Department of Pharmacognosy, Mansoura University, Mansoura, Egypt.
Department of Pharmacognosy, Horus University, New Damietta, Egypt.
PLoS One. 2021 Sep 10;16(9):e0257071. doi: 10.1371/journal.pone.0257071. eCollection 2021.
Aspergillus niger metabolites exhibited a wide range of biological properties including antioxidant and neuro-protective effects and some physical properties as green synthesis of silver nanoparticles AgNP. The present study presents a novel evidence for the various biological activities of green synthesized AgNPs. For the first time, some isolated naphtho-γ-pyrones from marine-derived Aspergillus niger, flavasperone (1), rubrofusarin B (2), aurasperone A (3), fonsecinone A (4) in addition to one alkaloid aspernigrin A (7) were invistigated for their inhibitory activity of acetylcholine esterase AChE, a hallmark of Alzheimer's disease (AD). The ability to synthesize AgNPs by compounds 3, 4 and 7 has been also tested for the first time. Green synthesized AgNPs were well-dispersed, and their size was ranging from 8-30 nm in diameter, their morphology was obviously spherical capped with the organic compounds. Further biological evaluation of their AChE inhibitory activity was compared to the parent compounds. AgNps dramatically increased the inhibitory activity of Compounds 4, 3 and 7 by 84, 16 and 13 fold, respectively to be more potent than galanthamine as a positive control with IC50 value of 1.43 compared to 0.089, 0.311 and 1.53 of AgNPs of Compounds 4, 3 and 7, respectively. Also compound 2 showed moderate inhibitory activity. This is could be probably explained by closer fitting to the active sites or the synergistic effect of the stabilized AgNPs by the organic compouds. These results, in addition to other intrinsic chemical and biological properties of naphtho-γ-pyrones, suggest that the latter could be further explored with a view towards other neuroprotective studies for alleviating AD.
黑曲霉代谢产物表现出广泛的生物特性，包括抗氧化和神经保护作用，以及一些物理特性，如银纳米粒子（AgNP）的绿色合成。本研究为绿色合成的 AgNP 的各种生物活性提供了新的证据。首次从海洋来源的黑曲霉中分离出一些萘并γ-吡喃酮，包括 flavasperone（1）、rubrofusarin B（2）、aurasperone A（3）、fonsecinone A（4），以及一种生物碱aspernigrin A（7），研究它们对乙酰胆碱酯酶（AChE）的抑制活性，AChE 是阿尔茨海默病（AD）的标志。还首次测试了化合物 3、4 和 7 合成 AgNP 的能力。绿色合成的 AgNP 分散良好，直径在 8-30nm 之间，其形态明显为球形，表面覆盖有有机化合物。进一步比较了它们对 AChE 抑制活性的生物评价与母体化合物。AgNps 使化合物 4、3 和 7 的抑制活性分别提高了 84、16 和 13 倍，比阳性对照加兰他敏更有效，IC50 值分别为 1.43、0.089、0.311 和 1.53。化合物 2 也表现出中等抑制活性。这可能是由于化合物与活性部位更吻合，或者 AgNP 被有机化合物稳定时产生协同效应。除了萘并γ-吡喃酮的其他内在化学和生物学特性外，这些结果表明，后者可以进一步探索，以期进行其他神经保护研究，以缓解 AD。
