Toxicity to sea urchin egg development of the quinone fraction obtained from Auxemma oncocalyx. (1/34)

Auxemma oncocalyx Taub. belongs to the Boraginaceae family and is native to the Brazilian northeast where it is known as "pau-branco". We investigated the ability of the water soluble fraction isolated from the heartwood of A. oncocalyx to inhibit sea urchin egg development. This fraction contains about 80% oncocalyxone A (quinone fraction), a compound known to possess strong cytotoxic and antitumor activities. In fact, the quinone fraction inhibited cleavage in a dose-dependent manner [IC50 of 18.4 (12.4-27.2) microg/ml, N = 6], and destroyed the embryos in the blastula stage [IC50 of 16.2 (13.7-19.2) microg/ml, N = 6]. We suggest that this activity is due to the presence of oncocalyxone A. In fact, these quinones present in A. oncocalyx extract have strong toxicity related to their antimitotic activity.  (+info)

Cholinesterase inhibitory constituents from Onosma hispida. (2/34)

Hispidone, a new flavanone, has been isolated from Onosma hispida and assigned the structure (2S)-5,2'-dihydroxy-7,4',5'-trimethoxyflavanone (1) by spectroscopic methods. In addition, (2S)-5,2'-dihydroxy-7,5'-dimethoxyflavanone (2), benzoic acid (3), and 4-hydroxy benzoic acid (4) are also reported for the first time from this species.  (+info)

Antioxidant effects in the quinone fraction from Auxemma oncocalyx TAUB. (3/34)

In previous studies in vitro we showed that the quinone fraction (QF) from the heartwood of Auxemma oncocalyx TAUB. presented antiplatelet and antioxidant activities. In the present work, the QF antioxidant property was evaluated in models of CCl(4)-induced hepatotoxicity in rats, and prolongation of pentobarbital-induced sleeping time in mice. Our results showed that levels of plasma glutamate-pyruvate-transaminase (GPT), as well as glutamate-oxalate-transaminase (GOT), were increased by the administration of CCl(4). On the other hand, only GPT levels were reduced by the QF treatment. Pentobarbital sleeping time was prolonged by the administration of CCl(4) and reduced by the QF treatment. Moreover, QF did not alter the pentobarbital-induced sleeping time. In conclusion, we showed that QF, represented mainly by oncocalyxone A, has hepatoprotective activity, and this effect is at least in part due to the antioxidant activity of this quinone.  (+info)

Anti-inflammatory cyathane diterpenoids from Sarcodon scabrosus. (4/34)

Four novel diterpenoids were isolated from the fruiting bodies of Sarcodon scabrosus (Fr.) Karst. (Boraginaceae) together with neosarcodonin A. One of the novel compounds was elucidated to be a cyathane diterpenoid, namely neosarcodonin O, by its spectral data. The others were characterized as 19-O-linoleoyl, 19-O-oleoyl and 19-O-stearoyl derivatives of sarcodonin A, after comparison with the authentic samples synthetically prepared from sarcodonin A. These compounds, together with the five 19-O-acyl derivatives synthesized from sarcodonin A, each exhibited inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation on mouse ears by topical application.  (+info)

Molecular systematics of Boraginaceae tribe Boragineae based on ITS1 and trnL sequences, with special reference to Anchusa s.l. (5/34)

BACKGROUND AND AIMS: Boragineae is one of the main tribes of Boraginaceae, but delimitation and intergeneric classification of this group are unclear and have not yet been studied using DNA sequences. In particular, phylogenetic relationships in Anchusa s.l. still need to be elucidated in order to assess its taxonomic boundaries with respect to the controversial segregate genera Hormuzakia, Gastrocotyle, Phyllocara and Cynoglottis. METHODS: Phylogenetic relationships among 51 taxa of tribe Boragineae were investigated by comparative sequencing of the trnL(UAA) intron of the plastid genome and of the ITS1 region of the nuclear ribosomal DNA. Exemplar taxa from 16 genera of Boragineae and all subgenera of Anchusa s.l. were included, along with two selected outgroups from tribes Lithospermeae and Cynoglosseae. KEY RESULTS: Phylogenies generated by maximum parsimony and combined ITS1-trnL sequences support the monophyly of the tribe and a split into two clades, Pentaglottis and the remainder of Boragineae. The latter contains two large monophyletic groups. The first consists of three moderately to well-supported branches, Borago-Symphytum, Pulmonaria-Nonea and Brunnera. In the Pulmonaria-Nonea subclade, the rare endemic Paraskevia cesatiana is sister to Pulmonaria, and Nonea appears to be paraphyletic with respect to Elizaldia. The second main group corresponds to the well-supported clade of Anchusa s.l., with the megaphyllic, polyploid herb Trachystemon orientalis as sister taxon, although with low support. Anchusa s.l. is highly paraphyletic to its segregate genera and falls into four subclades: (1) Phyllocara, Hormuzakia, Anchusa subgenus Buglossum and A. subgenus Buglossoides; (2) Gastrocotyle; (3) A. subgenus Buglossellum and Cynoglottis; and (4) A. subgenus Anchusa, Lycopsis and Anchusella. All species of Anchusa subg. Anchusa, including the South African A. capensis, are included in a single unresolved clade. Anchusa subgenus Limbata is also included here despite marked divergence in floral morphology. The low nucleotide variation of ITS1 suggests a recent partly adaptive radiation within this group. CONCLUSIONS: Molecular data show that nine of the usually accepted genera of the Boragineae consisting of two or more species are monophyletic: Anchusella, Borago, Brunnera, Cynoglottis, Gastrocotyle, Hormuzakia, Nonea, Pulmonaria and Symphytum. In addition, the tribe includes the four monotypic genera Paraskevia, Pentaglottis, Phyllocara and Trachystemon. The morphologically well-characterized segregate genera in Anchusa s.l. are all confirmed by DNA sequences and should be definitively accepted. Most of the traditionally recognized subgenera of Anchusa are also supported as monophyletic groups by both nuclear and plastid sequence data. In order to bring taxonomy in line with phylogeny, the institution of new, independent generic entities for subgenera Buglossum, Buglossellum and Buglossoides and a narrower but more natural concept of Anchusa are advocated.  (+info)

