Machado AR et al. (2015) Parasit Vectors "Nematicidal activity of Annona crassiflora leaf extract on Caenorhabditis elegans."

da Silva Medeiros F, Pimenta LP, Machado AR, Fujiwara RT, Ferreira SR, de Souza Filho JD

[Parasit Vectors, 2015]

BACKGROUND: The aim of this work was to investigate the potential nematicidal activity of Annona crassiflora leaf extract against Caenorhabditis elegans. METHODS: The hydroalcoholic leaf extract and its fractions (dichloromethane, ethyl acetate, methanol and water) were submitted to mobility assay against the roundworm Caenorhabditis elegans. GC-MS and NMR analysis were performed in order to identify metabolites. RESULTS: The dichloromethane and ethyl acetate fractions showed to be the most active among the hydroalcoholic leaf extracts and its four fractions. The percentages of C. elegans larvae immobility were 98.13 and 89.66%, respectively, at a concentration of 1000g.mL(-1). Besides some amino acids, palmitic acid methyl ester, 2-isopropyl-5-methylcyclohexanol, oleic acid methyl esther, stearic acid methyl ester, quercetin and kaempferol were also identified in these fractions. CONCLUSION: The results indicated that of A. crassiflora leaf ethanolic extract has a good potential as a source for natural nematicide.

Mak JW et al. (1990) Parasitol Res "Experimental infection of the leaf-monkey, Presbytis cristata, with subperiodic Brugia malayi."

Suresh K, Lam PL, Mak JW, Choong MF

[Parasitol Res, 1990]

Presbytis cristata monkeys infected through the inoculation of between 200 and 400 subperiodic Brugia malayi infective larvae (L3) in the right thigh, in both thighs or in the dorsum of the right foot were followed up for varying periods of up to about 8 months after infection. All 148 inoculated animals became patent, with mean prepatent periods being between 66 and 76 days. In animals injected in the thigh, the patterns of microfilaraemia were similar, there being a rapid rise in the geometric mean counts (GMCs) of microfilariae during the first 10-12 weeks of patency, which then plateaued at levels of greater than 1000/ml. Adult worm recovery, expressed as the percentage of the infective dose, was significantly higher in animals injected with 100 L3 in each thigh, being 9.4% as compared with 2.8%-4.8% in other groups. It is therefore recommended that animals should be injected with 100 L3 in each thigh and that the testing of potential filaricides in this model be carried out during the phase of rapid increase in microfilaraemia to ensure that any microfilaricidal effect can easily be detected.

Mak JW et al. (1988) Parasitol Res "Effect of ivermectin against subperiodic Brugia malayi infection in the leaf monkey, Presbytis cristata."

Mak JW, Lam PL, Suresh K, Rain AN

[Parasitol Res, 1988]

Ivermectin at single doses of 0.2-1.0 mg/kg body weight reduced the microfilarial counts of subperiodic Brugia malayi in Presbytis cristata by 59.9%-89.6% of initial counts, 4 weeks after treatment. Adult filaricidal activity was poor, live adult worms being recovered from all animals at autopsy. There was no serious side effect at these doses.

Murthy PK et al. (1999) Parasitology "Longitudinal humoral immune responses of Indian leaf monkey (Presbytis entellus) to Brugia malayi infection."

Murthy PK, Murthy PS, Ghosh RP, Chatterjee RK, Tyagi K

[Parasitology, 1999]

Humoral immune responses of the Indian leaf monkey (Presbytis entellus) experimentally infected with Brugia malayi and exhibiting disease manifestations were studied. Microfilaraemia, filaria-specific IgG and circulating immune complexes (CICs) were determined in the monkeys at different time-points after inoculation of B. malayi 3rd-stage larvae. Sera were analysed for recognition pattern of adult parasite antigen molecules by immunoblotting. More than 60% of the infected monkeys developed episodic or persistent limb oedema with or without fever and with low or no microfilaraemia. While both CIC and filaria specific IgG levels were comparable in animals showing no disease symptoms (asymptomatics) and some animals showing symptoms (symptomatics), IgG levels peaked during pre-patent stage in symptomatics and during latent stage in asymptomatic animals. However, some of the symptomatic animals showed a low level of filaria-specific IgG as compared to asymptomatic and other symptomatic animals. The immunoblot analysis showed non-reactivity of 17 and 55 kDa antigens with sera of symptomatic animals. The results thus suggest that humoral immune responses as measured in the present study do not precede the development of the manifestations. However, 2 non-reactive antigen molecules identified by symptomatic sera need further study to establish their possible involvement, if any, in the development of acute disease manifestations in this model.

