Chemical and Pharmaceutical Bulletin
Online ISSN : 1347-5223
Print ISSN : 0009-2363
ISSN-L : 0009-2363
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Minor Withanolides of Physalis longifolia: Structure and Cytotoxicity
Huaping ZhangHashim MotiwalaAbbas SamadiVictor DayJeffrey AubéMark CohenKelly KindscherRao GollapudiBarbara Timmermann
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Supplementary material

2012 Volume 60 Issue 10 Pages 1234-1239

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Abstract

In our recent publication on bioactive guided isolation of compounds from Physalis longifolia (Solanaceae) novel anti-proliferative agents withalongolides A (4) and B (5), and their highly cytotoxic analogues, withalongolide A 4,19,27-triacetate (4a) and withalongolide B 4,19-diacetate (5a) were elucidated. In this study, the two lead compounds (4, 5) were re-isolated in gram quantities for the purpose of further analogue preparation and in vivo testing that would continue to probe structure–activity relationships. During this process, two additional withanolides, named withalongolides O (1) and P (2), were elucidated. Their structures were determined by spectroscopic techniques with 1 being subsequently confirmed by X-ray crystallographic analysis. Utilizing a MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] viability assay, withalongolide O (1) and its 4,7-diaceatate (1a), both containing the functionalities of Δ2-1-oxo- in A ring, a 5β,6β-epoxy in B ring, and a lactone ring in the nine-carbon side chain, exhibited potent cytotoxicity against human head and neck squamous cell carcinoma (JMAR and MDA-1986), melanoma (B16F10 and SKMEL-28), and normal fetal lung fibroblast (MRC-5) cells with IC50 values in the range between 0.15 and 2.95 µM. In addition, the previously reported α orientation of 7-acetate group in acnistins C and D should be revised to the β orientation on the basis of NMR data comparison.

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© 2012 The Pharmaceutical Society of Japan
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