scholarly journals Combretastatins: An Overview of Structure, Probable Mechanisms of Action and Potential Applications

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2560 ◽  
Author(s):  
Gökçe Şeker Karatoprak ◽  
Esra Küpeli Akkol ◽  
Yasin Genç ◽  
Hilal Bardakcı ◽  
Çiğdem Yücel ◽  
...  

Combretastatins are a class of closely related stilbenes (combretastatins A), dihydrostilbenes (combretastatins B), phenanthrenes (combretastatins C) and macrocyclic lactones (combretastatins D) found in the bark of Combretum caffrum (Eckl. & Zeyh.) Kuntze, commonly known as the South African bush willow. Some of the compounds in this series have been shown to be among the most potent antitubulin agents known. Due to their structural simplicity many analogs have also been synthesized. Combretastatin A4 phosphate is the most frequently tested compounds in preclinical and clinical trials. It is a water-soluble prodrug that the body can rapidly metabolize to combretastatin A4, which exhibits anti-tumor properties. In addition, in vitro and in vivo studies on combretastatins have determined that these compounds also have antioxidant, anti-inflammatory and antimicrobial effects. Nano-based formulations of natural or synthetic active agents such as combretastatin A4 phosphate exhibit several clear advantages, including improved low water solubility, prolonged circulation, drug targeting properties, enhanced efficiency, as well as fewer side effects. In this review, a synopsis of the recent literature exploring the combretastatins, their potential effects and nanoformulations as lead compounds in clinical applications is provided.

2018 ◽  
Vol 25 (36) ◽  
pp. 4740-4757 ◽  
Author(s):  
Ashita Sharma ◽  
Mandeep Kaur ◽  
Jatinder Kaur Katnoria ◽  
Avinash Kaur Nagpal

Polyphenols are a group of water-soluble organic compounds, mainly of natural origin. The compounds having about 5-7 aromatic rings and more than 12 phenolic hydroxyl groups are classified as polyphenols. These are the antioxidants which protect the body from oxidative damage. In plants, they are the secondary metabolites produced as a defense mechanism against stress factors. Antioxidant property of polyphenols is suggested to provide protection against many diseases associated with reactive oxygen species (ROS), including cancer. Various studies carried out across the world have suggested that polyphenols can inhibit the tumor generation, induce apoptosis in cancer cells and interfere in progression of tumors. This group of wonder compounds is present in surplus in natural plants and food products. Intake of polyphenols through diet can scavenge ROS and thus can help in cancer prevention. The plant derived products can also be used along with conventional chemotherapy to enhance the chemopreventive effects. The present review focuses on various in vitro and in vivo studies carried out to assess the anti-carcinogenic potential of polyphenols present in our food. Also, the pathways involved in cancer chemopreventive effects of various subclasses (flavonoids, lignans, stilbenes and phenolic acids) of polyphenols are discussed.


2020 ◽  
Vol 26 (45) ◽  
pp. 5783-5792
Author(s):  
Kholood Abid Janjua ◽  
Adeeb Shehzad ◽  
Raheem Shahzad ◽  
Salman Ul Islam ◽  
Mazhar Ul Islam

There is compelling evidence that drug molecules isolated from natural sources are hindered by low systemic bioavailability, poor absorption, and rapid elimination from the human body. Novel approaches are urgently needed that could enhance the retention time as well as the efficacy of natural products in the body. Among the various adopted approaches to meet this ever-increasing demand, nanoformulations show the most fascinating way of improving the bioavailability of dietary phytochemicals through modifying their pharmacokinetics and pharmacodynamics. Curcumin, a yellowish pigment isolated from dried ground rhizomes of turmeric, exhibits tremendous pharmacological effects, including anticancer activities. Several in vitro and in vivo studies have shown that curcumin mediates anticancer effects through the modulation (upregulation and/or downregulations) of several intracellular signaling pathways both at protein and mRNA levels. Scientists have introduced multiple modern techniques and novel dosage forms for enhancing the delivery, bioavailability, and efficacy of curcumin in the treatment of various malignancies. These novel dosage forms include nanoparticles, liposomes, micelles, phospholipids, and curcumin-encapsulated polymer nanoparticles. Nanocurcumin has shown improved anticancer effects compared to conventional curcumin formulations. This review discusses the underlying molecular mechanism of various nanoformulations of curcumin for the treatment of different cancers. We hope that this study will make a road map for preclinical and clinical investigations of cancer and recommend nano curcumin as a drug of choice for cancer therapy.


