Page 470 - Applied Pharmacognosy

• 3-The day and night time of collection:
The composition of a number of secondary
metabolites varies throughout the day and
night.

• Example: The content of glycosides in Digitalis
leaves is higher in the afternoon than during
night (photosynthesis, hydrolyzing enzymes)

• Throughout the day the overall amount of
glycosides may not change but there is an inter-
conversion of the various glycosides present.

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