An overview of anti-Hepatitis B virus flavonoids and their mechanisms of action.

Flavonoids, a diverse group of polyphenolic compounds found in various plant-based foods, have garnered attention for their potential in combating Hepatitis B Virus (HBV) infection. Flavonoids have demonstrated promising anti-HBV activities by interfering with multiple stages of the HBV life cycle, making them promising candidates for novel antiviral agents. Certain plant families, such as Theaceae, Asteraceae, Lamiaceae, and Gentianaceae, are of particular interest for their flavonoid-rich members with anti-HBV activities. Evidences, both in vitro and in vivo, supports the anti-HBV potential of flavonoids. These subsets of compound exert their anti-HBV effects through various mechanisms, including inhibiting viral entry, disrupting viral replication, modulating transcription factors, enhancing the immune response, and inducing autophagy. The antioxidant properties of flavonoids play a crucial role in modulating oxidative stress associated with HBV infection. Several flavonoids like epigallocatechin gallate (EGCG), proanthocyanidin (PAC), hexamethoxyflavone, wogonin, and baicalin have shown significant anti-HBV potential, holding promise as therapeutic agents. Synergistic effects between flavonoids and existing antiviral therapies offer a promising approach to enhance antiviral efficacy and reduce drug resistance. Challenges, including limited bioavailability, translation from preclinical studies to clinical practice, and understanding precise targets, need to be addressed. Future research should focus on clinical trials, combination therapies, and the development of flavonoid derivatives with improved bioavailability, and optimizing their effectiveness in managing chronic HBV infections.

Endophytic fungi as a potential source of anti-cancer drug.

Endophytes are considered one of the major sources of bioactive compounds used in different aspects of health care including cancer treatment. When colonized, they either synthesize these bioactive compounds as a part of their secondary metabolite production or augment the host plant machinery in synthesising such bioactive compounds. Hence, the study of endophytes has drawn the attention of the scientific community in the last few decades. Among the endophytes, endophytic fungi constitute a major portion of endophytic microbiota. This review deals with a plethora of anti-cancer compounds derived from endophytic fungi, highlighting alkaloids, lignans, terpenes, polyketides, polyphenols, quinones, xanthenes, tetralones, peptides, and spirobisnaphthalenes. Further, this review emphasizes modern methodologies, particularly omics-based techniques, asymmetric dihydroxylation, and biotic elicitors, showcasing the dynamic and evolving landscape of research in this field and describing the potential of endophytic fungi as a source of anticancer drugs in the future.

Expanding the therapeutic arsenal against cancer: a computational investigation of hybrid xanthone derivatives as selective Topoisomerase 2α ATPase inhibitors.

The DNA topoisomerase II (topo II) enzyme plays an important role in the replication, recombination, and repair of DNA. Despite their widespread applications in cancer therapy, new, selective, and potent topo II inhibitors with better pharmaceutical profiles are needed to handle drug resistance and severe adverse effects. In this respect, an array of 36 new anticancer compounds was designed based on a Xanthone core tethered to multifunctional Pyridine-amines and Imidazole scaffold via alkyl chain linkers. An integrated in silico approach was used to understand the structural basis and mechanism of inhibition of the hybrid xanthone derivatives. In this study, we established an initial virtual screening workflow based on pharmacophore mapping, docking, and cancer target association to validate the target selection process. Next, a simulation-based docking was conducted along with pharmacokinetic analysis to filter out the five best compounds (7, 10, 25, 27, and 30) having binding energies within the range of -60.45 to -40.97 kcal/mol. The screened compounds were further subjected to molecular dynamics simulation for 200 ns followed by MM-GBSA and ligand properties analysis to assess the stability and binding affinity to hTOP2α. The top-ranking hits 3,7-bis(3-(2-aminopyridin-3-ylhydroxy)propoxy)-1-hydroxy-9H-xanthen-9-one (ligand 7) and 3,8-bis(3-(2-aminopyridin-3-ylhydroxy)propoxy)-1-hydroxy-9H-xanthen-9-one (ligand 25) were found to have no toxicity, optimum pharmacokinetic and, DFT properties and stable intermolecular interactions with the active site of hTopo IIα protein. In conclusion, further in vitro and in vivo experimental validation of the identified lead molecules is warranted for the discovery of new human Topoisomerase 2 alpha inhibitors.Communicated by Ramaswamy H. Sarma.

Recent Advances on Natural and Non-Natural Xanthones as Potential Anticancer Agents: A Review.

BACKGROUND: Xanthones, natural or synthetic, due to their wide range of biological activities, have become an interesting subject of investigation for many researchers. Xanthonic scaffold has proven to have a vital role in anticancer drug development since many of its derivatives have shown anticancer activities on various cell lines. In addition, targeting epigenetic markers in cancer has yielded promising results. There have also been reports on the impact of xanthone and related polyphenolic compounds on epigenetics markers in cancer prevention and therapy. OBJECTIVE: The objective of this review is to comprehensively highlight the main natural and nonnatural sources of xanthones having potential anti-cancer effects along with their key structural elements, structure-activity relationships (SARs), mechanisms of action, and epigenetic profile of xanthone- based anti-cancer compounds. The challenges and future directions of xanthone-based therapies are also discussed briefly. METHOD: The methods involved in the preparation of the present review included the collection of all recent information up to November 2021 from various scientific databases, indexed periodicals, and search engines such as Medline Scopus, Google Scholar, PubMed, PubMed Central, Web of Science, and Science Direct. RESULTS: Exploration of the diversity of the xanthone scaffold led to the identification of several derivatives having prominent anti-cancer activity. Their unique structural diversity and synthetic modifications showed the ongoing endeavour of enriching the chemical diversity of the xanthone molecular framework to discover pharmacologically interesting compounds. However, studies regarding their modes of action, pharmacokinetic properties, clinical data, epigenetics, and safety are limited. CONCLUSION: Elucidation of the exact biological mechanisms and the associated targets of xanthones will yield better opportunities for these compounds to be developed as potential anticancer drugs. Further clinical studies with conclusive results are required to implement xanthones as treatment modalities in cancer.