Mak JW et al. (1987) J Helminthol "Chemoprophylactic studies with ivermectin against subperiodic Brugia malayi infection in the leaf monkey, Presbytis cristata."

Mak JW, Suresh K, Lam PL, Rain AN

[J Helminthol, 1987]

Four Presbytis cristata were treated with oral ivermectin at the same time as the subcutaneous inoculation of 100 infective larvae monthly for three months. Two animals given 0.2 mg/kg monthly and two others given 0.3 mg/kg monthly as well as three control animals became patent for microfilaraemia. However, only 1% of the infective dose was recovered as adult worms from animals in the higher drug dosage group compared to 8.2% and 6.2% in the lower dosage and control groups respectively.

Upadhyay A et al. (2013) Biosci Biotechnol Biochem "Significant longevity-extending effects of Alpinia zerumbet leaf extract on the life span of Caenorhabditis elegans."

Chompoo J, Tawata S, Upadhyay A, Fukuta M, Taira N

[Biosci Biotechnol Biochem, 2013]

The beneficial effects of the phytochemical compounds in fruits and vegetables have been extrapolated mainly from in vitro studies or short-term dietary supplementation studies. Recent approaches using animal models of Caenorhabditis elegans are becoming quite popular, and in this regard the effects of Alpinia zerumbet leaf extract (ALP) on C. elegans lifespan were investigated under both normal and stress conditions. ALP significantly increased, mean lifespan by 22.6%, better than the positive control, resveratrol. Furthermore, both under thermal and oxidative stressed conditions, ALP increased the survival rate significantly better than quercetin. Further studies indicated that the significant longevity-extending effects of ALP on C. elegans can be attributed to its in vitro free-radical scavenging effects and its upregulation of stress-resistance proteins, including superoxide dismutase 3 (SOD-3) and heat-shock protein (HSP-16.2). These results suggest that phytochemical compounds in A. zerumbet have beneficial effects on the lifespan of C. elegans, and that they can be used as a source of dietary supplements for aging and age-related diseases.

Ghosh RP et al. (1999) J Parasitol "Longitudinal cellular immune responses in asymptomatic and symptomatic Brugia malayi-infected Indian leaf monkey Presbytis entellus."

Chatterjee RK, Murthy PS, Tyagi K, Murthy PK, Ghosh RP

[J Parasitol, 1999]

To investigate the cell-mediated immune (CMI) responses of the host during the development of acute filarial disease manifestations, we studied the sequential changes in CD4+ and CD8+ T-cell subsets, leukocyte migration inhibition (LMI) response to Brugia malayi adult worm antigen, and concanavalin-A (ConA) and filarial antigen-induced lymphocyte transformation (LT) in the Indian leaf monkey (Presbytis entellus)-B. malayi model. Filarial infection was established in monkeys by subcutaneous inoculations of infective larvae (L3) (700-1,250 L3/monkey) in multiple doses, and the infected monkeys were categorized as symptomatic (Sym) and asymptomatic (Asym) depending on whether or not acute clinical manifestations were shown by them. In Sym monkeys, LMI response to homologous adult parasite antigen was significantly suppressed as compared to Asym monkeys. In Asym monkeys, LMI response varied among the animals; 2 showed an increase throughout the study period and 2 showed suppression at different time points. When compared with Asym monkeys, CD8+ T cells in Sym monkeys showed a trend of significant increase after day 180 postinoculation (PI). CD4+ T cells remained within the normal range till day 300 (PI), after which they showed a marginal increase. ConA-stimulated LT was suppressed in Asym monkeys from day 60 PI. Antigen-stimulated LT was unresponsive in both Asym and Sym animals. Thus, the host's LT response to ConA is suppressed in Asym animals, and alteration in CD8+ T-cell number and LMI response in Sym monkeys may be involved in the development of the acute disease manifestations in this model.

