Prolonged exposure to Ultra Violet Radiation (UVR) adversely alters the functions of many skin cell types causing skin cancer and photoaging, which had led to increase in demand for more safe and natural sunscreens against UVR. The present study focuses on production, structural characterization and evaluation of photoprotective nature of melanin pigment derived from lime dwelling Pseudomonas sp. Melanin was characterized by solubility, UV–Vis, FT-IR, ¹³C-CPMAS, ESI-MS spectroscopy, including particle size, melting point and elemental analyses. In vitro cytotoxicity and photo-protective effect of Pseudomonas derived melanin (Mel-P) against UV-B (Broad Band-BB) radiations were assessed on mouse fibroblasts NIH 3 T3 cell lines. Reactive Oxygen Species (ROS) generated in NIH 3 T3 cells upon UV-B (BB) exposure was determined and quantified by Fluorescent microscopic and Flow cytometric analyses. A natural melanin obtained from Pseudomonas sp. contains 5,6- dihydroxy indole 2-carboxyic acid (DHICA) as its basic constituent and possess typical properties of eumelanin as revealed by the characterization studies. Mel-P has shown cell viability of 61.33 ± 6.58% at the concentration of 500 μg/mL proving its non-cytotoxic effect. Owing to its anti-oxidant property, melanin efficiently protected the mouse fibroblast cells from UV-B (BB) irradiation in a dose dependant manner demonstrating its potential as an active photoprotective agent.

长时间暴露于紫外线（UVR）会不利地改变许多皮肤细胞类型的功能，从而导致皮肤癌和光老化，这导致对更安全，更天然的UVR防晒霜的需求增加。本研究的重点是来源于生石灰的假单胞菌（Pseudomonas sp。）黑色素色素的生产，结构表征和光防护性质的评估。黑色素的特征在于溶解度，UV-Vis，FT-IR，¹³ C-CPMAS，ESI-MS光谱，包括粒径，熔点和元素分析。假单胞菌衍生的黑色素（Mel- P）的体外细胞毒性和光保护作用在小鼠成纤维细胞NIH 3 T3细胞系上评估了抗UV-B（宽带BB）辐射的能力。通过荧光显微镜和流式细胞术分析，确定并定量了暴露于UV-B（BB）后NIH 3 T3细胞中产生的活性氧（ROS）。从假单胞菌sp。获得的天然黑色素。包含5,6-二羟基吲哚2-羧酸（DHICA）作为其基本成分，并具有特征性研究揭示的Eumelanin的典型特性。梅尔P在500μg/ mL的浓度下显示出61.33±6.58％的细胞活力，证明其无细胞毒性作用。由于其抗氧化特性，黑色素以剂量依赖性方式有效保护了小鼠成纤维细胞免受UV-B（BB）辐射，证明了其作为活性光保护剂的潜力。