Agatonovic-Kustrin Snezana, Morton David W, Ristivojević Petar
Faculty of Pharmacy, Universiti Teknologi MARA, Puncak Alam Campus, Bandar Puncak Alam, Selangor, 42300, Malaysia.
School of Pharmacy and Applied Science, La Trobe Institute for Molecular Sciences, La Trobe University, Edwards Rd, Bendigo, 3550, Australia.
J Chromatogr A. 2016 Oct 14;1468:228-235. doi: 10.1016/j.chroma.2016.09.041. Epub 2016 Sep 21.
The aim of this study was to develop and validate a rapid and simple high performance thin layer chromatographic (HPTLC) method to screen for antioxidant activity in algal samples. 16 algal species were collected from local Victorian beaches. Fucoxanthin, one of the most abundant marine carotenoids was quantified directly from the HPTLC plates before derivatization, while derivatization either with 2,2-diphenyl-1-picrylhydrazyl (DPPH) or ferric chloride (FeCl) was used to analyze antioxidants in marine algae, based on their ability to scavenge non biological stable free radical (DPPH) or to chelate iron ions. Principal component analysis of obtained HPTLC fingerprints has classified algae species into 5 groups according to their chemical/antioxidant profiles. The investigated brown algae samples were found to be rich in non-and moderate-polar compounds and phenolic compounds with antioxidant activity. Most of the phenolic iron chelators also have shown free radical scavenging activity. Strong positive and significant correlations between total phenolic content and DPPH radical scavenging activity showed that, phenolic compounds, including flavonoids are the main contributors of antioxidant activity in these species. The results suggest that certain brown algae possess significantly higher antioxidant potential when compared to red or green algae and could be considered for future applications in medicine, dietary supplements, cosmetics or food industries. Cystophora monilifera extract was found to have the highest antioxidant concentration, followed by Zonaria angustata, Cystophora pectinate, Codium fragile, and Cystophora pectinata. Fucoxanthin was found mainly in the brown algae species. The proposed methods provide an edge in terms of screening for antioxidants and quantification of antioxidant constituents in complex mixtures. The current application also demonstrates flexibility and versatility of a standard HPTLC system in the drug discovery. Proposed methods could be used for the bioassay-guided isolation of unknown natural antioxidants and subsequent identification if combined with spectroscopic identification.
本研究的目的是开发并验证一种快速简便的高效薄层色谱（HPTLC）方法，用于筛选藻类样品中的抗氧化活性。从维多利亚州当地海滩采集了16种藻类。岩藻黄质是最丰富的海洋类胡萝卜素之一，在衍生化之前直接从HPTLC板上进行定量，而基于其清除非生物稳定自由基（DPPH）或螯合铁离子的能力，用2,2 - 二苯基 - 1 - 苦基肼（DPPH）或氯化铁（FeCl）进行衍生化，以分析海藻中的抗氧化剂。对获得的HPTLC指纹图谱进行主成分分析，根据其化学/抗氧化特征将藻类物种分为5组。研究发现，所研究的褐藻样品富含非极性和中等极性化合物以及具有抗氧化活性的酚类化合物。大多数酚类铁螯合剂也表现出自由基清除活性。总酚含量与DPPH自由基清除活性之间存在强正相关且显著相关，表明包括黄酮类化合物在内的酚类化合物是这些物种抗氧化活性的主要贡献者。结果表明，与红藻或绿藻相比，某些褐藻具有显著更高的抗氧化潜力，可考虑在未来医学、膳食补充剂、化妆品或食品工业中应用。发现念珠囊藻提取物的抗氧化浓度最高，其次是狭叶带藻、栉囊藻、脆弱松藻和栉状囊藻。岩藻黄质主要存在于褐藻物种中。所提出的方法在筛选抗氧化剂和定量复杂混合物中的抗氧化成分方面具有优势。当前的应用还展示了标准HPTLC系统在药物发现中的灵活性和多功能性。如果与光谱鉴定相结合，所提出的方法可用于生物测定指导下未知天然抗氧化剂的分离及后续鉴定。
