Fig. 4: Toxic effects of the topical application of hydroxy-octadecenoic acids.

Toxic effects of topical application of hydroxy-octadecenoic acids on Guinea pig’s skin inflammation (a–i) and the toxic effects of subcutaneous application of hydroxy-octadecenoic acids on mouse tail necrosis and tail tip detachment (m–p). Fifty μl DMSO containing 0, 2, 10 or 100 mg l⁻¹ hydroxy-octadecenoic acids was evenly applied to the surface of the shaved skin of the Guinea pigs and then covered with a piece of medical gauze and fixed by bandage tapes. The higher the concentration resulted in the heavier inflammation and the longer healing time. As shown in Fig. 4i–l, the Guinea pig had severe pathological changes inside the skin after the application of hydroxy-octadecenoic acids. A large number of inflammatory cells in the skin of the mice treated at higher concentrations of hydroxy-octadecenoic acids. a–d one week after application; e–h four weeks after application; i–l skin pathological sections (Bar, 10 µm). a, e, i control; b, f, j treated at 2 mg l⁻¹; c, g, k treated at 10 mg l⁻¹; d, h, l treated at 100 mg l⁻¹. Hydroxy-octadecenoic acids was applied to mouse tail at 100 mg kg⁻¹ body mass by subcutaneous injection using 30 μl DMSO as vehicle; mice in the control group only received 30 μl DMSO. m and n (control), one week and two weeks after subcutaneous injection of the same dose of DMSO alone as the hydroxy-octadecenoic acids-treated group on mouse tail, respectively; o and p, one week and two weeks after subcutaneous injection of hydroxy-octadecenoic acids at 100 mg kg⁻¹ body mass on mouse tail, showing the tail prior to and after tail tip detachment, respectively. Hydroxy-octadecenoic acids is an isomeric mixture of 11-hydroxy-9E-octadecenoic acid, 12-hydroxy-10E-octadecenoic acid and 12-hydroxy-10Z-octadecenoic acid obtained from the kernel cake of Jatropha.