Mak JW et al. (1990) Acta Trop "Experimental infection of the leaf-monkeys, Presbytis cristata and Presbytis melalophos with subperiodic Brugia malayi."

Mak JW, Lam PL, Choong MF, Suresh K

[Acta Trop, 1990]

The leaf-monkeys, Presbytis cristata and Presbytis melalophos, experimentally infected with subperiodic Brugia malayi, have been used for studies on the pathoimmunology of the infection and the screening of potential filaricides during the last 6-8 years, and considerable information on the pattern of microfilaraemia and adult worm recoveries have been obtained. The prepatent periods in 97 P. cristata and 45 P. melalophos, each infected with about 200 infective larvae, were similar, these being approximately 70 and 68 days respectively. Although all infected animals became microfilaraemic, the peak geometric mean count was much higher in P. cristata than in P. melalophos, this being 182.0 and 65.8 per ml blood respectively. Mean adult worm recovery expressed as the percentage of the infective dose was 4.7% and 2.5%, respectively. Most worms were recovered from the sacral nodes/thoracic duct or inguinal lymph nodes in these animals. In view of the higher worm recovery and the higher peak microfilaraemia attained, it is concluded that P. cristata is a better model for the infection than P. melalophos.

Manoharan RK et al. (2017) Front Microbiol "Antibiofilm and Antihyphal Activities of Cedar Leaf Essential Oil, Camphor, and Fenchone Derivatives against Candida albicans."

Manoharan RK, Lee JH, Lee J

[Front Microbiol, 2017]

Candida albicans can form biofilms composed of yeast, hyphal, and pseudohyphal elements, and C. albicans cells in the hyphal stage could be a virulence factor. The present study describes the chemical composition, antibiofilm, and antihyphal activities of cedar leaf essential oil (CLEO), which was found to possess remarkable antibiofilm activity against C. albicans but not to affect its planktonic cell growth. Nineteen components were identified in CLEO by gas chromatography/mass spectrometry, and phenolics were the main constituents. Of these, camphor, fenchone, fenchyl alcohol, -thujone, and borneol significantly reduced C. albicans biofilm formation. Notably, treatments with CLEO, camphor, or fenchyl alcohol at 0.01% clearly inhibited hyphal formation, and this inhibition appeared to be largely responsible for their antibiofilm effects. Transcriptomic analyses indicated that camphor and fenchyl alcohol downregulated some hypha-specific and biofilm related genes (ECE1, ECE2, RBT1, and EED1). Furthermore, camphor and fenchyl alcohol reduced C. albicans virulence in a Caenorhabditis elegans nematode model. These results demonstrate CLEO, camphor, and fenchyl alcohol might be useful for controlling C. albicans infections.

Spiegler V et al. (2015) Molecules "Bioassay-Guided Fractionation of a Leaf Extract from Combretum mucronatum with Anthelmintic Activity: Oligomeric Procyanidins as the Active Principle."

Spiegler V, Sendker J, Hensel A, Petereit F, Liebau E

[Molecules, 2015]

Combretum mucronatum Schumach. & Thonn. is a medicinal plant widely used in West African traditional medicine for wound healing and the treatment of helminth infections. The present study aimed at a phytochemical characterization of a hydroalcoholic leaf extract of this plant and the identification of the anthelmintic compounds by bioassay-guided fractionation. An EtOH-H2O (1:1) extract from defatted leaves was partitioned between EtOAc and H2O. Further fractionation was performed by fast centrifugal partition chromatography, RP18-MPLC and HPLC. Epicatechin (1), oligomeric proanthocyanidins (OPC) 2 to 10 (mainly procyanidins) and flavonoids 11 to 13 were identified as main components of the extract. The hydroalcoholic extract, fractions and purified compounds were tested in vitro for their anthelmintic activity using the model nematode Caenorhabditis elegans. The bioassay-guided fractionation led to the identification of OPCs as the active compounds with a dose-dependent anthelmintic activity ranging from 1 to 1000 M. Using OPC-clusters with a defined degree of polymerization (DP) revealed that a DP 3 is necessary for an anthelmintic activity, whereas a DP > 4 does not lead to a further increased inhibitory effect against the helminths. In summary, the findings rationalize the traditional use of C. mucronatum and provide further insight into the anthelmintic activity of condensed tannins.