A new γ-pyrone, sterols and triterpenes from Helichrysum bracteatum, Gazania nivea and Dimorphotheca ecklonis

A new γ-pyrone, 3-ethyl-6-(7'-hydroxy-7'-methyl-nonyl)-2-methoxy-5-methyl-pyran-4-one (helichrysone) (3) was isolated from the aerial parts of Helichrysum bracteatum. In addition, twelve known compounds; six triterpenes viz. α-amyrin (1), oleanolic acid (6), lupeol acetate (8), β-amyrin (9), ursolic acid (11) and lupeol (13), three steroidal compounds viz. spinasterol (2), stigmasterol (5) and β-sitosterol (10) and their glycosides 4, 7 and 12, respectively, were isolated from H. bracteatum, Gazania nivea and Dimorphotheca ecklonis. This is the first report for the isolation of compounds 1, 5, 6, and 7 from H. bracteatum, compounds 2 and 4 from genus Helichrysum, compounds 1, 8 and 10 from G. nivea, compounds 5, 7, 9, 11 and 12 from genus Gazania and compounds 1, 5, 7, 9, 10, 12 and 13 from genus Dimorphotheca. Compound 3 showed only a mild activity against cervix and breast cancer cell lines in-vitro as well as a mild anti-HIV activity.