Lucia Battinelli

Antimicrobial properties of the linalol‐rich essential oil of Hyssopus officinalis L. var decumbens (Lamiaceae)

The antimicrobial activity of essential oil of Hyssopus officinalis L. var decumbens (Jordan & Fourr.) Briq. from France (Banon) and Hyssopus officinalis L. from Italy (Piedmont) was studied taking account of their chemical composition determined by GC and GC–MS. Pinocamphone and isopinocamphone are present in H. officinalis (4.4% and 43.3%, respectively), according to the ISO 9841 Standard (1991 E) but they are lacking in var. decumbens, where linalol (51.7%), 1,8-cineole (12.3%) and limonene (5.1%) instead are predominant. The disc diffusion tests carried out on Gram-positive (Staphylococcus aureus and Enterococcus spp.) and Gram-negative bacteria (Klebsiella oxytoca, Escherichia coli, Proteus mirabilis, Pseudomonas spp. and two strains of Salmonella spp.) showed an antimicrobial activity generally negligible for H. officinalis, but broader, and in a few cases more evident (Enterococcus spp. and E. coli), for var. decumbens. All yeasts (seven strains of Candida albicans, C. krusei and C. tropicalis) were strongly inhibited by both species. In liquid medium the MIC of H. officialis was always >1.2% v/v for bacteria and between 0.6 and 1.2% v/v for yeasts, while the MIC of var. decumbens was between 0.15 and 0.6% v/v for the Gram-positive bacteria, 0.3 and 1.2% v/v for the Gram-negative bacteria and 0.15 and 0.3% v/v for the yeasts. The effect of var. decumbens was generally bactericidal. Linalol, and in a lesser way, 1,8-cineole, may contribute to the greater antimicrobial activity of var. decumbens in comparison with H. officinalis, while limonene may be responsible for the antimycotic action observed in both oils, as suggested by results of the disc diffusion tests carried out on the pure reference substances.

Antimicrobial and Anti-Lipase Activity of Quercetin and its C2-C16 3-O-Acyl-Esters

Neither quercetin (Q), nor 3-O-acylquercetines, up to 100 microg/mL, had any significant activity on selected gram-positive strains (Staphylococcus aureus, Bacillus subtilis, Listeria ivanovi, Listeria monocytogenes, Listeria serligeri), gram-negative strains (Escherichia coli, Shigella flexneri, Shigella sonnei, Salmonella enteritidis, Salmonella tiphymurium) and yeasts (Candida albicans and Candida glabrata). In addition, we confirmed the known anti-HIV activity of Q (80% inhibition at 40 microM), which might depend on the free hydroxyl in the C-3 position, as suggested by the lack of activity of the 3-O-acylquercetines. Finally, we described an interesting inhibitory activity on Candida rugosa lipase by Q (IC(16)=10(-4) M) and its esters (3-O-acylquercetines) which, in vivo, could play an important role against lipase producing microorganisms. In particular, 3-O-acyl-quercetines, being more active (IC(16)=10(-4)-10(-6) M) and more lipophilic, could be more effective than Q when applied to the skin or mucosae, and deserve to be studied further.

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 microgml 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.

Antimicrobial investigation of semipurified fractions of Ginkgo biloba leaves

A total methanolic extract of Ginkgo biloba leaves was fractionated by solvent partition using ethyl acetate (fraction A), n-butanol (fraction B) and water (fraction C). The antimicrobial activity of the three fractions was evaluated using a number of Gram-positive and -negative bacteria and yeasts. The apolar fraction A appeared to be the most interesting because of its activity against several microorganisms; this fraction was further separated by high performance liquid chromatography, and shown to contain substances with strong inhibitory activity against Enterococcus faecalis 31, different from the major known chemical components of G. biloba leaves.

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 1H and 13C 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 microg/ml, respectively. AcOEt and praeruptorin A showed antimicrobial activity on Streptococcus agalactiae; their MIC values were 250 and 100 microg/ml, respectively.

New class of poly(vinyl alcohol) polymers as column-chromatography stationary phases for Candida rugosa lipase isoforms separation

The preparation of new stationary phases of cross-linked polyvinyl alcohol esterified with various linear fatty acids is described. The physico-chemical properties of these polymers are reported, including electron microscopy and swelling measurements. Batch adsorption experiments were performed in order to characterize the basic separative properties of these phases. Cross-linked polyvinyl alcohol esterified with dodecanoic acid was used for hydrophobic interaction chromatography of a commercial crude preparation of Candida rugosa lipase. Characterization of the purified fractions was carried out via native electrophoresis and sodium dodecyl sulfate-polyacrylamide electrophoresis.

Purity control of some Chinese crude herbal drugs marketed in Italy.

The widespread use of herbal drugs, among which those coming from eastern Countries, has created a more compelling need for quality, a pre-requisite that can influence safety. In the present study, 10 Chinese crude herbal drugs marketed in Italy (Radix Ginseng, Radix Astragali, Rhizoma Coptidis, Rhizoma Atractylodis Macrocephalae, Radix Bupleuri, Radix Rehmanniae, Radix Paeoniae Alba, Pericarpium Citri Reticulatae, Radix Polygalae, Radix Salviae Miltiorrhizae) were analysed by the following purity assays: foreign matter, total ash, microbial and heavy metal contamination. Each herbal drug was purchased in Italy from three different sources: two Chinese firms and one Chinese herbal shop. Except for the heavy metal content, the tests were performed according to the European Pharmacopoeia. The presence of parasites was shown in two samples; moreover, level of ash (in three samples), lead content (in one sample) and total viable aerobic count (in one sample), were higher than the limits set by the European or Italian Pharmacopoeias. Our results, even if obtained from a small number of herbal drugs, show some purity issues and underline the importance of the quality control, particularly for this kind of products whose therapeutic value is not always demonstrated.

Biocatalysed hydrolysis of triglycerides in emulsion and as monolayers

Abstract The monolayer technique was employed to monitor the microbial lipase biocatalysed hydrolysis of triglycerides with different acyl chain lengths. The kinetic data were correlated with those obtained employing the substrate in an emulsion. The influence of the monofilm surface pressure on the hydrolysis rate and activation energy was evaluated.