deterrents from fungi and plants Flashcards Preview

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Flashcards in deterrents from fungi and plants Deck (18)
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1
Q

fungal antibiotics

A

penicillin

2
Q

insecticides

A
tobacco 
pyrthrum
neem
rotenone
mint oils
3
Q

penicillin

A
  • fungal mold
  • history in treatment of infected wounds
  • ebers papyrus -used for wounds and skin problems 4700years ago
  • staphylococcus aureus
  • alexander fleming discovered it accidentally
  • pill or needle
4
Q

cloxacillin

A

resistant to the b-lactamase enzyme produce by some penicillin resistance bacteria

5
Q

ampicillin

A

has a greater range of activity and was the first penicillin derivative to be effective against gram negative bacteria

6
Q

ticarcillin

A

developed to treat difficult gram-negative bacterial infections

7
Q

after the discovery of penicillin

A
  • new antibiotics were obtained from various species of soil bacteria
  • streptogramin antibacterials such as streptomycin from genus streptomyces
  • vancomycin from actinomycetales
8
Q

in situ

A

culturing of soil bacteria has led to the discovery of a number of potential anti-bacterial drugs - teixobactin

  • highly toxic to gram positive
  • harmless to mammalian tissue
  • a potentially important source of new drugs is the higher plants ,but few have been investigated in detail
9
Q

tobacco

A

-solanaceous annual herb (tomato or solanaceae fam)
-stimulant drug
-tobacco wash (leavens soaked in water) sprayed onto fruit trees
-mixing powered tobacco leaves with stored cereal grains to protect them from pest attack
-alkaloid nicotine
-seen as highly poisonous
-black leaf 40-40% concentration of nicotine sulfate-marketed as relatively safe
-harmful to human so the production decreased and a synthetic alternative used instead (neonicotine sulfate)
malathion and dichlorodiphenyltrichloroethan (DDT)

10
Q

nicotine

A
  • absorbed through direct contact or by ingestion
  • acetylcholine receptor agonist (mimic) that results in acetylcholine accumulation
  • leading to paralysis and death
11
Q

neonicotinoids

A

safer, semi-synthetic nicotine

  • first major insecticide to be introduced since 1950’s
  • in 2003-clothianidin and thiamethoxam-used on corn and soybean crops in the USA
  • imidacloprid-worlds must widely used insecticide- less toxic to mammals than insects
12
Q

Pyrethrum

A
  • herbaceous composite
  • native in asia
  • widely cultivated in africa and South America
  • german women noticed dead insects near her tanacetum flowers
  • concentrated in the flowering heads and hand harvested
  • most popular natural insecticide in the early 20Th century
  • these contact insecticides are neurosensor blockers-axonic poisons; they keep the sodium channels open wich results in repeated firing of the nerve cells and eventual insect paralysis
  • biodegradable -low toxicity to birds and mammals
  • high doses can be dangerous to humans
  • toxic to fish
13
Q

semi synthetic pyrethrin

A

allethring and permethring and transfluthrin

  • ten times more effective than natural pyrethrin
  • control animal ectopasasites: flea collars for pets, insecticidal dips for domestic animals and mosquito coils
14
Q

neem

A
  • fast growing tree native to indian subcontinent
  • 25-30 m
  • frost intolerant, prefers hot, arid environments and sandy soils
  • very tolerant species, but grows best in humid tropical regions
  • according to hindu mythology-the neem tree is of divine origin
  • recovered from archeological excavations dating 4000 years ago
  • many parts of the plant used in traditional ayurvedic med
  • neem oil and leaves used to deter insencts in granaries
  • also used in cosmetics
  • proven less successful than hoped (refined material is expensive to make and neem based are slow actin)
15
Q

biopiracy of neem

A

american patent law does not recognize oral tradition, meaning that companies in india would be completely excluded from the american market (kadidal 1998)
-would lipohilic solvent extraction be considered and innovation

16
Q

the active principles of neem

A

tetracyclotriterpenoids known as limonoids, particularly the compound azadirachtin

  • inhibits normal insect growth and development, blocks normal feeding behaviour, and inhibits reproduction
  • not harmful to mammals
17
Q

rotenon

A
  • tropical leguminous vine
  • used as fish poisons (inhibiting respiratory enzymes)
  • species lonchacarpus in amazonia
  • species derris in SE asiand pacific islands
  • species tephrosia in africa
  • active princile is isaflavanoid rotenone
  • concentrated in the roots of rhizomes
  • mammals unaffected
  • used for 150 years
  • insect mitochondrial poison -blocks electron transport chain
  • most comes from venezuala and peru where its known as cube root
  • insecticide in organic farming
  • piscicide to reclaim lakes and ponds
18
Q

mint oils

A
  • mixtures of monoterpenes and sesquiterpenes
  • used in asia nad europe as fumigants to deter insects in granaries
  • potent fumigants and contact insecticides
  • terpendoids are known broad-spectrum insect neurotoxins
  • essential oil mixtures are non toxic to mammals
  • used in food and cosmetics
  • terpenoids from: rosemary, thyme, and cloves
  • mainly used in commercial greenhouses