A preparation comprises a herbal extract and/or fraction, and a pharmaceutical preparation includes extract of Curcuma mangga Val. et Zipp., which has bioactivities in reducing expression levels of 5-alpha-reductase-1, androgen receptor, and PI3 in prostate cancer cells. The use of this present invention is directed to reduce prostate enlargement. Moreover, it also can be used to treat prostate cancer, lung cancer, and other diseases related to GPCR pathway.