In recent times, a great interest has been motivated in plant-derived compounds known as phytochemicals. The pentacyclic oleanane-, ursane-, lupane-type triterpenes are phytochemicals that exert significant activities against diseases like cancer. Lung cancer is the leading cause of cancer-related death worldwide. Although chemotherapy is the treatment of choice for lung cancer, its effectiveness is hampered by the dose‐limiting toxic effects and chemoresistance. Herein, we investigated the structure-activity relationship of six pentacyclic triterpenes: oleanolic acid (OleA), ursolic acid (UrA), asiatic acid (AsA), betulinic acid (BeA), betulin (Betu), lupeol (Lupe), on NSCLC A549 cells. From our studies, we confirmed that all these triterpenes showed cytotoxicity in the mid µM range, where BeA showed the strongest effect. Then, we determined that most of these triterpenes induced S-phase and G2/M phase cycle arrest, reactive oxygen species, mitochondrial depolarization, and caspase 3 activation. For chemoresistance markers, we elucidated that most triterpenes downregulated STAT3 and PDL1 genes. In contrast, ursane-type UrA and AsA also induced DNA damage, reactive nitrogen species and autophagy. These results showed that even slight structural changes in these triterpenes can influence the cellular response and mechanistic pathways. This study opens promising perspectives for further research on the pharmaceutical role of phytochemical triterpenoids.

Phytonutrients are plant foods that contain many natural bioactive compounds, called phytochemicals, which expose specific biological activities. These phytonutrients and their phytochemicals may play an important role in health care maintaining normal organism functions (as preventives) and fighting against diseases (as therapeutics). Phytonutrient’s components are the primary metabolites (i.e., proteins, carbohydrates, and lipids) and phytochemicals or secondary metabolites (i.e., phenolics, alkaloids, organosulfides, and terpenes). For years, several phytonutrients and their phytochemicals have demonstrated specific pharmacological and therapeutic effects in human health such as anticancer, antioxidant, antiviral, anti-inflammatory, antibacterial, antifungal, and immune response. This review summarizes the effects of the most studied or the most popular phytonutrients (i.e., turmeric, garlic, cinnamon, graviola, and oregano), and any contraindication found. This article also calculated the physicochemical properties of the main phytochemicals in the selected phytonutrients using Lipinski’s, Veber’s and Ghose’s rules. Based on our revisions for this article, all these phytonutrients have consistently shown several in vitro, in vivo, and clinical studies with great potential as preventives and therapeutics on many diseases.