Leishmanicidal activity of Maytenus illicifolia roots

In vitro evaluation of leishmanicidal activity of aqueous and ethanolic extracts of Maytenus illicifolia against three species of Leishmania. The root extracts showed differential activity against parasites, whereas the aerial part of the extracts was inactive.     

Antileishmanial properties of tropical marine algae extracts

Aqueous and organic extracts of twenty-seven species of marine algae (14 species of Rhodophyta, 5 species of Phaeophyta and 8 species of Chlorophyta) collected from the Gulf of Mexico and Caribbean coast of the Yucatan Peninsula (Mexico) were evaluated for their antileishmanial in vitro activity against Leishmania mexicana promastigote forms. The cytotoxicity of these extracts was also assessed using brine shrimp. Organic extracts from Laurencia microcladia (Rhodophyta), Dictyota caribaea, Turbinaria turbinata and Lobophora variegata (Phaeophyta) possessed promising in vitro activity against L. mexicana promastigotes (LC(50) values ranging from 10.9 to 49.9 mug/ml). No toxicity of algal extracts against Artemia salina was observed with LC(50) ranging from 119 to >/=1000 mug/ml. Further studies on bio-guided fractionation, isolation and characterization of pure compounds from these species as well as in vivo experiments are needed and are already in progress.     

Antimicrobial activity of alkaloidal fraction from barks of Himatanthus lancifolius

The alkaloidal fraction from Himatanthus lancifolius barks demonstrated a broad-spectrum in vitro antimicrobial activity for most of the Gram (+) and Gram (-) tested microorganisms.     

Antioxidant and antimicrobial activities of Onosma argentatum and Rubia peregrina

The n-hexane-dichloromethane (1:1) extract of the roots of Onosma argentatum and the methanol extract (partitioned between water and chloroform, ethyl acetate and n-butanol, respectively), of the underground parts (roots and rhizomes) of Rubia peregrina were tested in vitro for their antioxidant and antimicrobial activities. The highest antioxidant activity (98%) was observed at 0.1% concentration for the roots of O. argentatum. It was 96% at 0.25% concentration on the ethyl acetate fraction of R. peregrina. O. argentatum extract was effective on Staphylococcus aureus, Bacillus subtilis and Escherichia coli. The ethyl acetate and chloroform fractions of R. peregrina were effective on S. aureus and E. coli, respectively. These two species did not have any antifungal activity.     

Inhibition of Trypanosoma cruzi by plant extracts used in Chinese medicine

In this work, we assessed the effect of extracts obtained from 17 plants used in traditional Chinese medicine. These extracts were tested in vitro with the epimastigote form of Trypanosoma cruzi, clone Bra C(15) C(2), at 27 degrees C in F-29 medium at a concentration of 100 microg/ml in axenic cultures. Allopurinol was used as reference drug. Seven plant extracts showed inhibitory activities lower than 25%. Pueraria lobata, Mahonia beaei, Dictamus dasycarpus, Kochia scoparia, Sophora flavescens and Ligustrum lucidum showed effects with inhibition values between 25% and 60%, whereas Lithospermum erythrorhizon, Saussurea lappa, Melia toosendan and Cinnamomum cassia showed the greatest inhibitory activity of 100%. The IC(50) of these extracts were: 0.4, 2.4, 1.8 and 3.9 microg/ml, respectively. The MTT assay was made and did not show cytotoxic activity. These results allowed us to suggest that L. erythrorhizon, S. lappa, M. toosendan and C. cassia could be a source of new compounds against T. cruzi.     

Antioxidative activity of 6a-hydroxypterocarpan from the root of Sophora chrysophylla

The antioxidative activity of 6a-hydroxypterocarpan isolated from the root of Sophora chrysophylla has been investigated in vitro on lipid peroxidation by interaction of heamoglobin and hydrogen peroxide.     

Antimicrobial activity and constituents of Coccoloba acrostichoides

The ethanol extract and fractions from Coccoloba acrostichoides aerial parts were assayed for in vitro antimicrobial activity. The extract was active against the assayed bacteria while most of the fractions also inhibited fungal growth, especially the n-hexane and EtOAc fractions. The isolated beta-sitosterol and betulin were tested, being the last one active against Fusarium oxysporum.     

