Abstract：
The biopolymer melanin is reported for many biological processes to secure biological entities over unfavorable environmental factors. The present study aimed to isolate soil fungi and screen for melanin production. The potent fungus was identified as Penicillium citrinum NP4 based on morphological and molecular characterization with accession number OP070954. Using standardized tyrosine broth conditions melanin was produced by NP4 and extracted by acidification. Extracted melanin exhibited maximum UV-visible absorption at 223 nm; FTIR peaks validate the occurrence of CO, CN, CH, and CC functional groups present in the indole/pyrrole structure. TLC analysis exhibited a prominent single band with a Retardation factor (Rf) of 0.68, resonance peaks at 6.621, 7.061, and 7.185 ppm exhibited aromatic hydrogen in the indole/pyrole system in 1H NMR. The EDX peaks confirm the presence of carbon, oxygen, sulfur, and nitrogen elements which are the key factors in melanin structure, and TGA reports the thermal stability of the melanin. An in silico molecular docking approach on lung cancer causing proteins EGFR (3g5z), KRAS (6vc8), and TP53 (8 dc4) were conducted to determine the active binding sites of the melanin, and proteins exhibited binding affinity of -8.0 for 3g5z, -9.8 for 6vc8, and - 10.1 kcal/mol for TP53 protein with melanin. Anticancer activity of the melanin showed significant inhibition of A549 cells in dose-dependent mode with significant IC50 of 65.49 μg/mL; apoptotic examination reveals 46.14 % apoptosis for melanin and 46.36 % apoptosis for standard drug (cisplatin). Melanin exhibited good photoprotection capacity at 1 μg/mL. In conclusion, the extracted melanin exhibited significant results on many biological applications and it can be used in the pharmaceutical field to avoid chemical-based drugs.
摘要：
据报道，生物聚合物黑色素用于许多生物过程，以保护生物实体免受不利的环境因素的影响。本研究旨在分离土壤真菌并筛选黑色素的产生。根据形态学和分子特征，将有效的真菌鉴定为柑橘青霉NP4，登录号为OP070954。使用标准化的酪氨酸肉汤条件，NP4产生黑色素并通过酸化提取。提取的黑色素在223nm处表现出最大的紫外-可见吸收；FTIR峰验证了CO的发生，CN,CH,和存在于吲哚/吡咯结构中的CC官能团。TLC分析显示出突出的单带，延迟因子（Rf）为0.68，在1HNMR中，在6.621、7.061和7.185ppm处的共振峰显示出吲哚/吡咯系统中的芳香族氢。EDX峰证实了碳的存在，氧气,硫磺,和氮元素是黑色素结构中的关键因素，和TGA报告黑色素的热稳定性。肺癌致病蛋白EGFR（3g5z）的计算机分子对接方法，KRAS(6vc8),和TP53（8dc4）进行，以确定黑色素的活性结合位点，蛋白质对3g5z的结合亲和力为-8.0，对于6vc8为-9.8,对于具有黑色素的TP53蛋白为-10.1kcal/mol。黑色素的抗癌活性以剂量依赖性模式显示了对A549细胞的显着抑制，显着的IC50为65.49μg/mL；凋亡检查显示，黑色素显示黑色素的凋亡为46.14％，标准药物（顺铂）的凋亡为46.36％。黑色素在1μg/mL时表现出良好的光保护能力。总之,提取的黑色素在许多生物应用中表现出显著的结果，它可以用于制药领域，以避免基于化学的药物。
