The club face potential winding up proceedings before the end of the month if they cannot pay a tax bill of £308,000 and have raised around £90,000 so far.
Marsden will keep his 10% stake in the club and leaves the board after two years.
He told the club's official website: "Personally I think the main protagonists involved in the off-field war of words afflicting our club should be locked in a room and not let out until they have resolved their differences.
"If required I would be happy to act as a mediator - not as a director but as an independent shareholder - but you can only help people if they want to be helped.
"I would urge the people of Accrington to get behind the SOS campaign if they really want to save our fine old club. Time is running out fast."