Effects of Salvia officinalis L. and Chamaemelum nobile (L.) extracts on inflammatory responses in two models of human cells: Primary subcutaneous adipocytes and neuroblastoma cell line (SK-N-SH).

Salvia officinalis L. (sage), and Chamaemelum nobile (L.) (chamomile) have been used traditionally to treat various inflammatory conditions. Our study aims to investigate the anti-inflammatory properties of both plant extracts in IL-1β-stimulated neuroblastoma cells (SK-N-SH) and human subcutaneous mature adipocytes, as well as their potential protective effects against mature adipocytes conditioned media (ACM)-induced neuro-inflammation. Human subcutaneous mature adipocytes and neuroblastoma cells were treated with 5 μg/ml (low dose: LD) and 50 μg/ml (high dose: HD) of each extract, with or without 0.5 ng/ml of human recombinant IL-1β. To understand the cross talk between fat tissue and neuronal cells, SK-N-SH cell line was incubated with ACM 10%, in presence or absence of both extracts LD and HD. Following 4, and 24 h incubation, the released MCP-1, IL-6, IL-8, TNF-α, ICAM-1, VCAM-1 and SAA levels were measured using MSD Cytokines and Chemokines assay kits, and the cells were used for gene expression. RNA was quantified using Qubit™ RNA HS Assay. RNA aliquots were shipped to Eurofins Genomics (Aarhus, Denmark) for expression analysis on the human Clariom™ GO Screen Assay (952,361; ThermoFisher). Chamomile showed stronger effects compared to sage in both cell lines, at 4 and 24 h. Adipocytes acute treatment with sage decreased MCP-1, IL-6, IL-8 (p < 0.001), and TNF-α (p < 0.05) basal levels. This was mirrored at MCP-1 transcriptional level. Chronic treatment with both extracts resulted in a significant reduction in ICAM-1, VCAM-1 and SAA (p < 0.001) levels, in IL-1β-stimulated adipocytes. However, in SK-N-SH cells, sage increased the basal levels of many cytokines and chemokines on both protein and transcriptional levels. This was also observed in IL-1β-stimulated cells. In chamomile treated SK-N-SH cells, acute and chronic treatments decreased MCP-1 (p < 0.001), IL-6 (p < 0.01), TNF-α (p < 0.01), and IL-8 (p < 0.001) basal levels. In IL1-β-stimulated SK-N-SH cells, chamomile HD induced a significant reduction in TNF-α after both acute and chronic treatments respectively, by 52% and 81%. At transcriptional level, this effect was only reflected at 4 h. ICAM-1, VCAM-1 and SAA levels were reduced in most of the studied conditions. In IL-1β treated adipocytes, chamomile showed stronger reduction in MCP-1, ICAM-1 and VCAM-1 expression, however no significant reduction in TNF-α and IL-8 was observed, despite the decrease in basal levels. In SK-N-SH cells, ACM increased MCP-1, IL-6, IL-8, TNF-α, VCAM-1 and SAA levels. Sage HD acute treatment resulted in a reduction of ACM effect on IL-6, IL-8 and VCAM-1, with greater effect of chamomile on MCP-1 (p < 0.05); IL-6 (p < 0.001); TNF-α (p < 0.001); VCAM-1 (p < 0.001); and SAA (p < 0.001). This protective effect was also observed after chronic treatment. However, both extracts potentiated significantly the ACM-pro-inflammatory effect on IL-8 (p < 0.001). Sage decreased the pro-inflammatory markers mostly in human adipocytes, whereas chamomile showed a strong reduction in both cell populations. Both extracts reduced the ACM-induced inflammation effect and might be used as a preventive treatment for late-life cognitive impairment related to low-grade chronic inflammation associated with obesity. Further studies are needed to investigate their combination on other chronic inflammation-related diseases such as type 2 diabetes or rheumatoid arthritis.