Toxicology 168 (2001) 231 – 240 Camelliin B induced apoptosis in HeLa cell line Ching-Chiung Wang a , Lih-Geeng Chen a , Ling-Ling Yang a,b, * a Graduate Institute of Pharmacognosy Science, Taipei Medical Uniersity, 250 Wu -Hsing Street, Taipei 110, Taiwan, ROC b Graduate Institute of Biotechnology, Life Science College, National Chiayi Uniersity, 300, Uniersity Road, Chiayi 600, Taiwan, ROC Received 27 November 2000; received in revised form 30 May 2001; accepted 25 June 2001 Abstract Gordonia axillaris (Roxb.) Dietrich (Theaceae) is a native to Taiwan and the leaves have been used as an astringent folk medicine. Camelliin B (CB), a macrocyclic hydrolyzable tannin, was isolated from G. axillaris and showed cytotoxic effects in human carcinoma cells. Among the target cells (SKHep-1, Ha-22T, DU-145, AGS, and HeLa), the cervical carcinoma cell line, HeLa, was more sensitive to CB than were Chang normal liver cells and primary-cultured normal gingival and cervical fibroblasts. Furthermore, the cytotoxic effects of CB showed dose-dependency at 3.2–100.0 g/ml in HeLa for 1, 24, 48, and 72 h and with an IC 50 value of 46.3 g/ml for 48 h. However, the IC 50 value of CB in primary-cultured normal cervical fibroblasts was 108.0 g/ml. Therefore, the selectivity shown by CB was ascribed to the difference in growth speed between normal and tumor cells. HeLa cells and primary-cultured normal cervical fibroblasts were treated with 50.0 and 100.0 g/ml CB for 48 h, respectively, and exhibited chromatin condensation, indicating the occurrence of apoptosis. Flow cytometric analysis demonstrated the presence of apoptotic cells with low DNA content, a decrease of cell population at the G 1 phase, and a concomitant increase of cell population at the G 2 /M phase. CB also caused DNA fragmentation and inhibited PARP degradation in HeLa cells. However, CB did not significantly inhibit Bcl-2 expression in HeLa cells at 50.0 g/ml, only at 100.0 g/ml for 48 h. These results suggest that CB induced apoptosis, without direct inhibition of Bcl-2 expression in HeLa cells. © 2001 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Gordonia axillaris (Roxb.) Dietrich; Camelliin B; Macrocyclic hydrolyzable tannin; Apoptosis; HeLa www.elsevier.com/locate/toxicol 1. Introduction Natural products have been used in traditional and folk medicine for therapeutic purposes. Sev- eral anticancer drugs derived from natural sources, including the well-known Cantharanthus alkaloids, colchicine, etoposide, and taxol (Pez- zuto, 1997), have been used in cancer chemother- apy. Since cytotoxic and anti-proliferative drugs have had great success and will likely continue to play a major role in cancer treatment, we are interested in finding new active compounds from natural sources and studying their biological effects. G. axillaris (Roxb.) Dietrich (Theaceae) is a small tree native to Taiwan. The leaves of G. * Corresponding author. Tel.: +886-5-2717930; fax: +886- 5-2717931. E-mail address: llyang@ncyu.edu.tw (L.-L. Yang). 0300-483X/01/$ - see front matter © 2001 Elsevier Science Ireland Ltd. All rights reserved. PII:S0300-483X(01)00452-8