The anti-neuroinflammatory effects of Clinacanthus nutans leaf extract on metabolism elucidated through 1H NMR in correlation with cytokines microarray

Abstract

Clinacanthus nutans (CN) (Acanthaceae) is well-known for its anti-inflammatory properties among Asian communities; however, there are currently no data specifically focused on the anti-inflammatory effects of CN on the brain tissue. Neuroinflammation is a common consequence of toxin intrusion to any part of the central nervous system (CNS). As an innate immune response, the CNS may react through both protective and/or toxic actions due to the activation of neuron cells producing pro- and/or anti-inflammatory cytokines in the brain. The unresolved activation of the inflammatory cytokines’ response is associated with the pathogenesis of neurological disorders. The present study aimed to decipher the metabolic mechanism on the effects of 14 days oral treatment with CN aqueous extract in induced-lipopolysaccharides (LPS) rats through 1 H NMR spectroscopic biomarker profiling of the brain tissue and the related cytokines. Based on the principal component analysis (PCA) of the nuclear magnetic resonance (NMR) spectral data, twenty-one metabolites in the brain tissue were profiled as biomarkers for the LPS (10 μL)-induced neuroinflammation following intracerebroventricular injection. Among the twenty-one biomarkers in the neuroinflammed rats, CN treatment of 1000 and 500 mg/kg BW successfully altered lactate, pyruvate, phosphorylcholine, glutamine, and α-ketoglutarate when compared to the negative control. Likewise, statistical isolinear multiple component analysis (SIMCA) showed that treatments by CN and the positive control drug, dextromethorphan (DXM, 5 mg/kg BW), have anti-neuroinflammatory potential. A moderate correlation, in the orthogonal partial least squares (OPLS) regression model, was found between the spectral metabolite profile and the cytokine levels. The current study revealed the existence of high levels of pro-inflammatory cytokines, namely IL-1 α , IL-1 β , and TNF- α in LPS-induced rats. Both CN dose treatments lowered IL-1 β significantly better than DXM Interestingly, DXM and CN treatments both exhibited the upregulation of the anti-inflammatory cytokines IL-2 and 4. However, DXM has an advantage over CN in that the former also increased the expression of IL-10 of anti-inflammatory cytokines. In this study, a metabolomics approach was successfully applied to discover the mechanistic role of CN in controlling the neuroinflammatory conditions through the modulation of complex metabolite interactions in the rat brain.

Multi-Platform Metabolomics Analyses Revealed the Complexity of Serum Metabolites in LPS-Induced Neuroinflammed Rats Treated with Clinacanthus nutans Aqueous Extract

“…The induction of either 10 μl phosphate buffer saline (PBS) to the normal rat groups or lipopolysaccharides (LPS, 1 μg/1 μl) to the neuroinflammed groups have been described in previously published manuscripts ( Ahmad Azam et al, 2019 ; Ahmad Azam et al, 2020a ). To summarize, the rats were anesthetized with ketamine-xylazine (K-X); K: 80 mg/kg BW; X: 10 mg/kg of BW through intraperitoneal (i.p) route and they underwent stereotaxic surgery with a single intracerebroventricular (ICV) injection at the location of substantia nigra at the right side of the brain with a consistent rate of 3 μl per minute using a Harvard Apparatus Pump 11 elite infusion syringe via a Hamilton syringe (Holliston, Massachusetts, United States).…”

“…Clinacanthus nutans (CN) extracts (CNE) are well known for their anti-inflammatory activities ( Pongphasuk et al, 2005 ; Khoo et al, 2018 ). Extensive studies in a comprehensive metabolomics setting via proton nuclear magnetic resonance ( 1 H NMR) analysis have successfully elucidated the ameliorative effects of CNE treatments in the serum ( Ahmad Azam et al, 2019 ) and brain ( Ahmad Azam et al, 2020a ) of lipopolysaccharide (LPS)-induced neuroinflammed rats. The use of integrative omics between metabolomics and cytokines microarray (genomics) on brain tissue has resulted in the proposed ameliorating effects of CN treatment in an LPS-induced rat model.…”

Metabolomic Approach for Rapid Identification of Antioxidants in Clinacanthus nutans Leaves with Liver Protective Potential

“…Isoschaftoside and clinacoside B as well as clinacoside C are known to be strong antioxidants, while the former was also reported to exert hepatoprotective abilities [9]. Isoschaftoside, a major component of Abrus mollis extracts, exhibited hepatoprotective potential against carbon tetrachloride (CCL 4 )-induced hepatic fibrosis in a rat model [51].…”

“…Commonly, it is known as "Sabah Snake Grass" or "Belalai Gajah" [8]. This medicinal plant has demonstrated a range of pharmacological activities, including anti-inflammatory, anti-carcinogenic and antimicrobial effects [9]. The leaves of C. nutans possessed antioxidant as well as anti-cancer potential towards tumorbearing mice [10].…”

Anti-Inflammatory Effects of Phytochemical Components of Clinacanthus nutans

“…This could be due to an effect of its components, glyceryl 1,3-disterate, kaempferol 3- O -feruloyl-sophoroside 7- O -glucoside, and hydroxypthioceranic acid, which showed pro-surviving Bcl-2 and pro-apoptotic Bax expression activities [ 30 ]. Clinacanthus nutans aqueous extracts could reduce LPS-induced increase in proinflammatory IL-1β expression but increase anti-inflammatory IL-2 and IL-4 expression in brain tissue after oral administration in rats [ 105 ]. A recent study showed that C. nutans leaf, but not stem, extracts had a significant effect in reducing 7-kecoholesterol-induced brain endothelial cell death and suppressed inflammatory responses in endothelial cells, including reducing IL-1β, IL-6, IL-8, TNF-α, and COX-2 expression [ 106 ].…”