The potential role of polyphenolic acetate (PA) in causing diverse biological and pharmacological actions has
been well studied in our laboratory. Our investigations, for the first time, established the role of calreticulin transacetylase
(CRTAase) in catalyzing the acetylation of nitric oxide synthase (NOS) by Pas leading to robust activation of NOS. 7, 8-
Diacetoxy-4-methylcoumarin (DAMC) and other acetoxycoumarins augmented the expression of thioredoxin (TRX) and
vascular endothelial growth factor (VEGF) in human peripheral blood mononuclear cells (PBMCs). These findings substantiated
our earlier observations that DAMC was a superb inducer of angiogenesis. The enhanced expression of thioredoxin
reductase (TRXR) and diminished expression of thioredoxin interacting protein (TRXIP) leading to increased expression
and activity of TRX in PBMCs due to the action of DAMC was revealed by real time RT-PCR analysis. The possible
activation of TRX due to acetylation was confirmed by the fact that TRX activity of PBMCs was enhanced by variousacetoxycoumarins
in tune with their affinities to CRTAase as substrates. DAMC caused enhanced production of NO
by way of acetylation of NOS as mentioned above and thereby acted as an inducer of VEGF. Real time RT-PCR and
VEGF ELISA results also revealed the overexpression of TRX. DAMC and other PAs were found to reduce the oxidative
stress in cells as proved by significant reduction of intracellular ROS levels. Thus, the crucial role of TRX in DAMCinduced
angiogenesis with the involvement of VEGF was established.
Keywords: Calreticulin transacetylase, Vascular endothelial growth factor, Thioredoxin, Nitric oxide synthase.
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