In vitro anthelmintic effects of cysteine proteinases from plants against intestinal helminths of rodents

In vivo anthelmintic activity of Combretum mucronatum schumach & Thonn leaf extract against Haemonchus contortus in goats

Parasitic infections with gastrointestinal nematodes are a serious problem for the health and welfare of domestic animals and negatively affect the economics of animal production. Haemonchus contortus is a haematophagous nematode of small ruminants responsible for significant mortality and morbidity. In addition, the widespread resistance to synthetic anthelmintic drugs emphasizes the urgent need of alternative treatment options against haemonchosis. This work aims to investigate the anthelmintic activity of an hydroethanolic Combretum mucronatum leaf extract (CMLE) against Haemonchus contortus in goats. Goats were artificially infected with 3500 third-stage larvae of H. contortus, and 21 days later, treated with CMLE (1000, 500, 250 mg/kg) for 4 consecutive days. Different parameters such as faecal egg count reduction, weight and haematocrit were monitored during the experimental period. The number of eggs per gram of faeces (EPG) was concentration-depended lower and significantly reduced compared to the untreated control (p < 0.0001). The effect of the highest CMLE dose (4 ×1000 mg/kg body weight) was similar to the effect of albendazole (1 ×5 mg/kg of body weight). The ED50 and ED90 values calculated were 189.17 and 392.33 mg/kg body weight respectively. ED50 and ED90 values were time-dependent. Moreover, CMLE improved haematocrit and weight of goats in dose-dependent and time-dependent manner. These results showed that CMLE could be used for haemonchosis treatment in small ruminants.

Amazonian useful plants described in the book "Le Pays des Amazones" (1885) of the Brazilian propagandist Baron de Santa-Anna Nery: a historical and ethnobotanical perspective

BACKGROUND

Frederico José de Santa-Anna Nery (1848-1901) was a Brazilian Baron who referred to himself as a "volunteer propagandist" for Brazil in Europe, serving as an immigration agent to publicize the living conditions in the Amazon region, advocating for its development and modernization at the end of the nineteenth century. Santa-Anna Nery's most famous book is "Le Pays des Amazones" (The Lands of the Amazons), first published in 1885, which the author dedicated a chapter to introduce and report on the Amazonian useful plant species and its relationship with humans. The aim of this work is to understand the historical context and ethnobotanical value of the plant species in the Brazilian Amazon at the end of the nineteenth century through an analysis of the book "Le Pays des Amazones" (1885) by Baron de Santa-Anna Nery, as well as to bring to light the historical importance of this very influential propagandist, who has been forgotten nowadays.

METHODS

The original book "Le Pays des Amazones" (1885), as well as the original 3rd edition and its translated version into Portuguese, was carefully analyzed and all information about plants was systematized, with botanical names being updated. Finally, using the scientific name of medicinal plants alone or in combination with their traditional use, a search was carried out in databases in order to indicate current pharmacological studies that provide evidence about the described traditional uses.

RESULTS

A total of 156 plant species were identified in the book, although 132 species had their scientific names updated. These species belong to 45 different families, with Fabaceae and Arecaceae the most represented, and 109 plants are Brazilian native. Considering only the 36 medicinal plants, the main medicinal indications reported were astringent, purgative/laxative, stimulant and tonic, vermifuge, febrifuge, sudorific, emetic, diuretic and antidysenteric. Regarding other useful plants (non-medicinal), 97 species were cited for food, constructions and buildings, spices and condiments, ornaments and objects, carpentry, textile fibers, gums, oils, balms and essences, pigments and tanning, hunting and fishing.

CONCLUSIONS

When the book "Le Pays des Amazones" is analyzed from a timeless perspective, with a particular focus on historical ethnobotany, it is possible to observe the economic, social, and political importance of many useful plants for the Amazon at the end of the nineteenth century and how the relationship between local people, indigenous communities, and immigrants was established with plant biodiversity.

