Which preposition to use with adjuvant

to Occurrences 2%

It must, of course, be understood that I make no distinction between mental and material help; and in my case the one has ever been adjuvant to the other.

for Occurrences 1%

Concepts like Fate, Predestination, an all-guiding and all-wise Providence, relieved and shielded the adrenals, and acted as valuable adjuvants for the preservation of normality.

Which preposition to use with  adjuvant