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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 towards 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 remedy including clinically used anticancer drugs. These drugs mainly include the podophyllotoxin derivatives vinca alkaloids, curcumin, mistletoe plant extracts, taxanes, camptothecin, combretastatin, and others including colchicine, artesunate, homoharringtonine, ellipticine, roscovitine, maytanasin, tapsigargin,andbruceantin. 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.

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 non-natural 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.

Background: Gallic acid is a natural phenolic compound found in several fruits and medicinal plants. It is reported to have several health-promoting effects including antioxidant, anti-inflammatory, diabetic, antineoplastic properties, gastrointestinal, neuropsychological, metabolic and cardiovascular disorders. Aims: The aim of the present work was to study the influence of formulation factors on the physicochemical properties of gallic acid-loaded chitosan nanoparticles in order to optimize the formulation. Methods: Active chitosan nanoparticles could be used to support the modification of gallic acid delivery. The nanoparticles were prepared by the emulsification solvent evaporation method using sonication. A 3-factor, 2-level BBD (Box-Behnken Design) was applied for exploring and optimizing the main effects, quadratic effects as well as interaction effects of the ingredients of the formulation on the performance of the nanoparticles. The responses like particle size, polydispersity index, zeta potential and encapsulation efficiency were also determined. Results: The concentration of gallic acid nanoparticles seems to be the most critical element affecting their properties. The concentration of chitosan was increased, which resulted in an increase in particle size. The optimised drug-loaded nanoparticles have a zeta potential of -5.2 mV due to their largely negative surface charge. Although the measured zeta potential was low, the nanoparticle dispersion remained stable, and no significant change in the shape or particle size of the gallic acid-loaded chitosan nanoparticles was seen after two weeks at 4°C. The gallic acid-loaded nanoparticles have a particle size of 230 nm. Gallic acid reduced the particle size after it was added. One probable explanation for this is that the loaded medicine increased the cohesive force of the hydrophobic contact, resulting in the size reduction. A formulation was optimised based on the acquired results, and the experimental values were comparable to the expected values. FTIR examination revealed that gallic acid-loaded chitosan nanoparticles displayed both hydrogen bond and ionic interactions, allowing for active agent encapsulation and augmentation. Conclusions: The overall results indicated that decreasing the chitosan concentration drug entrapement efficiency increases and gallic acid concentration was the main factor influencing particle size, while entrapment efficiency was predominantly affected by the chitosan concentration.

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