24-Methylene cycloartanyl p-hydroxycinnamate from the orchid Cirrhopetalum elatum

Review article number 67Triterpenoids

Abstract: Triterpenoids isolated and characterized from various sources are reviewed. The newer techniques used in their isolation and structure elucidation, the newer skeleton triterpenoids characterized, chemical modifications and synthetic studies reported are discussed. A compilation of the triterpenoids isolated during the period 1982–1989 along with their occurrence, available physical data, spectroscopy and X-ray analysis used for their characterization, is included. The biological activities of the triterpenoids are also described.

Moscatilin, a bibenzyl derivative from the orchid Dendrobium moscatum

Abstract: Moscatilin, a new bibenzyl derivative isolated from the orchid Dendrobium moscatum , was shown to have the structure 4,4′-dihydroxy-3,3′,5-trimethoxybibenzyl.

Isolation and characterisation of intact steryl ferulates from seeds

Abstract: Approaches to the isolation and characterisation of intact steryl ferulates were investigated. Alkaline washing of the total lipid extract obtained from seeds allowed preliminary separation of a phenolic ester containing fraction from the abundant neutral lipids (comprising largely triacylglycerides, sterols and steryl fatty acyl esters). Subsequent thin-layer chromatography (silica gel) afforded purified steryl ferulates. Separation of individual molecular species was achieved by reversed-phase (ODS) high-performace liquid chromatography (HPLC) using the acetate derivatives of the steryl ferulates, or by high-temperature gas chromatography (GC) of the underivatised steryl ferulates or their acetates or trimethylsilyl ethers. Characterisation of intact individual molecular species was based on the electron impact mass spectra obtained by GC—mass spectrometry (MS) of the underivatised ferulates or their trimethylsilyl ethers, or by direct insertion probe MS of the acetates of the steryl ferulates obtained by preparative HPLC. The feasibility of the above approach was established using the well characterised steryl ferulate mixture γ-oryzanol obtained from rice bran oil. The methods were subsequently applied to the analysis of the steryl ferulates present in seeds of maize ( Zea mays ).

Structure of flavanthrin, the first dimeric 9,10-dihydrophenanthrene derivative from the orchid eria flava

Abstract: Flavanthrin, the first dimeric 9,10-dihydrophenanthrene derivative, was isolated from the orchid Eria flava which also yielded the previously reported 9,10-dihydrophenanthrene coelonin ( 2a ). The structure of flavanthrin was established as the 1.1'-dimer ( 1a ) of its congener coelonin from spectral and chemical evidence.

Confusarin and confusaridin two phenanthrene derivatives of the orchid Eria Confusa

Abstract: From the orchid Eria confusa were isolated two new polyoxygenated phenanthrene derivatives, confusarin and confusaridin, which were shown to be 2,7-dihydroxy-3,4,8-trimethoxyphenanthrene and 2,6-dihydroxy-3,4,7,8-tetramethoxyphenanthrene, respectively.

Lagerenyl acetate and lagerenol two tetracyclic triterpenoids with the cycloartane skeleton from Lagerstroemia lancasteri

Abstract: Lagerenyl acetate and lagerenol two new tetracyclic triterpenoids with the cycloartane skeleton together with four other triterpenoids 2α-hydroxy- 3β-E-p-coumaryloxy-urs-12-en-28-oic acid (jacoumaric acid, isolated as its monoacetylmethylcarboxylate derivative), 2α-hydroxyursolic acid (isolated as its diacetate), germanicyl acetate and friedelin, and sitosterol were isolated from the leaves and twigs of Lagerstroemia lancasteri. The structures of lagerenyl acetate and lagerenol were established as 3β-acetoxycycloart-24-one and 3β-hydroxycycloart-24-one, respectively, on the basis of spectral and chemical evidence.