A process for treating a hydrocarbon stream to remove polynuclear aromatic (PNA) and heavy polynuclear aromatic (HPNA) compounds includes contacting the hydrocarbon stream with an adsorbent in an adsorption unit to adsorb the PNA and HPNA compounds onto the adsorbent to produce a treated hydrocarbon stream and regenerating the adsorbent. Regenerating the adsorbent may include contacting the adsorbent with a solvent comprising a disulfide oil, such as a disulfide oil effluent from a mercaptan oxidation unit. The solvent comprising the disulfide oil desorbs the PNA and HPNA compounds from the adsorbent into the solvent to produce a desorption effluent. The treated hydrocarbon stream can be passed to a hydrocracking unit that hydrocracks the treated hydrocarbon stream to produce a hydrocracker effluent that includes greater value petrochemical products or intermediates.