Phenolic Constituents from Brainea insignis

Abstract

As the only species of the genus Brainea (Blechnaceae), Brainea insignis (HOOK.) J. SMITH a kind of fern is widely distributed in south China. It is used as herbal medicine to treat cold, burn, bleeding wound, and ascariasis, etc., as well as occasionally planted for ornament because of its beautiful shape.1,2) Previous chemical investigations of B. insignis have been shown the presence of lignans, 3) flavonoids, 4) pyrone glucosides, 5) stilbene, 5) steroids, 5) and a series of volatile compounds.6) As a part of our search for naturally occurring bioactive metabolites from ferns of China, 7-9) we investigated the chemical constituents of B. insignis, which led to the isolation of 16 phenolic compounds, including an unusual flavanol coupled with phenylpropyl and shikimic acid units, brainicin (1), and a new flavonol acylglycosides brainoside B (2). Herein, we describe the isolation and structure elucidation of new compounds. Results and DiscussionCompound 1 was isolated as a brown amorphous solid. The molecular formula was established as C 31 H 28 O 14 by a quasimolecular ion peak at m/z 623.1406 [MϪH] Ϫ in the negative HR-electrospray ionization (ESI)-MS analysis (Calcd for 623.1400), indicating 18 degrees of unsaturation. The IR spectrum showed absorption bands at 3426, 1710, 1627, 1606, 1527 and 1449 cm Ϫ1, revealing the presence of hydroxyl, carbonyl and aromatic rings groups, respectively. The aromatic region of the 1 H-NMR spectrum of 1 showed the presence of three sets of aromatic protons (Table 1). One set corresponded to a tetrasubstituted aromatic ring with two meta-coupling protons and appeared at d (Table 1). In combination with the observed heteronuclear multiple bond connectivity (HMBC) correlations (Fig. 1) from H-2 to C-1Ј, C-2Ј, and C-6Ј, from H-4 to C-4a and C-5, from H-7Љ to C-1Љ, C-2Љ, and C-6Љ, from H-8Љ to C-9Љ, and from H-2ٞ to C-7ٞ, 1 was suspected to be composed of a flavan-3-ol unit, a phenylpropyl unit, and shikimic acid unit and to be formed by coupling of these units. The HMBC correlations of H-5ٞ to C-9Љ, revealed the two oxygenated carbons C-5ٞЉ and C-9Љ were connected with Phytochemical investigation on the methanol extract of Brainea insignis led to the isolation of 16 phenolic compounds, including an unusual flavanol coupled with phenylpropyl and shikimic acid units, brainicin (1), and a new flavonol acylglycosides brainoside B (2). The structures of new compounds were elucidated on the basis of extensive spectroscopic analysis. Compounds 1-5 were evaluated for their cytotoxic effects. However, none of the compounds showed significant cytotoxic activity against the HL-60, A549, SMMC-7721, MCF-7, SW480 cell lines (IC 50 Ͼ Ͼ40 m mM).

A nutraceutical extract from Inula viscosa leaves: UHPLC-HR-MS/MS based polyphenol profile, and antioxidant and cytotoxic activities

“…Compounds 12 , 15 and 19 , with [M-H] − ions at m/z 513.1045 (or 513.1046), in accordance to the molecular formula C 25 H 22 O 12 (1.3 and 1.5 ppm error vs calculated mass), showed almost superimposable TOF-MS 2 spectra ( Fig. 2 ) and were tentatively identified as isomers of brainic acid, a shikimoyl derivative of blechnic acid widely reported as a characteristic lignan of blechnaceous ferns [ 20 ] or Brainea insignis [ 21 ]. A blechnic acid derivative, which displayed anti-inflammatory activity through inhibiting expression of i NOS and COX-2, was also described as constituent of Salvia miltiorrhiza Bunge [ 22 ].…”

Phytoecdysteroids from the rhizomes of Brainea insignis

“…The EtOAc-and nBuOH-soluble fractions were subjected to repeated column chromatography over silica gel and ODS, followed by preparative HPLC, and afforded five new compounds (1)(2)(3)(4)(5) along with the known phytoecdysteroids, ponasteroside A (6) (Takemoto et al, 1968;Fang et al, 2008), ponasterone A (7) (Nakanishi et al, 1966;Vokáč et al, 1998), and 20-hydroxyecdysone (8) (Vokáč et al, 1998;Buděšínský et al, 2008). The structures of known compounds were determined by interpretation of their spectroscopic data as well as by comparison with reported data.…”

“…Its rhizomes are used as a Chinese herb for the treatment of common cold, burn, trauma bleeding, and ascariasis (Committee for the Chinese Materia Medica, 1999). The isolation of ponasteroside A from this species was recently reported (Fang et al, 2008). In continuation of our studies on medicinal plants growing in South China, this fern was investigated and five new phytoecdysteroid glucosides, brainesterosides A-E (1-5), were isolated together with three known phytoecdysteroids, ponasteroside A (6), ponasterone A (7), and 20-hydroxyecdysone (8).…”

Design, Synthesis and Biological Evaluation of Novel 4-(4-Methoxynaphthalen-1-yl)-5-arylpyrimidin-2-amines as Tubulin Polymerization Inhibitors

“…Besides At present, molecular hybrid-based approach is a useful tool for the design of new tubulin inhibitors 26,27) . Based on these findings and in continuation of our search novel tubulin polymerization inhibitors 28,29) , we designed the synthesis of a novel series of 4-(4-methoxynaphthalen-1-yl)-5-arylpyrimidin-2-amines (5a-5s) and further evaluated for their antiproliferative and tubulin polymerization inhibitory activities.…”