The bamboo shoot of Pleioblastus amarus (Keng) Keng f. is a medicinal and edible plant product in China. In this study, the chemical composition of the total alkaloids from bamboo shoots and bamboo shoot shells of P. amarus (Keng) Keng f. (ABSP and ABSSP, respectively) were separated and investigated by UHPLC/QTOF-MS/MS. The results showed that a total of 32 alkaloids were extracted, with 15 common to both ABSP and ABSSP and 10 and 7 alkaloids distinct to ABSP and ABSSP, respectively. ABSP and ABSSP both decreased the lipopolysaccharide (LPS, 0.5 μg/mL)-induced nitric oxide (NO) production in RAW264.7 murine macrophages with half maximal inhibitory concentration (IC50) values of 78 and 55 μg/mL, respectively. We also found that ABSP and ABSSP (100 μg/mL) could decrease the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at both mRNA and protein levels in LPS-exposed RAW264.7 cells. Moreover, 100 μg/mL of ABSP and ABSSP also significantly inhibited LPS-induced mRNA expression of interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α). Additionally, ABSP and ABSSP (100 μg/mL) decreased the phosphorylation of extracellular regulated protein kinase (ERK) in LPS-stimulated RAW264.7 cells. Collectively, the total alkaloids from the bamboo shoots and shells of P. amarus exhibit anti-inflammatory effects in LPS-activated RAW264.7 cells through the inhibition of ERK signaling. This result can provide support for the medicinal use and further study of P. amarus.
Keywords: ERK signaling; LC-MS/MS; Pleioblastus amarus (Keng) Keng f.; RAW264.7 cells; anti-inflammatory activity; total alkaloids.