Beneficial Properties of Bromelain

Bromelain is a major sulfhydryl proteolytic enzyme found in pineapple plants, having multiple activities in many areas of medicine. Due to its low toxicity, high efficiency, high availability, and relative simplicity of acquisition, it is the object of inexhaustible interest of scientists. This review summarizes scientific reports concerning the possible application of bromelain in treating cardiovascular diseases, blood coagulation and fibrinolysis disorders, infectious diseases, inflammation-associated diseases, and many types of cancer. However, for the proper application of such multi-action activities of bromelain, further exploration of the mechanism of its action is needed. It is supposed that the anti-viral, anti-inflammatory, cardioprotective and anti-coagulatory activity of bromelain may become a complementary therapy for COVID-19 and post-COVID-19 patients. During the irrepressible spread of novel variants of the SARS-CoV-2 virus, such beneficial properties of this biomolecule might help prevent escalation and the progression of the COVID-19 disease.

Developing novel anthelmintics: the stability of cysteine proteinase activity in a supernatant extract of papaya latex

Plant derived cysteine proteinases (CPs) have long been known to possess anthelmintic properties but have attracted renewed attention recently because of the acute need to discover novel methods for controlling helminth infections as a result of increasing drug resistance. However, surprisingly little is known about the stability of these proteins under typical storage and in vivo exposure conditions. We found that CPs in a supernatant preparation from papaya latex (PLS) were stable during the initial refinement process and when stored under low temperatures, but lost activity during dialysis and within 7 days of storage when kept at ambient temperature (18–20 °C). The enzyme activity in PLS was not affected by repeated freeze-thaw cycles and was also stable under typical in vitro assay conditions at 37 °C used for quantifying effects on helminths. Active enzyme activity was still detectable in the colon 3–4 h after oral administration in rodent models.

Effects of topical gel formulation of Ficus carica latex on cutaneous leishmaniasis induced by Leishmania major in BALB/c mice

Objectives

The current study aimed to evaluate the effects of Ficus carica latex on the treatment of cutaneous leishmaniasis (CL), induced by Leishmania major. A 5% topical gel with F. carica latex was prepared. BALB/c mice were infected by inoculation of amastigotes form of L. major. Thirty BALB/c mice were divided into five groups, where the first group was treated daily, the second group twice per day, and the third group every other day with the 5% topical gel, for 3 weeks. The sizes of the lesions were measured before and during the course of treatment.

Results

Although the mean size of lesions in the mice group treated with the 5% F. carica gel, especially in the group receiving daily treatment, was less than the mean size of the lesions in the control group, yet, the differences was not statistically significant (p > 0.05). The findings of the current study demonstrated that the 5% F. carica latex with a 3-week course of treatment had no considerable effect in recovery or control of CL induced by L. major in the murine model. Using higher concentration of F. carica latex and with longer treatment lengths may increase its efficacy in the treatment of CL.

Chamomile Methanolic Extract Mitigates Small Bowel Inflammation and ROS Overload Related to the Intestinal Nematodes Infection in Mice

BACKGROUND

Chamomile (Matricaria recutita L.) is a plant which has been reported to be effective in treating several parasitic and digestive diseases. The present study was conducted to evaluate the anthelmintic activity of chamomile methanolic extract (CME).

METHODS

In vitro, the anthelmintic activities of CME were investigated on the L3 larvae of Heligmosomoides polygyrus in comparison to albendazole. In vivo, Swiss albino mice were infected with infective third (L3) larval stage of H. polygyrus by intragastric administration. Moreover, the effect of CME and albendazole on worm eggs, adult worms, serum cytokine production, and oxidative stress was studied.

RESULTS

All used doses of CME showed a potent anthelmintic activity both in vitro and in vivo and the effect being similar to treatment with albendazole. Moreover, H. polygyrus infestation was accompanied by an intestinal oxidative stress status characterized by an increased lipoperoxidation, a depletion of antioxidant enzyme activity, as well as an overload of hydrogen peroxide. We have also recorded an increase of pro-inflammatory mediator (TNF-α, IL-6, and IL-1β) levels after treatment with CME (14 ± 0.8; 41 ± 2; 58 ± 4 pg/mg protein, respectively, with the concentration 800 mg/kg, body weight) when compared with infected control mice (20 ± 1; 59 ± 2, and 83 ± 4 pg/mg protein, respectively). However, extract treatment alleviated all the deleterious effects associated with H. polygyrus infection.

