A systematic review of natural products for skin applications: Targeting inflammation, wound healing, and photo-aging

BACKGROUND

Every day the skin is constantly exposed to several harmful factors that induce oxidative stress. When the cells are incapable to maintain the balance between antioxidant defenses and reactive oxygen species, the skin no longer can keep its integrity and homeostasis. Chronic inflammation, premature skin aging, tissue damage, and immunosuppression are possible consequences induced by sustained exposure to environmental and endogenous reactive oxygen species. Skin immune and non-immune cells together with the microbiome are essential to efficiently trigger skin immune responses to stress. For this reason, an ever-increasing demand for novel molecules capable of modulating immune functions in the skin has risen the level of their development, particularly in the field of natural product-derived molecules.

PURPOSE

In this review, we explore different classes of molecules that showed evidence in modulate skin immune responses, as well as their target receptors and signaling pathways. Moreover, we describe the role of polyphenols, polysaccharides, fatty acids, peptides, and probiotics as possible treatments for skin conditions, including wound healing, infection, inflammation, allergies, and premature skin aging.

METHODS

Literature was searched, analyzed, and collected using databases, including PubMed, Science Direct, and Google Scholar. The search terms used included "Skin", "wound healing", "natural products", "skin microbiome", "immunomodulation", "anti-inflammatory", "antioxidant", "infection", "UV radiation", "polyphenols", "polysaccharides", "fatty acids", "plant oils", "peptides", "antimicrobial peptides", "probiotics", "atopic dermatitis", "psoriasis", "auto-immunity", "dry skin", "aging", etc., and several combinations of these keywords.

RESULTS

Natural products offer different solutions as possible treatments for several skin conditions. Significant antioxidant and anti-inflammatory activities were reported, followed by the ability to modulate immune functions in the skin. Several membrane-bound immune receptors in the skin recognize diverse types of natural-derived molecules, promoting different immune responses that can improve skin conditions.

CONCLUSION

Despite the increasing progress in drug discovery, several limiting factors need future clarification. Understanding the safety, biological activities, and precise mechanisms of action is a priority as well as the characterization of the active compounds responsible for that. This review provides directions for future studies in the development of new molecules with important pharmaceutical and cosmeceutical value.

Membrane-enriched proteome changes and prion protein expression during neural differentiation and in neuroblastoma cells

Background

The function of the prion protein, involved in the so-called prion diseases, remains a subject of intense debate and the possibility that it works as a pleiotropic protein through the interaction with multiple membrane proteins is somehow supported by recent reports. Therefore, the use of proteomic and bioinformatics combined to uncover cellular processes occurring together with changes in the expression of the prion protein may provide further insight into the putative pleiotropic role of the prion protein.

Results

This study assessed the membrane-enriched proteome changes accompanying alterations in the expression of the prion protein. A 2D-DIGE approach was applied to two cell lines after prefractionation towards the membrane protein subset: an embryonic stem cell line and the PK1 subline of neuroblastoma cells which efficiently propagates prion infection. Several proteins were differentially abundant with the increased expression of the prion protein during neural differentiation of embryonic stem cells and with the knockdown of the prion protein in PK1 cells. The identity of around 20% of the differentially abundant proteins was obtained by tandem MS. The catalytic subunit A of succinate dehydrogenase, a key enzyme for the aerobic energy metabolism and redox homeostasis, showed a similar abundance trend as the prion protein in both proteomic experiments. A gene ontology analysis revealed “myelin sheath”, “organelle membrane” and “focal adhesion” associated proteins as the main cellular components, and “protein folding” and “ATPase activity” as the biological processes enriched in the first set of differentially abundant proteins. The known interactome of these differentially abundant proteins was customized to reveal four interactors with the prion protein, including two heat shock proteins and a protein disulfide isomerase.

Conclusions

Overall, our study shows that expression of the prion protein occurs concomitantly with changes in chaperone activity and cell-redox homeostasis, emphasizing the functional link between these cellular processes and the prion protein.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3694-6) contains supplementary material, which is available to authorized users.

Effect of the herbicide Roundup on Perkinsus olseni in vitro proliferation and in vivo survival when infecting a permissive host, the clam Ruditapes decussatus

Coastal habitats are increasingly being exposed to herbicide contamination from urban and agricultural catchments. Data on its toxicity on aquatic ecosystems, especially those based on sediment, are relatively scarce. This study aimed at investigating whether the susceptibility of an aquatic filter-feeding organism, the carpet-shell clam (Ruditapes decussatus) to the parasite Perkinsus olseni was influenced by the herbicide Roundup and its active ingredient glyphosate. The effect of Roundup and glyphosate on P. olseni in vitro proliferation was also evaluated and appeared to confirm the higher toxicity of Roundup when compared with technical grade glyphosate.

Benzodiazepine receptors and avian macrophage activity: diazepam decreases spreading and phagocytosis

The complex interrelations between the nervous system and the immune system have led to the creation of a new research area denoted neuroimmunology. The effects of stress on the immune response have long been observed in chickens. Since benzodiazepine receptors are involved in the stress reaction, we proposed to assess the importance of these receptors in the activity of chick peritoneal macrophages. We used 420 viable embryonated eggs of the commercial Hubbard broiler line treated through the chorioallantoid membrane on the 11th day of incubation: falsely manipulated (Sham group), with 40% propyleneglycol (PG) in simple Ringer solution (Vehicle group), and treated with diazepam (DZ), 8 mg/kg (DZ group). After hatching, the chicks were housed in metal rearing cages of the "battery" type for 5 weeks. At 36 days of age, 24 chicks from each treated group were divided at random into two groups of 12 animals each which were treated with DZ (2 mg/kg) or with 40% PPG in an equal volume once a day by the oral route for 4 days. Peritoneal macrophages were collected and submitted to the spreading an phagocytosis tests. Data were analyzed statistically using the SAS software (p < 0.05). Administration of DZ in ovo did not cause a significant decrease in egg hatchability, birth weight or performance parameters during the 5 weeks of assessment. However, the rate of macrophage spreading and phagocytosis was reduced. When administered at 40 days of age, DZ did not change the spreading rate but reduced the phagocytosis rate. There was no interaction between treatments. These results indicate that benzodiazepine receptors seem to be important for macrophage activity also in birds, as previously observed in rodents and primates. Since benzodiazepine receptors are involved in the response to stress, it is possible that the effects of stress on avian immunity may be mediated in part by these receptors.