title: Pachydictyols B and C: new diterpenes from Dictyota dichotoma Hudson.
abstract: Two new diterpenoids, pachydictyol B (1a/1b) and C (2), were isolated from the dichloromethane extract of the marine brown alga, Dictyota dichotoma, collected from the Red Sea coast of Egypt, along with the known metabolites, pachydictyol A (3a), dictyol E (4), cis-africanan-1α-ol (5a), fucosterol (6), tetrahydrothiophen-1,1-dioxide and poly-β-hydroxybutyric acid. GC-MS analysis of the nonpolar fractions also indicated the presence of β-bourbonene and nonanal, along with three hydrocarbons and five fatty acids or their simple derivatives, respectively. GC-MS analysis of the unsaponifiable algal petroleum ether extract revealed the presence of a further eight compounds, among them 2,2,6,7-tetramethyl-10-oxatricyclo[4.3.0.1(1,7)]decan-5-one (7), N-(4-bromo-n-butyl)-pipe ridin-2-one (8) and tert-hexadecanethiol. Structures 1-6 were assigned by 1D and 2D NMR, mass spectra (EI, CI, HREI and HRESI) and by comparison with data from related structures. The crude algal extract was potently active against the breast carcinoma tumor cell line, MCF7 (IC₅₀ = 0.6 µg mL⁻¹); pachydictyol B (1a) and dictyol E (4) showed weak antimicrobial properties, and the other compounds were inactive. Pachydictyols B (1a) and C (2) demonstrated a weak and unselective cytotoxicity against twelve human tumor cell lines with a mean IC₅₀ of >30.0 µM.
authors: Department of Botany, Faculty of Science, Mansoura University, Algomhuria St. 60, El-Mansoura 35516, Egypt.
authors: Ghada S E
authors: GS
authors: Abou-El-Wafa
authors: Mohamed
authors: M
authors: Shaaban
authors: Khaled A
authors: KA
authors: Shaaban
authors: Mohamed E E
authors: ME
authors: El-Naggar
authors: Armin
authors: A
authors: Maier
authors: Heinz H
authors: HH
authors: Fiebig
authors: Hartmut
authors: H
authors: Laatsch
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy; D045744:Cell Line, Tumor; D004224:Diterpenes / Q000737:chemistry* / Q000494:pharmacology; D005260:Female; D006801:Humans; D000459:Phaeophyceae / Q000737:chemistry*; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D004224:Diterpenes; D010936:Plant Extracts
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