Is One Piece 18 plus?

I'm curious to know, is the manga and anime series "One Piece" considered appropriate for viewers aged 18 and above? The story revolves around a young pirate captain, Luffy, and his crew as they embark on adventures to find the legendary treasure known as "One Piece." While the series is known for its comedic elements and thrilling battles, does it contain any mature themes or content that may not be suitable for younger audiences?