Phenylpropenoic Acid Glucoside from Rooibos Protects Pancreatic Beta Cells against Cell Death Induced by Acute Injury.
OBJECTIVE
Previous studies demonstrated that a phenylpropenoic acid glucoside (PPAG) from rooibos (Aspalathus linearis) extract had anti-hyperglycemic activity and significant protective effects on the pancreatic beta cell mass in a chronic diet-induced diabetes model. The present study evaluated the cytoprotective effect of the phytochemical on beta cells exposed to acute cell stress.


METHODS
Synthetically prepared PPAG was administered orally in mice treated with a single dose of streptozotocin to acutely induce beta cell death and hyperglycemia. Its effect was assessed on beta cell mass, proliferation and apoptotic cell death. Its cytoprotective effect was also studied in vitro on INS-1E beta cells and on human pancreatic islet cells.


RESULTS
Treatment with the phytochemical PPAG protected beta cells during the first days after the insult against apoptotic cell death, as evidenced by TUNEL staining, and prevented loss of expression of anti-apoptotic protein BCL2 in vivo. In vitro, PPAG protected INS-1E beta cells from streptozotocin-induced apoptosis and necrosis in a BCL2-dependent and independent way, respectively, depending on glucose concentration. PPAG also protected human pancreatic islet cells against the cytotoxic action of the fatty acid palmitate.


CONCLUSIONS
These findings show the potential use of PPAG as phytomedicine which protects the beta cell mass exposed to acute diabetogenic stress.
Cell Differentiation Lab, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Eddy
E
Himpe
ULB Center for Diabetes Research, Université Libre de Bruxelles (ULB), Brussels, Belgium.
Daniel A
DA
Cunha
Cell Differentiation Lab, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Imane
I
Song
Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy.
Marco
M
Bugliani
Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy.
Piero
P
Marchetti
ULB Center for Diabetes Research, Université Libre de Bruxelles (ULB), Brussels, Belgium.|Division of Endocrinology, Erasmus Hospital, Brussels, Belgium.
Miriam
M
Cnop
Cell Differentiation Lab, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
Luc
L
Bouwens
D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D036903:Aspalathus / Q000737:chemistry*; D001786:Blood Glucose / Q000032:analysis; D016923:Cell Death / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy* / Q000473:pathology; D005960:Glucosides / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects* / Q000473:pathology; D008297:Male; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D010666:Phenylpropionates / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D020011:Protective Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*
D001786:Blood Glucose; D005960:Glucosides; D010666:Phenylpropionates; D010936:Plant Extracts; D020011:Protective Agents