Anti-Schistosomal Activity of Chenopodium ambrosoides Extracts in Adult Worms In vivo and In vitro

Plants may contain ingredients that have anti-parasitic activity against parasites of medical significance. Chenopodium ambrosoides (Wormseed) a wide spread herb in the Family Chenopodiacea was investigated for anti-schistosomal activity using, the human trematode parasite, Schistosoma mansoni, as the target. The plant is well known for its vermifuge and anti-helminthetic properties. The root, stem, leaves and fruit of the plant were extracted sequentially using n-hexane, dichloromethane, methanol and distilled water as solvents and tested for anti-schistosomal activity. The crude extracts of leaves and fruits remarkable and significant activity that resulted in significant egg counts reduction, compared to untreated controls (P < 0.05). Among the plant extracts (n – hexane, dichloromethane, methanol and aqueous), aqueous (leaf) and methanol (fruit) extracts showed responses closest to PZQ. Aqueous (leaf) had 46% worms reduction, methanol (fruit) had 23% worms reduction and Praziquantel had 34% worms reduction (P > 0.05). The in vitro results showed methanol (fruit) extract killed more adult worms of S. mansoni than the aqueous (leaf) extract. Methanol (fruit) extract potency depended on concentration. The higher the concentration, the faster the killing. The effect of both methanol (fruit) and aqueous (leaf) extracts on S. mansoni adult worms showed that methanol (fruit) extract had better potency than aqueous (leaf) extract.  The killing effect of methanol (fruit) and aqueous (leaf) extracts were statistically similar to Praziquantel. Keywords: Chenopodium ambrosoides (Wormseed),  In vivo and  In vitr

Acute Phase Response of Albumin and Haptoglobin in Experimental Infection of the Olive Baboon, Papio Anubis, with Schistosoma Mansoni

Following infection of baboons with Schistosoma mansoni cercariae, a rapid four-fold increase in mean  serum haptoglobin concentrations was observed. These concentrations dropped to near pre-infection levels  following curative treatment of the infected animals with praziquantel. On challenge of the animals with a  second cercarial dose, haptoglobin concentrations demonstrated a more gradual increase that did not attain  the heights of the initial infection. Albumin concentrations displayed an inversely disproportionate relationship  to those of haptoglobin and decreases were much less pronounced. Whereas albumin was not a  sensitive indicator of schistosomiasis mansoni, haptoglobin proved to be useful in detecting the acute infection  and in determining prognosis of the disease in the olive baboon.

Anti-Schistosomal Activity of Chenopodium ambrosoides Extracts in Adult Worms In vivo and In vitro

Plants may contain ingredients that have anti-parasitic activity against parasites of medical significance. Chenopodium ambrosoides (Wormseed) a wide spread herb in the Family Chenopodiacea was investigated for anti-schistosomal activity using, the human trematode parasite, Schistosoma mansoni, as the target. The plant is well known for its vermifuge and anti-helminthetic properties. The root, stem, leaves and fruit of the plant were extracted sequentially using n-hexane, dichloromethane, methanol and distilled water as solvents and tested for anti-schistosomal activity. The crude extracts of leaves and fruits wereremarkableand showedsignificant activity that resulted in significant egg counts reduction, compared to untreated controls (P < 0.05). Among the plant extracts (n – hexane, dichloromethane, methanol and aqueous), aqueous (leaf) and methanol (fruit) extracts showed responses closest to PZQ. Aqueous (leaf) had 46% worms reduction, methanol (fruit) had 23% worms reduction and Praziquantel had 34% worms reduction (P > 0.05). The in vitro results showed methanol (fruit) extract killed more adult worms of S. mansoni than the aqueous (leaf) extract. The effect of both methanol (fruit) and aqueous (leaf) extracts on S. mansoni adult worms showed that methanol (fruit) extract had better potency than aqueous (leaf) extract.  The killing effect of methanol (fruit) and aqueous (leaf) extracts were statistically similar to Praziquantel. Keywords:Chenopodium ambrosoides (Wormseed),  In vivo and  In vitr

