Protective Effects of a Cissus quadrangularis Stem Peel Ash Derived Salt Against Streptozotocin Induced Cellular Injury in SH-SY5Y Cells

Abstract

Neurodegenerative disorders are characterized by oxidative stress, mitochondrial dysfunction, and apoptosis, highlighting the need for effective neuroprotective agents. In the present study, we investigated the antioxidant and protective effects of a salt derived from the stem-peel ash of Cissus quadrangularis (CQS) against streptozotocin (STZ)-induced injury in SH-SY5Y human neuroblastoma cells. CQS was prepared as a dried water-soluble fraction of incinerated stem-peel ash and characterized using qualitative phytochemical screening, Fourier-transform infrared spectroscopy (FT-IR), and Gas chromatography–mass spectrometry (GC-MS). FT-IR showed the presence of several functional groups, while GC-MS detected volatile and semi-volatile constituents, with 4-tert-butyl-2-(4-methoxyphenyl)-6-p-tolyl-pyridine identified as the most abundant peak-area constituent (20.79%). CQS exhibited increasing DPPH radical-scavenging activity across the tested concentration range, with an IC₅₀ of 56.47 µg/mL. The MTT assay indicated that 20 mM STZ reduced cell viability to 24.63%, whereas treatment with 25 µg/mL CQS in the presence of STZ increased cell viability to 60.83%. STZ increased the percentage of cells with elevated H₂DCFDA fluorescence to 71.77% and increased caspase-3 expression to 73.82%, whereas CQS treatment reduced these values to 40.19% and 36.61%, respectively. CQS also increased the proportion of cells with preserved mitochondrial membrane potential from 21.02% in the STZ group to 71.31%. These findings suggest that CQS may attenuate STZ-induced oxidative stress, mitochondrial depolarization, and apoptosis-related markers in SH-SY5Y cells. Further compositional, mechanistic, and in vivo studies are required to establish its biological activity and translational relevance.