New Dihydrodibenzoxepins from Bulbophyllum kwangtungense

Abstract

Three new dihydrodibenzoxepins 7,8-dihydro-5-hydroxy-12,13-methylenedioxy-11-methoxyldibenz[b,f]oxepin (1), 7,8-dihydro-4-hydroxy-12,13-methylenedioxy-11-methoxyldibenz[b,f]oxepin (2), and 7,8-dihydro-3-hydroxy-12,13-methylenedioxy-11-methoxyldibenz[b,f]oxepin (3), were isolated from Bulbophyllum kwangtungense Schlecht, along with three known compounds, cumulatin (4), densiflorol A (5) and plicatol B (6). Their structures were established by a combination of 1D and 2D NMR spectroscopic techniques. All new compounds (1 - 3) and the known compound densiflorol A (5) exhibited anti-tumor activities against HeLa and K562 human tumor cell lines.

References

• 1 Leong Y -W, Kang C -C, Harrison L J, Powell A D. Phenanthrenes, dihydrophenanthrenes and bibenzyls from the Orchid Bulbophyllum vaginatum .  Phytochemistry. 1997;  44 157-65
• 2 Leong Y -W, Harrison L J. A biphenanthrene and a phenanthro[4,3-b]furan from the orchid Bulbophyllum vaginatum .  J Nat Prod. 2004;  67 1601-3
• 3 Majumder P L, Pal S, Majumder S. Dimeric phenanthrenes from the orchid Bulbophyllum reptans .  Phytochemistry. 1999;  50 891-7
• 4 Majumder P L, Kar A, Shoolery J N. Bulbophyllathrin, a phenanthrene of the orchid Bulbophyllum leopardium .  Phytochemistry. 1985;  25 2083-7
• 5 Majumder P L, Sen R C. Bulbophyllanthrone, a phenanthraquinone from Bulbophyllum odoratissimum .  Phytochemistry. 1991;  30 2092-4
• 6 Yi Y F, Xing F W, Huang X X, Chen H F. Medicinal plants of Bulbophyllum species in China.  J Trop Subtrop Bot. 2005;  13 65-9
• 7 Andrea S, Rudolf M, Floris E, Thawatchai S, Suttiporn C. Phenolic compounds from Anomianthus dulcis .  Phytochemistry. 1999;  50 1069-72
• 8 Pettit G R, Numata A, Iwamoto C, Usami Y, Yamada T, Ohishi H. Antineoplastic gents. 551. Isolation and structures of bauhiniastatins 1 - 4 from Bauhinia purpurea .  J Nat Prod. 2006;  69 323-7
• 9 Marina D G, Antonio F, Antonio M, Pietro M, Lucio P. A bioactive dihydrodibenzoxepin from Juncus effusus .  Phytochemistry. 1993;  34 1182-4
• 10 Reddy M VB, Reddy M K, Gunasekar D, Caux C, Bodo B. A flavanone and a dihydrodibenzoxepin from Bauhinia variegata .  Phytochemistry. 2003;  64 879-82
• 11 Majumder P L, Pal S. Cumulatin and tristin, two bibenzyl derivatives from the orchid Denrobium cumulatum and Bulbophyllum triste .  Phytochemistry. 1993;  32 1561-5
• 12 Fan C Q, Wang W, Wang Y P, Qin G, Zhao W. Chemical constituents from Dendroium densiflorum .  Phytochemistry. 2001;  57 1255-8
• 13 Chie H, Masae Y. Phenanthrenes from Dendrobium plicatile .  Phytochemistry. 2000;  53 987-90
• 14 Tweentyman P R, Luscombe M. A study of some variables in a tetrazolium dye (MTT) based assay for cell growth and chemosensitivity.  Brit J Cancer. 1987;  56 279-85
• 15 Wang K W, Sun H X, Wu B, Pan Y J. Two novel olean triterpenoids from Celastrus hypoleucus .  Helv Chim Acta. 2005;  88 990-5