Four novel and potently bioactive
Amaryllidaceae alkaloids, 4,8-dimethoxy-cripowellin C (1), 4,8-dimethoxy-cripowellin D (2), 9-methoxy-cripowellin
B (3), and 4-methoxy-8-hydroxy-cripowellin B (4), together with one known
alkaloid, cripowellin C (5) were isolated from the 95% EtOH extract of the bulbs of Crinum latifolium. Structural elucidation of all the compounds were performed by spectral methods such as 1D and 2D (1H-1H COSY,
HMQC, and HMBC) NMR as well as spectroscopy high resolution mass spectrometry. All isolates were in vitro evaluated for their cytotoxic activity against seven
lung cancer cell lines, in addition to antimicrobial activity for eight bacteria, scavenging potential using ABTS·+ and DPPH test, and anti-inflammatory activity for Cox-1 and Cox-2 which had not previously been tested for
crinane-type
alkaloids with the cleavage between C-1 and C-13. Consequently,
alkaloids 1-5 exhibited potent cytotoxicity against all of seven tested tumor cell lines with (IC50 < 30 nM).
Alkaloids 3 and 4 displayed the significant antimicrobial activity with IC50 values <0.50 mM and
antioxidant activity in the ABTS·+ and DPPH test. Additionally,
Alkaloids 1-5 exhibited comparable inhibition of Cox-1 (>64%) and Cox-2 (>90%) with positive control.