Cytotoxic effects of a triterpene‐enriched fraction of Cecropia pachystachya on the human hormone-refractory prostate cancer PC3 cell line

Novel steroidal oximes as antiproliferative agents: Design, synthesis and biological activity evaluation

Oximes have been the subject of extensive research given their interesting anticancer activity. Steroids are also important scaffolds in drug discovery, not only due to their ability to penetrate cell membranes and bind to the nuclear and membrane receptors but also due to their suitability for structural modifications, allowing their use as cytotoxic and cytostatic anticancer agents. Combining the oxime group with the steroidal skeleton can be a suitable strategy to create novel anticancer agents. In this study, we designed and synthesised several novel steroidal oximes (OX1, OX2, OX3, OX3.1, OX4, EP2OX, FormOX and ExeOX) and evaluated their anticancer activity in three of the most incident and deadliest types of cancer, prostate (PC3), lung (H1299) and triple-negative breast (HCC1806) cancers. Selectivity using a normal human cell line, MRC-5, and hemocompatibility were also assessed. EP2OX was the most active compound in the studied cancer cell lines (IC50 values ranging from 1.13 to 3.70 µM) followed by OX1 (IC50 values ranging from 18.69 to 29.95 µM). Further studies with EP2OX and OX1 showed that the first induced DNA damage by double-strand breaks triggered by ROS production, leading to apoptosis/necrosis (depending on the concentration), while the second induced cell death by apoptosis regardless of the concentration. Moreover, both compounds showed some selectivity towards cancer cells and proved to be non-haemolytic. Our results reinforce the importance of steroidal oximes in the oncology field, namely our novel compound EP2OX which might be the starting point for a potential drug candidate for treating these types of cancer.

Molecular Basis of Prostate Cancer and Natural Products as Potential Chemotherapeutic and Chemopreventive Agents

Prostate cancer is the second most common malignant cancer in males. It involves a complex process driven by diverse molecular pathways that closely related to the survival, apoptosis, metabolic and metastatic characteristics of aggressive cancer. Prostate cancer can be categorized into androgen dependent prostate cancer and castration-resistant prostate cancer and cure remains elusive due to the developed resistance of the disease. Natural compounds represent an extraordinary resource of structural scaffolds with high diversity that can offer promising chemical agents for making prostate cancer less devastating and curable. Herein, those natural compounds of different origins and structures with potential cytotoxicity and/or in vivo anti-tumor activities against prostate cancer are critically reviewed and summarized according to the cellular signaling pathways they interfere. Moreover, the anti-prostate cancer efficacy of many nutrients, medicinal plant extracts and Chinese medical formulations were presented, and the future prospects for the application of these compounds and extracts were discussed. Although the failure of conventional chemotherapy as well as involved serious side effects makes natural products ideal candidates for the treatment of prostate cancer, more investigations of preclinical and even clinical studies are necessary to make use of these medical substances reasonably. Therefore, the elucidation of structure-activity relationship and precise mechanism of action, identification of novel potential molecular targets, and optimization of drug combination are essential in natural medicine research and development.

Pharmacognostic Evaluation of Ten Species of Medicinal Importance of Cecropia: Current Knowledge and Therapeutic Perspectives

This work covers a systematic review of literature about the genus Cecropia from 1978 to 2020, emphasizing the analysis of 10 of the most relevant species and their associated biological activities. Cecropia is a neotropical genus, which comprises about 61 native species in the American continent where it is known to be part of the traditional medicine of numerous countries. Secondary metabolites described for this genus showed an elevated structural and functional diversity, where polyphenols have been the most abundant. Based on this diversity, Cecropia phytochemicals represent an important source of potential therapeutic agents yet to be exploited. This review also highlights the effectiveness of combining chemometrics and ultra-performance liquid chromatography-tandem mass spectrometry as a novel approach to successfully single out Cecropia species phytochemicals. While the medicinal use of Cecropia species is officially recognized in National Pharmacopoeias and Formularies of several Latin American countries, it is important to recognize that these phytomedicines are complex mixtures requiring a thorough understanding of their chemical composition and their correlation with biological activities to guarantee their quality, safety, and efficacy.