>Magister Scientiae - MSc / Salt stress is a major abiotic stress that accounts for huge agricultural losses worldwide, which in turn threaten food security and sustainable agriculture. Salt triggers the excessive production of reactive oxygen species (ROS) which accumulate to levels that become toxic to plants, resulting in cell death and reduced plant growth. Part of the plant’s mechanisms to counteract ROS-induced cell death involves the scavenging ability of the antioxidant defense system to maintain redox homeostasis. Gallic acid (GA) is an antioxidant that has been shown to reduce salt-induced ROS in legume plants. However, its effects on wheat plants have not been elucidated. This study thus investigated the role of exogenous GA (250 μM) on the physiological responses and antioxidant system of wheat plants under salt stress (150 mM). In addition, this study also investigated how GA and salt stress influenced changes in the membrane proteome of wheat plants using LC-MS proteomic analysis. / 2022

Gallic acid is a known antioxidant and has anti-inflammatory activity in addition to other biological activities, but GA efficiency is restricted due to low permeability and low oral bioavailability. This study was designed to investigate the solubility, permeability, oral bioavailability, enzymatic stability with cytochrome CYP2D6, antioxidant and anti-inflammatory activity of novel gallic acid sulfonamide derivatives; TMBS, and THBS. In addition, a novel in silico permeability model was designed to predict the permeability and bioavailability of eighty derivatives of GA. In sillico prediction of intestinal permeability of GA derivative indicated an increase in permeability with increased lipophilicity and decreased aqueous solubility, replacing the carboxylic group with sulfonamide group has increased intestinal permeability. A significant (P <0.01) increase was observed in the permeability of TMBS and THBS over GA, in both gastric fluids and HIEC cells. TMBS was O-demethylated by CYP2D6. TMBS had greater ROS scavenging activity than GA in HIEC-6 cells. There was a significant (P< 0.05) increase in anti-inflammatory activity of THBS, and TMBS compared to ibuprofen. TMBS, and THBS had better oral bioavailability than GA. This data suggests that the in silico permeability model can be used in the future to study new candidate of gallic acid, and further in vivo and clinical investigations are required to introduce TMBS and THBS as a new antioxidant and anti-inflammatory drugs.