Planta Medica ◽  
2018 ◽  
Vol 85 (04) ◽  
pp. 312-334 ◽  
Author(s):  
Fatai Balogun ◽  
Anofi Ashafa

AbstractSouth Africa contains 9% of the worldʼs higher plants, and despite its rich biodiversity, it has one of the highest prevalence of hypertension in Africa. This review provides information on medicinal plants embraced in South Africa for hypertension management, with the aim of reporting pharmacological information on the indigenous use of these plants as antihypertensives. This review not only focuses on the activity of antihypertensive medicinal plants but also reports some of its phytochemical constituents and other ethnopharmacological and therapeutic properties. Information obtained from scientific and or unpublished databases such as Science Direct, PubMed, SciFinder, JSTOR, Google Scholar, Web of Science, and various books revealed 117 documented antihypertensive plant species from 50 families. Interestingly, Asteraceae topped the list with 16 species, followed by Fabaceae with 8 species; however, only 25% of all plant species have demonstrated antihypertensive effects originating from both in vitro and in vivo studies, lending credence to their folkloric use. Only 11 plant species reportedly possess antihypertensive properties in animal models, with very few species subjected to analytical processes to reveal the identity of their bioactive antihypertensive compounds. In this review, we hope to encourage researchers and global research institutions (universities, agricultural research councils, and medical research councils), particularly those showing an interest in natural products, for the need for concerted efforts to undertake more studies aimed at revealing the untapped potential of these plants. These studies are very important for the development of new pharmaceuticals of natural origin useful for the management of hypertension.


1989 ◽  
Vol 8 (5) ◽  
pp. 853-859 ◽  
Author(s):  
Ronald C. Wester ◽  
Howard I. Maibach

Contaminants exist in ground and surface water. Human skin has the capacity to bind and then absorb these contaminants into the body during swimming and bathing. Powdered human stratum corneum will bind both lipid-soluble (alachlor, polychlorinated biphenyls [PCBs], benzene) and water-soluble (nitroaniline) chemicals. In vitro (human skin) and in vivo (Rhesus monkey) studies show that these chemicals readily distribute into skin, and then some of the chemical is absorbed into the body. Linearity in binding and absorption exists for nitroaniline over a 10-fold concentration range. Multiple exposure to benzene is at least cumulative. Binding and absorption can be significant for exposures as short as 30 min, and will increase with time. Absorption with water dilution increased for alachlor, but not for dinoseb. Soap reversed the partitioning of alachlor between human stratum corneum and water. The PCBs could be removed from skin by soap and water (70% efficiency) for up to 3 h and then decontamination potential decreased, due to continuing skin absorption. The model in vitro and in vivo systems used should permit easy estimation of this area of extensive human exposure effect on risk assessment.


2020 ◽  
Author(s):  
Kui Wu ◽  
Nathan Yee ◽  
Sangeetha Srinivasan ◽  
Amir Mahmoodi ◽  
Michael Zakharian ◽  
...  

