Chemistry wordoku #055 | Puzzle

Solve this ‘wordoku’ in the same way as a sudoku with letters instead of numbers (the nine letters once in each row, column and nine-square cell). Once solved, one of the overall diagonals can be rearranged into a chemical whose levels in the blood are reduced according to a Chemistry World feature in 2006.
This week’s letters are: A E I M N O R S T