Microglial activation has been found to play a crucial role in various neurological disorders. Proinflammatory substances overproduced by activated microglia, such as cytokines, chemokines, reactive oxygen species, and nitric oxide (NO), can result in neuroinflammation that further exacerbates the course of the diseases. This study aimed to explore the anti-inflammatory effect of the ethyl acetate extract of Pueraria mirifica on microglial activation. Lipopolysaccharide (LPS)-induced inflammation was used as a model to investigate the effects of P. mirifica on HAPI (highly aggressive proliferating immortalized), a rat microglial cell line. Administration of ethyl acetate extract from the tuberous roots of P. mirifica to HAPI cells dose-dependently reduced NO production and iNOS expression induced by LPS. Attenuation of IRF-1 (interferon regulatory factor-1) induction, one of the transcription factors governing iNOS expression, suggested that the inhibitory effect on NO production by the plant extract was at least partially mediated through this transcription factor. In addition, LPS-stimulated mRNA expression of MCP-1 (monocyte chemoattractant protein-1), IL-6 (interleukin-6), and TNF-α (tumor necrosis factor-α) was also suppressed with P. mirifica extract pretreatment. This study indicates that the ethyl acetate extract of P. mirifica could potentially serve as an anti-inflammatory mediator and may be useful in relieving the severity of neurological diseases where microglia play a role.

Thampithak A, et al. Infect Chemother. 2022 Nov;54:e73. https://doi.org/10.3947/ic.2022.0098

Trachyspermum roxburghianum (DC.) Craib is an edible plant found in Northern and Northeastern Thailand. This plant is used in household remedies to relieve carminative and digestive problems, hiccups, vomiting, bladder pain, etc. This study aims to assess the bioactive compounds, consisting of phenolics and flavonoids, and evaluate the biological activities of this plant. The aerial portion was macerated in EtOH1 to obtain EtOH1 crude extracts. Then, the EtOH1 was divided and separated by the solvents’ polarity to obtain Petr, EtOAc, and EtOH2 crude extracts. All crude extracts were assessed for their total phenolics and flavonoids and subsequentially evaluated for their antioxidants (using DPPH, ABTS and FRAP), enzymatic inhibitory effects (on tyrosinase and collagenase), anti-inflammatory activity (protein denaturation assay) and cytotoxicity (MTT assay). The results presented that a high amount of phenolics and flavonoids were observed in EtOH2 (56.57 mg GAE/g ext. and 22.75 mg QE/g ext.) followed by EtOAc (57.95 mg GAE/g ext. and 7.41 mg QE/g ext.), EtOH1 (47.14 mg GAE/g ext. and 4.23 mg QE/g ext.), and Petr (37.05 mg GAE/g ext. and 2.08 mg QE/g ext.), respectively. All crude extracts represented antioxidants in all assays; EtOAc presented a high level of antioxidants on ABTS (IC50 54.96 µg/mL) and DPPH (IC50 133.32 µg/mL), while EtOH2 revealed a high ability to reduce the Fe3+-TPTZ complex (155.85 Fe2+g ext.). Remarkably, for all crude extracts used for anti-collagenase enzyme activity, the percentage of inhibition ranged from 78.35 - 97.96 %. Besides, only Petr and EtOH2 showed the activity of the anti-protein denaturation (IC50 1.926 and 2.578 mg/mL). The cytotoxicity test showed that EtOH1, Petr, and EtOAc exhibited a concentration-dependent manner of inducing cell death in 24 and 48 h, while EtOH2 showed less toxicity to the cell line. This information would be valuable and pave the way for future study and application of this plant to other products. HIGHLIGHTS Trachyspermum roxburghianum (DC.) Craib from Northern Thailand High antioxidant and high anti-collagenase activities of Trachyspermum roxburghianum (DC.) Craib ethanolic extracts. GRAPHICAL ABSTRACT

Moringa oleifera Lam has been used as a medicinal plant in many Asian countries including Thailand. The plant has a variety of pharmacological effects such as antioxidant, anti-inflammation, hypolipidemic, anti-infection, anticancer, and antidiabetic. The leaves and young pods, which contain various nutritional compounds including proteins, fatty acids, and vitamins, are widely consumed. In this study, we investigated the effects of hexane, ethyl acetate, methanol and ethanol crude extracts of M. oleifera Lam leaves on the viability of microglial cells and on the lipopolysaccharide-induced microglial activation. which is widely used as a model for neuroinflammation. Our findings suggested that all of the crude extracts at concentrations ranging from 10–9 to 10–5 g/mL did not significantly affect the viability of microglial cells and exhibited similar effects. Subsequently, we focused on ethanol extract for investigation of the molecular mechanism involving neuroinflammation. We found that the ethanol extract of M. oleifera Lam leaves at the concentrations of 10–9 to 10–5 g/mL significantly reduced inducible nitric oxide synthase (iNOS) protein expression and nitric oxide (NO) production, accompanied by the reduction of phospho-NF-κB and phospho-IκBα expressions. The results suggested that the ethanol extract of M. oleifera Lam leaves reduced NO production through reduction of iNOS protein expression following the inhibition of NF-κB/IκBα signaling pathways. Our study underscored the therapeutic potential of M. oleifera Lam leaves extract in neurodegenerative diseases associated with neuroinflammation. HIGHLIGHTS The ethanol extract of M. oleifera Lam leaves dose-dependently reduced NO production in LPS-activated microglia The reduction in NO production correlated with the reduction in iNOS protein expression The extract inhibited the expression of NF-kB/I-kBα protein expression in a dose-dependent manner The ethanol extract of oleifera Lam leaves exhibited anti-inflammatory effect via the inhibition of NF-kB/I-kBα signaling pathway GRAPHICAL ABSTRACT