The pentose phosphate pathway chiefly generates reduction equivalents in the form of NADPH:
3 G6P + 6 NADPH+ + 3 H2O = 6 NADPH + 6 H+ + 3 CO2 + 2 F6P + GAP
6 equivalents of NADPH is quite a lot for just three sugars. NADPH might scavenge ROS.
It also creates F6P and GAP, which can be go into glycolysis and oxidative phosphorylation (necessary for respiration) or via the gluconeogenesis regenerate G6P (i.e. phosphorylated glucose).
An intermediate product is R5P which is used for nucleotide biosynthesis and hence might influence DNA metabolism like repair processes.
Genes involved in the pentose phosphate pathway are upregulated by dietary restriction . Up-regulation of the pentose phosphate pathway is a transition from fermentation to respiration  and therefore may relate to the lifespan extension conferred by dietary restriction.