Research Centre for Plant Growth and Development, School of Life Sciences, University of KwaZulu-Natal Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa.
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, 16610 Prague-6, Czech Republic.
J Ethnopharmacol. 2018 Jun 28;220:169-176. doi: 10.1016/j.jep.2018.03.035. Epub 2018 Mar 28.
Leucosidea sericea is a southern African tree used for treating different diseases including microbial infections and inflammatory-related conditions.
To isolate and identify the chemicals in Leucosidea sericea which possibly account for the diverse therapeutic effects of the species.
Leaf material was extracted using 20% methanol and subsequently partitioned with different solvents (hexane, dichloromethane, ethyl acetate and butanol). Resultant fractions were subjected to bioactive (antimicrobial)-guided isolation and the structural elucidation was conducted using NMR (1D and 2D) spectroscopic methods. Given the broad uses of Leucosidea sericea in traditional medicine, the extract, fractions and isolated compounds were evaluated in five (5) biological assays in vitro (antimicrobial, antioxidant, acetylcholinesterase (AChE) and anti-inflammatory inhibition as well as cytotoxicity effect).
As the most active fractions, from ethyl acetate yielded 5,7-dihydroxychromone (1); 1-hydroxy-2-oxopomolic acid (2); 3,5,7,3´,4´-pentahydroxyflavone (3) and Tiliroside (4). For the first time, these four (4) compounds were isolated from leaves of Leucosidea sericea. These aforementioned compounds demonstrated broad-spectrum antibacterial activity (1.95-125 µg/mL) and noteworthy antifungal (3.9-250 µg/mL) potential. In addition to its noteworthy antimicrobial activity, compound 3 also demonstrated significant antioxidant (EC = 14 µg/mL in DPPH assay) and anti-inflammatory (inhibited the level of ELAM by approximately 36% and decreased also the viability of endothelial cells) activities in vitro. Overall, AChE inhibition activity and cytotoxic response was generally weak for the extracts, fractions and isolated compounds.
The pool of chemicals in Leucosidea sericea were enriched with the isolation and identification of four (4) compounds obtained from the leaf extract. Among these compounds, the significant antimicrobial activity of compound 3 provides strong evidence that support the use of Leucosidea sericea for microbial-related infections in folk medicine.
Leucosidea sericea 是一种南非树种，用于治疗多种疾病，包括微生物感染和炎症相关病症。
从 Leucosidea sericea 中分离并鉴定可能解释该物种多种治疗效果的化学物质。
使用 20%甲醇提取叶片材料，然后用不同溶剂（己烷、二氯甲烷、乙酸乙酯和正丁醇）进行分配。得到的馏分进行生物活性（抗菌）导向分离，使用 NMR（一维和二维）光谱方法进行结构阐明。鉴于 Leucosidea sericea 在传统医学中的广泛用途，提取物、馏分和分离化合物在五个（5）体外生物测定中进行评估（抗菌、抗氧化、乙酰胆碱酯酶（AChE）和抗炎抑制以及细胞毒性作用）。
作为最活跃的馏分，乙酸乙酯馏分得到 5,7-二羟基色原酮（1）；1-羟基-2-氧代pomolic 酸（2）；3,5,7,3´,4´-五羟基黄酮（3）和tiliroside（4）。这四种（4）化合物首次从 Leucosidea sericea 的叶片中分离得到。这些化合物表现出广谱的抗菌活性（1.95-125μg/mL）和显著的抗真菌（3.9-250μg/mL）潜力。除了显著的抗菌活性外，化合物 3 在体外还表现出显著的抗氧化（DPPH 测定中 EC=14μg/mL）和抗炎（抑制 ELAM 水平约 36%，并降低内皮细胞活力）活性。总体而言，提取物、馏分和分离化合物对 AChE 抑制活性和细胞毒性反应通常较弱。
从叶提取物中分离和鉴定得到的四种（4）化合物丰富了 Leucosidea sericea 中的化学物质库。在这些化合物中，化合物 3 的显著抗菌活性为 Leucosidea sericea 在民间医学中用于微生物相关感染提供了强有力的证据支持。
