Olugbami J Olorunjuwon, Gbadegesin Michael A, Odunola Oyeronke A
Department of Biochemistry, Cancer Research and Molecular Biology Laboratories, College of Medicine, University of Ibadan, Ibadan, Nigeria.
Pharmacognosy Res. 2015 Jan-Mar;7(1):49-56. doi: 10.4103/0974-8490.147200.
Reactive oxygen species (ROS) are implicated in various pathological conditions. Synthetic antioxidants have adverse health effects, while many medicinal plants have antioxidant components that can prevent the harmful effects of ROS.
This study quantitatively determined the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant properties of ethanol extract of the stem bark of Terminalia glaucescens (EESTG).
The objectives were achieved based on in vitro assays. Data were analyzed by Sigma Plot (version 11.0).
Using gallic acid as the standard compound, TPC value obtained was 596.57 μg GAE/mg extract. TFC content of EESTG, determined as quercetin equivalent was 129.58 μg QE/mg extract. Furthermore, EESTG significantly (P < 0.001) displayed higher reducing power activity than the standard compounds (ascorbic acid and butylated hydroxytoluene [BHT]). Total antioxidant capacity assay, measured by phosphomolybdate method, was 358.33 ± 5.77 μg butylated hydroxytoluene equivalents [BHTE]/mg extract. β-carotene-linoleate bleaching method affirmed the potency of EESTG because of its significantly (P < 0.001) higher anti-oxidant activity when compared with quercetin and BHT. Based on DPPH assay, EESTG displayed significantly (P < 0.001) higher activity than BHT, while the hydroxyl radical scavenging activities of BHT and quercetin significantly (P < 0.001) exceeded that of the extract, although EESTG still displayed a high level of activity obtained as 83.77% in comparison to 92.80% of the standard compounds.
Findings from this study indicate the presence of promisingly potent phytoconstituents in EESTG that have the capability to act as antioxidants and free radical scavengers.
活性氧（ROS）与多种病理状况有关。合成抗氧化剂对健康有不良影响，而许多药用植物含有可预防ROS有害作用的抗氧化成分。
本研究定量测定了灰毛诃子茎皮乙醇提取物（EESTG）的总酚含量（TPC）、总黄酮含量（TFC）及抗氧化性能。
基于体外试验实现研究目的。数据采用Sigma Plot（11.0版）进行分析。
以没食子酸为标准化合物，测得TPC值为596.57μg没食子酸当量/mg提取物。EESTG的TFC含量以槲皮素当量计为129.58μg槲皮素当量/mg提取物。此外，EESTG的还原力活性显著高于标准化合物（抗坏血酸和丁基羟基甲苯[BHT]）（P<0.001）。通过磷钼酸盐法测定的总抗氧化能力为358.33±5.77μg丁基羟基甲苯当量[BHTE]/mg提取物。β-胡萝卜素-亚油酸漂白法证实了EESTG的效力，因为与槲皮素和BHT相比，其抗氧化活性显著更高（P<0.001）。基于DPPH试验，EESTG的活性显著高于BHT（P<0.001），尽管EESTG的清除羟自由基活性仍达到较高水平，为83.77%，而标准化合物为92.80%，但BHT和槲皮素的清除羟自由基活性显著高于提取物（P<0.001）。
本研究结果表明EESTG中存在有前景的强效植物成分，具有作为抗氧化剂和自由基清除剂的能力。
