Extracts and purified compounds from select Kaempferia species are used for the treatment of knee osteoarthritis and the inhibition of a breast cancer resistance protein (BCRP), anti-inflammatory, anti-acne, anticholinesterase, anti-obesity-induced dermatopathy, wound healing, anti-drug resistant strains of Mycobacterium tuberculosis, neuroprotective, anti-nociceptive, human immunodeficiency virus type-1 (HIV-1) inhibitory activity, in vitro anti-allergenic, and larvicidal activity against Aedes aegypti [4,6,7,8,9,10,11]. The gene discussed is ABCG2; the disease is osteoarthritis, knee.