Questions to think about '

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• Questions to think about .
• a) Which of the compounds below are phenolics?
• b) One of the compounds below has a color (its
  yellow). Which one do you think and why?

1)
2)
4)
3)
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TodayPlant Defenses (cont.)Next time -
Quiz 5! on Pigments Plant Defenses (including
todays class). Review Quiz 4. Do Practice
questions - More plant toxins
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Chemical Plant Defenses (secondary metabolites!)

• Strong odors monoterpenes, sulfurous compounds
  (glucosinolates, allicin)
• Sticky resins and gums di and triterpenes,
  carbohydrates (oligomers and polymers)
• Today Irritants phenolics, enzymes
• Defensive tastes tannins, carboxylic acids
• Sharp crystals of calcium oxalate
• Allelopaths often phenolics
• Toxins cyanogenic glycosides, alkaloids

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Irritants
Urushiol A phenolic in poison oak
Phenol
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Irritants
Irritants in Stinging Nettle
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Defensive Taste
a phenolic!
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Defensive Taste Sour Acids
Organic acids like citric acid, malic acid in
unripe fruit
Carboxylic acid functional group
-COOH (Definition of acid?)
Rhubarbs
In rhubarbs, in sour grass
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Sharp crystals of calcium oxalate
forms sharp crystals (raphides) especially
found in plants of the Arum family (Calla lilies,
lots of houseplants!)
Dieffenbachia
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Phenolics in Allelopathy
stains hands yellow! a good plant dye
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Plant ToxinsCyanogenic Glycosides
Cyanogenic glycosides produce hydrogen cyanide
(HCN)
Catalina Cherry
Smells like almond
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Cyanogenic glycosides
destroyed during milling and cooking
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Plant Toxins Alkaloids
N-containing complex organic compounds from plants

Coniine in poison hemlock
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Alkaloids

• are basic (alkaline)
• in plants found as salts

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Solanine a steroid alkaloid
a steroid! a glycoside!
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Capsaicin Irritant
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Alkaloids
Lentiginosine in speckled locoweed (Astragalus
lentiginosus) a highly toxic alkaloidlethal to
cattle
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Alkaloids
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Alkaloids

Chiral carbon?
LD50 Nicotine oral, rats 50 mg/kg Aspirin
oral, rats 1500 mg/kg Strychnine oral, rats
5.8 mg/kg
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Next time -Your questions - More on Plant
Toxins- Quiz 5! on Pigments, Plant
Defenses (including todays class). Review Quiz
4. Do Practice questions. Study and review class
material and your resp. Reader chapters.