An antioxidant-promoting composition that increases antioxidant defense potential in a subject is disclosed. The composition contains Bacopa monnieri extract comprising a Bacopa monnieri active ingredient; a Silybum marianum (milk thistle) extract comprising a Silybum marianum active ingredient; a Withania somnifera (ashwagandha) extract comprising a Withania somnifera active ingredient; a Camellia sinensis (green tea) extract comprising a Camellia sinensis active ingredient; a Curcuma longa (turmeric) extract comprising at least one Curcuma longa active ingredient, and optionally a Centella asiatica (Gotu kola) extract; a Ginko biloba extract; an Aloe vera extract; and N-acetyl cysteine. The process for quantifying Nrf2 transcription factor activating potential of the botanical extracts comprising the botanical active ingredients is described.