Preservatives are necessary in products that contain water, to ensure their safety and longevity. An antioxidant, on the other hand, help to prevent or slow down oil oxidation leading to rancidity.
The two are different and while an antioxidant can helps to prolong the shelf-life of oils, it will not inhibit the growth of micro-organisms (a preservative), which will occur wherever moisture molecules are present.
There are numerous preservatives and antioxidants available to the formulator and here we hope to grow an information bank that are at your disposal.