Intestinal antiinflammatory activity of a lyophilized infusion of Turnera ulmifolia in TNBS rat colitis

Turnera ulmifolia is a plant popularly known in Brazil and South America as chanana. Some species of Turnera are widely used in folk medicine for different types of inflammatory diseases. In this study, the preventive intestinal antiinflammatory activity of a lyophilized infusion obtained from the aerial parts of T. ulmifolia was tested in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis. The results obtained revealed that pretreatment to colitic rats with the extract, at 250 and 500 mg/kg, significantly attenuated the colonic damage induced by TNBS. This beneficial effect was associated with an improvement in the colonic oxidative status, since the infusion prevented the glutathione depletion that occurred as a consequence of the colonic inflammation. On the other hand, this antioxidant activity was confirmed in in vitro studies. In conclusion, the preventive effect exerted by the lyophilized infusion of T. ulmifolia in the TNBS model of rat colitis is probably related to its antioxidant properties, due to its flavonoids content.     

Antimutagenic, antioxidant and antimicrobial properties of Maytenus krukovii bark

The hydroalcoholic extract of Maytenus krukovii bark was investigated for its in vitro mutageno-protective activities by means of the Ames Salmonella/microsome assay. The extract showed an inhibitory effect in both T98 and T100 strains against the mutagenic activity of promutagen 2-aminoanthracene but was not protective against directly acting mutagens sodium azide and 2-nitrofluorene. When tested as a radical scavenger and antioxidant it produced a dose-dependent inhibition. The extract did not show significant antibacterial properties, and was weakly active against dermatophyte and phytopathogenic fungi, but inhibited the growth of phytopathogen Pithyum ultimum.     

A bioactive biflavonoid from Campnosperma panamense

Lanaroflavone (1), a biflavonoid isolated from the methanol extract of the aerial part of Campnosperma panamense by bioguided fractionation, has been assessed for in vitro antiprotozoal activity. Lanaroflavone showed both antimalarial and leishmanicidal activities, but was inactive against Chagas disease vector, Trypanosoma cruzi.     

Antidiabetic activity of hydro-ethanolic extract of Cyperus rotundus in alloxan induced diabetes in rats

In light of the traditional claim of Cyperus rotundus in the treatment of diabetes, investigations were carried out to evaluate its effect on alloxan induced hyperglycemia in rats. Oral daily administration of 500 mg/kg of the extract (once a day for seven consecutive days) significantly lowered the blood glucose levels. This antihyperglycemic activity can be attributed to its antioxidant activity as it showed the strong DPPH radical scavenging action in vitro.     

Antiplatelet activity of Varthemia iphionoides

Aqueous and alcoholic extracts, volatile oil and four flavonoids, xanthomicrol (1), kumatokenin (2), jaceidin (3) and 3, 3'-di-O-methylquercetin (4), isolated from Varthemia iphionoides were investigated for their in vitro anti-platelet activity. Aqueous extract and compounds (1), (2) and (4) showed anti-platelet activity. Volatile oil and the alcoholic extract did not exhibit any anti-platelet activity. Structures of the isolated compounds (1)-(4) were determined by spectroscopic methods (UV, IR, MS, (1)H-NMR).     

Isolation and partial characterization of a pectic polysaccharide from the fruit pulp of Spondias cytherea and its effect on peritoneal macrophage activation

The total carbohydrate content of the intact pulp of Spondias cytherea was 41%. Polysaccharides were obtained via hot aqueous extraction after defatting with organic solvents. The aqueous extract was treated with excess ethanol to form a precipitate, which was then solubilized in water. The material precipitated upon acidification when HCl was removed. The resulting supernatant fraction was submitted to freeze-thawing treatment yielding a soluble fraction (sFTS). This fraction had Ara, Rha, Gal and GalA in its structure as determined by GC-MS. 13C NMR analysis showed signals assigned to alpha-L-Araf, beta-D-Galp, alpha-D-GalpA and alpha-L-Rhap units, in addition to galacturonic acid units, which were present also as methyl ester. These results suggest a type I rhamnogalacturonan with arabinogalactan branches. Cell eliciting activity in a dose-depending pattern was observed in vitro on peritoneal macrophages treated with sFTS.     

Bioactive saponins from the fruits of Aesculus pavia L

Continued chemical investigation on the fruits of Aesculus pavia L. resulted in theisolation and identification of two new oleanolic acid saponins, namely vaccaroside A (1) andvaccaroside B (2). The isolated furostanol saponins were evaluated for cytotoxic activity againsthuman normal amniotic and human lung carcinoma cell lines using neutral red and MTT assays.In vitro experiments showed significant cytotoxicity in a dose dependent manner with IC50 valuesin the range of 27.80–79.02 μM.     