Life history traits in selfing versus outcrossing annuals: exploring the 'time-limitation' hypothesis for the fitness benefit of self-pollination. (6/34)

BACKGROUND: Most self-pollinating plants are annuals. According to the 'time-limitation' hypothesis, this association between selfing and the annual life cycle has evolved as a consequence of strong r-selection, involving severe time-limitation for completing the life cycle. Under this model, selection from frequent density-independent mortality in ephemeral habitats minimizes time to flower maturation, with selfing as a trade-off, and/or selection minimizes the time between flower maturation and ovule fertilization, in which case selfing has a direct fitness benefit. Predictions arising from this hypothesis were evaluated using phylogenetically-independent contrasts of several life history traits in predominantly selfing versus outcrossing annuals from a data base of 118 species distributed across 14 families. Data for life history traits specifically related to maturation and pollination times were obtained by monitoring the start and completion of different stages of reproductive development in a greenhouse study of selfing and outcrossing annuals from an unbiased sample of 25 species involving five pair-wise family comparisons and four pair-wise genus comparisons. RESULTS: Selfing annuals in general had significantly shorter plant heights, smaller flowers, shorter bud development times, shorter flower longevity and smaller seed sizes compared with their outcrossing annual relatives. Age at first flower did not differ significantly between selfing and outcrossing annuals. CONCLUSIONS: This is the first multi-species study to report these general life-history differences between selfers and outcrossers among annuals exclusively. The results are all explained more parsimoniously by selection associated with time-limitation than by selection associated with pollinator/mate limitation. The shorter bud development time reported here for selfing annuals is predicted explicitly by the time-limitation hypothesis for the fitness benefit of selfing (and not by the alternative 'reproductive assurance' hypothesis associated with pollinator/mate limitation). Support for the time-limitation hypothesis is also evident from published surveys: whereas selfers and outcrossers are about equally represented among annual species as a whole, selfers occur in much higher frequencies among the annual species found in two of the most severely time-limited habitats where flowering plants grow--deserts and cultivated habitats.  (+info)

Isolation of onosmins A and B, lipoxygenase inhibitors from Onosma hispida. (7/34)

Onosmins A (1) and B (2), lipoxygenase inhibitors, have been isolated from Onosma hispida. Their structures were established as 2-[(4-methylbenzyl)amino]benzoic acid (1) and methyl 2-[(4-methylbenzyl)amino]benzoate (2) through spectroscopic studies, including 2D-NMR. The known compounds apigenin (3), 6,4'-dimethoxy-3,5,7-trihydroxyflavone (4), 6,7-dimethoxy-3,5,4'-trihydroxyflavone (5) and apigenin 7-O-beta-D-glucoside (6) are also reported for the first time from this species. Compounds (1) and (2) inhibited lipoxygenase (LOX, EC enzyme in a concentration-dependent fashion with IC50 values of 24.0 and 36.2 microM, respectively. Lineweaver-Burk as well as Dixon plots and their secondary replots indicated that the nature of inhibition was purely a non-competitive type, with K(i) values 22.0 microM and 31.1, respectively.  (+info)

Phenyl polypropanoids from Lindelofia stylosa. (8/34)

A phytochemical investigation on the aerial parts of Lindelofia stylosa has resulted in the isolation of seven phenyl propanoids. This includes three analogs of lithospermic acid, along with rosmarinic acid and its ester derivatives. Compound 1 was identified as a new natural product. These compounds were studied for their antioxidant properties.  (+info)