Anti-Inflammatory Effect of Pineapple Rhizome Bromelain through Downregulation of the NF-B- and MAPKs-Signaling Pathways in Lipopolysaccharide (LPS)-Stimulated RAW264.7 Cells

Abstract

Bromelain is a mixture of proteolytic enzymes derived from pineapple (Ananas comosus) fruit and stem possessing several beneficial properties, particularly anti-inflammatory activity. However, the molecular mechanisms underlying the anti-inflammatory effects of bromelain are unclear. This study investigated the anti-inflammatory effects and inhibitory molecular mechanisms of crude and purified rhizome bromelains on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophage cells. RAW264.7 cells were pre-treated with various concentrations of crude bromelain (CB) or purified bromelain (PB), and then treated with LPS. The production levels of pro-inflammatory cytokines and mediators, including nitric oxide (NO), interleukin (IL)-6, and tumor necrosis factor (TNF)-α were determined by Griess and ELISA assays. The expressions of inducible nitric oxide synthetase (iNOS), cyclooxygenase (COX)-2, nuclear factor kappa B (NF-κB), and mitogen-activated protein kinases (MAPKs)-signaling pathway-related proteins were examined by western blot analysis. The pre-treatment of bromelain dose-dependently reduced LPS-induced pro-inflammatory cytokines and mediators, which correlated with downregulation of iNOS and COX-2 expressions. The inhibitory potency of PB was stronger than that of CB. PB also suppressed phosphorylated NF-κB (p65), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha, extracellular signal-regulated kinases, c-Jun amino-terminal kinases, and p38 proteins in LPS-treated cells. PB then exhibited potent anti-inflammatory effects on LPS-induced inflammatory responses in RAW264.7 cells by inhibiting the NF-κB and MAPKs-signaling pathways.

Bromelain Extract Exerts Antiarthritic Effects via Chondroprotection and the Suppression of TNF-α–Induced NF-κB and MAPK Signaling

“…The inhibitory effects of bromelain on NF-κB and MAPK signaling pathways in this study agree with previous findings demonstrating the inhibitory effects of bromelain on the NF-κB pathway and AP-1 molecules [44,45]. Recently, the inhibitory effects of bromelain on LPS-induced NF-κB and MAPK signaling were demonstrated in RAW cells [10,46].…”

“…The HPLC profile revealed that the bromelain extract used in this study was identical to stem bromelain, and the peak of bromelain extract appeared at a retention time of 0.9 min. The bromelain extract examined in this study was previously characterized for protease activity, and its molecular weight was calculated as 25-27 kDa [10]. The HPLC profile (Figure 1) revealed that bromelain extract was not a pure compound, in line with the results of a previous study reporting that stem bromelain consisted of four proteases, one jacalin-like lectin, and two protease inhibitors according to LC-MS/MS [11].…”

“…In previous research, bromelain extract from pineapple rhizome was characterized and revealed to exhibit protease activity with a molecular weight of approximately 25-27 kDa [10]. In this study, the HPLC profile illustrated that the bromelain extract was identical to commercially available stem bromelain with protease activity and many beneficial biological and pharmacological activities [50].…”

“…Pineapple rhizome was used as raw material and kindly supported from the pineapple factory in Chonburi Province, Thailand. Bromelain enzyme was extracted as previously described [10]. Briefly, pineapple rhizome was chopped into small pieces and mixed with water (1:1 w/v) to prepare a slurry.…”

Anti-inflammatory effects of two lupane-type triterpenes from leaves of Acanthopanax gracilistylus on LPS-induced RAW264.7 macrophages

“…Therefore, finding effective and low-toxicity anti-inflammatory drugs to control inflammation is critical for the prevention or treatment of these diseases (Tang et al, 2021). Inflammation results in the production of proinflammatory cytokines and other inflammatory mediators such as tumor necrosis factor (TNF)-α, and IL-1β, and high mobility group box 1 (HMGB1) (Insuan et al, 2021). HMGB1 plays a critical role in the pathophysiology of inflammatory diseases like sepsis (Yang et al, 2021;Hur et al, 2021).…”