CONCLUSION

These findings suggest that CME can be used in the control of gastrointestinal helminthiasis and associated oxidative stress.

Papaya latex supernatant has a potent effect on the free-living stages of equid cyathostomins in vitro

The control of equid gastrointestinal nematodes in developed countries, in particular the cyathostomins, is threatened by high levels of anthelmintic resistance. In recent years, there has been increasing interest in the evaluation of traditional 'ethnoveterinary' medicines as alternatives to chemical anthelmintics. The cysteine proteinases (CPs), a group of enzymes derived from fruits such as papaya (Carica papaya), pineapple (Ananas comosus) and figs (Ficus spp.), have shown good efficacy against adult stages of a range of parasitic nematodes, in vitro and in vivo. The efficacy of CPs against cyathostomins remains to be explored. In this study, the efficacy of a crude preparation of CPs, papaya latex supernatant (PLS), against the free-living stages of cyathostomins was evaluated using two in vitro tests, the egg hatch test (EHT) and the larval migration inhibition test (LMIT). It was demonstrated that PLS had a potent effect in the EHT, with EC-50 values in the range of 0.12-0.22μM. At concentrations above 6.25μM the eggs did not develop, below this concentration the L1 developed but they lost integrity of the cuticle upon hatching. These effects were inhibited by pre-incubation of PLS with the CP inhibitor L-trans-epoxysuccinyl-l-leucylamido-(4-guanidino butane) (E64), indicating that CPs were responsible for the anti-parasitic activity. A dose-dependent inhibition of migration of third stage larvae (L3) in the LMIT was demonstrated at higher concentrations of PLS, with EC-50 values in the range of 67.35-106.31μM. Incubation of PLS with E64 prior to use in the LMIT did not reverse the anti-migratory effect, suggesting that CPs were not responsible for the reduced migration of cyathostomin L3 and that PLS also contains an additional active compound. This is the first report of PLS and/or CPs showing activity against the free-living stages of a parasitic helminth. In addition, it suggests that cyathostomins are highly sensitive to the effects of CPs and further evaluation of their efficacy against parasitic stages and in vivo are strongly indicated.

The anthelmintic efficacy of natural plant cysteine proteinases against the equine tapeworm, Anoplocephala perfoliata in vitro

Papaya latex has been demonstrated to be an efficacious anthelmintic against murine, porcine, ovine and canine nematode parasites, and even those infecting poultry, and it has some efficacy against rodent cestodes. The active ingredients of papaya latex are known to be cysteine proteinases (CPs). The experiments described in this paper indicate that CPs in papaya latex, and also those in pineapples, are highly efficacious against the equine cestode Anoplocephala perfoliata in vitro, by causing a significant reduction in motility leading to death of the worms. The susceptibility of A. perfoliata to damage by CPs was considerably greater than that of the rodent cestodes Hymenolepis diminuta and H. microstoma. Our results are the first to report anthelmintic efficacy of CPs against an economically important equine helminth. Moreover, they provide further evidence that the spectrum of activity of CPs is not restricted to nematodes and support the idea that these plant-derived enzymes can be developed into useful broad-spectrum anthelmintics.

