Neuroprotection is a proactive approach to safeguarding the nervous system, including the brain, spinal cord, and peripheral nerves, by preventing or limiting damage to nerve cells and other components. It primarily defends the central nervous system against injury from acute and progressive neurodegenerative disorders. Oxidative stress, an imbalance between the body's natural defense mechanisms and the generation of reactive oxygen species, is crucial in developing neurological disorders. Due to its high metabolic rate and oxygen consumption, the brain is particularly vulnerable to oxidative stress. Excessive ROS damages the essential biomolecules, leading to cellular malfunction and neurodegeneration. Several neurological disorders, including Alzheimer's, Parkinson's, Amyotrophic lateral sclerosis, multiple sclerosis, and ischemic stroke, are associated with oxidative stress. Understanding the impact of oxidative stress in these conditions is crucial for developing new treatment methods. Researchers are exploring using antioxidants and other molecules to mitigate oxidative stress, aiming to prevent or slow down the progression of brain diseases. By understanding the intricate interplay between oxidative stress and neurological disorders, scientists hope to pave the way for innovative therapeutic and preventive approaches, ultimately improving individuals' living standards.

OBJECTIVEGeophila repens (L.) I. M. Johnst. (Rubiaceae), a small, creeping, perennial herb, is claimed to have memory-enhancing property. The goal of this study was to assess its antioxidant and anticholinesterase activity and conduct a rapid bioautographic enzyme assay for screening acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition of G. repens extracts.

METHODSAntioxidant activity of G. repens extracts was assessed by performing 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide (NO), superoxide (SOD), hydroxyl (OH) and total antioxidant capacity (TAC) assays. Anticholinesterase activity was investigated by quantifying the AChE and BChE inhibitory activities of chloroform (CGR), ethyl acetate (EGR) and methanol (MGR) extract fractions from G. repens leaves. A rapid high-performance thin-layer chromatography (HPTLC) bioautographic method for the detection of AChE and BChE inhibition was performed.

RESULTSAmong all extract fractions, EGR exhibited the highest half maximal inhibitory concentration (IC) in DPPH, SOD, NO, OH and TAC assays, with ICof (38.33 ± 3.21), (45.14 ± 1.78), (59.81 ± 1.32), (39.45 ± 0.79) and (43.76 ± 0.81) μg/mL respectively. EGR displayed competitive, reversible inhibition of AChE and BChE activities with ICof (68.63 ± 0.45) and (59.45 ± 0.45) μg/mL, respectively. Total phenolic and flavonoids contents of EGR were found to be 360.42 mg gallic acid equivalents and 257.31 mg quercetin equivalents per gram of extract. Phytoconstituents of the EGR extract that were inhibitors of cholinesterase produced white spots on the yellow background of HPTLC plates in the bioautographic test.

CONCLUSIONThe results of this study revealed that phenols and flavonoids could be responsible for the antioxidant, anticholinesterase activities of G. repens.