Taechowisan Thongchai, Chuen-Im Thanaporn, Phutdhawong Waya S
Pak J Biol Sci. 2025 Jan;28(1):27-37. doi: 10.3923/pjbs.2025.27.37.
<b>Background and Objectives:</b> This study characterized a bacterial strain, BN122, isolated from the root tissues of purple sticky rice (<i>Oryza sativa</i> L. var. glutinosa). Identified as <i>Streptomyces antimicrobicus</i> based on 16S rDNA analysis and physical-chemical properties, the aim was to isolate and evaluate the antibacterial and anticancer activities of its bioactive compounds. <b>Materials and Methods:</b> The major compounds were purified from BN122's culture extract using column chromatography and TLC. The NMR spectroscopy and mass spectrometry confirmed their identities as Cyclo-(L-Pro-L-Val), Cyclo-(L-Pro-L-Leu), Cyclo-(L-Pro-L-Trp) and Cyclo-(L-Pro-L-Phe). The antibacterial and anticancer activities of these compounds were subsequently assessed. Statistical significance was determined using SPSS software. <b>Results:</b> Isolated compounds exhibited potent antibacterial activity against Gram-positive bacteria. Minimum inhibitory concentrations (MICs) ranged from 32 to 256 μg/mL, while minimum bactericidal concentrations (MBCs) were between 128 and 512 μg/mL. Compounds demonstrated potent cytotoxic activity against cancer cells, with IC<sub>50</sub> values ranging from 32.00 to 57.08 μg/mL for MDA-MB-231 cells, 85.73 to 158.93 μg/mL for HeLa cells and 276.89 to 323.48 μg/mL for HepG2 cells. Notably, these compounds exhibited moderate toxicity towards non-cancerous Vero cells (IC<sub>50</sub> = 482.73 to 680.87 μg/mL). <b>Conclusion:</b> The findings suggested that <i>Streptomyces antimicrobicus</i> BN122 produces compounds with promising antibacterial and anticancer properties. Further research on these compounds could contribute to developing novel therapeutic strategies for bacterial infections and certain cancers.
背景与目的：本研究对从紫糯米（Oryza sativa L. var. glutinosa）根组织中分离出的一株细菌BN122进行了特性分析。基于16S rDNA分析和理化性质鉴定为抗微生物链霉菌（Streptomyces antimicrobicus），目的是分离并评估其生物活性化合物的抗菌和抗癌活性。材料与方法：主要化合物通过柱色谱和薄层色谱从BN122的培养提取物中纯化得到。核磁共振光谱和质谱确定它们分别为环（L-脯氨酸-L-缬氨酸）、环（L-脯氨酸-L-亮氨酸）、环（L-脯氨酸-L-色氨酸）和环（L-脯氨酸-L-苯丙氨酸）。随后评估了这些化合物的抗菌和抗癌活性。使用SPSS软件确定统计学显著性。结果：分离出的化合物对革兰氏阳性菌表现出强效抗菌活性。最低抑菌浓度（MIC）范围为32至256μg/mL，而最低杀菌浓度（MBC）在128至512μg/mL之间。化合物对癌细胞表现出强效细胞毒性活性，MDA-MB-231细胞的IC50值范围为32.00至57.08μg/mL，HeLa细胞为85.73至158.93μg/mL，HepG2细胞为276.89至323.48μg/mL。值得注意的是，这些化合物对非癌细胞Vero细胞表现出中等毒性（IC50 = 482.73至680.87μg/mL）。结论：研究结果表明抗微生物链霉菌BN122产生具有良好抗菌和抗癌特性的化合物。对这些化合物的进一步研究可能有助于开发针对细菌感染和某些癌症的新型治疗策略。
