Phytochemical and antimicrobial study of Pilocarpus pennatifolius Lemaire.

The investigation of the crude extract of leaves and bark of Pilocarpus pennatifolius Lemaire allowed isolated of a not yet described coumarin, together with three known coumarins (bergapten, xanthotoxin and dimethyl allyl xanthyletin), and a not yet described imidazole alkaloid. All structures were established by means of spectral analysis, including extensive 2D NMR studies. In addition, the alkaloid had its absolute stereochemistry determined by X-ray diffraction. Meanwhile, extracts and pure compounds were tested against various strains of bacteria and fungi, showing promising antimicrobial activities. We highlight the activities of crude bark methanol extract (CBME), of the leaf basic acetate fraction (LBAcF), and of compound 2 against the Gram negative bacteria Shigella flexneri (MICs = 7.8, 7.8 and 3.12 µg·mL-1, respectively), of compound 5 against the Gram positive Enterococcus fecalis (MIC = 1.56 µg·mL-1), and against two Gram negative bacteria Salmonella enteritidis (MIC = 1.56 µg·mL-1), and Pseudomonas aeruginosa (MIC = 6.25 µg·ml-1). On the other hand, CBME and compounds 3-5 showed excellent activity against the fungus Candida krusei with MICs of 15.6, 1.56, and 3.12 µg·mL-1 respectively, as actives or better than the antifungal standard fluconazole (MIC = 3.12 µg·mL-1).

Ultrasound-assisted acid hydrolysis of cellulose to chemical building blocks: Application to furfural synthesis.

In this work, the use of ultrasound energy for the production of furanic platforms from cellulose was investigated and the synthesis of furfural was demonstrated. Several systems were evaluated, as ultrasound bath, cup horn and probe, in order to investigate microcrystalline cellulose conversion using simply a diluted acid solution and ultrasound. Several acid mixtures were evaluated for hydrolysis, as diluted solutions of HNO3, H2SO4, HCl and H2C2O4. The influence of the following parameters in the ultrasound-assisted acid hydrolysis (UAAH) were studied: sonication temperature (30 to 70°C) and ultrasound amplitude (30 to 70% for a cup horn system) for 4 to 8molL-1 HNO3 solutions. For each evaluated condition, the products were identified by ultra-performance liquid chromatography with high-resolution time-of-flight mass spectrometry (UPLC-ToF-MS), which provide accurate information regarding the products obtained from biomass conversion. The furfural structure was confirmed by nuclear magnetic resonance (1H and 13C NMR) spectroscopy. In addition, cellulosic residues from hydrolysis reaction were characterized using scanning electron microscopy (SEM), which contributed for a better understanding of physical-chemical effects caused by ultrasound. After process optimization, a 4molL-1 HNO3 solution, sonicated for 60min at 30°C in a cup horn system at 50% of amplitude, lead to 78% of conversion to furfural. This mild temperature condition combined to the use of a diluted acid solution represents an important contribution for the selective production of chemical building blocks using ultrasound energy.

Phytochemical analysis of bark from Helietta apiculata Benth and antimicrobial activities.

Extraction and characterization of natural products from the bark of the trunk of Helietta apiculata Benth (Rutaceae) afforded nine alkaloids, eight furoquinoline and one quinolone, limonine, three cinnamic acid derivatives, three neolignans, tetracosanoic acid, six coumarins, of which apiculin A and apiculin B (neolignans), and tanizin (coumarin) are previously undescribed compounds. The structures of all compounds were determined by spectroscopic methods, and the crystal structures of two of the newly undescribed compounds, apiculin A and apiculin B, were determined by X-ray analysis. Extracts and pure compounds isolated from Helietta apiculata showed promising antimicrobial activities.

Chemical composition and evaluation of prolyl oligopeptidase and acetylcholinesterase inhibitory activities of Leonurus Sibiricus L. from Brazil.

Chemical investigation of the aerial parts of Leonurus sibiricus L. used in Brazilian folk medicine led to the identification of the following constituents: the labdane-type diterpenoid leojaponin, the phytosterols ß-sitosterol and ß-sitosterol glucoside and the alkaloid leonurine. The crude extracts obtained from methanol and methanol/1% HCl and pure compounds isolated from L. sibirius were investigated as acetylcholinesterase (AChE) and prolyl oligopeptidase (POP) inhibitors. Extracts obtained by maceration were active against POP (53-58%), but showed weak activity against AChE. The isolated leojaponin and leonurine were evaluated as POP inhibitors.

