Cytotoxic and anti-inflammatory activity of labdane and cis-clerodane typediterpenes

Two labdane type diterpenes, labd-13(E)-ene,-8 alpha ,15-diol (1) and labd- 13(E)-ene,-8 alpha ,15-yl acetate (2) were isolated from the hexane extract of Cistus creticus subsp. eriocephalus (Viv.) Greuter & Burdet leaves, whi le (+)-19-acetoxy-cis-clerodan-3-en-15-oic acid (3) was isolated from the h exane extract of Cistus monspeliensis L. leaves. The compounds were examine d for their in vitro cytostatic and cytotoxic activity against nine human l eukemic cell lines, three of which exhibited a multidrug resistant phenotyp e. They were also evaluated for their anti-inflammatory activity in vivo on the back of hairless mice. The cytostatic and cytotoxic activity of the te sted diterpenes followed the order 1 >2 >3. Topical application of the dite rpenes on barrier disrupted skin did not seem to have a significant contrib ution to the repair rate of the skin barrier.