Sorghum stem extract modulates Na⁺/K⁺-ATPase, ecto-5′-nucleotidase, and acetylcholinesterase activities

Sorghum stem (Sorghum bicolor) has been in use in traditional medicine systems for the management of neurodegenerative conditions. However, there is dearth of information on the scientific basis for its use in the treatment of such conditions. This study sought to assess the antioxidant activity and effects of phenolic extract from sorghum stem (Sorghum bicolor) on some cholinergic (acetylcholinesterase (AChE)) and purinergic (Na⁺/K⁺-ATPase and ecto-5′-nucleotidase) enzymes associated with neurological conditions. Phenolic-rich extract was prepared using methanol: 1 N HCl (1:1, v/v) mixture and characterized using high-performance liquid chromatography-diode array detector (HPLC-DAD). In vitro tests were used to investigate the effects of the phenolic extract on AChE, Na⁺/K⁺-ATPase, and ecto-5′-nucleotidase activities. Furthermore, the hydroxyl (OH) radical scavenging and Fe²⁺-chelating abilities of the extract were investigated. HPLC-DAD analysis revealed the presence of some phenolic acids such as caffeic acid (120.58 mg/g), ferulic acid (76.45 mg/g), gallic acid (17.48 mg/g), chlorogenic acid (16.25 mg/g), and flavonoids such as kaempferol (15.98 mg/g), rutin (51.07 mg/g), quercetin (263.16 mg/g), and quercitrin (89.21 mg/g) in the phenolic extract. The extract significantly inhibited AChE and ecto-5′-nucleotidase activities in a dose dependent manner with IC₅₀ = 24.88 μg/ml and IC₅₀ = 37.49 μg/ml, respectively, and increased Na⁺/K⁺-ATPase activity in a dose dependent manner. Furthermore, the phenolic extract also scavenged OH radicals and was able to chelate Fe²⁺ in a dose dependent manner with IC₅₀ = 54.27 μg/ml and 18.47 μg/ml, respectively. This study revealed the antioxidant and modulatory effects of phenolic extracts from sorghum stem on some cholinergic and purinergic enzymes.