Bulbophyllum

Bulbophyllum vaginatum Reich, f. is an epiphytic orchid that grows in Thailand, Indonesia, and Malaysia. The stems are 3 mm in diameter. The petiole is 2 X 6 mm, swollen, and deeply channeled. The blade is elliptic, thick, spongy, and 8x3 cm. The flowers are arranged in clusters of 12-15 pale yellow, 5-cm-long flowers with elongated corollas (Fig. 57). 

Fig. 57. Bulbophyllum vaginatum. From Flora of the Malay Peninsula. Geographical localization Rantau Panjang, Selangor. 10/30/1930. Field collector Symington, No 24330. 

Tan K-H. and Nishida R. (2000) Mutual reproductive benefits between a wild orchid, Bulbophyllum patens and Bactrocera fruit flies via a floral synomone. J. Chem. Ecol. 26, 533-546. 

Compound 417 from the stems of Dendrobium plicatile [192], agrostonin (421) and agrostonidin (422) from the orchids Agrostophyllum khasiyanum and A. callosum [193], reptanthrin (418) from Bulbophyllum replans [194] are symmetrical dimers, in contrast, isoreptanthrin (419) [194], phoyurmanin E (420) [5], denthyrsinol (423) [195] and gymconopin C (425) [105] appeared to have a dimeric formulation composed of the same monomeric units but linked in an unsymmetrical manner. 

Anoectochilus yatesae Bailey Bulbophyllum bracteatum Bailey... 

Most of the phenanthrenes are present in the form of monomers, containing about 210 compounds. Hydroxyl and methyloxyl are the most common substitutes located in the phenanthrene skeletons and occupy about 50% of aU monomers. For instance, coeloginanthrin 158 from Coelogyne cristata [88], 4-methoxyphenanthrene-2,3,7-triol 159 and 4-methox3 phenanthrene-2,3,6,7-tetrol 160 from Bulbophyllum vaginatum [89], as well as 2-methoxy-3,4,7-trihydroxy-phenanthrene 161 from B. inconsipicum [90] are hydroxyl- and/or methyloxyl-substituted ones. 

With the exception of hydroxy and methyloxy groups, methyl-, hydroxymethyl-, carboxy-, formyl-, prenyl-, and vinyl-substituted compounds are observed, with stemanthrenes A-D 162-165,166,167, dehydroeffusal 168, and gancaonin U 169 as the representatives [91-94]. Furthermore, glycosides were isolated from the plants of Juncus effusus, Epimedium koreanum, Dendrobium chrysanthum, and Bulbophyllum striata, for example, effuside 1170, epimedoicarisoside A 171, and denchryside A 172 [95-97]. 

Majumder PL, Roychowdhury M, Chakraborty S (1997) Bibenzyl derivatives from the orchid Bulbophyllum protractum. Phytochemistry 44 167-172... 

Leong Y-W, Harrison LJ. Powell AD (1999) Phenanthrene and other aromatic constituents of Bulbophyllum vaginatwn. Phytochemistry 50 1237—1241... 

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