I'm after the title of a book I read in the eighties, so it was first printed in the sixties or seventies.
I can't remember the title but it revolved about a guy trading in space, who encountered a jungle planet and fought a green furred ape-like creature. He also found a ring which gave him healing and longevity powers.
The space ship he travelled in required him going into a trance-like state and I recall a scene where spitting at the feet of another pilot was a compliment.
There was another big fight scene against armed troops.
It wasn't Dune.