1. Activity of Tea Extracts & (-)-Catechin on GluT1 Transport
Laura Blohm, Adamove Osho, Dr. Larry Louters, Calvin College
GluT1 is a membrane transporter that
is present in all mammalian cells. Its
major function is to transport glucose
across the cell membrane for use
within the cell.
Green tea is thought to have glycemic
effects. One of the active ingredients
in tea is (-)-Catechin.
Catechins belong to the flavonoid
family. They are called flavan-3-ols
and serve as a phenol and organic
antioxidant found mainly in green tea.
• To Determine if green tea extracts
affect transport activity of GluT1
• To investigate the effects of (-)-
catechin on glucose uptake in
L929 fibroblast cells
• To determine the effects of (-)-
catechin with pH
• L929 fibroblast cells were placed
on 24-well plates
• Cells were pretreated with green
tea extracts or purified catechins
for 30 minutes at 37 degrees C.
• 10-minute uptakes were
measured using 3H-deoxyglucose
• Cells were lysed with 0.3 NaOH
and radioactivity was measured
by scintillation spectroscopy
Figure 2: The Dose-Dependent
Effect of tea extracts on L929
cells.
Figure3: The Time-Dependent
Effect of Pretreatment with Tea
Extracts on L929 Cells.
Figure 3: The Recovery of L929
cells Treated with Tea Extracts.
Figure 4: The Dose-Dependent
Effect of (-)-Catechin on L929 cells.
Figure 5: The pH-Dependent Effect
of (-)-Catechin on L929 cells.
Objectives
Introduction
Methods
Results
References
Conclusions
• Green tea extracts and (-)-
Catechin, which is an active
ingredient in green tea,
activates the uptake of
glucose by the transporter
GluT1.
• Green tea extracts activate
GluT1 rapidly, with full
activation achieved by 10
minutes.
• The rate of recovery from
activation with green tea
extracts is slow.
• (-)-Catechin has an additive
effect on pH at 6 and 7, but at
8 it is already fully activated.
• Work with other catechins to
see if they activate GluT1 as
well.
• Perform coincubations with
other known activators.
• Investigate pathway of
catechin activation.
Calvin College Chemistry and
Biochemistry department
Funding provided by NIH
Future Work
Acknowledgements