Apple has announced that Oracle CEO Larry Ellison is resigning from its board of directors.

Ellison said that his schedule doesn't allow him "to attend enough of the formal board meetings to warrant a role as a director".

Ellison has been a member of Apple's board since 1997 and he has in the past described Apple's CEO, Steve Jobs as his "best friend" and one of the most remarkable people on the planet.

He commented: "Steve's accomplishments are of such epic proportions it gnaws away at our egalitarian sense of the world."

Ellison once wanted to take Apple over himself and boot out the company's then chief executive Gil Amelio. He hoped to secure the support of friend Jobs in the takeover attempt but he finally dropped efforts to do so in 1997.

After rejoining Apple as a consultant in 1997, Jobs went on to win back control of the company, persuading the board to sack Amelio. Ellison joined the board later that year.

Apple's board will continue to have a stable of influential names including William Campbell, chairman at Intuit; Millard Drexler, CEO of apparel retailer Gap; and Arthur Levinson, CEO of Genentech, the world's first biotechnology company.

Recently Ellison spent $85 million in the pursuit of the America's Cup.

Just a fraction of Ellison's $23 billion fortune, the money is being used to construct one of the nine teams from six countries that will compete for the Cup in Auckland, New Zealand starting October 1.

Ellison is ranked among the 10 wealthiest men in the US and for a brief moment was judged the richest in the world in 2000.

He will always have a place in America's Cup history for his Cup campaigning comments: "It's cheap I'm surprised more people don't do it."

His lower middle-class roots - he was abandoned by his mother as a child – belie his current wealth. Ellison launched his first Oracle information management system in 1979, with $2,000 and ended up with a software empire.