Phenolic Compounds in Prevention and Treatment of Skin Cancers: A Review.

Several clinical studies have shown that exposure of skin to solar ultraviolet (UV) radiation causes adverse effects, such as inflammation, oxidative stress and DNA damage. As a result, different skin disorders can arise, among which are skin cancer, including non-melanoma skin cancer (NMSC) and melanoma (MM). Phenolic compounds are plant-derived secondary metabolites with a well-known antioxidant activity, able to counteract the negative effects of UV radiation. In this review, we discuss the effects of some selected phenols on NMSC and MM, demonstrating that they can be useful in the prevention and in the treatment of these types of tumors. Moreover, we report the mechanisms by which these phenols carry out their antitumor action. In vitro and in vivo studies have highlighted that many phenols are capable of inducing photoprotection, apoptosis and autophagy. They can also reduce DNA methylation, tumorigenesis, tumor incidence and proliferation. Moreover, we describe some examples of plant extracts, whose anticancer activity appears to be better than that of single phenols. A great concordance of results emerged, despite the differences in experimental methods. Therefore, the knowledge compiled here could provide the basis for conducting some well-organized clinical trials to validate the chemopreventive and the therapeutic potential of some phenolic compounds in patients with NMSC and MM.

A Proteomic Approach to Uncover Neuroprotective Mechanisms of Oleocanthal against Oxidative Stress.

Neurodegenerative diseases represent a heterogeneous group of disorders that share common features like abnormal protein aggregation, perturbed Ca2+ homeostasis, excitotoxicity, impairment of mitochondrial functions, apoptosis, inflammation, and oxidative stress. Despite recent advances in the research of biomarkers, early diagnosis, and pharmacotherapy, there are no treatments that can halt the progression of these age-associated neurodegenerative diseases. Numerous epidemiological studies indicate that long-term intake of a Mediterranean diet, characterized by a high consumption of extra virgin olive oil, correlates with better cognition in aged populations. Olive oil phenolic compounds have been demonstrated to have different biological activities like antioxidant, antithrombotic, and anti-inflammatory activities. Oleocanthal, a phenolic component of extra virgin olive oil, is getting more and more scientific attention due to its interesting biological activities. The aim of this research was to characterize the neuroprotective effects of oleocanthal against H2O2-induced oxidative stress in neuron-like SH-SY5Y cells. Moreover, protein expression profiling, combined with pathways analyses, was used to investigate the molecular events related to the protective effects. Oleocanthal was demonstrated to counteract oxidative stress, increasing cell viability, reducing reactive oxygen species (ROS) production, and increasing reduced glutathione (GSH) intracellular level. Proteomic analysis revealed that oleocanthal significantly modulates 19 proteins in the presence of H2O2. In particular, oleocanthal up-regulated proteins related to the proteasome, the chaperone heat shock protein 90, the glycolytic enzyme pyruvate kinase, and the antioxidant enzyme peroxiredoxin 1. Moreover, oleocanthal protection seems to be mediated by Akt activation. These data offer new insights into the molecular mechanisms behind oleocanthal protection against oxidative stress.

Oleocanthal and oleacein contribute to the in vitro therapeutic potential of extra virgin oil-derived extracts in non-melanoma skin cancer.

Although the anticancer properties of extra virgin olive oil (EVOO) extracts have been recognized, the role of single compounds in non-melanoma skin cancer is still unknown. The in vitro chemopreventive and anticancer action of EVOO extracts and oil-derived compounds in non-melanoma skin cancer models were evaluated on cutaneous squamous cell carcinoma cells and on immortalized human keratinocytes stimulated with epidermal growth factor. Preparation of EVOO extracts and isolation of single compounds was carried out by chromatographic methods. Antitumor activity was assessed by cell-based assays (cell viability, migration, clonogenicity, and spheroid formation) and apoptosis documented by internucleosomal DNA fragmentation. Finally, inhibition of key oncogenic signaling nodes involved in the progression from actinic keratosis to cutaneous squamous cell carcinoma was studied by western blot. EVOO extracts reduced non-melanoma skin cancer cell viability and migration, prevented colony and spheroid formation, and inhibited proliferation of atypical keratinocytes stimulated with epidermal growth factor. Such a pharmacological activity was promoted by oleocanthal and oleacein through the inhibition of Erk and Akt phosphorylation and the suppression of B-Raf expression, whereas tyrosol and hydroxytyrosol did not have effect. The current study provides in vitro evidence for new potential clinical applications of EVOO extracts and/or single oil-derived compounds in the prevention and treatment of non-melanoma skin cancers.

