Ch 4 Part 1: Bioactive Phytochemicals (Alkaloids)

2 categories of phytochemicals

primary metabolites

secondary metabolites

difference between primary and secondary metabolites

primary metabolites are usually modified/involved in a cycle to yield secondary metabolites

primary metabolites are not known for any adaptational significance to plants

secondary metabolites are formed by secondary metabolic pathways and act as defensive agents

Are active compounds usually primary or secondary metabolites?

secondary

How many kinds of secondary metabolites have been discovered so far?

over 200,000 (so far)

increasing with more research

How many alkaloids have been discovered so far?

over 20,000

(1/10 of all secondary metabolites)

alkaloids

basic nitrogen-containing secondary metabolites

can be crystalline or liquid

colorless, brown, or yellow

What percentage of medicinal plants contain alkaloids?

~15% of all medicinal plants

opium poppy binomial

Papaver somniferum

Where is the opium poppy native to?

SE Europe

W Asia

alkaloids in the opium poppy

>23 total

including morphine and codeine

crude opium

coagulated latex from young capsules of the opium poppy

What type of alkaloids are morphine and codeine?

depressant narcotics

analgesics

What plant does morphine come from?

opium poppy

effects of morphine

pain reliever

hypnotic

more potent than codeine

What plant does codeine come from?

opium poppy

effects of codeine

sedative (milder than morphine)

cough suppressant

What medicine was frequently used as a painkiller before morphine?

laudanum

opiates

morphine-like drugs

can be natural or synthetic

nux-vomica binomial

Strychnos nux-vomica

Where is nux-vomica native to?

tropical rainforests of S Asia

indigenous uses of nux-vomica

used to make curare poison for hunting

alkaloids derived from nux-vomica

strychnine

brucine

Where do the alkaloids in nux-vomica come from?

the seeds (which are not real nuts)

effects of strychnine

increases digestion and appetite (strychnine causes starving)

used to be used as a tonic in small doses (not anymore)

modern importance of strychnine

paralyzes prey → important in physiological and neuroanatomical research

blocks ACh, also has an antidote

Why is strychnine no longer used as a tonic?

narrow safety margin

effects of brucine

alcohol denaturant

very bitter taste

modern uses for brucine

mixed with ethanol to stop consumption (gasoline for cars)

devil doer/bush rope binomial

Strychnos toxifera

indigenous uses for devil doer/bush rope

used by natives to make curare poison

Where is bush rope/devil doer native to?

South America

alkaloid found in devil doer/bush rope

toxiferine

effects of toxiferine

prevents muscle contraction

modern uses for devil doer/bush rope

local paralyzer in surgery

now synthetic and controlled

coca plant binomial

Erythroxylum coca

Where is the coca plant native to?

South America

What part of the coca plant are alkaloids derived from?

leaves (folium)

14 alkaloids are derived

native name for coca

Qoka

“food for travelers and workers”

(an Imran word?)

indigenous consumption of coca

leaves were chewed for energy

What main alkaloid is derived from coca?

cocaine

effects of cocaine

local anesthetic and euphoric

induces physiological dependence

very addictive

uses for cocaine in Australia

local anesthetic for mouth and lung ulcers

What replaced cocaine in western medicine?

synthetic local anesthetics

e.g. lidocaine, benzocaine (mimic the structure of cocaine)

deadly nightshade binomial

Atropa belladonna

part of Solanaceae family

Where is deadly nightshade native to?

Europe and Asia

alkaloids found in deadly nightshade

tropane/belladonna alkaloids

e.g. atropine, hyoscamine

What part of deadly nightshade are its alkaloids derived from?

leaves and roots

effects of tropane alkaloids

sedative effects at low doses

can induce hallucinations, insomnia, death at high doses

uses of pure atropine in modern medicine

dilating eye drops in ophthalmology

treatment of bradycardia and hyperhidrosis

(tip: seeing a pretty lady (belladonna) makes your eyes dilate, your heart race (treatment of bradycardia), and make you start sweating)

two modern uses for hyoscyamine

treating GI disorders

reducing Parkinson’s symptoms

Indian snakeroot/Sarpagantha binomial

Rauwolfia serpentina

Where is Indian snakeroot native to?

India and adjacent countries

What alkaloid is found in Indian snakeroot?

reserpine

What part of Indian snakeroot is reserpine found in?

roots

effects of Indian snakeroot

antihypertensive (as a tea)

can induce uterine contractions (as a root decoction)

previous Indian uses for Indian snakeroot

treatment of snake bites

treatment of schizophrenia (aka moon disease)

induction of uterine contractions for childbirth

Chinese happy tree/cancer tree binomial

Camptotheca acuminata

alkaloid found in Chinese happy tree/cancer tree

camptothecine

What part of the Chinese happy tree is camptothecine found in?

bark and leaves

Who discovered camptothecine?

Dr. Wall and Wani in 1966

effects of camptothecine

treats cancers, malignant melanoma

curare plant binomial

Chondrodendron tomentosum (“cartilage tree”)

Where is curare plant native to?

South America

makes a variety of arrow poisons

alkaloid found in curare plant

tubocurarine

What part of curare plant is tubocurarine found in?

tree bark

effect of crude extract from curare plant

paralyzing effect

reverses strychnine poisoning

modern uses for tubocurarine

relaxes skeletal muscles in surgery, anesthesia