This is, as best as I could find, the most current information on the property that was formerly the site of Brian's "Radiant Radish" health food store. The property is currently listed for sale and I believe available to lease in West Hollywood, asking price a cool $2,895,000
Some information from the listing: The current building which as we saw in the other Radish threads formerly housed a "Relax The Back" franchise which has since relocated farther east on Melrose, was actually built in 1990. This would suggest the former structure that we saw in the original Radish photos was razed completely rather than renovated. If it were renovated it would have been listed as such with a specific year the work was done, at least that's what I'd think.
But it would seem the original Radiant Radish building itself has been gone since at least 1990, so any traces of a direct connection to Brian or the original store are most likely in address only. So the new owner(s) won't find some old supplies or items left by Brian and company stashed in the walls or anything of that sort...

This is a link to a pdf file posted by the realtor (westmac.com) with multiple photos, details, and all related info:
http://www.westmac.com/downloads/setups/90069/melrose_8700_-_s.pdfI'd say that pretty much answers the question of whatever happened to the Radiant Radish.