Determination of water-soluble vitamins in multivitamin dietary supplements and in artichokes by micellar electrokinetic chromatography.

Several procedures of extraction with solvents for the simultaneous determination of vitamin C and some vitamins belonging to the B group (thiamine, riboflavine, nicotinic acid and nicotinamide) in multivitamin preparations and in artichokes (Cynara cardunculus subsp. scolymus [L.] Hegi) were developed. Different experimental conditions were used, in terms of heat treatment, composition and pH of the extraction mixture, with particular attention to high-temperature steps; purification of the extracts with solid phase extraction and stabilisation through lyophilisation were discussed. Analyses of the extracts were conducted by capillary electrophoresis in micellar electrokinetic chromatography modality. Borate buffer at pH 8.2 was used, and sodium dodecyl sulphate was added to the background electrolyte as surfactant. A range of linearity was determined and calibration curves were plotted for all the analytes.

Rational design, synthesis, and pharmacological properties of new 1,8-naphthyridin-2(1H)-on-3-carboxamide derivatives as highly selective cannabinoid-2 receptor agonists.

The CB(2) receptor activation can be exploited for the treatment of diseases such as chronic pain and tumors of immune origin, devoid of psychotropic activity. On the basis of our already reported 1,8-naphthyridin-4(1H)-on-3-carboxamide derivatives, new 1,8-naphthyridin-2(1H)-on-3-carboxamide derivatives were designed, synthesized, and tested for their affinities toward the human CB(1) and CB(2) cannabinoid receptors. Some of the reported compounds showed a subnanomolar CB(2) affinity with a CB(1)/CB(2) selectivity ratio greater than 200 (compounds 6, 12, cis-12, 13, and cis-13). Further studies revealed that compound 12, which presented benzyl and carboxy-4-methylcyclohexylamide substituents bound in the 1 and 3 positions, exerted a CB(2)-mediated inhibitory action on immunological human basophil activation. On the human T cell leukemia line Jurkat the same derivative induced a concentration-dependent decrease of cell viability. The obtained results suggest that 1,8-naphthyridin-2(1H)-on-3-carboxamides represent a new scaffold very suitable for the development of new promising CB(2) agonists.

Synthesis and biological evaluation of 1,8-naphthyridin-4(1H)-on-3-carboxamide derivatives as new ligands of cannabinoid receptors.

Cannabinoid receptors have been studied extensively in view of their potential functional role in several physiological and pathological processes. For this reason, the search for new potent, selective ligands for subtype CB receptors, CB(1) and CB(2), is still of great importance, in order to investigate their role in various physiological functions. The present study describes the synthesis and the biological properties of a series of 1,8-naphthyridine derivatives, characterised by the presence of some important structural requirements exhibited by other classes of cannabinoid ligands, such as an aliphatic or aromatic carboxamide group in position 3, and an alkyl or arylalkyl substituent in position 1. These compounds were assayed for binding both to the brain and to peripheral cannabinoid receptors (CB(1) and CB(2)). The results obtained indicate that the naphthyridine derivatives examined possess a greater affinity for the CB(2) receptor than for the CB(1) receptor. In particular, derivatives 6a and 7a possess an appreciable affinity for the CB(2) receptor, with K(i) values of 5.5 and 8.0 nM respectively; also compounds 4a, 5a and 8a exhibit a good CB(2) affinity, with K(i) values in the range of 10-44 nM. Furthermore, compounds 3g-i and 18 revealed a good CB(2) selectivity, with a CB(1)/CB(2) ratio >20.

Synthesis of variously substituted 1,8-naphthyridine derivatives and evaluation of their antimycobacterial activity.

A series of 1,8-naphthyridine derivatives variously substituted in the 2, 3, 4 and 7 positions were synthesized for in vitro evaluation of antimycobacterial activity in accordance with an international program with the tuberculosis antimicrobial acquisition and coordinating facility (TAACF). Several compounds 4, 8, 12, 14, 19, 29 and 30, when tested at a concentration of 6.25 microg/ml against Mycobacterium tuberculosis H37Rv, showed an interesting activity with % inhibition in the range 38-96%. The most effective substituent in position 2, 4 or 7 of the 1,8-naphthyridine nucleus seem to be the piperidinyl group.