Phytotoxic Activity of Bibenzyl Derivatives from the Orchid Epidendrum rigidum

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• 作者：Yanet Herná ; ndez-Romero ; Laura Acevedo ; Marí ; a de Los Á ; ngeles Sá ; nchez ; W. Thomas Shier ; Hamed K. Abbas ; and Rachel Mata
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：August 10, 2005
• 年：2005
• 卷：53
• 期：16
• 页码：6276 - 6280
• 全文大小：166K
• 年卷期：v.53,no.16(August 10, 2005)
• ISSN：1520-5118

文摘

A whole plant chloroform-methanol extract of the orchid Epidendrum rigidum inhibited radicle growthof Amaranthus hypochondriacus seedlings (IC₅₀ = 300 mages/entities/mgr.gif">g/mL). Bioassay-guided fractionation furnishedfour phytotoxins, namely, gigantol (1), batatasin III (2), 2,3-dimethoxy-9,10-dihydrophenathrene-4,7-diol (9), and 3,4,9-trimethoxyphenanthrene-2,5-diol (11), along with the known flavonoids apigenin,vitexin, and isovetin and the triterterpenoids 24,24-dimethyl-9,19-cyclolanostane-25-en-3mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-ol (14) and24-methyl-9,19-cyclolanostane-25-en-3mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-ol (15). Stilbenoids 1, 2, 9, and 11 inhibited radicle growthof A. hypochondriacus with IC₅₀ values of 0.65, 0.1, 0.12, and 5.9 mages/entities/mgr.gif">M, respectively. Foliar applicationof gigantol (1) at 1 mages/entities/mgr.gif">M to 4 week old seedlings of A. hypochondriacus reduced shoot elongation by69% and fresh weight accumulation by 54%. Bibenzyls 1 and 2, as well as synthetic analogues 4'-hydroxy-3,3',5-trimethoxybibenzyl (3), 3,3',4',5-tetramethoxybibenzyl (4), 3,4'-dihydroxy-5-methoxybibenzyl (5), 3'-O-methylbatatasin III (6), 3,3',5-trihydroxybibenzyl (7), and 3,4',5-trihydroxybibenzyl(8), were tested for phytotoxicity in axenic cultures of the small aquatic plant Lemna pausicostata. Allbibenzyls derivatives except 7 and 8 inhibited growth and increased cellular leakage with IC₅₀ valuesof 89.9-180 and 89.9-166 mages/entities/mgr.gif">M, respectively. The natural and synthetic bibenzyls showed marginalcytotoxicity on animal cells. The results suggest that orchid bibenzyls may be good lead compoundsfor the development of novel herbicidal agents.Keywords: Epidendrum rigidum; orchidaceae; bibenzyls; phenantrenes; stilbenoids; phytotoxicity;cytotoxicity; Lemna pausicostata; duckweed; Amaranthus hypochondriacus; gigantol; batatsin III