exp 8: phytochemical screening for sec plant metabolites

Question 1

these are synthesized plants are often unique to a particular species

Answer 1

secondary metabolite

Question 2

these compounds are responsible for the biological activity demonstrated by medicinal plants

Answer 2

sec metabolites

Question 3

examples of sec plant metabolites and how they act

Answer 3

examples:
alkaloids
steroids
flavonoids

they act as:
anti-feedant
sex attractant
antibiotics
while many have no apparent biological role in the plant

Question 4

how many grams of desired plant

Answer 4

100g
pulverized using a household blender

Question 5

reagents for
day 1

Answer 5

99% ethanol (AR grade)

Question 6

where do you place the pulverized dried leaves after

Answer 6

large container immersed with ethanol, enough to cover all of the leaves
seal the container
sit at least 48 hrs
filter the extract by vacuum filtration

Question 7

what do u do with the filtrate and residue after vacuum filtration

Answer 7

residue - discard

filtrate - concentrate in vacu by using the rotary evaporator
then put extract int a preweighed evaporating dish to evaporatethen weigh the concentrated extract

Question 8

day 1:
day 2:

Answer 8

day 1: preparing the plant materials for study
day 2: phytochemical screening

Question 9

what are the procedures in day 2
part 1:
part 2:

Answer 9

part 1:
dragendoffs reagent
keller-kiliani test
liebermann-burchard test
kedde reagent

part 2:
borntrager test
bate-smith and metcalf test
froth test
ferric chloride test

Question 10

waste disposal

Answer 10

organic waste bottle

Question 11

which test requires heating and for how long

Answer 11

dragendorff’s test
5min

bate-smith and metcalf test

Question 12

in dragendoff’s reagent
conc. extract -
HCI -
NaCl -

Answer 12

conc. extract - spoonful of coffee stirrer
HCI - dissolve in 5ml (hydrolysis)
NaCl - 0.5g (helps in separation)
filter the residue then wash HCI

Question 13

drops needed for each tet in part 1 of day 2
dragendorff’s reagent:
keller-kiliani test:
liebermann burchard test:
kedde reagent:

Answer 13

dragendorff’s reagent:
1ml of filtrate + 5 drops of dragenroff’s reagent

keller-kiliani test:
3ml keller-kiliani reagent
incline tube then add 1ml conc. HCI

liebermann burchard test:
3 drops of acetic acid anhydride + 1 drop conc, HCI

kedde reagent:
treat DCM layer w 4 drops of kedde reagent

Question 14

libermann-burchard and kedde reagent
dichloromethane:

Answer 14

5ml dichloromethane + portion obtained in B3 > stand for 10min

Question 15

hoe much extract for keller-kiliani test

Answer 15

3 spoons using coffee stirrer
defat using 2:1 v/v hexane water mixture (to extract sec metabolite)

Question 16

how much extratct needed for part 2 day 3
borntrager test:
bate-smith and metcalf test:
froth test:
ferric chloride test:

Answer 16

borntrager test:
spoonful from day 1 B6
dissolve in 10ml distilled water

bate-smith and metcalf test:
a spoon of extract
5ml of 2:1 v/v hexane-water mixture
heat
cool then add 10ml methanol
dilute into 2 portions
- add .5ml conc. HCI

froth test:
spoon-full extract
to 10ml of distilled water
shake for 30sec
allow to stand for 10min

ferric chloride test:
spoon-full
to 10ml hot distilled water
5 drops of 10% NaCL
the filtrate to 2 portions
- one will act as a control
- add other to 3 drops of ferric chloride reagent