Flavonoids: Promising Natural Products for Treatment of Skin Cancer (Melanoma)

Melanoma, which is the most malignant skin cancer type, has got one of the fastest increasing incidence rates of all cancer types in the world. When belatedly diagnosed, melanoma is extremely invasive and metastatic. Although there are effective drugs used to treat melanoma, some cell lines have proven resistant to chemotherapy. In this context, several research groups on natural products have investigated the anticancer effect of new natural molecules in the treatment of melanoma. Flavonoids have shown to play an important role in chemoprevention and inhibition of the proliferation, migration, and invasion of melanoma cells. In this chapter, we present a systematic review performed through a literature search over a period of 20 years, using specialized databases. Analysis of all selected manuscripts demonstrated that at least 97 flavonoids have already been investigated for the treatment of melanoma using in vitro or in vivo models. Most of the bioactive flavonoids belong to the classes of flavones (38.0%), flavonols (17.5%), or isoflavonoids (17.5%). Apigenin, diosmin, fisetin, luteolin, and quercetin were considered as the most studied flavonoids for melanoma treatment. In general, flavonoids have shown to be a promising source of molecules with great potential for the treatment of melanoma

Reverse and Forward Engineering of Local Voltage Control in Distribution Networks

The increasing penetration of renewable and distributed energy resources in distribution networks calls for real-time and distributed voltage control. In this paper we investigate local Volt/VAR control with a general class of control functions, and show that the power system dynamics with non-incremental local voltage control can be seen as distributed algorithm for solving a well-defined optimization problem (reverse engineering). The reverse engineering further reveals a fundamental limitation of the non-incremental voltage control: the convergence condition is restrictive and prevents better voltage regulation at equilibrium. This motivates us to design two incremental local voltage control schemes based on the subgradient and pseudo-gradient algorithms respectively for solving the same optimization problem (forward engineering). The new control schemes decouple the dynamical property from the equilibrium property, and have much less restrictive convergence conditions. This work presents another step towards developing a new foundation -- network dynamics as optimization algorithms -- for distributed realtime control and optimization of future power networks

Chemical composition, antioxidant and antibacterial activities and evaluation of cytotoxicity of the fractions obtained from Selaginella convoluta (Arn.) Spring (Selaginellaceae)

The aim of this study was to evaluate the chemical composition, antioxidant and antibacterial activities and cytotoxicity of fractions from Selaginella convoluta, obtained by liquid–liquid extraction using hexane (Sc-Hex), chloroform (Sc-CHCl3) and ethyl acetate (Sc-AcOEt). The phenolic and flavonoid contents were measured by the Folin-Ciocalteu and aluminium chloride methods, respectively. Antioxidant activities were evaluated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and β-carotene-linoleic acid bleaching test. The antibacterial effect was evaluated by the method of microdilution and the cytotoxicity analysis in HCT-116 (colon), OVCAR-8 (ovarian) and SF-295 (brain) cells were carried out for MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) test. The fractions were positive for the presence of anthracene derivatives, flavonoids, lignans, naphthoquinones, steroids and triterpenoids. The Sc-Hex and Sc-AcOEt showed good antioxidant activities. The fractions of S. convoluta demonstrated antibacterial activity and showed weak cytotoxicity. These activities were correlated with presence of phenolic compounds in active fractions

Essential Oils and Their Major Compounds in the Treatment of Chronic Inflammation: A Review of Antioxidant Potential in Preclinical Studies and Molecular Mechanisms

Inflammatory diseases result from the body’s response to tissue damage, and if the resolution is not adequate or the stimulus persists, there will be progression from acute inflammation to chronic inflammation, leading to the development of cancer and neurodegenerative and autoimmune diseases. Due to the complexity of events that occur in inflammation associated with the adverse effects of drugs used in clinical practice, it is necessary to search for new biologically active compounds with anti-inflammatory activity. Among natural products, essential oils (EOs) present promising results in preclinical studies, with action in the main mechanisms involved in the pathology of inflammation. The present systematic review summarizes the pharmacological effects of EOs and their compounds in in vitro and in vivo models for inflammation. The research was conducted in the following databases: PubMed, Scopus, BIREME, Scielo, Open Grey, and Science Direct. Based on the inclusion criteria, 30 articles were selected and discussed in this review. The studies listed revealed a potential activity of EOs and their compounds for the treatment of inflammatory diseases, especially in chronic inflammatory conditions, with the main mechanism involving reduction of reactive oxygen and nitrogen species associated with an elevation of antioxidant enzymes as well as the reduction of the nuclear factor kappa B (NF-κB), reducing the expression of proinflammatory cytokines. Thus, this review suggests that EOs and their major compounds are promising tools for the treatment of chronic inflammation

Flavonoids as Therapeutic Agents in Alzheimer’s and Parkinson’s Diseases: A Systematic Review of Preclinical Evidences

Alzheimer’s and Parkinson’s diseases are considered the most common neurodegenerative disorders, representing a major focus of neuroscience research to understanding the cellular alterations and pathophysiological mechanisms involved. Several natural products, including flavonoids, are considered able to cross the blood-brain barrier and are known for their central nervous system-related activity. Therefore, studies are being conducted with these chemical constituents to analyze their activities in slowing down the progression of neurodegenerative diseases. The present systematic review summarizes the pharmacological effects of flavonoids in animal models for Alzheimer’s and Parkinson’s diseases. A PRISMA model for systematic review was utilized for this search. The research was conducted in the following databases: PubMed, Web of Science, BIREME, and Science Direct. Based on the inclusion criteria, 31 articles were selected and discussed in this review. The studies listed revealed that the main targets of action for Alzheimer’s disease therapy were reduction of reactive oxygen species and amyloid beta-protein production, while for Parkinson’s disease reduction of the cellular oxidative potential and the activation of mechanisms of neuronal death. Results showed that a variety of flavonoids is being studied and can be promising for the development of new drugs to treat neurodegenerative diseases. Moreover, it was possible to verify that there is a lack of translational research and clinical evidence of these promising compounds

Effect of LASSBio-1586 (10, 20 and 40 mg/kg, p.o.) and indomethacin (20 mg/kg, p.o.) on cotton pellet-induced granuloma.

<p>Values are expressed as the mean ± S.E.M. (n = 6, per group), where <i>a</i> indicates <i>p</i><0.05, significantly different from the control group, according to ANOVA, followed by Tukey’s test.</p

Results of the docking procedures for LASSBio-1586.

<p><b>(A)</b> Conformations obtained from the most populous and stable cluster in the binding site of COX-2; <b>(B)</b> most stable docked conformation for LASSBio-1586 (Binding Energy = −7.84 Kcal/mol); <b>(C)</b> native conformation of meloxicam (magenta) and most stable conformation for LASSBio-1586 (cyan).</p

2D comparative representation of the NSAID meloxicam and LASSBio-1586.

<p>2D comparative representation of the NSAID meloxicam and LASSBio-1586.</p

Effect of LASSBio-1586 (40 mg/kg, p.o.) on paw edema induced by histamine in mice.

<p>The sham group was treated only with saline, whereas the control group received saline and histamine. Values are expressed as the mean ± S.E.M. (n = 6, per group), where <i>a</i> indicates <i>p</i><0.05, significantly different from the control group, according to ANOVA, followed by Tukey’s test.</p