Spilanthes acmella Murr., a well-known
Thai traditional medicine, has been used for treatment of
toothache,
rheumatism, and
fever. Diverse pharmacological activities of S. acmella Murr. have been reported. In this study, antioxidative and
neuroprotective effects of S. acmella Murr. extracts as well as bioactive
scopoletin,
vanillic acid, and
trans-ferulic acid found in the aerial parts of this plant species have been described. Protective effect of S. acmella Murr. extracts and bioactive compounds on
dexamethasone-induced neuronal cell death was investigated. Different plant crude
ethyl acetate (EtOAc) and
methanol (MeOH) extracts including pure compounds of S. acmella Murr. were evaluated in human
neuroblastoma SH-SY5Y cells. Cytotoxic effects were performed by
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Mechanisms involved in the
antioxidant effects of S. acmella Murr. regarding the activation of
antioxidant marker
proteins such as
superoxide dismutase 2 (SOD2) and
sirtuin 3 (
SIRT3) were determined using
2',7'-dichlorodihydrofluorescein diacetate (
DCFH-DA) assay, Western blot analysis, and immunocytochemistry.
Dexamethasone significantly caused the decrease of SH-SY5Y cell viability. Conversely, the increases in
reactive oxygen species (ROS), autophagy, and apoptosis were observed in
dexamethasone-treated cells. S. acmella Murr. MeOH and EtOAc extracts, as well as the bioactive compounds, reversed the toxic effect of
dexamethasone by increasing the cell viability,
SIRT3 protein expression but reducing the ROS, autophagy, and apoptosis. This study demonstrated that S. acmella Murr. may exert its protective effects against ROS through SOD2 and
SIRT3 signaling pathways in
dexamethasone-induced neurotoxicity. S. acmella Murr. may be a candidate
therapy for neuroprotection.