Barbara Piasecka Johnson, who married into the Johnson & Johnson fortune, will sell a "Madonna and Child" painting in London next month, giving part of the proceeds to a Polish children's charity. Orazio Gentileschi's "Madonna and Child," bought by Johnson in 1981, has a top estimate of 2.5 million pounds ($5 million) from Christie's International, which will auction the picture on Dec. 6. Christie's said it didn't know how much of the proceeds will go to charity. Johnson, whose fortune is valued at $2.7 billion by Forbes magazine, has been disposing of old master paintings and furniture in recent years. In December 2004, Christie's sold Johnson's so-called "Badminton" cabinet, crafted by the Ducal workshops in Florence in the 18th century, for 19 million pounds, making it the most expensive piece of furniture ever auctioned. The buyer was Prince Hans-Adam II of Liechtenstein, who founded Vienna's Liechtenstein Museum. Johnson moved homes and no longer had room for the cabinet, which she had bought in 1990 for 8.6 million pounds, Christie's said at the time. In July 2006, Johnson offered Francois Boucher's "Le Sommeil de Venus" through Christie's at a top estimate of 800,000 pounds. A European collector paid a record 1.1 million pounds for the 1730 painting of the naked goddess, asleep in a chariot as a dove swoops down. Polish-born Johnson, who lives in Monte Carlo, is the widow of the late John Seward Johnson, heir to the founder of the New Brunswick, New Jersey-based healthcare company, according to Forbes magazine's Web site. Forbes in September gave her age as 70. Italian-born painter Gentileschi died in London in 1639. While prices for pre-1900 pictures have lagged behind contemporary works, the most expensive old masters appreciated almost 22 percent this year, according to index maker Art Market Research.