Biflorin

Oldenlandia chrysotricha L. O. corymbosa L. Shi Da Chuan Shui Xian Cao (leaf) Biflorine, biflorone, gamma-sitosterol, stigmasterol, ursolic acid, oleanolic acid.50 Ferbrifuge, for hepatomegaly, lymphadenitis, neophasia, splenomegaly. 

Achromone C-glucoside, isobiflorin (5,7-dihy-droxy-2-methoxychromone-8-C-j3-D-gluco-pyranoside) and biflorin were isolated from... 

Simple chromones (Phe ] y-pyran-4-one) include the glucoside biflorin (a cAMP phosphodiesterase inhibitor and free radical scavenger) and the 2-phenoxychromone capillarisin (an aldose reductase inhibitor) as well as a number of variously cytotoxic and antimicrobial compounds. 

Protopine (= Biflorine Corydalis C Corydinine Fumarine Macleyine) (benzylisoquinoline)... 

Structurally related is biflorin (351), isolated from Capraria biflora, and the first naphtho[l,8-hc]pyranquinone found in nature. It has antibiotic properties. Its structure was determined by Prelog and co-workers (58HCA1386 63HCA409, 63HCA415) and it was synthesized by an intramolecular Diels-Alder addition between a benzyne and furan (86AJC647). 

One of the early examples of an intramolecular Diels-Alder reaction of benzynes involved cycloaddition to a furan that was tethered to the benzyne moiety . Diazoti-zation of anthranilic acid 669 gave in 86% yield the cycloadduct 670, which was subsequently converted to the o-naphthoquinone 671 (mansonone E 7 steps) as well as to the structurally related mansonones F and I and biflorin. ... 

Many other serrulatanes have been isolated from different species of Eremophila (77,103-105). A number contain an asymmetric carbon atom at C15 (eg 124), the configuration of which was determined by X-ray diffraction methods (106). Apart from the oxygenation sites in dihydroxyserrulatic acid, others are observed at C2, C5, C7, C13, Cl8 and C20. The structurally more interesting serrulatanes include biflorin (125) from E. latrobei (104), an antibiotic originally... 

Only a few compounds have the carbon skeleton of the geranylmenthane cation (471), mostly isolated from genus Helichrysum - e.g., peroxide 474 from roots of H. acutatum (40). Compounds of the prenylgermacrane type (472) have not, so far, been isolated from higher plants however, the bluish-red antibiotic biflorin (475), occurring in the roots of Capraria biflora (105), is an example of a type arising from further cyclization of 472 (cf. cadalanes in Sect. 8.1.3.3.2, Ses-quiterpenoids). 

Comin J, Goncalves de Lima O, Grant H N, Jackman L M, Keller-Schierlein W, Prelog V 1963 Uber die Konstitution des Biflorins, eines o-Chinons der Diterpen-Reihe. Helv Chim Acta 46 409- 415... 

A reexamination of this plant (see Volume V, p. 318) as well as O. herbacea ( ) showed that they contained no alkaloids. Commercial Khet-papra was identified as Fumaria parviflora Lam. and it was found to contain protopine. Biflorine is therefore regarded as being protopine 175). This leaves unexplained its reported optical activity nor does it explain the reported transformations and its oxidation to biflorone 176). 

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