Planta Med 2002; 68(6): 528-533
DOI: 10.1055/s-2002-32551
Original Paper
Natural Product Chemistry
© Georg Thieme Verlag Stuttgart · New York

Cytotoxic ent-Kaurane Diterpenoids from Isodon eriocalyx var. laxiflora

Xue-Mei Niu1 , Sheng-Hong Li1 , Ma-Lin Li2 , Qin-Shi Zhao1 , Shuang-Xi Mei1 , Zhi Na1 , Su-Jun Wang2 , Zhong-Wen Lin1 , Han-Dong Sun1
  • 1Laboratory of Phytochemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, P. R. China
  • 2Yunnan Pharmacological Laboratory of Natural Products, Kunming Medical College, Kunming, P. R. China
Further Information

Publication History

August 24, 2001

December 9, 2001

Publication Date:
01 July 2002 (online)

Abstract

Three new ent-kaurane diterpenoids laxiflorin E (1), laxiflorin H (6) and laxiflorin I (8) were isolated from the leaves of Isodon eriocalyx var. laxiflora, along with nine known diterpenoids, eriocalyxin A (2), laxiflorin C (3), laxiflorin D (4), laxiflorin A (5), maoecrystal S (7), maoecrystal Q (9), eriocalyxin B (10), maoecrystal C (11) and enmelol (12). The structures of the new compounds were determined by spectroscopic methods. Compounds 1 - 5 are 6,7-seco-ent-kaurane-7,20-olide diterpenoids, and 6 - 12 belong to 7,20-epoxy-ent-kauranoids. The spectral data of enmelol (12) are reported here for the first time. Ten of these compounds were tested for their cytotoxicity toward K562 and T24 human tumor cells. Compounds 1, 3 and 10 showed significant inhibitory effects on K562 cells with IC50 values 0.077, 0.569 and 0.373 μg/mL, and compounds 1 and 10 also demonstrated significant inhibitory activities toward T24 cells with IC50 values 0.709 and 0.087 μg/mL. Compounds 8 and 11 also displayed inhibitory effect on both two kinds of cells with IC50 value less than 6.5 μg/mL.

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Prof. Dr. Han-Dong Sun

Laboratory of Phytochemistry

Kunming Institute of Botany

The Chinese Academy of Sciences

Heilongtan

Kunming 650204

People’s Republic of China

Email: hdsun@mail.kib.ac.cn

Fax: +86 871 5216343

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