Lanostane-type triterpenes from the fungal endophyte Scleroderma UFSMSc1 (Persoon) Fries.

Two lanostane triterpenoids (sclerodols A and B) were isolated from the culture of the Eucalyptus grandis derived from the endophyte Scleroderma UFSM Sc1(Persoon) Fries together with three known compounds: one related triterpenoid lanosta-8,23-dien-3ß,25-diol, the disaccharide α,ß-trehalose, and the sugar alcohol mannitol. Their structures were elucidated on the basis of 2D NMR, HRME, and single-crystal X-ray diffraction data. The methanol crude extract and the isolated lanostane triterpenoids showed promising anticandidal activities.

Cyclopeptide alkaloids: stereochemistry and synthesis of the precursors of discarines C and D and myrianthine A.

The stereochemistry of discarines C (1) and D (2) and myrianthine A (3), three cyclopeptide alkaloids isolated from Discaria febrifuga, was determined by a combination of NMR studies of 1-3, enantioselective gas chromatography, and comparison of NMR data with those of synthetic tripeptides. For the synthesis of peptides, the nonproteinogenic amino acid 3-phenylserine was also obtained in its four diastereoisomeric forms (l and d threo, obtained by recrystallization of the diastereoisomeric tripeptide, and l and d erythro, obtained by a Mitsunobu reaction with the threo-tripeptides). The general synthetic strategy described in this paper allows the tripeptide to be obtained with the free N-terminal extremity protected or dimethylated. This strategy also allows the synthesis of the corresponding peptide with an imidazolidinone ring.

Antimicrobial activity of Schinus lentiscifolius (Anacardiaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Schinus lentiscifolius Marchand (syn. Schinus weinmannifolius Engl) is a plant native to Rio Grande do Sul (Southern Brazil) and has been used in Brazilian traditional medicine as antiseptic and antimicrobial for the treatment of many different health problems as well as to treat leucorrhea and to assist in ulcer and wound healing. Although it is a plant widely used by the population, there are no studies proving this popular use. MATERIAL AND METHODS: The crude aqueous extract, the crude neutral methanol extract, fractions prepared from this extract (n-hexane, ethyl acetate, and n-butanol), pure compounds isolated from these fractions, and derivatives were investigated in vitro for antimicrobial activities against five Gram positive bacteria: Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus pyogenes, three Gram negative bacteria: Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei, and four yeasts: Candida albicans, Candida tropicalis, Cryptococcus neoformans, and Saccharomyces cerevisiae. The isolated compound moronic acid, which is the most active, was tested against a range of other bacteria such as two Gram positive bacteria, namely, Bacillus cereus, Enterococcus spp, and six Gram negative bacteria, namely, Burkholderia cepacia, Providencia stuartii, Morganella morganii, Enterobacter cloacae, Enterobacter aerogenes, and Proteus mirabilis. RESULTS: The leaf aqueous extract (decoction) of Schinus lentiscifolius showed a broad spectrum of antibacterial activity, ranging from 125 to 250 µg/ml (MIC) against the tested bacteria and fungi. The n-hexane extract, despite being very little active against bacteria, showed an excellent antifungal activity, especially against Candida albicans (MIC=25 µg/ml), Candida tropicalis (MIC=15.5 µg/ml), and Cryptococcus neoformans, (MIC=15.5 µg/ml). From the acetate fraction (the most active against bacteria), compounds 1-6 were isolated: nonadecanol (1), moronic acid (2), gallic acid methyl ester (3), gallic acid (4), quercetin (5) and quercitrin (6). The minimal inhibitory concentration (MIC) of moronic acid between 1.5 and 3 µg/ml against most of the tested bacteria shows that it is one of the metabolites responsible for the antibacterial activity of Schinus lentiscifolius. CONCLUSION: The antimicrobial activity and some constituents of Schinus lentiscifolius are reported for the first time. The results of the present study provide scientific basis for the popular use of Schinus lentiscifolius for a number of different health problems.

Alkaloids from Melochia chamaedrys.

