The active fraction was concentrated in vacuo to an aqueous solution and lyophilized to yield 1.62g of crude powder KB425796-A.
The powder was dissolved in 2 ml methanol and applied to the top of a silica gel 60 column packed with chloroform.
The column was eluted with a mixture of chloroform-methanol (10:1, 150ml), and fractions containing KB425796-A were collected and dried to give 1.50g of white powder KB425796-A.