Department of Pharmacognosy, Faculty of Pharmacy, University of Maiduguri, Maiduguri, Nigeria.
Department of Pharmacognosy and Traditional Medicine, Faculty of Pharmacy, Delta State University, Abraka, Nigeria.
J Ethnopharmacol. 2023 Oct 5;314:116632. doi: 10.1016/j.jep.2023.116632. Epub 2023 May 19.
Newbouldia laevis is a popular medicinal plant whose leaves and roots are used in Nigeria as ethnomedicinal prescriptions for pain, inflammation, convulsion, and epilepsy. These claims have not been scientifically verified prior to this study.
To determine pharmacognostic profiles of the leaves and roots and evaluate the analgesic, anti-inflammatory, and anticonvulsant activities of methanol leaf and root extracts in Wistar rats.
The pharmacognostic profiles of the leaves and roots were determined using standard procedures to serve as fingerprints for the plant. The methanol leaf and root extracts of Newbouldia laevis were tested for acute toxicity using the OECD's up and down method at the maximum dose of 2000 mg/kg (orally) in Wistar rats. Analgesic studies were carried out in acetic acid-induced writhing in rats and tail immersion. The anti-inflammatory activity of the extracts was evaluated using carrageenan-induced rat paw-oedema and formalin-induced inflammation in rats' mode. The anticonvulsant activity was determined using strychnine-induced, pentylenetetrazol-induced, and maximal electroshock-induced rat convulsion models. For each of these studies, the extracts doses of 100, 200 and 400 mg/kg were administered to the rats following the oral route.
The pharmacognostic profiles showed that the leaves possessed deep-sunken paracytic stomata (5-8-16 mm; adaxial, 8-11-24 mm; abaxial epidermis), vein islets (2-4-10 mm; adaxial), vein terminations (10-14-18 mm; adaxial), palisade ratio (8.3-12.5-16.4 mm; adaxial, 2.5-6.8-12.2 mm; adaxial), covering unicellular trichome (8-14; adaxial), spheroidal calcium oxalate crystals (3-5 μm), and oval-shaped striated starch grain with no hilum (0.5-4.3 μm). The transverse section of the leaf showed the presence of spongy and palisade parenchyma as well as a closed vascular bundle. The root powder showed the presence of brachy sclereid, fibers without lumen, and lignin. All physicochemical parameters fall within the acceptable limits, phytochemical contents showed mainly glycosides, alkaloids, and steroids while acute oral toxicity (LD) of the parts for 14 days did not produce any toxicity signs or mortality in the rats. The extracts produced dose-dependent (100-400 mg/kg) analgesic involving opioid receptors, anti-inflammatory, and anticonvulsant activities in the rats which were significant (p ≤ 0.05) when compared to the standard drugs. The leaf extract possessed the most potent analgesic and anti-inflammatory effects in the rats, while the most anticonvulsant effects were observed in rats treated with the leaf extract. Both extracts showed elevated levels of protection against strychnine-induced, pentylenetetrazol-induced, and maximal electroshock-induced seizure in rats.
Our study revealed some pharmacognostic profiles of Newbouldia laevis leaves and roots that are vital for its identification from closely related species often used for adulteration in traditional medicine. The study further showed that the leaf and root extracts of the plant possessed dose-dependent analgesics, anti-inflammatory and anti-convulsant activities in rats, thus, justifying its use for the treatment of these diseases in Nigerian traditional medicine. There is a need to further study its mechanisms of action towards drug discovery.
Newbouldia laevis 是一种流行的药用植物，其叶子和根部在尼日利亚被用作民间医学处方，用于治疗疼痛、炎症、惊厥和癫痫。这些说法在本研究之前尚未得到科学验证。
确定叶子和根部的生药学特征，并评估甲醇叶和根提取物在 Wistar 大鼠中的镇痛、抗炎和抗惊厥活性。
使用标准程序确定叶子和根部的生药学特征，作为植物的指纹。使用 OECD 的上下法在 Wistar 大鼠中进行最大剂量为 2000mg/kg（口服）的急性毒性测试，以确定 Newbouldia laevis 的甲醇叶和根提取物。在醋酸诱导的大鼠扭体和尾巴浸泡中进行镇痛研究。使用角叉菜胶诱导的大鼠足肿胀和甲醛诱导的大鼠炎症模型评估提取物的抗炎活性。使用士的宁诱导、戊四唑诱导和最大电休克诱导的大鼠惊厥模型确定抗惊厥活性。对于这些研究中的每一项，都以 100、200 和 400mg/kg 的剂量经口服途径给予大鼠提取物。
生药学特征表明，叶子具有深陷的副环式气孔（5-8-16mm；上表皮，8-11-24mm；下表皮）、脉岛（2-4-10mm；上表皮）、脉端（10-14-18mm；上表皮）、栅栏比（8.3-12.5-16.4mm；上表皮，2.5-6.8-12.2mm；上表皮）、覆盖的单细胞毛（8-14；上表皮）、球状草酸钙晶体（3-5μm）和椭圆形有条纹的淀粉粒（0.5-4.3μm）。叶片的横切面显示出海绵状和栅栏状薄壁组织以及封闭的血管束的存在。根粉显示出短厚细胞、无腔纤维和木质素的存在。所有理化参数均在可接受范围内，植物化学物质主要含有糖苷、生物碱和类固醇，而 14 天的急性口服毒性（LD）在大鼠中未产生任何毒性迹象或死亡率。提取物在大鼠中产生了剂量依赖性（100-400mg/kg）的镇痛作用，涉及阿片受体，具有抗炎和抗惊厥活性，与标准药物相比具有显著的（p≤0.05）效果。叶提取物在大鼠中具有最强的镇痛和抗炎作用，而叶提取物治疗的大鼠表现出最强的抗惊厥作用。两种提取物均表现出对士的宁、戊四唑和最大电休克诱导的大鼠惊厥的保护作用增强。
我们的研究揭示了 Newbouldia laevis 叶子和根部的一些生药学特征，这些特征对其从常用于传统医学掺假的密切相关物种中进行鉴定至关重要。该研究进一步表明，植物的叶和根提取物在大鼠中具有剂量依赖性的镇痛、抗炎和抗惊厥活性，因此，这证明了其在尼日利亚传统医学中用于治疗这些疾病的用途。有必要进一步研究其作用机制，以实现药物发现。
