In the present study we show that pentacyclic but not tetracyclic oxindole alkaloids
from Uncaria tomentosa (Willd.) DC. (Rubiaceae) induced EA.hy926 endothelial cells to release some yet to
be determined factor(s) into the supernatant; this factor was shown to significantly
enhance proliferation of normal human resting or weakly activated B and T lymphocytes.
In contrast, proliferation of normal human lympho-blasts and of both the human lymphoblastoid
B cell line Raji and the human lymphoblastoid T cell line Jurkat was inhibited significantly
while cell viability was not affected. Tetracyclic oxindole alkaloids dose-dependently
reduce the activity of pentacyclic oxindole alkaloids on human endothelial cells.
Uncaria tomentosa
- Rubiaceae - pentacyclic oxindole alkaloids - lymphoblasts - lymphocytes - endothelial
cells
