Anti-Inflammatory Properties and Identification of Putative Protein Targets of Phytochemicals Present in Mashua (Tropaeolum Tuberosum) Tuber and Acerola (Malpighia Emarginata) Leaf by DARTS Methodology
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Cellular targets for the majority of dietary phytochemicals remain unknown, presenting a challenge for the understanding of how these dietary components provide health benefits. Recently a new methodology, drug affinity responsive target stability (DARTS), was developed for this purpose. The objective of this study was to evaluate the anti-inflammatory properties of mashua (Tropaeolum tuberosum) tuber and acerola leaf (Malpighia emarginata) extracts and to identify the protein targets of its phytochemicals by using DARTS methodology. The first aim was to investigate the anti-inflammatory properties of mashua extracts and to identify the cellular targets of its phytochemicals. Mashua 203040 and 203081 extracts exerted anti-inflammatory properties in LPS-stimulated macrophages. Through DARTS methodology we identified pyruvate kinase M (PKM) as a potential target of the phytochemicals present in both extracts. Additionally, mashua extracts reduced reactive oxygen species (ROS) levels and consequently affected the expression of ROS dependent LPS-induced pro-inflammatory genes. LC-MS profiling revealed that both mashua extracts contained mainly phenolics and isothiocyantes. In this study, we demonstrated that phytochemicals from mashua reduce LPS-induced inflammation in RAW264.7 macrophages by targeting PKM and reducing ROS. The second aim was to identify the bioactive compounds acting as COX-2 inhibitors in acerola leaf by using bioassay-guided fractionation and DARTS methodology. The leaf extract (F4) was fractionated into three fractions (F1, F2, and F3) and results indicated that F4, F2, and F3 inhibited COX-2 activity. F2 showed the highest COX-2 inhibitory effect among the fractions, and also showed binding to COX-2 by DARTS. Thus, its subfractions (F2A, F2B, and F2C) were further tested for their ability to bind and inhibit COX-2 activity. All subfractions inhibited COX-2 activity but only F2A and F2C showed binding by DARTS. F2C was further fractionated and only fraction F2C4, containing terpenes, inhibited COX-2 activity. In this study, we identify the group of compounds from acerola leaf, which are responsible for the inhibition of COX-2 activity. In conclusion we were able to characterize many of the phytochemicals present in mashua tuber and acerola leaf and to identify the putative targets responsible for their anti-inflammatory effect in vitro.
Schreckinger Minoli, Maria Elisa (2016). Anti-Inflammatory Properties and Identification of Putative Protein Targets of Phytochemicals Present in Mashua (Tropaeolum Tuberosum) Tuber and Acerola (Malpighia Emarginata) Leaf by DARTS Methodology. Doctoral dissertation, Texas A & M University. Available electronically from