Manzano Joe Anthony H, Abanto John Cyril D, Dayo Beaver Andrei F, Llames Lloyd Christian J, Gonzaga Mary Grace E, Brogi Simone, Macabeo Allan Patrick G
Department of Biological Sciences, College of Science, and UST Laboratories for Vaccine Science, Molecular Biology, and Biotechnology, University of Santo Tomas, España Blvd., Manila, 1015, Philippines.
Research Center for the Natural and Applied Sciences, University of Santo Tomas, España Blvd., Manila, 1015, Philippines.
Arch Microbiol. 2025 Aug 28;207(10):239. doi: 10.1007/s00203-025-04429-6.
Fungi of the order Diaporthales are prolific sources of antimicrobial secondary metabolites. In this paper, we describe antimicrobial and antituberculosis anthraquinones (AQs) from Diaporthe perseae, an endophytic fungus isolated and identified from the endemic Philippine medicinal plant Uvaria alba (Annonaceae). Large-scale rice fermentation of D. perseae yielded an ethyl acetate extract which was subjected to a series of chromatographic purification to yield three compounds. Spectroscopic analyses allowed the identification of the anthraquinone compounds citreorosein (1), skyrin (2), and rugulosin A (3). AQs 1 and 3 showed broad-spectrum against Gram-positive bacteria (Micrococcus luteus, Bacillus subtilis, and Staphylococcus aureus) (MIC = 1.0-2.0 µg/mL), however only 3 demonstrated strong inhibition against Gram-negative bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Chromobacterium violaceum) and non-TB mycobacteria (Mycobacterium smegmatis) (MIC = 8.25-66.0 µg/mL). AQ 3 also exhibited inhibition against both M. tuberculosis (Mtb) HRv (Microplate Alamar Blue Assay; MABA MIC = 29.2 µg/mL) and its non-replicating persistent strain (Low-Oxygen Recovery Assay; LORA MIC = 30.3 µg/mL). To explore the potential mechanism of 3, DNA supercoiling assay was performed. Thus, rugulosin A (3) displayed inhibition of Mtb. DNA gyrase, an enzyme necessary for genomic replication via ATP-dependent DNA relaxation mechanisms. Molecular docking and molecular dynamics revealed strong, stable binding affinity of 3 (BE = -9.5 kcal/mol) and its tautomer 4 (BE = -9.6 kcal/mol) within the active pocket of the MtbDNA gyrase. Overall, rugulosin A (3) represents a promising antibiotic prototype with in vitro and in silico activity against M. tuberculosis, and identifies DNA gyrase as therapeutic target for anthraquinone antimycobacterials.
座囊菌目真菌是抗菌次生代谢产物的丰富来源。在本文中，我们描述了从菲律宾特有药用植物白紫玉盘（番荔枝科）中分离并鉴定的内生真菌——樟疫霉中的抗菌和抗结核蒽醌（AQs）。对樟疫霉进行大规模大米发酵，得到乙酸乙酯提取物，对其进行一系列色谱纯化，得到三种化合物。通过光谱分析鉴定出蒽醌化合物柠檬玫瑰红素（1）、天精（2）和皱盘菌素A（3）。AQs 1和3对革兰氏阳性菌（藤黄微球菌、枯草芽孢杆菌和金黄色葡萄球菌）具有广谱抗菌活性（MIC = 1.0 - 2.0 μg/mL），然而只有3对革兰氏阴性菌菌株（大肠杆菌、铜绿假单胞菌和紫色色杆菌）和非结核分枝杆菌（耻垢分枝杆菌）表现出强烈抑制作用（MIC = 8.25 - 66.0 μg/mL）。AQ 3还对结核分枝杆菌（Mtb）HRv（微孔板阿拉玛蓝检测法；MABA MIC = 29.2 μg/mL）及其非复制性持留菌株（低氧恢复检测法；LORA MIC = 30.3 μg/mL）均有抑制作用。为了探究3的潜在作用机制，进行了DNA超螺旋检测。因此，皱盘菌素A（3）显示出对Mtb DNA促旋酶的抑制作用，该酶是通过ATP依赖的DNA松弛机制进行基因组复制所必需的酶。分子对接和分子动力学研究表明，3（结合能 = -9.5 kcal/mol）及其互变异构体4（结合能 = -9.6 kcal/mol）在Mtb DNA促旋酶的活性口袋内具有强烈、稳定的结合亲和力。总体而言，皱盘菌素A（3）是一种有前景的抗生素原型，具有体外和计算机模拟的抗结核活性，并确定DNA促旋酶为蒽醌类抗分枝杆菌药物的治疗靶点。
