Piperine, one of the main components of Piper longum Linn. and P. nigrum Linn., is a plant alkaloid with a long history of medicinal use. Piperine has been shown to modulate the immune response, but the mechanism underlying this modulation remains unknown. Here, we examined the effects of piperine on lipopolysaccharide (LPS)-induced inflammatory responses in bone-marrow-derived dendritic cells (BMDCs). Piperine significantly inhibited the expression of major histocompatibility complex class II, CD40 and CD86 in BMDCs in a dose-dependent manner. Furthermore, piperine treatment led to an increase in fluorescein-isothiocyanate-dextran uptake in LPS-treated dendritic cells and inhibited the production of tumour necrosis factor alpha and interleukin (IL)-12, but not IL-6. The inhibitory effects of piperine were mediated via suppression of extracellular signal-regulated kinases and c-Jun N-terminal kinases activation, but not p38 or nuclear factor-κB activation. These findings provide insight into the immunopharmacological role of piperine.
Lupeol is a triterpenoid commonly found in fruits and vegetables and is known to exhibit a wide range of biological activities, including antiinflammatory and anti-cancer effects. However, the effects of lupeol on acute pancreatitis specifically have not been well characterized. Here, we investigated the effects of lupeol on cerulein-induced acute pancreatitis in mice. Acute pancreatitis was induced via an intraperitoneal injection of cerulein (50 µg/kg). In the lupeol treatment group, lupeol was administered intraperitoneally (10, 25, or 50 mg/kg) 1 h before the first cerulein injection. Blood samples were taken to determine serum cytokine and amylase levels. The pancreas was rapidly removed for morphological examination and used in the myeloperoxidase assay, trypsin activity assay, and real-time reverse transcription polymerase chain reaction. In addition, we isolated pancreatic acinar cells using a collagenase method to examine the acinar cell viability. Lupeol administration significantly attenuated the severity of pancreatitis, as was shown by reduced pancreatic edema, and neutrophil infiltration. In addition, lupeol inhibited elevation of digestive enzymes and cytokine levels, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1, and interleukin (IL)-6. Furthermore, lupeol inhibited the cerulein-induced acinar cell death. In conclusion, these results suggest that lupeol exhibits protective effects on cerulein-induced acute pancreatitis.
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