Isolation and Characterization of Buchholztrienone A, a Novel Trienone Glycosidic Polyketide from the Stem Bark of Buchholzia coriacae Engler (Capparaceae)

Abstract

Buccholzia coriacea has been used in traditional medicine to treat hypertension, headache, and infectious diseases among others. This study was undertaken to isolate and characterize a new secondary metabolites from the stem bark of Buchholzia coriacea. Cold maceration in ethanol was used to obtain the crude extract which was partitioned between chloroform and n-hexane (1:1). Column chromatography was employed to purify the chloroform fraction, while thin layer chromatography (TLC) was used to monitor the purification process. The structure of the isolated compound was elucidated through characterization of its infra-red (IR) spectrum, proton nuclear magnetic resonance (¹HNMR) spectrum, carbon-13 nuclear magnetic resonance (¹³CNMR) spectrum, distortionless enhancement by polarization transfer (DEPT); 2-dimensional hetronuclear single quantum coherence (HSQC) as well as quadrupule time-of-flight positive electron spray mass spectrometry (Q-Tof MS ES⁺). The isolated compound was proposed as Buchholztrienone A, a trienone glycosidic polyketide. The IUPAC name is (2Z, 4Z, 6E)-(tetrahydro - 2,3,5,6 - tetramethoxy-2H-pyran-2yl)methoxy)-17-(1,3-dioxan-5-yl)-21-hydroxy-8-(hydroxymethyl)-9-methlyhenicosa-2,4,6-trien-11-one, with molecular formular C₃₇H₆₄O₁₁, showing  a molecular ion (M⁺) peak at 684, a white crystalline solid with R_f 0.86 in n-hexane/chloroform/methanol (40:30:30). The isolated compound is a remarkable contribution to Natural Products research.