Isolation of praeruptorins A and B from Peucedanum praeruptorum Dunn. and their general pharmacological evaluation in comparison with extracts of the drug

The root of Peucedanum praeruptorum Dunn. was extracted with solvents at different polarity obtaining three chemical fractions: aqueous (H2O), n-butanol (BuOH) and ethyl acetate (AcOEt). From AcOEt praeruptorins A and B were isolated by column chromatography on silica gel, using toluene/ethyl acetate as eluent, and identified by H-1 and C-13 NMR analysis. The extracts and the praeruptorins were tested for gross behavioural effects and acute toxicity in mice; the cytotoxicity on Artemia salina Leach and the antimicrobial activity were also evaluated. None of the tested substances evoked behavioural effects or acute toxicity after oral administration in mice; delayed mortality was observed with AcOEt and praeruptorin A only after intraperitoneal administration of high doses (1 g/kg). In Artemia salina test AcOEt, and praeruptorins A and B had LC50 values of 40.2, 121.2 and 34.5 mug/ml, respectively. AcOEt and praeruptorin A showed antimicrobial activity on Streptococcus agalactiae; their MIC values were 250 and 100 mug/ml, respectively. (C) 2001 Editions scientifiques et medicales Elsevier SAS

Antimicrobial activity of Epilobium spp. extracts

The antimicrobial activity of the Epilobium angustifolium, E. hirsutum, E. palustre, E. tetragonum and E. rosmarinifolium ethanolic extracts was studied in vitro on Gram-positive and Gram-negative bacteria, yeasts and fungi. The cytotoxicity of the extracts was also evaluated using the Artemia salina test. All the extracts showed antimicrobial activity in a range of concentrations between 10 and 650 mug/ml of dry extract. E. angustifolium and E. rosmarinifolium had the most broad spectrum of action inhibiting bacteria, yeasts and fungi. The extracts were devoid of toxicity on Artemia salina within the range of antimicrobial concentrations, suggesting that the action is selective on microorganisms. (C) 2001 Editions scientifiques et medicales Elsevier SAS

Inhibition of Candida rugosa lipase by berberine and structurally related alkaloids, evaluated by high-performance liquid chromatography

It is known that certain microorganisms produce extracellular lipase to better colonize the skin and mucosal surfaces. Since different extracts from medicinal plants have anti-lipase activity (Shimura et al., Biosci. Biotechnol. Biochem., 56: 1478-1479, 1992), we examined the effects of selected natural substances on Candida rugosa lipase. In the presence of the compounds under examination, the enzyme was incubated with beta-naphthyl laurate, and beta-naphthol, produced by the enzymatic reaction, was extracted with ethyl acetate and analyzed by reversed phase HPLC, using a C-18 column. Thus, the inhibitory activity was calculated by a proper formula based on the variations of the area under the chromatographic peak of beta-naphthol. The method was validated by analyzing substances with known anti-lipase activity such as saturated fatty acids (C10-16) and tetracycline. Berberine and a number of structurally related alkaloids such as chelidonine, chelerythrine, and sanguinarine appeared active. This property of berberine and sanguinarine is of interest because they are used in pathological conditions in which microbial lipases could play a pathogenic role

In vitro antifungal, and anti-elastase activity of some aliphatic aldehydes from Olea europaea L. fruit

Olea europaea preparations are traditionally employed in a variety of troubles, including skin infections. Olive extracts and some of their pure compounds have shown antimicrobial activity in vitro. The present study deals with the antifungal activity of some aliphatic aldehydes from olive fruit [hexanal, nonanal, (E)-2-hexenal, (E)-2-heptenal, (E)-2-octenal, (E)-2-nonenal] against Tricophyton mentagrophytes (6 strains), Microsporum canis (1 strains) and Candida spp. (7 strains). The capability of these substances to inhibit elastase, a virulence factor essential for the dermatophytes colonization, and their cytotoxicity on cultures of reconstructed human epidermis, are also described. Aldehydes tested, inhibited the growth of T. mentagrophytes and M. canis in the range of concentration between < 1.9 and 125 mu g/ml; the unsaturated aldehydes showed the most broad spectrum of activity in that inhibited all strains tested. None of the aldehydes exhibited activity against Candida spp. strains. (E)-2-octenal and (E)-2-nonenal inhibited the elastase activity in a concentration-dependent manner; the anti-elastase activity suggests an additional target of the antimicrobial activity of these compounds. Aldehydes were devoid of cytotoxicity on cultures of human reconstructed epidermis. The antifungal activity of the aldehydes from olive fruit here reported, substantiates the use of olive and olive oil in skin diseases and suggests' that these natural compounds could be useful agents in the topical treatment of fungal cutaneous infections. (c) 2005 Elsevier GmbH. All rights reserved

Effect of limonin and nomilin on HIV-1 replication on infected human mononuclear cells

In the last years several plant-derived natural compounds have been screened for their anti-HIV activity in order to find lead compounds with novel structures or mechanisms of action. Among these, several triterpenoids have been found to exhibit an antiretroviral activity with different mechanisms of action. In this study the effect of two limonoids, limonin and nomilin, on the growth of human immunodeficiency virus-1 (HIV-1) in culture of human peripheral blood mononuclear cells (PBMC) and on monocytes/macrophages (M/M) is described. Limonin and nomilin were found to inhibit the HIV-1 replication in all cellular systems used. A dose-dependent inhibition of viral replication was observed in PBMC isolated from healthy donors and infected with HIV-1 strain after incubation with limonin and nomitin (EC50 values: 60.0 muM and 52.2 muM, respectively). The two terpenoids inhibited at all concentrations studied the production of HIV-p24 antigen even when the PBMC employed were chronically infected (EC50 values of 61.0 muM for limonin and 76.2 muM for nomilin). Moreover, these compounds inhibited the HIV-1 replication even in infected M/M. In this cellular system the inhibitory effect was significant at the concentrations of 20 muM, 40 muM and 80 muM starting from day 14 and reached the maximum effect after 18 days of incubation. As regards the mechanism of action, limonin and nomilin inhibit in vitro HIV-1 protease activity. In general, the results obtained point out a similar anti-HIV activity of limonin and nomilin indicating that this activity is not drastically influenced by the structural difference between the two compounds