Comparative analysis of active constituents in Centella asiatica samples from Madagascar: application for ex situ conservation and clonal propagation

A comparative quantitative analysis of the active triterpenoids in Centella asiatica samples collected in different locations in Madagascar was carried out to evaluate the natural variability in triterpenoid content and to select elite samples for further ex situ germplasm conservation and clonal propagation. The highest asiaticoside content (6.42%) was measured in samples collected in Mangoro region. In vitro propagation of C. asiatica was successfully achieved in hormone-free medium. Although lower asiaticoside content was detected in 8-week-old vitro plants, the Mangoro sample still showed the highest content in this triterpenoid constituent (1.78%). Acetoxycentellynol, a C(15)-polyacetylene, was found to be accumulated up to 18 times more in in vitro plants as compared to plant material collected in situ.     

Antioxidant compounds from <Emphasis Type="Italic">Eucalyptus grandis</Emphasis> biomass by subcritical liquid water extraction

The effectiveness of subcritical liquid water processing for extraction of antioxidants from the leaves of Eucalyptus grandis biomass was evaluated by determining the capability of the processed samples to scavenge peroxynitrite radicals in vitro, as compared with the extracts obtained by conventional extraction. Pyrogallol (1), 5-hydroxymethyl-2-furaldehyde (2), and 4,4,6,6-tetramethyl-3,5-dioxo-cyclohex-1-enecarboxylic acid (3) were identified as the major products obtained from the subcritical liquid water extracts. Among these, pyrogallol (1) exhibited stronger antioxidant activity than butylated hydroxytoluene, which was used as a standard for the antioxidant activity measurement. This research was presented at the conference of the Japan Society for Bioscience, Biotechnology, and Agrochemistry (JSBBA) in Tokyo, March 2007.     

Spice oil cinnamaldehyde exhibits potent anticandidal activity against fluconazole resistant clinical isolates

Fluconazole resistance is becoming an important clinical concern. We studied the in vitro effects of cinnamaldehyde against 18 fluconazole-resistant Candida isolates. MIC₉₀ of cinnamaldehyde against different Candida isolates ranged 100–500 μg/ml. Growth and sensitivity of the organisms were significantly affected by cinnamaldehyde at different concentrations. The rapid irreversible action of this compound on fungal cells suggested membrane-located targets for its action. Insight studies to mechanism suggested that cinnamaldehyde exerts its antifungal activity by targeting sterol biosynthesis and plasma membrane ATPase activity. Inhibition of H⁺-ATPase leads to intracellular acidification and cell death. Toxicity against H9c2 rat cardiac myoblasts was studied to exclude the possibility of further associated cytotoxicity. The observed selectively fungicidal characteristics against fluconazole-resistant Candida isolates signify a promising candidature of this essential oil as an antifungal agent in treatments for candidosis.     

Effects of Pithecellobium clypearia Benth extract and its main components on inflammation and allergy

The ethanol extract of Pithecellobium clypearia Benth (PCE) was characterized to be rich in polyphenols by HPLC analysis, and investigated for its anti-inflammatory and anti-allergic activities. In our assay, PCE showed anti-inflammatory activity in both acute and auto-immune inflammation animal models. Administration of PCE can effectively inhibit the croton oil-induced ear edema and capillary permeability, the carrageenin-induced paw edema, and the liver injury caused by propionibacterium acnes plus lipopolysaccharide. PCE was also found to possess anti-allergic activity in inhibiting the DNFB-induced delayed hypersensitivity reaction. Meanwhile, seven main components (1–7) from PCE were studied for their effect on histamine release stimulated by compound 48/80 from rat peritoneal mast cells in vitro. Compound 2 ((−)-epigallocatechin-7-gallate), 3 ((−)-5, 7, 3′, 4′, 5′-pentahydroxyflavan), and 5 ((−)-tetra hydroxyflavan-7-gallate) showed significant inhibition effect on histamine release.     

In vitro screening of angiotensin I-converting enzyme inhibitors from Japanese cedar (Cryptomeria japonica)

Screening and isolation of angiotensin I-converting enzyme (ACE) inhibitors from Japanese cedar (Cryptomeria japonica) based on the in vitro ACE inhibitory assay were attempted. The ethanol extract from outer bark showed the highest inhibitory activity (IC₅₀ is 16g/ml) among 24 extracts prepared from roots, leaves, heartwood, sapwood, inner bark, and outer bark by successive extraction with four solvents. The fractionation of the outer bark ethanol extract followed by the bioassay resulted in the isolation of two strong ACE inhibitors, catechin and dimeric procyanidin B3. The bioassay of three flavan-3-ols including (+)-catechin and six flavones revealed that most of these compounds have high ACE inhibitory activity. The results suggest that the phenolic hydroxyl group at the C7 position and heterocyclic oxygen atom of these compounds are important for expressing the inhibitory activity.