Triterpenoids from Vitellaria paradoxa Stem Barks Reduce Nitrite Levels in LPS-Stimulated Macrophages
Carmina Sirignano, Pascal Nadembega, Ferruccio Poli, Barbara Romano, Giuseppe Lucariello, Daniela Rigano, Orazio Taglialatela‐Scafati
Abstract
Vitellaria paradoxa C. F. Gaertn is widely used in African traditional medicine as an anti-inflammatory remedy to treat rheumatism, gastric problems, diarrhea, and dysentery. The phytochemical investigation of the ethyl acetate extract of V. paradoxa stem bark collected in Burkina Faso led to the isolation of eight known and two triterpenes undescribed to date (7 and 10), in the free alcohol form or as acetyl and cinnamyl ester derivatives. The stereostructures of the new compounds were elucidated using HR-ESIMS and 1D and 2D NMR data. The isolated compounds were evaluated in vitro for their inhibitory effect on nitrite levels on murine macrophages J774 stimulated with the lipopolysaccharide (LPS). Among all the compounds tested, lupeol cinnamate (3) and betulinic acid (5) showed a beneficial effect in reducing nitrite levels produced after LPS stimulation.