Determination of Anti-schistosomal Finger Profiles of Chenopodium ambrosoide Crude Extracts in BALB/c Mice Using Thin Layer Chromatography (TLC)

Plants may contain ingredients that have anti-parasitic activity against parasites of medical siginificance. Chenopodium ambrosoides (Wormseed) a wide spread herb in the Family: Chenopodiacea was investigated for anti-schistosomal activity using, the human trematode parasite, Schistosoma mansoni, as the target. The plant is well known for its vermifuge and anti-helminthetic properties. The root, stem, leaves and fruit of the plant were extracted sequentially using n-hexane, dichloromethane, methanol and distilled water as solvents and tested for anti-schistosomal activity. TLC finger profiles mobile of C. ambrosoides extracts showed aqueous (leaf) extract had  more Rf spots than methanol (fruit) extract but they were not significantly different (P > 0.05). The results of this study suggest that Chenopodium ambrosoides aqueous (leaf) and methanol (fruit) extracts has remarkable anti-schistosomal properties, and should be investigated to determine their toxicity and also tested against other parasites as a source novel anti-parasitic compounds. Keywords: Rf - Mobility Relative to front TLC - Thin Layer Chromatograph

Influence of age of mice on the susceptibility to murine schistosomiasis infection

Intensity of human schistosomiasis infection increases with age, a peak being attained at early puberty. Hormones could be involved in the age-related changes in susceptibility to schistosomiasis. Male BALB/c mice were infected with Schistosoma mansoni either before or after puberty and worm numbers, cellular immune responses, hormonal levels and pathology analysed. Pre-puberty infected mice had a significantly higher number of adult worms (

Studies on the Interaction of Schistosoma Mansoni and Leishmania Major in Experimentally Infected Balb/c Mice

Schistosoma mansoni and Leishmania major are important tropical human parasites. It is crucial to know the effect of the two infecting man concurrently. Two groups of BALB/c mice were infected with each of the parasites separately; another group was co-infected with both parasites and there was a na\uefve control. Draining lymph node and spleen cells from mice infected with either of the parasites showed high proliferative responses to their specific parasite antigen. However, crossreactivity occurred between S. mansoni and L. major. Spleen and Lymph node cells from co-infected group demonstrated high and sustained proliferative responses to schistosome soluble worm antigen preparation and killed Leishmania major antigen, respectively. There was high and sustained IgG levels for both the single and coinfected groups. At 10 weeks post-infection, co-infected mice had significantly larger nodules than mice with L. major infection alone. However, co-infected animals had less severe liver pathology and less enlarged mesenteric lymph nodes than those infected with S. mansoni only. This work shows that co-infection results in two different outcomes: protection against S. mansoni and exacerbated pathogy in L. major. We suggest that cellular responses possibly protect against S. mansoni, while high IgG levels lead to exacerbated L. major response

Cellular and humoral immune responses and protection against schistosomes induced by a radiation-attenuated vaccine in chimpanzees

The radiation-attenuated Schistosoma mansoni vaccine is highly effective in rodents and primates but has never been tested in humans, primarily for safety reasons. To strengthen its status as a paradigm for a human recombinant antigen vaccine, we have undertaken a small-scale vaccination and challenge experiment in chimpanzees (Pan troglodytes). Immunological, clinical, and parasitological parameters were measured in three animals after multiple vaccinations, together with three controls, during the acute and chronic stages of challenge infection up to chemotherapeutic cure. Vaccination induced a strong in vitro proliferative response and early gamma interferon production, but type 2 cytokines were dominant by the time of challenge. The controls showed little response to challenge infection before the acute stage of the disease, initiated by egg deposition. In contrast, the responses of vaccinated animals were muted throughout the challenge period. Vaccination also induced parasite-specific immunoglobulin M (IgM) and IgG, which reached high levels at the time of challenge, while in control animals levels did not rise markedly before egg deposition. The protective effects of vaccination were manifested as an amelioration of acute disease and overall morbidity, revealed by differences in gamma-glutamyl transferase level, leukocytosis, eosinophilia, and hematocrit. Moreover, vaccinated chimpanzees had a 46% lower level of circulating cathodic antigen and a 38% reduction in fecal egg output, compared to controls, during the chronic phase of infection

