[A new alkaloid from Opuntia vulgaris].

Aim: To study the chemical constituents of the stems of Opuntia vulgaris Mill(Cactaceae).

Methods: The compounds of Opuntia vulgaris were isolated by chromatography of Amberlite Dowex 50 and silica gel, and identified by means of UV, IR, MS, 1D and 2D NMR.

Results: Three compounds were isolated and identified as: opuntin B(I), 4-hydroxyproline(II) and tyrosine(III).

Conclusion: Compound I is a new alkaloid.