Anthraquinones and Lignans from Cassia occidentalis

One new anthraquinone glycoside, 6‐ O ‐( α ‐ L ‐rhamnopyranosyl‐(1→6)‐ β ‐ d‐ glucopyranosyl)emodin ( 1 ), and two new sesquilignans, seslignanoccidentaliols A ( 2 ) and B ( 3 ), were isolated from the whole plant of Cassia occidentalis. The structures of the new compounds were established by means of spectroscopic methods, especially 2D‐NMR data ( 1 H, 1 H‐COSY, HMQC, HMBC, and ROESY), as well as HR‐ESI‐MS analysis. One previously reported sesquilignan, erythro ‐guaiacylglycerol‐ β ‐ O ‐4′‐(5′)‐methoxylariciresinol, was revised to be seslignanoccidentaliol A ( 2 ). The 6‐ O ‐( α ‐ L ‐rhamnopyranosyl‐(1→6)‐ β ‐ d‐ glucopyranosyl)emodin ( 1 ) exhibited moderate anti‐HIV‐1 activity with an EC 50 value of 2.90 μg/ml and a therapeutic‐index ( TI ) value of 260.