Introduction
!Prostate cancer (PCa) is one of the most common malignancies in men and a leading cause of death worldwide for men. Taking into consideration that chemotherapy has severe side effects and usually a poor outcome, there is an intensive need for the development of safer and more effective agents. Since plants have been used by traditional medicine for the treatment of various diseases, in the last decades, many natural products have been isolated from plants and tested for their tumor selectivity and cytotoxic efficacy. Several of these naturally occurring compounds have been found to inhibit PCa growth and metastasis and are thus a promising approach for the treatment of this malignancy. Laboratory studies in different in vitro and in vivo systems have shown that these natural products modulate cellular processes, exhibit chemopreventive and/or chemotherapeutic effects, and induce apoptosis and autophagy. Accordingly, the antiproliferative and autophagic effects of nontoxic dietary agents could be of additional significance for the prevention, control, and management of PCa, specifically for the advanced and androgen-independent stage of the malignancy [1][2][3]. As there is increasing data on how natural compounds interfere with diverse molecular pathways in cancer cells, this review discusses the mechanism of action of bioactive natural products in the field of PCa and emphasizes the implicated molecular pathways of apoptosis and autophagy as important processes that control cellular homeostasis and that have been highlighted as promising targets for novel cancer therapies.Apigenin ! Apigenin (4′,5,7-trihydroxyflavone) is a flavone found in plants of the Asteraceae family, such as Anthemis sp., and many fruits and vegetables [4]. Apigenin has been tested in various types of cancer cell lines (breast, colon, liver, lung) showing promising results [5]. In prostate cancer in particular, apigenin administered in various concentrations (1-20 μΜ) for 24, 48, and 72 h not only causes G1 cell cycle arrest both in androgen-dependent (LNCaP) and -independent (DU145 and PC-3) PC cell lines through the decreased expression of cyclins D1, D2, and E, but also induces apoptosis through a shift in the Bax/Bcl-2 ratio [6,7]. Further studies in PC-3 cells have also demonstrated that apigenin (5-40 μΜ), delivered for 24 h, suppresses cell proliferation and induces apoptosis by inhibiting IGF-IGF-IR signaling and inactivating the PI3k/Akt pathway [8]. Apigenin Abstract ! Prostate cancer is one of the leading causes of death worldwide for men. There is increasing evidence that diet and lifestyle play a crucial role in prostate cancer biology and tumorigenesis. Due to the fact that conventional chemotherapy is not adequately effective against prostate cancer and has severe side effects, numerous in vitro studies have been conducted in order to identify the potent cytotoxic or chemopreventive activity of naturally occurring compounds and their respective molecular mechanisms of action. In this context, many natural compo...