Antioxidant and anti hyperalgesia activity of ethanol extract and fraction from red ginger (Zingiber officinale var. Rubrum) in early painful diabetic neuropathy mice

Background: Gingerol and shogaol are two major bio-components of Zingiber officinale var. Rubrum (red ginger) has been widely reported as an antioxidant crucial in painful diabetic neuropathy (PDN). Objective: Determines the activity of the ethanolic extract of red ginger rhizome and its fraction by in vitro antioxidant and the in vivo study in PDN mice. Method: Red ginger was extracted using ethanol and fractionated with n-hexane, chloroform, ethyl acetate, and n-butanol. The antioxidant was tested using DPPH and CUPRAC. Diabetes was induced using alloxan 225 mg/kg BW ip in male BALB/c mice. After 14 days, mice were randomly divided into normal, diabetic, ethanol extract, chloroform fraction, ethyl acetate fraction on the same dose of 400 mg/kg BW, metformin (200 mg/kg BW), and gabapentin (100 mg/kg BW). Treatments were given orally, once daily, for 21 days. Latency time and blood glucose levels were measured every week. Histology of the spinal cord was analysed using Hematoxylin-eosin staining. Result: The ethyl acetate fraction had the best antioxidant activity using DPPH (IC50 13.93 ± 0.06) and CUPRAC (IC50 4.07 ± 0.06). This fraction showed the most potent ability to decrease BGL (69.78 ± 18.36%), same as metformin, and hyperalgesia (59.34 ± 7.90%) better than gabapentin. This treatment repaired the spinal cord by reducing the number of inflammatory cells and neuron degeneration in PDN mice. Conclusion: The EERG of 400 mg/kg BW significantly affects arthritis-induced hyperalgesia.