Investigation of the chemical constituents from the roots of Melochia chamaedrys (Sterculiaceae) resulted in the isolation of two quinolinone alkaloids: a new alkaloid, named chamaedrone (1), and a known alkaloid, antidesmone (2). Their structures and stereochemistry were elucidated on the basis of 2D NMR and X-ray crystallographic analysis. Furthermore, alkaloids 1 and 2, and the synthetic analogues 3-6 obtained from 2, were screened for antimicrobial activities.

Cyclopeptide alkaloids from Scutia buxifolia Reiss and their antimicrobial activity.

The present study reports a cyclopeptide alkaloid, scutianine M, isolated from the methanolic root bark extract of Scutia buxifolia Reiss (Rhamnaceae) along with six known compounds, scutianines-B, -C, -D, -E, -F, and scutianene D. Its structure was established on the basis of spectroscopic analyses, including application of 2D NMR spectroscopic techniques. As part of a study of the bioactive compounds of medicinal plants from southern Brazil, we also compared the antimicrobial activity of the isolated compounds towards Gram (+), Gram (-) bacteria, and yeasts.

Essential oil from Zanthoxylum hyemale.

The essential oils from aerial parts of young (sample A) and mature leaves (sample B), fruit (sample C), and flowers (sample D) of Zanthoxylum hyemale were obtained by hydrodistillation and analyzed by GC, GC/MS, and chiral phase gas chromatography (CPGC). Thirty-four compounds were identified from the essential oils, representing approximately 90.71, 91.19, 87.33, and 89.08 % of the oils, respectively. The major constituent of the young leaf essential oil was the sesquiterpene trans-nerolidol (51 %), while the main constituent of mature leaf (31 %) and flower oils (22 %) was an as yet unknown humulane-type sesquiterpenoid, which was characterized by spectral techniques (EI-MS and 1D-, 2D-NMR) as 3,7,10,10-tetramethylcycloundeca-3,7-dien-1-ol ( 1) and given the trivial name "hyemalol". In the fruit essential oil, the most abundant components were the monoterpenes beta-pinene (25 %) and alpha-pinene (10 %). The antimicrobial activity of the essential oils and some isolated compounds is also reported.

Cyclic peptide alkaloids from the bark of Discaria americana.

The isolation and structure determination of cyclic peptide alkaloids, discarine-M and discarine-N, along with seven known cyclic peptide alkaloids, adouetine-Y', franganine, frangulanine, discarines-A, -B, -C, and -D from the root bark of Discaria americana are described. Structures were determined spectroscopically, especially using 2D NMR spectroscopic analysis. The crude methanol extract, the basic ether extract, and the alkaloids 6 and 7 also weakly inhibited growth of gram-negative and gram-positive bacteria.

Antibacterial cyclopeptide alkaloids from the bark of Condalia buxifolia.

The cyclopeptide alkaloid, named condaline-A, was isolated from the root bark of Condalia buxifolia Reissek (Rhamnaceae), along with the known compounds adouetine-Y', scutianine-B, and scutianine-C. Their structures were determined by spectroscopic analyses, with their antibacterial activities being evaluated by use of a direct bioautography method.

Chemical analysis and antifungal activity of the essential oil of Calea clematidea.

The chemical composition of the essential oils of Calea clematidea Baker obtained by hydrodistillation of the leaves and flowers was analysed by GC and GC/MS and the oils were assayed for their antifungal activities. The essential oil of the leaves showed a high content of a new natural epoxy terpenoid, named clemateol (ca. 70 %), with minor amounts of o-vanillin (6.5 %), spathulenol (4.2 %), alpha-terpinene (4.0 %), germacrene B (2.9 %), yomogi alcohol (1.8 %), ( E)-caryophylene (1.7 %), m-cymenene (1.6 %), and alpha-gurjunene (1.5 %), while the essential oil of the flowers was characterized by a higher content of thymol methyl ether (ca. 80 %), with minor amounts of clemateol (4.8 %) and o-cymene (4.7 %). The antimicrobial activity of the oils was also evaluated against dermatophytes for their possible use in pharmaceutical preparations for topical applications. The oil of the leaves (MIC > 3.57 mg/ml), clemateol (MIC > 1.52 mg/ml), and the alcohol 2 (MIC > 2.82 mg/ml) showed a moderate antifungal activity against Trichophyton tonsurans, Trichophyton rubrum, Trichophyton menthagrophytes var. i nterdigitale, Epidermophyton floccosum, Microsporum gypseum, Microsporum canis and Microsporum nanum.