The cytotoxic and tyrosine kinase inhibitory properties of C₂₁ steroids and iridoids from the tubers of Alocasia cucullata

Ten steroids and iridoids were isolated from the tubers of Alocasia cucullata (Lour.) G. Don. Among them, alocasgenin A (1) and alocasgenoside B–C (2–3) were new compounds and the aglycone of compound 1, obtained from the acid hydrolysis of 1, was named alocasgenol (1a). Also, for the first time, tenacigenin B (4), 17β-tenacigenin-B (5), 3-O-6-deoxy-3-O-methyl-β-d-allopyranosyl-(1→4)-β-d-oleandropyranosyl-tenacigenin C (6), marsdenoside A–B (7–8) and tenacigenoside A–B (9–10) were isolated from the genus Alocasia. The chemical structures were elucidated by the extensive analysis of spectral data and compared with the literature. By evaluation of the cytotoxic and tyrosine kinase inhibition, compounds 1–10, 1a and compound 2 showed significant growth inhibition against two tumour cell lines, MGC-803 and HT-29, while compounds 1, 1a, 3, 6 and 8 presented moderate inhibition. Furthermore, compound 2 had the inhibitory property against the enzyme activity biochemically.