Amira Arciniegas

Mode of action of Buddleja cordata verbascoside against Staphylococcus aureus.

We evaluate the mode of action of verbascoside obtained from Buddleja cordata against Staphylococcus aureus by killing kinetics and incorporation of precursors methods. Verbascoside induced lethal effect on S. aureus, by affecting protein synthesis and inhibiting leucine incorporation.

Seco-eremophiladiolides and Eremophilane Glucosides from Pittocaulon velatum

Two seco-eremophiladiolides, velatumolide and epi-velatumolide, the trihydroxyfuranoeremophilane velatumin, and three eremophilane glucosides were isolated from Pittocaulon velatum, together with several known compounds. The structures of these compounds were elucidated by spectroscopic analysis and chemical reactions. The anti-inflammatory activity of the isolated compounds was investigated using the TPA-induced ear edema model.

Anti-inflammatory constituents of Mortonia greggii Gray.

A new phytochemical study of Mortonia greggii (Celastraceae) afforded four friedelan derivatives (1-4), three lupanes (5-7), retusine (8), two esterified polyhydroxyagarofurans (9-10), mortonin C (11) and photomortonin C (12). The anti-inflammatory activity on carrageenan and 12-O-tetradecanoylphorbol-13-acetate induced models of inflammation, as well as the ability to inhibit the nitric oxide (NO) produced by lipopolysaccharide-stimulated mouse peritoneal macrophages were evaluated for the main metabolites. Our results showed that the friedelan dehydrocanophyllic acid methyl ester (1) exhibits an anti-inflammatory effect which could be related to an inhibition of prostaglandin and NO production. The activity of lupeol (5), 29-hydroxylupeol (6) and 29-hydroxylupenone (7) might be involved with the prostanoid synthesis. The presence of the hydroxy groups in 6 appears to be important for activity. The edema inhibition capacity of retusine (8) could be related to a reduction of the prostaglandin production. The agarofuran derivative 10 is an NO inhibitor whose activity is probably not involved in the synthesis of prostaglandins.

In vitro evaluation of the amebicidal activity of Buddleia cordata (Loganiaceae, H.B.K.) on several strains of Acanthamoeba

Infectious diseases produced by free-living amoebae from the genus Acanthamoeba have been recently recognized. The need for antiamebic compounds is urgent as the occurrence of these diseases is being registered more frequently since the late sixties. We screened the aqueous and methanolic extract of a plant used by folk medicine (Buddleia cordata) against eye and skin inflammation for antiamebic activity. We tested the extracts on 29 strains of free-living amoebae, with the result that they were amebostatic for 14 and 15 strains, respectively. We obtained linarin and vanillic acid from the extracts, but only linarin was amebostatic to all the strains and vanillic acid had no activity. However, acetyl vanillic acid had similar effects on amoebae to linarin. Threshold values of these two active compounds ranged from 31.25 microg/ml to 4 mg/ml and from 31.25 microg/ml to 8 mg/ml for linarin and acetyl vanillic acid, respectively. These differences in threshold values were observed even on several strains belonging to the same species (as in the case of A. castellanii and A. polyphaga) indicating the need of susceptibility testing for each clinical isolate of free-living amoebae.

Eremophilane derivatives from Pittocaulon praecox

Five new compounds; two eremophilane glucosides (1, 2) and three eremophilanolides (3, 11, 12), together with several known compounds were isolated from Pittocaulon praecox. Their structures were elucidated by spectroscopic methods. The anti-inflammatory activity of extracts and main isolated metabolites was evaluated on 2-O-tetradecanoylphorbol-13-acetate (TPA) induced model of acute inflammation.

Furanoeremophilanes and other constituents of Pittocaulon bombycophole

Three new eremophilanes (1-3) and a new oplopane (4) were isolated from Pittocaulon bombycophole. Additionally, three known sesquiterpenes (5-7) and the alkaloid 7-angeloylplatynecine (8) were isolated. The structures of the new compounds were elucidated by spectroscopic methods.

PYRROLIZIDINE ALKALOIDS FROM SENECIO MULGEDIIFOLIUS, TWO NEW 13-MEMBERED MACROCYCLIC 7,9-DIESTERS

Abstract The structure and absolute configuration of the new 13-membered macrocyclic alkaloids mulgediifoline and oxyretroisosenine were determined on the basis of chemical reactions and conventional spectral studies including differential nOe and 2D NMR techniques, COSY, HETCOR, COLOC, HMBC and NOESY. The absolute stereochemistry of the already known compounds retroisosenine and cis -nemorensic acid was assigned unambiguously.

Sesquiterpenoids from Pittocaulon filare

The phytochemical study of Pittocaulon filare afforded three oplopanes (1-3), a eudesmane (6), and three oplopane glucosides (7-9), one of them reported as its acetyl derivative (7a), together with several known compounds. The structures of the compounds were elucidated by spectroscopic analysis and chemical reactions. The anti-inflammatory activity of compounds 1-5 was determined using the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema model, and the effect of compounds 1-4 on the recruitment of neutrophils was evaluated using the myeloperoxidase test. Compounds 1 and 2 were the more active anti-inflammatory agents, with lower ID50 values (0.17 and 0.18 μmol/ear, respectively) than indomethacin (0.24 μmol/ear), but they had a lesser effect on the inhibition of neutrophil infiltration than both indomethacin and compound 3, indicating that the tested compounds do not have the same ability to inhibit edema and to prevent cell infiltration.

Modified eremophilanes and anti-inflammatory activity of Psacalium cirsiifolium

Four new modified eremophilanes, together with ten known cacalol derivatives, two caryophyllenes, one aromadendrene and one flavonoid were isolated from Psacalium cirsiifolium. The structures of these compounds were elucidated by spectroscopic analysis. The anti-inflammatory activity of extracts and of seven of the isolated compounds was evaluated on 12-O-tetradecanoylphorbol-13-acetate (TPA) model of induced acute inflammation. The new compound 2α -hydroxyadenostin B (4) showed a dose dependent activity (IC50 0.41 µmol per ear) and a neutrophil inhibition effect as measured by the myeloperoxidase (MPO) assay similar to that of indomethacin at 0.31 and 1.0 µmol per ear.

Chemical composition and biological activity of Laennecia schiedeana.

The chemical study of Laennecia schiedeana afforded three sterols, five diterpenes, five flavonoids, three caffeoyl derivatives of quinic acid, and two triterpenes. Evaluation of the cytotoxic activity of the extracts and isolated metabolites showed that 15-methoxy-16-oxo- 15,16H-strictic acid was the most active compound [(15.05 ± 2.2) μg/mL against U-251 cells]. In antibacterial assays the acetonic extract of leaves was the only active extract exhibiting its highest effect against the multiresistant Staphylococcus epidermidis (MIC 0.25 mg/mL). The anti-inflammatory activity observed was mild in the extracts and not relevant in the isolated compounds