Spermacoce princeae (K. Schum) has been used in the treatment of bacterial skin infections in Uganda. Pharmacological studies revealed that extracts of S. princeae exhibited antibacterial, antioxidant, and sun protection potential. This study aimed at isolating and identifying pure compounds from the extracts based on comprehensive analytical characterization by multiple analytical techniques. The plant samples were extracted by sequential maceration using n-hexane, ethyl acetate, methanol, and distilled water. The compounds were isolated using a combination of chromatographic techniques and their structures were elucidated by multiple spectroscopic techniques. The antibacterial and antifungal activity determination of the isolated compounds was carried out using an agar well diffusion and potato dextrose assay against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Candida albicans, and Aspergillus flavus while the antioxidant activity was screened with the 2,2-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay. The sun protection factor was determined using a Shimadzu Ultra Violet-visible (UV–VIS) double beam spectrophotometer between 290 to 320 nm. Eleven compounds; quercetin (1), kaempferol-3-O-rutinoside (2), rutin (3, 12), myo-inositol (4), asperulosidic acid (5), hexadecanoic acid (6), β-sitosterol (7), stigmasterol (8), campesterol (9), ursolic acid (10), and β-sitosterol glucoside (11) were identified in the S. princeae extracts. Compound 2 had good antifungal activity against C. albicans (zone of inhibition, 23.0 ± 0.1 mm). Compound 10 showed antibacterial and antifungal activity against S. aureus, P. aeruginosa, C. albicans, and A. flavus. Compound 2 had a good percentage radical scavenging effect (IC50 = 64.81 µg/ml) and a good sun protection factor (SPF = 26.83). This study reports the first-time isolation and identification of compounds 1 to 11 from S. princeae, which contribute to its antimicrobial, antioxidant, and sun protection potential.

中文翻译：

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从 Spermacoce princeae 中分离出的化合物的抗菌、抗氧化和防晒潜力 (K. Schum)

Spermacoce princeae (K. Schum) 在乌干达已被用于治疗细菌性皮肤感染。药理学研究表明，S. princeae 的提取物具有抗菌、抗氧化和防晒的潜力。本研究旨在基于多种分析技术的综合分析表征，从提取物中分离和鉴定纯化合物。使用正己烷、乙酸乙酯、甲醇和蒸馏水通过顺序浸渍提取植物样品。使用色谱技术的组合分离化合物，并通过多种光谱技术阐明其结构。使用琼脂扩散和马铃薯葡萄糖测定法对铜绿假单胞菌进行分离化合物的抗菌和抗真菌活性测定，金黄色葡萄球菌、大肠杆菌、肺炎克雷伯菌、白色念珠菌和黄曲霉，同时使用 2,2-二苯基-2-苦基-肼 (DPPH) 自由基清除试验筛选抗氧化活性。使用 Shimadzu 紫外可见 (UV-VIS) 双光束分光光度计在 290 至 320 nm 之间测定防晒系数。十一种化合物；槲皮素 (1)、山柰酚-3-O-芸香苷 (2)、芦丁 (3、12)、肌醇 (4)、asperulosidic acid (5)、十六烷酸 (6)、β-谷甾醇 (7)、豆甾醇(8)、菜油甾醇 (9)、熊果酸 (10) 和 β-谷甾醇葡糖苷 (11) 在 S. princeae 提取物中被鉴定出来。化合物 2 对白色念珠菌具有良好的抗真菌活性（抑菌圈，23.0 ± 0.1 mm）。化合物 10 显示出对金黄色葡萄球菌、铜绿假单胞菌、白色念珠菌、和 A. flavus。化合物 2 具有良好的自由基清除率 (IC50 = 64.81 µg/ml) 和良好的防晒系数 (SPF = 26.83)。本研究报告了首次从 S. princeae 中分离和鉴定化合物 1 至 11，这有助于其抗菌、抗氧化和防晒潜力。