Yes, end sealer can help reduce splitting at the end of the logs/boards. Especially with some hard woods and a dry climate. What happens is the wood dries much faster from the cut end grain than from the sides. When it dries, it shrinks, so the ends shrink before the rest of the log/board = a split.
A thick layer of paint, or even better, wax slows down the endgrain drying = less splits.
You can buy a good wax based endsealer from Baileys (look in the sponsors links up top).
Generally it's only used on hardwoods, pine etc doesn't split the same, and you have to apply it ASAP after cutting the log (same day). Once the splits have started it's too late.
Cheers
Ian