Department of Pharmacy, University of Rajshahi, Rajshahi, 6205, Bangladesh.
Bangladesh Council of Scientific and Industrial Research, Rajshahi Laboratories, Bangladesh, Rajshahi, 6206, Bangladesh.
J Ethnopharmacol. 2024 Jan 30;319(Pt 1):117095. doi: 10.1016/j.jep.2023.117095. Epub 2023 Aug 25.
Drynaria quercifolia is an epiphytic fern distributed all over Bangladesh with traditional use in treating neurological disorders and other ailments. Although several pharmacological activities of D. quercifolia have been investigated, the neuroprotective potential of this plant is still unexplored.
In this study, we evaluated the in vitro anticholinesterase and antioxidant activities of D. quercifolia and the neuroprotective effect in scopolamine-induced memory-impaired mouse model.
The crude methanol extract (DCM) of the plant was fractionated to prepare n-hexane (DHF), chloroform (DCF), ethyl acetate (DEF), and aqueous (DAF) factions. All the fractions were evaluated for anticholinesterase activity by modified Ellman's method and the antioxidant activity by several in vitro assays such as DPPH and hydroxyl free radicals scavenging, reducing power, and inhibition of brain lipid peroxidation. The effect of the most active fractions (both DCF and DEF) on learning and memory was assessed in scopolamine-induced mouse model of memory-impairment by Morris water maze tasks. Biochemical assays were performed in brain tissue. The active compound was isolated and characterized by chromatographic, spectroscopic, and molecular docking methods.
Phytochemical analysis demonstrated a high content of phenolic and flavonoid in DEF. In vitro studies revealed a strong antioxidant power of DEF and anticholinesterase activity of DCF. Both the DCF and DEF significantly (P˂0.05) reduced the escape latency time in the Morris's water maze tasks, and increased the time spent in the northeast quadrant in the probe trial. Biochemical data demonstrated that treatment with DCF and DEF at different doses significantly (P˂0.0001) inhibited acetylcholinesterase activity, restored GSH levels, and reduced MDA levels in the brain of scopolamine-induced memory-impaired mice, indicating the protective effect of D. quercifolia, possibly by acetylcholinesterase inhibition and oxidative stress prevention. Chromatographic methods of separation led to he isolation of catechin and protocatechuric acid from DEF and 3,4-dihydroxy benzoic acid from DCF. The structure of the compounds was determined by studies of their H-NMR spectra. Molecular docking as well as in vitro study suggests the anticholinesterase and antioxidant activity of the isolated compounds.
Our study suggested that the extracts of D. quercifolia, due to anticholinesterase and antioxidant activity, ameliorate the scopolamine-induced memory impairment in mice and thus may represent therapeutics in the treatment of Alzheimer's disease.
槲蕨分布于孟加拉国各地，为附生蕨类，传统上用于治疗神经紊乱和其他疾病。尽管已经研究了槲蕨的几种药理学活性，但该植物的神经保护潜力仍未得到探索。
本研究评估了槲蕨的体外乙酰胆碱酯酶和抗氧化活性，以及在东莨菪碱诱导的记忆障碍小鼠模型中的神经保护作用。
植物的粗甲醇提取物（DCM）被分离为正己烷（DHF）、氯仿（DCF）、乙酸乙酯（DEF）和水（DAF）部分。通过改良的 Ellman 法评估所有馏分的乙酰胆碱酯酶抑制活性，通过 DPPH 和羟基自由基清除、还原能力和抑制脑脂质过氧化等几种体外测定方法评估抗氧化活性。通过 Morris 水迷宫任务评估在东莨菪碱诱导的记忆障碍小鼠模型中具有最强活性的馏分（DCF 和 DEF）对学习和记忆的影响。在脑组织中进行生化测定。通过色谱、光谱和分子对接方法对活性化合物进行分离和表征。
植物化学分析表明 DEF 中含有高含量的酚类和类黄酮。体外研究表明 DEF 具有强大的抗氧化能力，而 DCF 具有很强的乙酰胆碱酯酶抑制活性。DCF 和 DEF 均显著（P˂0.05）降低了 Morris 水迷宫任务中的逃避潜伏期时间，并增加了在探测试验中东北象限的停留时间。生化数据表明，用不同剂量的 DCF 和 DEF 治疗可显著（P˂0.0001）抑制乙酰胆碱酯酶活性，恢复脑内 GSH 水平，并降低东莨菪碱诱导的记忆障碍小鼠的 MDA 水平，表明槲蕨具有保护作用，可能通过乙酰胆碱酯酶抑制和预防氧化应激。分离的色谱方法导致从 DEF 中分离出儿茶素和原儿茶酸，从 DCF 中分离出 3,4-二羟基苯甲酸。通过对其 H-NMR 光谱的研究确定了化合物的结构。分子对接以及体外研究表明，分离出的化合物具有乙酰胆碱酯酶抑制和抗氧化活性。
我们的研究表明，槲蕨提取物由于具有乙酰胆碱酯酶抑制和抗氧化活性，可改善东莨菪碱诱导的小鼠记忆障碍，因此可能成为治疗阿尔茨海默病的治疗方法。
