Chemical constituents, antioxidant and antimicrobial activities of essential oil from stem of Napoleonaea vogeli

Background: Napoleonaea vogelii is used in traditional medicine for the treatment of pains and inflammatory disorders but little is known about its other pharmacological activities. This study aimed at investigating the chemical constituents as well as antioxidant and antimicrobial activities of the essential oil from the stem of plant.

Methods: Stem of Napoleonaea vogelii was subjected to soxhlet extraction method, for the extraction of its essential oil. The Essential oil extracted was analyzed using GCMS technique and screened for antioxidant activities using DPPH radical scavenging method; and antimicrobial activities using Agar Well Diffusion Method on different clinical isolates of bacterial and fungal strains.

Results: Stigmasterol (7.68%), 9,12- octadecanoic acid (7.63%), tetradecanoic acid (5.62%) were the major constituents while phytol (0.62%), squalene (0.74%), eicosane (0.14%) were the minor constituents of the essential oil. The antioxidant evaluation of the essential oil revealed that at 100 µg/ml, the radical scavenging activity of 79.36 % was significant and comparable to that of the standard ascorbic acid. The IC50 value was also significant and at a moderate value of 35.56 µg/ml. At 25 to 50 µg/ml, the % radical scavenging activity was also comparable to the ascorbic acid values. At concentrations of 50 to100 mg/ml, the essential oil was active against all bacteria and fungi except Aspergillus Niger.

Conclusion: This study revealed that Napoleonaea vogelii could be good source of bioactive compounds with antimicrobial and antioxidant activities which may also justify the use of the plant in the treatment of ailments in traditional medicine.

背景：沃格尔拿破仑木（Napoleonaea vogelii）在传统医学中被用于治疗疼痛与炎症性疾病，但目前对其其他药理活性的研究尚少。本研究旨在探究该植物茎部精油的化学成分，以及其抗氧化与抗菌活性。
方法：采用索氏提取法（Soxhlet extraction method）提取沃格尔拿破仑木茎部的精油。采用气相色谱-质谱联用（GC-MS）技术对所得精油进行成分分析；采用DPPH自由基清除法（DPPH radical scavenging method）评估其抗氧化活性；采用琼脂打孔扩散法（Agar Well Diffusion Method）对不同临床分离的细菌及真菌菌株进行抗菌活性筛选。
结果：该精油的主要成分为豆甾醇（Stigmasterol，7.68%）、9,12-十八烷酸（9,12-octadecanoic acid，7.63%）与肉豆蔻酸（tetradecanoic acid，5.62%）；次要成分为植醇（phytol，0.62%）、角鲨烯（squalene，0.74%）与二十烷（eicosane，0.14%）。抗氧化活性评估结果显示，当浓度为100 μg/ml时，其自由基清除率可达79.36%，活性显著且与阳性对照抗坏血酸相当。其半抑制浓度（IC50）同样具有统计学意义，为35.56 μg/ml，属于中等活性水平。在25~50 μg/ml浓度区间内，其自由基清除率也与抗坏血酸的水平相当。当浓度为50~100 mg/ml时，该精油对除黑曲霉（Aspergillus niger）外的所有受试细菌与真菌均表现出抑菌活性。
结论：本研究表明，沃格尔拿破仑木可作为兼具抗菌与抗氧化活性的生物活性化合物的优质来源，这也为该植物在传统医学中用于治疗各类疾病提供了科学依据。