Spectroscopic studies have established the structure (l'RS,2'SR,6'RS)-(2,6-dihydroxy-4-methoxy- phenyl)[3'-methyl-2'-(3''-methylbut-2''enyl)-6'-phenylcyclohex-3'-enyl]methanone for panduratin A which, together with pinostrobin and two known chalcones, boesenbergin A and rubranine, has been isolated from the red rhizomes of a variety of Boesenbergia pandurata (Roxb.) Schltr. A synthesis of rubranine, in moderate yield, has also been achieved.

Partly racemized pinostrobin and pinocembrin, together with 2',6'-dihydroxy-4'-methoxychalcone, cardamonin and a new chalcone (�) boesenbergin A, have been isolated from Boesenbergia pandurata Schl. (syn. Kaempferia pandurata Roxb., Zingiberaceae). Spectroscopic studies and X-ray crystallographic analysis have established the structure (�)-(E)-1-[7'-hydroxy-5'-methoxy-2'-methyl- 2'-(4''-methylpent-3''-enyl)-2'H-chromen-8'-yl]-3-phenylprop-2-enone for boesenbergin A. A simple synthesis of boesenbergin A has been achieved and its acid-catalysed cyclization has been studied.

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The genus Clinacanthus consists of two species, C. nutans LINDAU and C. siamensis BREM. and belongs to the family Acanthaceae.1) Both species are small shrubs occurring throughout South East Asia. C. nutans (Thai name: phaya yo or phaya plongtong) is often confused with C. siamensis (Thai name: lin nguu hao). C. nutans has long been used in Thailand as a traditional medicine for the treatment of insectand snake-bite and skin rashes, including herpes simplex virus (HSV) and varicella-zoster virus (VZV) lesions. The anti-inflammatory activity of a n-BuOH-soluble fraction from the leaves has been reported.2) In a series of in vitro models a crude extract of the leaves showed significant inhibitory activity on VZV.3) Likewise, ethanol extracts of C. nutans were found to be virucidal against HSV-2 in vitro. 4)However, negative results have also been reported. 5)Nonetheless, clinical trials have reported the successful use of a C. nutans preparation (cream) for treatment of genital herpes and varicella-zoster lesions in patients.6-9) Previous chemical studies on C. nutans have revealed the presence of lupeol, b-sitosterol, stigmasterol and myricyl alcohol. 10,11) Six known C-glycosyl flavones, vitexin, isovitexin, shaftoside, isomollupentin 7-O-b-glucopyranoside, orientin and isoorientin have been isolated from the n-BuOH-and watersoluble portion of the methanolic extract of the stems and leaves of C. nutans collected in Thailand.12) Five sulfur-containing glucosides were isolated from the n-BuOH-soluble portion of a methanolic extract of the stems and leaves of plant material said to be C. nutans. 13)As part of our work on bioactive substances from natural sources, a mixture of cerebrosides (1) and a monoacylmonogalactosylglycerol (4) were isolated from the EtOAc-soluble fraction of the ethanolic extract of the fresh leaves of C. nutans. We are now reporting the isolation and structure elucidation of 1 and 4 by spectroscopic methods and chemical reactions.The fresh leaves of C. nutans were extracted with EtOH at room temperature. After evaporation of the extract, the residue obtained was dissolved in H 2 O and partitioned with EtOAc and then n-BuOH. The EtOAc-soluble fraction was subjected to flash column chromatography to give 13 fractions, among which fraction 9 possessed anti-HSV-1 activity with IC 50 value of 7.86 mg/ml. Further chromatographic purification of this fraction gave 1 as a colorless solid and 4 as a pale yellow wax.The Jϭ9.6, 4.8 Hz; d C 128.9, 129.2). The data were suggestive of a glycosphingolipid structure.The 13 C-NMR spectrum of 1 (Table 1) was assigned by a combination of distortionless enhancement by polarization transfer (DEPT), heteronuclear multiple quantum coherence (HMQC) and heteronuclear multiple bond correlation January 2004 Chem. Pharm. Bull. 52(1) 27-32 (2004) 27 * To whom correspondence should be addressed.

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