Natural Product Research, Vol. 19, No. 6, September 2005, 597–602 Latazienone, a new lathyrane-type diterpenoid from Euphorbia latazi Kunth MARIA RONDO ´ Ny*, ANTONIO MORALESy, JUAN M. AMARO-LUISz, ALI BAHSASz, JANNE ROJASy and DIOLIMAR BUITRAGOy yInstituto de Investigaciones, Facultad de Farmacia zLaboratorio de Resonancia Magne´tica Nuclear, Grupo de Productos Naturales, Facultad de Ciencias, Universidad de Los Andes, Me´rida, Venezuela-5101 (Received 9 January 2004; in final form May 2004) A new lathyrane-type diterpene 8,15-diacetoxy-7-benzoyloxy-3-(2-methylpropanoyloxy)- 4H,9H, 11H-lathyra-5E,12E-dien-14-one (latazienone) has been isolated from the latex of Euphorbia latazi Kunth. The structure of the new diterpene was determined by a combination of 1D- and 2D-NMR techniques. Keywords: Euphorbia latazi Kunth; Euphorbiaceae; Diterpene; Lathyrane 1. Introduction The genus Euphorbia (Euphorbiaceae) comprises a large group of plants with over 1000 species [1], which are characterised by the presence of a white milky latex [2]. Many species of the genus Euphorbia have been used in folk medicine as anti- inflammatory [3], analgesic and antipyretic agents [4] and to treat cancer [5], diarrhoea [6], warts [5] and skin diseases [5]. Thus, several chemical and pharmacological investigations have been carried out. It has been demonstrated that a number of lathyrane, tigliane, ingenane and jatrophane type diterpenes isolated from different species of Euphorbia, are responsible for the pro-inflammatory, tumor-promoting and skin irritant activities [7]. We now report the isolation and structure elucidation of a new diterpene with a lathyrane nucleus which was named latazienone (1). 2. Results and discussion Latazienone (1) was obtained as a white amorphous powder, m.p. 208–210  C. Its HREI-MS exhibited a molecular ion peak at m/z 608.2437 which agreed with the *Corresponding author. Email: rondonr@cantu.net Natural Product Research ISSN 1478-6419 print: ISSN 1029-2349 online ß 2005 Taylor & Francis Group Ltd http://www.tandf.co.uk/journals DOI: 10.1080/14786410412331280096