Milugo Trizah K, Omosa Leonida K, Ochanda James O, Owuor Bethwell O, Wamunyokoli Fred A, Oyugi Julius O, Ochieng Joel W
Center for Biotechnology and Bioinformatics, University of Nairobi, P,O, Box 30197, Nairobi 00100, Kenya.
BMC Complement Altern Med. 2013 Oct 26;13:285. doi: 10.1186/1472-6882-13-285.
The Quinine tree (Rauvolfia caffra) is used as a medicinal plant among traditional communities in many countries to manage tumors and other diseases associated with oxidative stress. To validate indigenous knowledge and possibly position this herb for technology uptake and utilization, we established the level of antioxidant activity in R. caffra, and probed for the presence of associated phytochemicals.
Antioxidant activity was determined on 1,1-diphenyl-2-picrylhydrazyl (DPPH) while major phytochemicals were identified by multiple tests on methanol fractions.
R. caffra showed promise as a cure, with antioxidant activity comparable to the commercially used drug quercetin (R. caffra = 79.7% ±1.9; quercetin = 82.6% ± 2.0). However, we found two phytochemicals with possible antagonistic effect: co-occurrence of alkaloids and saponins significantly reduced antioxidant activity (alkaloids only = 63%; alkaloids plus saponins = 15%; steroids, terpenoids and cardiac glycosides = 82%), thus alkaloids and saponins should be exclusive to each other in drug formulations.
Antagonistic relationship among phytochemicals would affect the efficacy of crude extracts as used in traditional medicine. Unlike in herbal medicine, use of modern biotechnology in extraction, purification and design of optimal combinations will ensure efficient drug formulations with optimum bioactivity and minimum toxicity. Metabolic pathway engineering under a controlled environment may optimize availability of desired compounds.
在许多国家的传统社区中，金鸡纳树（Rauvolfia caffra）被用作药用植物来治疗肿瘤和其他与氧化应激相关的疾病。为了验证本土知识，并可能使这种草药适用于技术吸收和利用，我们测定了金鸡纳树的抗氧化活性水平，并探究了相关植物化学物质的存在情况。
采用1,1-二苯基-2-苦基肼（DPPH）法测定抗氧化活性，同时通过对甲醇提取物进行多项测试来鉴定主要植物化学物质。
金鸡纳树显示出有望成为一种治疗药物，其抗氧化活性与商业使用的药物槲皮素相当（金鸡纳树=79.7%±1.9；槲皮素=82.6%±2.0）。然而，我们发现两种可能具有拮抗作用的植物化学物质：生物碱和皂苷同时存在时会显著降低抗氧化活性（仅生物碱=63%；生物碱加皂苷=15%；甾体、萜类和强心苷=82%），因此在药物配方中生物碱和皂苷应相互排斥。
植物化学物质之间的拮抗关系会影响传统医学中粗提物的疗效。与草药不同，在提取、纯化和设计最佳组合时使用现代生物技术将确保高效的药物配方具有最佳的生物活性和最低的毒性。在可控环境下进行代谢途径工程可能会优化所需化合物的可得性。
