2. Evolution & Natural History Of Medicinal Plants

Question 1

At what period did photosynthesized plants appeared?

Answer 1

The Silurian Period (443M years ago)

Question 2

What is the name of the first branching plant?

Answer 2

Cooksonia

Question 3

Why did terrestrial plants started to produce Phytochemicals? (3 reasons)

Answer 3

• To protect themselves from herbivores
• To discourage growth of other seedlings
• To inhibit soil bacteria and fungi

Question 4

Why do aquatic plants not produce lots of Phytochemicals?

Answer 4

The basis of the food chain in water are phytoplankton not plants. Herbivores were not a big threat.

Question 5

What were the early strategies developed by plants to protect themselves from the environment? (5)

Answer 5

1. Water loss: epidermal cells coated with wax
2. UV radiation: water filtered direct sunlight
3. Flavonoid pigments: reflect UV wavelengths
4. Anthocyanins: provide blue/red/violet pigments to plants
5. Tannins: Limit plant’s palatability and cause indigestion/cancers

Question 6

How to recognize a flavonoid? (MUST KNOW)

Answer 6

“6-3-6” technique
6 carbons forming an aromatic hydrocarbon, then 3 more C attaches to the first ring with 2O, then another 6C as aromatic hydrocarbon a bit further

Question 7

How do you recognize a phenol?

Answer 7

Benzene ring (aromatic ring) with OH attached
Phenols are found in flavonoids

Question 8

How do you recognize a tannic acid?

Answer 8

Massive web-like structure of branched-out phenolic compounds