Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Experiment 9: Phytochemical Screening > Flashcards

Experiment 9: Phytochemical Screening Flashcards

1
Q

Phytochemicals

A

-Plant chemicals
-Natural bioactive compounds (activities in the biological system once consumed) found on different parts of a plant (leaves, roots, stems, flowers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Secondary Metabolites

A

-Organic compounds that are not directly involved in a plant’s growth, reproduction, and development, basically provide other needs of a plant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Secondary Metabolites Major Classes

A
  1. Terpenes
  2. Phenolics
  3. Polyketides
  4. Alkaloids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Terpenes

A

-Unsaturated
-Based on isoprene molecule (2-methyl,1-3-butadiene)
-Essential oils, spices, flavorings (e.g. citronella, camphor, eucalyptus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Terpenoids

A

-Oxygenated derivatives of terpenes
-Contains -OH, -C=O
-Unsaturated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Flavonoids

A

-Derived from Phe and acetate metabolism
-Contain flavan (C6-C3-C6) skeleton

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Alkaloids

A

-Basic nitrogenated compounds
-Largest class of secondary metabolites
-Analgesics, narcotics, CNS stimulants, antimicrobial
*e.g. morphine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Glycosides

A

-Sugar (glycone) + non-sugar (aglycone) molecule via a glycosidic bond
-Sugar derivatives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Saponins

A

-Kind of glycoside
-Steroid/tritepenoid glycosides
-Used as detergents
-Forms froth when agitated in an aqueous solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Tannins

A

-Polyphenols
-Can react with and precipitate proteins
-Tanning agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Types of Tannins

A

-Hydrolyzable
-Condensed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Hydrolyzable Tannins

A

Can be hydrolyzed by enzymes
-phenolic acid + glc via ester linkage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Condensed Tannins

A

-Derivatives of flavonoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sample Preparation

A

(1) Sun dried (60-80% moisture removed).
(2) Grind into fine particles (increase surface area)
(3) Immersion of sample to 95% ethanol for several days (Increase phytochemicals yield)
(4) Increase of extract concentration via rotary evaporator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Drying Methods of Sample

A

-Natural Drying
-Artificial
*Cold-air drying
*Warm-air drying

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Natural Drying

A

-Sun drying
-Sample can be damaged by the weather

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Cold-air drying

A

Use of fans that blow unheated air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is oven drying recommended for this experiment?

A

No, phytochemicals may detoriate at high temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Dragendorff’s Test

A

Test for alkaloids (nitrogenated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Dragendorff’s Test Positive and Negative Results

A

-Positive Result: Colored precipitate (red, orange, brown, or yellow)
-Negative: No precipitate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dragendorff’s Test Procedure

A

(1) +Concentrated extract
(2) +5mL of 2 M HCl
(3) Heat with stirring for 5 minutes
(4) Filter residue
(5) +2M HCl for washing
(6) Discard residue
(7) +1 mL of filtrate
(8) +5 drops of Dragendorff’s reagent
(9) Note of the color of precipitate and the amount of precipitation observed
+ slight turbidity
++ definite turbidity
+++ heavy precipitation

20
Q

Keller Killani Test

A

Test for glycosides with deoxysugars (no 2’ OH)

21
Q

Keller Killani Test Reaction

A

Acid hydrolysis of sugar-aglycone (destroy glycoside bonds)

22
Q

Keller Killani Test Positive Results

A

Red-brown ring

23
Q

Keller Killani Test Procedure

A

(1) +3 spoons of concentrated extract
(2) +10 mL of 2:1 v/v hexane-water mixture for defatting
(3) Get aqueous layer
(4) Heat over water bath
(5) Cool mixture
(6) Divide into three portions
(7) Portion 1: +3 mL Keller-Killani reagent and stir
+ 1 mL of concentrated sulfuric acid
(8) Let test tube be and observe color at interface

24
Q

Liebermann-Burchard Test

A

Test for steroids

25
Q

Liebermann-Burchard Test Positive Result

A

Purple blue or blue-green solution

26
Q

Liebermann-Burchard Test Procedure

A

(1) Portion 2 in Keller-Killani: +5mL dichloromethane
(2) Stir mixture and stand for 10 mins
(3) Get funnel with filter paper
(4) +anhydrous sodium sulfate on filter paper
(5) Filter dichloromethane layer on filter paper with anhydrous sodium sulfate

