A bioactive sesquiterpene from Bixa orellana L.

The dichloromethane extract of the air-dried leaves of Bixa orellana L. afforded ishwarane, phytol, polyprenol, and a 1:3 mixture of β-stigmasterol and β-sitosterol by silica gel chromatography. The structure of ishwarane was elucidated by extensive 1D and 2D NMR spectroscopy. It was also tested for analgesic, hypoglycemic, antispasmodic, and prophylactic activity at three dosages (25, 50 and 100 mg/kg BW) and for antimicrobial potential. Results of the prophylactic assay demonstrated the anti-toxic property of ishwarane at 100 mg/kg BW where signs of recovery were already evident at 2.5 hours after treatment administration, while the negative control showed signs of recovery only at 5 hours postreatment. The 50 mg/kg BW ishwarane (88.38±13.59%) resulted to a more propulsive movement of the gastrointestinal tract compared to the negative control (78.47±10.61%) which might indicate a possible cholinergic activity. It did not, however, exhibit any hypoglycemic activity or analgesic potential using the acetic acid writhing assay. Ishwarane exhibited moderate antifungal activity against C. albicans (AI = 0.3), low activity against T. mentagrophytes (AI = 0.3) and low antibacterial activity against E. coli (AI = 0.1), S. aureus ( AI = 0.1) and P. aeruginosa (AI = 0.3). It was inactive against B. subtilis and A. niger