*1.2. The Basic Introduction of Tanshinone*

Tanshinone is the fat-soluble component of the active ingredient of Salvia miltiorrhiza. Since the Japanese scholar Nakao first isolated Tanshinone IIA from salvia miltiorrhiza and identified its chemical structure in 1934, with the development of clinical application of salvia miltiorrhiza and the progress of extraction and separation technology in traditional Chinese medicine, the specific composition of Tanshinone has gradually become clear. So far, more than 40 Tanshinones have been isolated from salvia miltiorrhizae, among which the most important ones are Tanshinone I (TsI), Tanshinone II A (Ts II A), Dihydrotanshinone I (DHTI) and Cryptotanshinone (CYT) (Figure 1) [7,8]. The main precursor of Tanshinone biosynthesis is geraniyldiphosphate (GPP), which is derived from mevalproic acid and the 2-c-methyl-d-erythritol 4-phosphate pathway. GPP is eventually converted into Tanshinone through a series of downstream enzymes involved in various steps of catalytic biosynthesis [9,10]. Tanshinone has powerful pharmacological effects with anti-inflammatory, antioxidant stress, and anti-metabolic syndrome, and its water-soluble derivative, Tanshinone SODIUM IIA sulfonate, has been widely used in the clinical treatment of cardiovascular diseases [11]. Interestingly, more and more studies have reported the anti-tumor potential of Tanshinone, and previous studies have shown that Tanshinone can inhibit the proliferation, metastasis, and progression of various cancer cells (including PCa) by regulating transcription and growth factors, inflammatory cytokines, and intracellular signaling pathways [12,13]. Interestingly, a growing number of studies report the effects of Tanshinone on PCa cells. These studies shed light on their mechanisms of action and their potential as anti-PCa drugs. Here, we review the available evidence for Tanshinone against PCa and the molecular targets of its action.

**Figure 1.** Chemical structures of four Tanshinone monomers.