<div> <div> <div> <p>A desired goal of targeted cancer treatments is to achieve high tumor specificity with minimal side effects. Despite recent advances, this remains difficult to achieve in practice as most approaches rely on biomarkers or physiological differences between malignant and healthy tissue, and thus benefit only a subset of patients in need of treatment. To address this unmet need, we introduced a Click Activated Protodrugs Against Cancer (CAPAC) platform that enables targeted activation of drugs at a specific site in the body, i.e., a tumor. In contrast to antibodies (mAbs, ADCs) and other targeted approaches, the mechanism of action is based on in vivo click chemistry, and is thus independent of tumor biomarker expression or factors such as enzymatic activity, pH, or oxygen levels. The platform consists of a tetrazine-modified sodium hyaluronate-based biopolymer injected at a tumor site, followed by one or more doses of a trans-cyclooctene (TCO)- modified cytotoxic protodrug with attenuated activity administered systemically. The protodrug is captured locally by the biopolymer through an inverse electron-demand Diels-Alder reaction between tetrazine and TCO, followed by conversion to the active drug directly at the tumor site, thereby overcoming the systemic limitations of conventional chemotherapy or the need for specific biomarkers of traditional targeted therapy. Here, TCO-modified protodrugs of four prominent cytotoxics (doxorubicin, paclitaxel, etoposide and gemcitabine) are used, highlighting the modularity of the CAPAC platform. In vitro evaluation of cytotoxicity, solubility, stability and activation rendered the protodrug of doxorubicin, SQP33, as the most promising candidate for in vivo studies. Studies in rodents show that a single injection of the tetrazine-modified biopolymer, SQL70, efficiently captures SQP33 protodrug doses given at 10.8-times the maximum tolerated dose of conventional doxorubicin with greatly reduced systemic toxicity. </p> </div> </div> </div>


Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2196 ◽  
Author(s):  
Silvana Alfei ◽  
Anna Maria Schito ◽  
Guendalina Zuccari

Ursolic acid (UA) is a pentacyclic triterpenoid found in many medicinal plants and aromas endowed with numerous in vitro pharmacological activities, including antibacterial effects. Unfortunately, UA is poorly administered in vivo, due to its water insolubility, low bioavailability, and residual systemic toxicity, thus making urgent the development of water-soluble UA formulations. Dendrimers are nonpareil macromolecules possessing highly controlled size, shape, and architecture. In dendrimers with cationic surface, the contemporary presence of inner cavities and of hydrophilic peripheral functions, allows to encapsulate hydrophobic non-water-soluble drugs as UA, to enhance their water-solubility and stability, and to promote their protracted release, thus decreasing their systemic toxicity. In this paper, aiming at developing a new UA-based antibacterial agent administrable in vivo, we reported the physical entrapment of UA in a biodegradable not cytotoxic cationic dendrimer (G4K). UA-loaded dendrimer nanoparticles (UA-G4K) were obtained, which showed a drug loading (DL%) much higher than those previously reported, a protracted release profile governed by diffusion mechanisms, and no cytotoxicity. Also, UA-G4K was characterized by principal components analysis (PCA)-processed FTIR spectroscopy, by NMR and elemental analyses, and by dynamic light scattering experiments (DLS). The water solubility of UA-G4K was found to be 1868-fold times higher than that of pristine UA, thus making its clinical application feasible.


2021 ◽  
Author(s):  
Andang Miatmoko ◽  
Qurrota Ayunin ◽  
Widji Soeratri

Skin aging is a phenomenon resulting in reduced self-confidence, thus becoming a major factor in social determinants of health. The use of active cosmetic ingredients can help prevent skin aging. Transfersomes are well known to be capable of deeply penetrating the dermis. This scoping review provides an insight into transfersomes and their prospective use in anti-aging cosmetics. Numerous reports exist highlighting the successful skin delivery of therapeutic agents such as high-molecular-weight, poorly water soluble and poorly permeable active ingredients by means of transfersomes. Moreover, in vitro and in vivo studies have indicated that transfersomes increase the deposition, penetration and efficacy of active ingredients. However, the use of transfersomes in the delivery of active cosmetic ingredients is limited. Considering their similar physicochemical properties, transfersomes should possess considerable potential as a delivery system for anti-aging cosmetics.