(6) Divide filtrate into two portions
(7) Portion 1: +3 drops of acetic anhydride and +1 drop of concentrated sulfuric acid

(8) Observe for any immediate color change

(9) Stand for 1 hour then compare with untreated portion

26
Q

Kedde Test

A

Test for glycosides with lactone ring (non-sugar)

27
Q

Kedde Test Positive Result

A

Purple color fading gradually to red-brown and white precipitate

28
Q

Kedde Test Procedure

A

(1) +5mL of dichloromethane to portion in Keller-KIllani
(2) Stir mixture and allow to stand for 10 minutues
(3) Collect dichloromethane layer using a dropper
(4) +4 drops of Kedde reagent
(5) Record observed color

29
Q

Bornträger’s Test

A

Test for glycosides with anthracene (3 benzene ring)

30
Q

Bornträger’s Test Positive Result

A

Pink color in lower layer

31
Q

Bornträger’s Test Procedure

A

(1) Spoonful of concentrated extract
(2)+10 mL distilled water
(3) Filter solution
(4) +5mL benzene to filtrate
(5) Collect benzene layer
(6) Divide into two portions
(7) Portion 1: +5mL of ammonia solution

(8) Compare the results with the untreated portion

32
Q

Bate-Smith and Metcalf Test

A

Test for flavonoids, leucoanthocyanins

33
Q

Bate-Smith and Metcalf Test Positive Result

A

Red purple color

34
Q

Bate-Smith and Metcalf Test Procedure

A

(1) +Concentrated extract
(2) +5 mL 2:1 v/v hexane-water mixture for defatting
(3) Collect aqueous layer
(4) Heat over a water bath
(5) Cool mixture
(6) +10 mL methanol
(7) Divide into two portions
(8) Portion 1: +0.5 mL concentrated HCl
(9) Note for any color changes
(10) Warm solution for 15 minutes
(11) Note color changes within an hour
(12) Compare with untreated portion

35
Q

Froth Test

A

Test for saponins

36
Q

Froth Test Positive Result

A

-2cm layer of forth
-Hydrophobic (fat-soluble) sapogenin + Hydrophilic (water souble) sugar

37
Q

Froth Test Procedure

A

(1) +Concentrated extract
(2) +10mL distilled water
(3) Shake mixture for 30 seconds
(4) Allow to stand for 10 minutes
(5) Wait for formation of “honeycomb froth” and measure the height

38
Q

Ferric Chloride Test

A

Test for tannins, phenolics

39
Q

Ferric Chloride Test Positive and Negative Result

A

Positive: Dark blue/black color
Negative: Colorless solution

40
Q

Ferric Chloride Test Procedure

A

(1) +Concentrated extract
(2) +10 mL hot distilled water
(3) +5 drops of 10% sodium chloride solution
(4) Filter
(5) Divide filtrate into two portions
(6) Portion 1: Control
Portion 2: +3 drops of ferric chloride reagent

(7) Compare results with control

41
Q

Parts of an Rotary Evaporator

A
  1. Rotary motor
  2. Vacuum source
  3. Glass tube
  4. Heating bath
  5. Condenser
  6. Receiving flask
  7. Rotary flask
  8. Feeder valve
42
Q

Rotary Motor

A

-Electrically powered motor that rotates evaporation flask at a continuous and constant speed to increase surface area for evaporation and even mixing.

43
Q

Glass Tube

A

-Protect and support sample during rotation
-Help in creating a vacuum

43
Q

Heating Bath

A

Heat sample and aid in temperature regulation

44
Q

Receiving flask

A

Distilled sample goes here

44
Q

Vacuum source

A

System for creating a vacuum within the airtight set-up and reduce the pressure within the system.

45
Q

Condenser

A

Condensate the evaporated sample and enhance convenient sample collection

46
Q

Feeder valve

A

Ensures safe, efficient, and controlled evaporation process in a rotavap by gradual introduction of the sample and maintain vacuum.

46
Q

Rotary Flask

A

Where the mixture is placed to be rotated and heated.

Biochemistry (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions