Yalo Masande, Makhaba Masixole, Hussein Ahmed A, Sharma Rajan, Koki Mkhuseli, Nako Ndikho, Mabusela Wilfred T
Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa.
Chemistry Department, Cape Peninsula University of Technology, Symphony Rd., Bellville 7535, South Africa.
Plants (Basel). 2022 Jun 30;11(13):1751. doi: 10.3390/plants11131751.
(king protea) is a flowering plant that belongs to the Proteaceae family. This multi-stemmed shrub is the national flower of South Africa and has important economic and medicinal values. Traditionally, the main therapeutic benefits of this plant species include the treatment of cancer, bladder, and kidney ailments. There are very limited reports on the isolation of phytochemicals and their biological evaluation from . In this study, the leaves of were air-dried at room temperature, powdered, and extracted with 80% methanol followed by solvent fractionation (hexane, dichloromethane, ethyl acetate, and butanol). The ethyl acetate and butanol extracts were chromatographed and afforded four new (-) and four known (-) compounds, whose structures were characterized accordingly as 3,4-bis(4-hydroxybenzoyl)-1,5-anhydro-D-glucitol (), 4-hydroxybenzoyl-1,5-anhydro-D-glucitol (), 2-(hydroxymethyl)-4-oxo-4-pyran-3-yl-6--benzoate-β-D-glucopyranoside (), 3-hydroxy-7,8-dihydro-β-ionone 3--β-D-glucopyranoside (), 4-hydroxybenzoic acid (), 1,5-anhydro-D-glucitol (), 3,4-dihydroxybenzoic acid (), and 3-hydroxykojic acid (). The structural elucidation of the isolated compounds was determined based on 1D and 2D NMR, FTIR, and HRMS spectroscopy, as well as compared with the available literature data. The tyrosinase inhibitory activities of the extracts and isolated compounds were also determined. According to the results, compounds and exhibited potent competitive tyrosinase inhibitory activity against L-tyrosine substrates with IC values of 0.8776 ± 0.012 and 0.7215 ± 0.090 µg/mL compared to the control (kojic acid, IC = 0.8347 ± 0.093), respectively. This study is the first chemical investigation of compounds - from a natural source and the first report of the biological evaluation of compounds - against the tyrosinase enzyme. The potent anti-tyrosinase activity exhibited by constituents will support future exploration of the plant in the cosmetic field upon further biological and clinical investigations.
帝王花是一种属于山龙眼科的开花植物。这种多茎灌木是南非的国花，具有重要的经济和药用价值。传统上，该植物物种的主要治疗益处包括治疗癌症、膀胱和肾脏疾病。关于从该植物中分离植物化学物质及其生物学评价的报道非常有限。在本研究中，将帝王花的叶子在室温下风干、研磨，并用80%甲醇提取，然后进行溶剂分级分离（己烷、二氯甲烷、乙酸乙酯和丁醇）。对乙酸乙酯和丁醇提取物进行色谱分析，得到了四种新的（-）化合物和四种已知的（-）化合物，其结构分别被表征为3,4-双（4-羟基苯甲酰基）-1,5-脱水-D-葡萄糖醇（化合物1）、4-羟基苯甲酰基-1,5-脱水-D-葡萄糖醇（化合物2）、2-（羟甲基）-4-氧代-4-吡喃-3-基-6-O-苯甲酸酯-β-D-吡喃葡萄糖苷（化合物3）、3-羟基-7,8-二氢-β-紫罗兰酮3-O-β-D-吡喃葡萄糖苷（化合物4）、4-羟基苯甲酸（化合物5）、1,5-脱水-D-葡萄糖醇（化合物6）、3,4-二羟基苯甲酸（化合物7）和3-羟基曲酸（化合物8）。通过一维和二维核磁共振、傅里叶变换红外光谱和高分辨率质谱光谱对分离得到的化合物进行结构解析，并与现有文献数据进行比较。还测定了提取物和分离化合物的酪氨酸酶抑制活性。结果表明，与对照（曲酸，IC50 = 0.8347 ± 0.093）相比，化合物1和化合物2对L-酪氨酸底物表现出较强的竞争性酪氨酸酶抑制活性，IC50值分别为0.8776 ± 0.012和0.7215 ± 0.090 μg/mL。本研究是对来自天然来源的化合物1 - 8的首次化学研究，也是化合物1 - 8对酪氨酸酶的生物学评价的首次报道。帝王花成分所表现出的强大抗酪氨酸酶活性将支持在进一步的生物学和临床研究后，对该植物在化妆品领域的未来探索。
