clinically suitable for treatment of type II diabetes

Question 14

name another drug prototype?

Answer 14

Atropine (15) is an artifact of the tropane alkaloid (−)-hyoscyamine, extracted from Atropa belladonna.

Question 15

what is the mechanism of atropine?

Answer 15

antagonist of muscarinic acetylcholinereceptors (antimuscarinic agent).

Question 16

how is it used?

Answer 16

in the ophthalmology
area as a mydriatic agent

therapeutic uses as an
antispasmodic.

a premedication for anesthesia, to decrease bronchial and salivary secretions, and to block the bradycardia (low heart rate)
associated with the administration of anesthetic drugs

Question 17

how is it a drug prototype?

Answer 17

studies of a large number of synthetic atropine analogs have led to
the introduction of new drugs with different therapeutic applications than the parent compound

Question 18

examples of drugs from atropine?

Answer 18

droperidol (antipsychotic),

ipratropium bromide (bronchodilator
for the treatment of asthma),

loperamide (antidiarrheal),

methadone (a morphine substitute for addicts)

pethidine (analgesic)

Question 19

other use of plant secondary metabolites?

Answer 19

as pharmacological probes

Question 20

what are Pharmacological probes?

Answer 20

help researchers to understand the mechanism of action of intracellular signal transductions and biological mechanisms related to human disease, which can aid the design of better drugs

Question 21

an example of a probe?

Answer 21

Genistein,

Question 22

where is it isolated from?

Answer 22

an isoflavone found naturally in soybean (Glycine max Merr.),

Question 23

what mechanism does it help us understand?

Answer 23

is an inhibitor of various protein tyrosine kinases (PTK), which are essential
enzymes involved in intracellular signal transduction
used to probe the interaction between PTK and cyclic nucleotide-gated (CNG)
channels

Question 24

why is this helpful?

Answer 24

important in mammalian olfactory and visual systems

Question 25

an example in cancer research?

Answer 25

Phorbol

Question 26

where is it isolated from?

Answer 26

is a tetracyclic diterpenoid plant secondary metabolite isolated as a hydrolysis product of croton oil from the seeds of Croton tiglium L.

Question 27

how is it helpful?

Answer 27

Various 12,13-diesters of phorbol have the capacity to act as tumor promoters, due in part to their role as protein kinase C (PKC) activators

Question 28

why is this helpful?

Answer 28

been used in biomedical research in standard laboratory models of carcinogenesis promotion