scholarly journals Preparation, Characterization, Cytotoxicity and Antioxidant Activity of DOPA Melanin Modified by Amino Acids: Melanin-Like Oligomeric Aggregates

Author(s):  
Thiago G. Costa ◽  
Mateus J. Feldhaus ◽  
Felipe S. Vilhena ◽  
Melina Heller ◽  
Gustavo A. Micke ◽  
...  
2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Gabriela Dubiago ◽  
Anna Nowak ◽  
Adam Klimowicz

Honey is produced by bees (Apis mellifera) from flower nectar and insect secretions. Like other bee products it is used as an adjuvant for treatment of many diseases. It also finds its uses for producing cosmetics. The main components of honey include carbohydrates, which represent approximately 80% of the dry matter, and water. Monosaccharides, mainly fructose and glucose, constitute approximately 70% of the sugars, whilst the remaining saccharides are disaccharides and oligosaccharides. Moreover, honey consists vitamins, minerals, polyphenols, amino acids and enzymes. Beneficial effect of natural honey on human health has been known for a long time because of its biological and therapeutic properties. It is used to treat some cardiovascular and gastrointestinal diseases. Among the best-known properties of honey are its antibacterial, antifungal, antiviral and anti-inflammatory activities. Important is also its antioxidant activity, which could be useful for producing anti-aging cosmetics.


Antioxidants ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1001
Author(s):  
Daniele Barbieri ◽  
Morena Gabriele ◽  
Martina Summa ◽  
Raffaele Colosimo ◽  
Donatella Leonardi ◽  
...  

Bee pollen is made by honey bees (Apis Mellifera) from the pollen of plants and flowers and represents an apiary product enriched in essential amino acids, polyphenols, omega-3, and omega-6 fatty acids. This study investigated the botanical origin, micronutrient profile, and antioxidant activity of bee pollen samples (n = 10) harvested in Lucca and Massa Carrara (Tuscany, Italy) between 2016 and 2017. The palynological analysis showed that bee pollen samples were composed of nine botanical families. Front-face fluorescence spectroscopy was performed on bee pollen samples in bulk, without any treatment, and in ethanol extracts to determine the characteristic fluorescent profile and, to identify the main chemical compounds with biological activity. The main chemical compounds detected were polyphenols (mainly flavonoids and phenolic acids), hydro-soluble vitamins (B2, B3, B6, and B9), amino acids, and pigments. Furthermore, the antioxidant activity was investigated, and one of the two Viburnum pollens resulted in the highest polyphenols and flavonoids content (20.15 ± 0.15 mg GAE/g fw and 23.46 ± 0.08 mg CE/g fw, respectively). However, Prunus and Eucalyptus families showed the highest in vitro (190.27 ± 8.30 µmol Fe2+/g) and ex vivo (54.61 ± 8.51 CAA unit) antioxidant capacity, respectively. These results suggested that Tuscan bee pollen, depending on the botanical family, is rich in essential nutrients and potential nutraceutical product.


Metabolites ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 114 ◽  
Author(s):  
Vuanghao Lim ◽  
Sara Ghorbani Gorji ◽  
Venea Dara Daygon ◽  
Melissa Fitzgerald

Selected Australian native fruits such as Davidson’s plum, finger lime and native pepperberry have been reported to demonstrate potent antioxidant activity. However, comprehensive metabolite profiling of these fruits is limited, therefore the compounds responsible are unknown, and further, the compounds of nutritional value in these native fruits are yet to be described. In this study, untargeted and targeted metabolomics were conducted using the three fruits, together with assays to determine their antioxidant activities. The results demonstrate that targeted free and hydrolysed protein amino acids exhibited high amounts of essential amino acids. Similarly, important minerals like potassium were detected in the fruit samples. In antioxidant activity, Davidson’s plum reported the highest activity in ferric reducing power (FRAP), finger lime in antioxidant capacity (ABTS), and native pepperberry in free radical scavenging (DPPH) and phosphomolybdenum assay. The compounds responsible for the antioxidant activity were tentatively identified using untargeted GC×GC-TOFMS and UHPLC-QqQ-TOF-MS/MS metabolomics. A clear discrimination into three clusters of fruits was observed using principal component analysis (PCA) and partial least squares (PLS) analysis. The correlation study identified a number of compounds that provide the antioxidant activities. GC×GC-TOFMS detected potent aroma compounds of limonene, furfural, and 1-R-α-pinene. Based on the untargeted and targeted metabolomics, and antioxidant assays, the nutritional potential of these Australian bush fruits is considerable and supports these indigenous fruits in the nutraceutical industry as well as functional ingredients for the food industry, with such outcomes benefiting Indigenous Australian communities.


1948 ◽  
Vol 21 (3) ◽  
pp. 752-764 ◽  
Author(s):  
R. F. A. Altman

Abstract An elaborate investigation on the identity and usefulness of the antioxidants naturally occurring in Hevea latex is of value because there is an increasing demand for special types of rubber with low nitrogen and ash contents, less water absorption, better electrical properties, and less odor than common crepe, and because these rubbers are generally unstable in comparison with the usual grades of rubber crepe and sheet. for the purpose of the investigation, fresh latex was separated into main-fractions, the most important of which have been called water-solubles and ether-solubles. These were further separated into various subfractions, which, one by one, have been tested for their antioxidant activity on raw rubber. In the following table only those fractions which show an outstanding antioxidant action are recorded. It is shown further that the amino acids are most remarkable in their antioxidant action : minute quantities exert a strong retarding action on the oxidation of raw rubber. Choline and cephaline are most probably the active components of the second water layer. The active ether-soluble fractions could not be identified due to the small quantities separated.


2001 ◽  
Vol 14 (3) ◽  
pp. 339-353
Author(s):  
Alexander A. Ermoshin ◽  
◽  
Irina S. Kiseleva ◽  
Irina V. Nikkonen ◽  
Dominique S. Nsengiyumva ◽  
...  

The search for new natural sources of biologically active substances is a major issue in pharmaceutical industry. Xylotrophic basidiomycetes are common in forests worldwide, but as a prospective raw source of biologically active compounds they have not been studied as extensively as plants and other groups of fungi. The study is aimed to determine the chemical composition and antioxidant activity of extracts from 10 species of tinder fungi growing on birch and common in the forests in Russia. The chaga muchroom (Inonotus obliquus), traditionally used in medicine, was chosen as a standard species. Extracts from fruiting bodies were obtained with water or 95 % ethanol. They contained 4 to 8 types of free amino acids including 2 to 6 essential ones. Perennial basidiocarps were shown to be richer in phenolic compounds and poorer in amino acids than annual ones. Alkaloids and saponins were found in perennial basidiocarps of two species, saponins were also found in annual basidiocarps of one species. Water and alcohol extracts differed in composition and concentration of extractives, and showed different antioxidant (inhibition of lipid peroxidation) and antiradical (ABTS‑test, inhibition of NO production) activity. This way it was shown that the nature of the solvent extraction agent is important for the manifestation of biological activity. In most tests, water extracts from chaga showed better antioxidant properties; extracts from Piptoporus betulinus and Fomitopsis pinicola were also effective as antioxidants, which may be promising avenues for future research


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