Pheomelanin Effect on UVB Radiation-Induced Oxidation/Nitration of L-Tyrosine

Pheomelanin is a natural yellow-reddish sulfur-containing pigment derived from tyrosinase-catalyzed oxidation of tyrosine in presence of cysteine. Generally, the formation of melanin pigments is a protective response against the damaging effects of UV radiation in skin. However, pheomelanin, like other photosensitizing substances, can trigger, following exposure to UV radiation, photochemical reactions capable of modifying and damaging cellular components. The photoproperties of this natural pigment have been studied by analyzing pheomelanin effect on oxidation/nitration of tyrosine induced by UVB radiation at different pH values and in presence of iron ions. Photoproperties of pheomelanin can be modulated by various experimental conditions, ranging from the photoprotection to the triggering of potentially damaging photochemical reactions. The study of the photomodification of l-Tyrosine in the presence of the natural pigment pheomelanin has a special relevance, since this tyrosine oxidation/nitration pathway can potentially occur in vivo in tissues exposed to sunlight and play a role in the mechanisms of tissue damage induced by UV radiation.

Betalains in Edible Fruits of Three Cactaceae Taxa—Epiphyllum, Hylocereus, and Opuntia—Their LC-MS/MS and FTIR Identification and Biological Activities Evaluation

Epiphyllum, Hylocereus, and Opuntia plants belong to the Cactaceae family. They are mostly known as ornamental plants but also for their edible fruits, which can potentially be sources of betalains, such as betanin, a natural pigment used in the food industry, e.g., under the European label code E 162. The aim of this work was the identification of betalains (using LC-MS/MS), evaluation of total betalain content (spectrophotometrically), analysis of functional groups (using FT-IR), evaluation of antioxidant activity (using DPPH, ABTS, FRAP, DCFH-DA, and reducing power methods) and evaluation of antimicrobial activity (S. aureus, E. coli, and C. albicans) in fruits of Epiphyllum, Hylocereus, and Opuntia taxa. A total of 20 betalains were identified in the studied Cactaceae fruits. The Epiphyllum pink hybrid had the highest values of total betalains amongst all samples. The highest antioxidant activity was observed in the Epiphyllum pink hybrid, in Opuntia zacuapanensis and O. humifusa fruits. The antimicrobial activity assay showed that cacti fruits were not able to effectively inhibit the growth of E. coli, S. aureus, or C. albicans. Our results prove that these fruits are good sources of natural pigments—betalains. They do not contain toxic compounds in significant amounts and they exhibit antioxidant activity.

Penetapan Kadar Senyawa β-Karoten Dalam Buah Semangka Kuning (Citrullus vulgaris Schrad) Dengan Metode Spektrofotometri UV-Vis

Watermelon is a fruit that favored by the peoples because it tastes sweet and is good for health, watermelon also contains β-carotene. β-carotene is a natural pigment that is found in large amounts in red-orange fruits, including yellow watermelons. The purpose of this study was to determine β-carotene compounds and β-carotene levels in yellow watermelon flesh. The method used in this study for qualitative analysis using TLC method with chloroform: ethyl acetate (5: 5) mobile phase and for quantitative analysis using UV-Vis Spectrophotometry method. The test results showed that the yellow watermelon flesh sample contained β-carotene with a maximum wavelength of 458 nm and the β-carotene content of the yellow watermelon flesh was 146,253 µg/100 grams. Levels of β-carotene compounds in yellow watermelon flesh are included in the low category.Keywords: Yellow watermelon, β-carotene, TLC, UV-Vis spectrophotometry AbstrakSemangka merupakan buah yang banyak digemari oleh masyarakat karena rasanya manis dan baik bagi kesehatan, juga memiliki kandungan β-karoten. β-karoten adalah pigmen alami yang terdapat dalam jumlah besar pada buah-buahan yang berwarna merah-orange termasuk pada buah semangka kuning. Tujuan peneltian ini adalah untuk mengetahui senyawa β-karoten dan kadar β-karoten pada daging buah semangka kuning. Metode yang digunakan dalam penelitian ini untuk analisis kualitatif menggunakan metode KLT dengan fase gerak kloroform : etil asetat (5 : 5) dan untuk analisis kuantitatif menggunakan metode Spektrofotometri UV-Vis. Hasil pengujian menunjukkan sampel daging buah semangka kuning megandung β-karoten dengan Panjang gelombang maksimum yaitu 458 nm dengan kadar β-karoten pada daging buah semangka kuning yaitu 146,253 µg/100 gram. Kadar senyawa β-karoten dalam daging buah semangka kuning termasuk dalam kategori rendah.Kata kunci: Semangka kuning; β-karoten; KLT; spektrofotometri UV-Vis

IDENTIFICATION, CHARACTERIZATION OF CAROTENOID PIGMENT PRODUCING BACTERIA FROM VEGETABLE, FRUITS AND MINI-SURVEY ON PERCEPTION OF URBAN POPULATION TOWARDS BACTERIAL PIGMENTS

Pigments are largely exploited compounds due to their chromophoric variations and enticing properties in several applications such as food, dairy, printing, textile and pharmaceutical industries etc. While synthetic pigments are widely used, toxic reactions and effects of the pigments has led to the prompt diversion of consumers towards natural pigment sources such as microbial pigments (MP). MP hold great promise against existent synthetic counterparts with additional properties such as biodegradability, non-toxicity, therapeutics (anti-inflammatory, antioxidant, anticancer etc.