Cancer is, globally, one of the main causes of death. Even though various therapies are available, they are still painful because of their adverse side effects. Available treatments frequently fail due to unpromising responses, resistance to classical anticancer drugs, radiation therapy, chemotherapy, and low accessibility to tumor tissues. Developing novel strategies to minimize adverse side effects, improve chemotherapy sensitivity, and control cancer progression is needed. Many studies have suggested small dietary molecules as complementary treatments for cancer patients. Different components of herbal/edible plants, known as flavonoids, have recently garnered attention due to their broad biological properties (e.g., antioxidant, antiviral, antimicrobial, anti-inflammatory, anti-mutagenic, anticancer, hepatoprotective, and cardioprotective). These flavonoids have shown anticancer activity by affecting different signaling cascades. This article summarizes the key progress made in this area and discusses the role of flavonoids by specifically inhibiting the PI3K/Akt/mTOR pathway in various cancers.

Natural products play a critical role in the discovery and development of numerous drugs for the treatment of various types of cancer. These phytochemicals have demonstrated anti-carcinogenic properties by interfering with the initiation, development, and progression of cancer through altering various mechanisms such as cellular proliferation, differentiation, apoptosis, angiogenesis, and metastasis. Treating multifactorial diseases, such as cancer with agents targeting a single target, might lead to limited success and, in many cases, unsatisfactory outcomes. Various epidemiological studies have shown that the steady consumption of fruits and vegetables is intensely associated with a reduced risk of cancer. Since ancient period, plants, herbs, and other natural products have been used as healing agents. Likewise, most of the medicinal ingredients accessible today are originated from the natural resources. Regardless of achievements, developing bioactive compounds and drugs from natural products has remained challenging, in part because of the problem associated with large-scale sequestration and mechanistic understanding. With significant progress in the landscape of cancer therapy and the rising use of cutting-edge technologies, we may have come to a crossroads to review approaches to identify the potential natural products and investigate their therapeutic efficacy. In the present review, we summarize the recent developments in natural products-based cancer research and its application in generating novel systemic strategies with a focus on underlying molecular mechanisms in solid cancer.

The present study evaluated the anticancer potential of copper oxide nanoparticles (CuO NPs) synthesized from pumpkin seed extract in human breast cancer cell line (MDA‐MB‐231) using a battery of tests such as MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide] assay, morphological alteration, reactive oxygen species (ROS) generation, and changes in mitochondrial membrane potential (MMP). The biogenic CuO NPs showed a dose‐dependent decline in cell viability with 50% inhibitory concentration (IC50) at 20 μg/ml. Treatment with an IC50 dose of CuO NPs resulted in considerable morphology changes, such as shrinkage, detachment, membrane blebbing, and deformed shape in MDA‐MB‐231 cells. We also observed a significant dose‐dependent increase in ROS production and MMP modulation due to CuO NP treatment. Overall, CuO NPs showed significant anticancer potential in the breast cancer cell line. However, further validation of our data is required in ex vivo and in vivo models before this nanoformulation could be exploited for the treatment/management of human breast cancer.

Pancreatic cancer remains a lethal disease and a major public health problem globally. Nuclear factor-kappa B (NF-κB) has been identified as a therapeutic target in several cancers and plays an important role in inflammatory responses. Many phytochemicals, including catechins, have been reported in the scientific literature with efficient anticancer potential and minimal side effects. This study aims to gain insights into the inhibitory mechanism of catechin derivatives epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) using in silico and in vitro studies especially considering NF-κB targeting. We explored the binding pose, interacting residues and molecular interactions for catechin derivatives with NF-κB. Docking analysis showed that the catechin derivatives acted as covalent inhibitors with the p65 subunit of NF-κB and interacted with other residues through non-bonding interactions and hydrogen bonds. Further, we validated the effect of EGCG on NF-κB activity in pancreatic cancer cell lines MIAPaCa-2 and SU 86.86. Our in vitro data showed EGCG effectively reduced cell growth and proliferation, induced apoptosis, and inhibited NF-κB activity in the studied cell lines. In addition, EGCG repressed the expression of NF-κB target genes including MMP9, MMP2, cMyc, and BCL-2. Thus, targeting NF-κB with EGCG could be a potential therapeutic alternative for pancreatic cancer treatment.

Cancer has been one of the leading causes of mortality worldwide over the past few years. Some progress has been made in the development of more effective cancer therapeutics, resulting in improved survival rates. However, the desired outcome in the form of successful treatment is yet to be achieved. There is high demand for the development of innovative, inexpensive, and effective anticancer treatments using natural resources. Natural compounds have been increasingly discovered and used for cancer therapy owing to their high molecular diversity, novel biofunctionality, and minimal side effects. These compounds can be utilized as chemopreventive agents because they can efficiently inhibit cell growth, control cell cycle progression, and block several tumor-promoting signaling pathways. PI3K is an important upstream protein of the PI3K-Akt-mTOR pathway and a well-established cancer therapeutic target. This study aimed to explore the small molecules, natural flavonoids, viz. quercetin, luteolin, kaempferol, genistein, wogonin, daidzein, and flavopiridol for PI3Kγ kinase activity inhibition. In this study, the binding pose, interacting residues, molecular interactions, binding energies, and dissociation constants were investigated. Our results showed that these flavonoids bound well with PI3Kγ with adequate binding strength scores and binding energy ranging from (−8.19 to −8.97 Kcal/mol). Among the explored ligands, flavopiridol showed the highest binding energy of −8.97 Kcal/mol, dock score (−44.40), and dissociation constant term, pKd of 6.58 against PI3Kγ. Based on the above results, the stability of the most promising ligand, flavopiridol, against PI3Kγ was evaluated by molecular dynamics simulations for 200 ns, confirming the stable flavopiridol and PI3Kγ complex. Our study suggests that among the selected flavonoids specifically flavopiridol may act as potential inhibitors of PI3Kγ and could be a therapeutic alternative to inhibit the PI3Kγ pathway, providing new insights into rational drug discovery research for cancer therapy.

Nuclear Factor-κappa B (NF-κB) is a family of critical transcription factors of the inflammatory pathway and plays an imperative role in the progression of various cancers such as breast, lung, liver, pancreatic, prostate and multiple types of lymphoma. NF- κB develops an inherent relationship between inflammation and cancer. It is a crucial factor that controls the ability of malignant and pre-neoplastic cells to prevent programmed cell death-based tumor-surveillance channels. Due to its high significance in the onset and progression of various cancers, it has become an excellent target for cancer therapy. The emerging targeted therapies provide a lot of hope, whereby a single protein or generally the target enzyme is completely blocked. Several natural compounds have shown anticancer and anti-inflammatory activities by inhibiting the NF-κB pathway in various cancer types. About 750 natural and synthetic inhibitors of the NF-κB have been reported. These inhibitors include microbial and viral proteins, small RNA/DNA, antioxidants, small molecules, peptides, and engineered constitutively active polypeptides, all of which may inhibit canonical and alternative NF-κB pathways. Thus, blocking or targeting the NF-κB-signaling pathways using natural and synthetic compounds could be a potential mechanism to cure the NF-κB induced tumors.