Immunomodulatory effect of mushrooms and their bioactive compounds in cancer: A comprehensive review.

Despite enormous development in the field of drug development, cancer still remains elusive. Compromised immunity stands as a roadblock to the successful pharmacological execution of anti-cancer drugs used clinically currently. Recently some breakthrough cancer treatment strategy like nano-formulation, extracellular vesicles treatment, natural antioxidant therapy, targeted immunotherapy, gene therapy, thermal ablation and magnetic hyperthermia, and pathomics and radiomics has been developed and tested pre-clinically as well as clinically. However, clinical efficacy of such therapies is yet to establish and some are too costly to be utilized by patients from poor and developing countries. At this juncture, researchers are heading towards the search of medicines from natural sources that is higher safety margin and multitarget pharmacological efficacy compared to conventional treatments. Mushroom is used traditionally as food as well as drug since time immemorial due to its immunomodulatory effect which is loaded with proteins, low fat content and cholesterol. Mushrooms are recommended as one of the best vegetarian diets for immunosuppressed cancer and HIV/AIDS patients. Mushrooms are well-known for their anti-cancer activity that impacts hematopoietic stem cells, lymphocytes, macrophages, T cells, dendritic cells (DCs), and natural killer (NK) cells in the immune system. This comprehensive review article emphasizes on the molecular mechanisms of cancer genesis, conventional anti-cancer therapy as well as reported some significant breakthrough in anti-cancer drug development, anti-cancer activity of some selected species of mushrooms and their bioactive phytoconstituents followed by a brief discussion of recent anti-cancer efficacy of some metallic nanoparticles loaded with mushrooms.

Emerging advances in nanomedicine for breast cancer immunotherapy: opportunities and challenges.

Breast cancer is one of the most common causes of cancer-related morbidity and mortality in women worldwide. Early diagnosis and an appropriate therapeutic approach for all cancers are climacterics for a favorable prognosis. Targeting the immune system in breast cancer is already a clinical reality with notable successes, specifically with checkpoint blockade antibodies and chimeric antigen receptor T-cell therapy. However, there have been inevitable setbacks in the clinical application of cancer immunotherapy, including inadequate immune responses due to insufficient delivery of immunostimulants to immune cells and uncontrolled immune system modulation. Rapid advancements and new evidence have suggested that nanomedicine-based immunotherapy may be a viable option for treating breast cancer.

Cancer that begins in the breast is referred to as breast cancer. It may originate in either one or both breasts. It is one of the main causes of cancer-related death among women worldwide. Cancer immunotherapy is a game-changing treatment that improves the ability of the host defense system to spot and eliminate cancer cells with pinpoint accuracy. Cancer immunotherapy, also referred to as immuno-oncology, is a type of treatment option for breast cancer that uses the body's natural defense system to prevent, regulate and eliminate breast cancer. Immunotherapy is used to enhance or alter the functioning of the immune system so that it can locate and destroy cancer cells. Knowing how immunotherapy works and what to anticipate can often offer peace of mind to the patient who can then make informed decisions about care, especially if immunotherapy is part of the treatment plan for a particular patient.

Cancer Chemotherapy via Natural Bioactive Compounds.

BACKGROUND: Cancer-induced mortality is increasingly prevalent globally, which skyrocketed the necessity to discover new/novel, safe and effective anticancer drugs. Cancer is characterized by the continuous multiplication of cells in the human, which is unable to control. Scientific research is drawing its attention toward naturally-derived bioactive compounds as they have fewer side effects compared to the current synthetic drugs used for chemotherapy. OBJECTIVE: Drugs isolated from natural sources and their role in the manipulation of epigenetic markers in cancer are discussed briefly in this review article. METHODS: With advancing medicinal plant biotechnology and microbiology in the past century, several anticancer phytomedicines were developed. Modern pharmacopeia contains at least 25% herbal-based remedies, including clinically used anticancer drugs. These drugs mainly include the podophyllotoxin derivatives vinca alkaloids, curcumin, mistletoe plant extracts, taxanes, camptothecin, combretastatin, and colchicine artesunate, homoharringtonine, ellipticine, roscovitine, maytansine, tapsigargin,and bruceantin. RESULTS: Compounds (psammaplin, didemnin, dolastin, ecteinascidin, and halichondrin) isolated from marine sources and animals such as microalgae, cyanobacteria, heterotrophic bacteria, invertebrates. They have been evaluated for their anticancer activity on cells and experimental animal models and used chemotherapy.Drug-induced manipulation of epigenetic markers plays an important role in the treatment of cancer. CONCLUSION: The development of a new drug from isolated bioactive compounds of plant sources has been a feasible way to lower the toxicity and increase their effectiveness against cancer. Potential anticancer therapeutic leads obtained from various ethnomedicinal plants, foods, marine, and microorganisms are showing effective yet realistically safe pharmacological activity. This review will highlight important plant-based bioactive compounds like curcumin, stilbenes, terpenes, other polyphenolic phyto-compounds, and structurally related families that are used to prevent/ ameliorate cancer. However, a contribution from all possible fields of science is still a prerequisite for discovering safe and effective anticancer drugs.