2018 ◽  
Vol 18 (5) ◽  
pp. 667-674 ◽  
Author(s):  
Didem Sohretoglu ◽  
Shile Huang

The mushroom Ganoderma lucidum (G. lucidum) has been used for centuries in Asian countries to treat various diseases and to promote health and longevity. Clinical studies have shown beneficial effects of G. lucidum as an alternative adjuvant therapy in cancer patients without obvious toxicity. G. lucidum polysaccharides (GLP) is the main bioactive component in the water soluble extracts of this mushroom. Evidence from in vitro and in vivo studies has demonstrated that GLP possesses potential anticancer activity through immunomodulatory, anti-proliferative, pro-apoptotic, anti-metastatic and anti-angiogenic effects. Here, we briefly summarize these anticancer effects of GLP and the underlying mechanisms.


Planta Medica ◽  
2019 ◽  
Vol 85 (16) ◽  
pp. 1233-1241
Author(s):  
Michael Kirchinger ◽  
Lara Bieler ◽  
Julia Tevini ◽  
Michael Vogl ◽  
Elisabeth Haschke-Becher ◽  
...  

AbstractThe chroman-like chalcone Xanthohumol C, originally found in hops, was demonstrated to be a potent neuroregenerative and neuroprotective natural product and therefore constitutes a strong candidate for further pharmaceutical research. The bottleneck for in vivo experiments is the low water solubility of this chalcone. Consequently, we developed and validated a suitable formulation enabling in vivo administration. Cyclodextrins were used as water-soluble and nontoxic complexing agents, and the complex of Xanthohumol C and 2-hydroxypropyl-β-cyclodextrin was characterized using HPLC, HPLC-MS, NMR, and differential scanning calorimetry. The water solubility of Xanthohumol C increases with increasing concentrations of cyclodextrin. Using 50 mM 2-hydroxypropyl-β-cyclodextrin, solubility was increased 650-fold. Furthermore, in vitro bioactivity of Xanthohumol C in free and complexed form did not significantly differ, suggesting the release of Xanthohumol C from 2-hydroxypropyl-β-cyclodextrin. Finally, a small-scaled in vivo experiment in a rat model showed that after i. p. administration of the complex, Xanthohumol C can be detected in serum, the brain, and the cerebrospinal fluid at 1 and 6 h post-administration. Mean (± SD) Xanthohumol C serum concentrations after 1, 6, and 12 h were determined as 463.5 (± 120.9), 61.9 (± 13.4), and 9.3 (± 0.8) ng/mL upon i. v., and 294.3 (± 22.4), 45.5 (± 0.7), and 13 (± 1.0) ng/mL after i. p. application, respectively. Accordingly, the formulation of Xanthohumol C/2-hydroxypropyl-β-cyclodextrin is suitable for further in vivo experiments and further pharmaceutical research aiming for the determination of its neuroregenerative potential in animal disease models.


Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2922
Author(s):  
Alyssa Francavilla ◽  
Iris J. Joye

Coloured (black, purple, blue, red, etc.) cereal grains, rich in anthocyanins, have recently gained a lot of attention in the food industry. Anthocyanins are water-soluble flavonoids, and are responsible for red, violet, and blue colours in fruits, vegetables, and grains. Anthocyanins have demonstrated antioxidant potential in both in vitro and in vivo studies, and the consumption of foods high in anthocyanins has been linked to lower risks of chronic diseases. As such, whole grain functional foods made with coloured grains are promising new products. This paper will review the characteristics of cereal anthocyanins, and assess their prevalence in various commercially relevant crops including wheat, barley, maize, and rice. A brief overview of the antioxidant potential, and current research on the health effects of cereal-based anthocyanins will be provided. Finally, processing of coloured cereals in whole grain products will be briefly discussed. A full understanding of the fate of anthocyanins in whole grain products, and more research targeted towards health outcomes of anthocyanin supplementation to/inclusion in cereal food products are the next logical steps in this research field.


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