Attenuated Leishmania induce pro-inflammatory mediators and influence leishmanicidal activity by p38 MAPK dependent phagosome maturation in Leishmania donovani co-infected macrophages

Promastigote form of Leishmania, an intracellular pathogen, delays phagosome maturation and resides inside macrophages. But till date limited study has been done to manipulate the phagosomal machinery of macrophages to restrict Leishmania growth. Attenuated Leishmania strain exposed RAW 264.7 cells showed a respiratory burst and enhanced production of pro-inflammatory mediators. The augmentation of pro-inflammatory activity is mostly attributed to p38 MAPK and p44/42 MAPK. In our study, these activated macrophages are found to induce phagosome maturation when infected with pathogenic Leishmania donovani. Increased co-localization of carboxyfluorescein succinimidyl ester labeled pathogenic L. donovani with Lysosome was found. Moreover, increased co-localization was observed between pathogenic L. donovani and late phagosomal markers viz. Rab7, Lysosomal Associated Membrane Protein 1, Cathepsin D, Rab9, and V-ATPase which indicate phagosome maturation. It was also observed that inhibition of V-type ATPase caused significant hindrance in attenuated Leishmania induced phagosome maturation. Finally, it was confirmed that p38 MAPK is the key player in acidification and maturation of phagosome in attenuated Leishmania strain preexposed macrophages. To our knowledge, this study for the first time reported an approach to induce phagosome maturation in L. donovani infected macrophages which could potentiate short-term prophylactic response in futur

Do schistosome vaccine trials in mice have an intrinsic flaw that generates spurious protection data?

The laboratory mouse has been widely used to test the efficacy of schistosome vaccines and a long list of candidates has emerged from this work, many of them abundant internal proteins. These antigens do not have an additive effect when co-administered, or delivered as SWAP homogenate, a quarter of which comprises multiple candidates; the observed protection has an apparent ceiling of 40–50 %. We contend that the low level of maturation of penetrating cercariae (~32 % for Schistosoma mansoni) is a major limitation of the model since 68/100 parasites fail to mature in naïve mice due to natural causes. The pulmonary capillary bed is the obstacle encountered by schistosomula en route to the portal system. The fragility of pulmonary capillaries and their susceptibility to a cytokine-induced vascular leak syndrome have been documented. During lung transit schistosomula burst into the alveolar spaces, and possess only a limited capacity to re-enter tissues. The acquired immunity elicited by the radiation attenuated (RA) cercarial vaccine relies on a pulmonary inflammatory response, involving cytokines such as IFNγ and TNFα, to deflect additional parasites into the alveoli. A principal difference between antigen vaccine protocols and the RA vaccine is the short interval between the last antigen boost and cercarial challenge of mice (often two weeks). Thus, after antigen vaccination, challenge parasites will reach the lungs when both activated T cells and cytokine levels are maximal in the circulation. We propose that “protection” in this situation is the result of physiological effects on the pulmonary blood vessels, increasing the proportion of parasites that enter the alveoli. This hypothesis will explain why internal antigens, which are unlikely to interact with the immune response in a living schistosomulum, plus a variety of heterologous proteins, can reduce the level of maturation in a non-antigen-specific way. These proteins are “successful” precisely because they have not been selected for immunological silence. The same arguments apply to vaccine experiments with S. japonicum in the mouse model; this schistosome species seems a more robust parasite, even harder to eliminate by acquired immune responses. We propose a number of ways in which our conclusions may be tested