Maloof and Lopez were part of the Have a Heart Auction in Honor of Zeke (HelpZeke.com) ... an event to raise money for Zeke Kendall, a 20-year-old man who underwent heart transplant surgery last month.
The auction -- held at Mixology at The Grove -- featured a red dress from the Kim Kardashian collection (worn by Kim herself) and a signed Charlie Sheen jersey from the movie "Major League" (see below).
"Extra" co-host Maria Menounos put herself -- along with Jaime Pressley and Jane Seymour -- on the auction block … and some lucky guy got to kiss all three of them … with a winning bid of $30,000.
But "Real Housewives of Beverly Hills" star (for now) Adrienne Maloof saved her money for the chance to lay one on the hunky Lopez ... forking over 25 large in the process.
Maloof either has a huge heart or she's a huge fan of "Saved by the Bell" ... or both.