The anthelmintic efficacy of natural plant cysteine proteinases against the rat tapeworm Hymenolepis diminuta in vivo

Hymenolepis diminuta is a natural parasite of the common brown rat Rattus norvegicus, and provides a convenient model system for the assessment of the anthelmintic activity of novel drugs against cestodes. The experiments described in this paper indicate that treatment of rats infected with H. diminuta with a supernatant extract of papaya latex, containing a mixture of four cysteine proteinases, was moderately efficacious, resulting in a significant, but relatively small, reduction in worm burden and biomass. However, faecal egg output was not affected by treatment. In our experiments these effects were only partially dose-dependent, although specific inhibition by E-64 confirmed the role of cysteine proteinases as the active principles in papaya latex affecting worm growth but not statistically reducing worm burden. Data collected for a further 7 days after treatment indicated that the effects of papaya latex supernatant on worm loss and on worm growth were not enhanced. Our findings provide a starting point for further refinement in formulation and delivery, or assessment of alternative natural plant-derived cysteine proteinases in efforts to develop these naturally occurring enzymes into broad-spectrum anthelmintics, with efficacy against cestodes as well as nematodes.

The anthelmintic efficacy of natural plant cysteine proteinases against Hymenolepis microstoma in vivo

Little is known about the efficacy of cysteine proteinases (CP) as anthelmintics for cestode infections in vivo. Hymenolepis microstoma is a natural parasite of house mice, and provides a convenient model system for the assessment of novel drugs for anthelmintic activity against cestodes. The experiments described in this paper indicate that treatment of H. microstoma infections in mice with the supernatant of papaya latex (PLS), containing active cysteine proteinases, is only minimally efficacious. The statistically significant effects seen on worm burden and biomass showed little evidence of dose dependency, were temporary and the role of cysteine proteinases as the active principles in PLS was not confirmed by specific inhibition with E-64. Worm fecundity was not affected by treatment at the doses used. We conclude also that this in vivo host-parasite system is not sensitive enough to be used reliably for the detection of cestocidal activity of compounds being screened as potential, novel anthelmintics.

Developing a rapid throughput screen for detection of nematicidal activity of plant cysteine proteinases: the role of Caenorhabditis elegans cystatins

Plant cysteine proteinases (CPs) from papaya (Carica papaya) are capable of killing parasitic nematode worms in vitro and have been shown to possess anthelmintic effects in vivo. The acute damage reported in gastrointestinal parasites has not been found in free-living nematodes such as Caenorhabditis elegans nor among the free-living stages of parasitic nematodes. This apparent difference in susceptibility might be the result of active production of cysteine proteinase inhibitors (such as cystatins) by the free-living stages or species. To test this possibility, a supernatant extract of refined papaya latex (PLS) with known active enzyme content was used. The effect on wild-type (Bristol N2) and cystatin null mutant (cpi-1(-/-) and cpi-2(-/-)) C. elegans was concentration-, temperature- and time-dependent. Cysteine proteinases digested the worm cuticle leading to release of internal structures and consequent death. Both cystatin null mutant strains were highly susceptible to PLS attack irrespective of the temperature and concentration of exposure, whereas wild-type N2 worms were generally resistant but far more susceptible to attack at low temperatures. PLS was able to induce elevated cpi-1 and cpi-2 cystatin expression. We conclude that wild-type C. elegans deploy cystatins CPI-1 and CPI-2 to resist CP attack. The results suggest that the cpi-1 or cpi-2 null mutants (or a double mutant combination of the two) could provide a cheap and effective rapid throughput C. elegans-based assay for screening plant CP extracts for anthelmintic activity.

Oral dosing with papaya latex is an effective anthelmintic treatment for sheep infected with Haemonchus contortus

BACKGROUND

The cysteine proteinases in papaya latex have been shown to have potent anthelmintic properties in monogastric hosts such as rodents, pigs and humans, but this has not been demonstrated in ruminants.

METHODS

In two experiments, sheep were infected concurrently with 5,000 infective larvae of Haemonchus contortus and 10,000 infective larvae of Trichostrongylus colubriformis and were then treated with the supernatant from a suspension of papaya latex from day 28 to day 32 post-infection. Faecal egg counts were monitored from a week before treatment until the end of the experiment and worm burdens were assessed on day 35 post-infection.

RESULTS

We found that the soluble fraction of papaya latex had a potent in vivo effect on the abomasal nematode H. contortus, but not on the small intestinal nematode T. colubriformis. This effect was dose-dependent and at tolerated levels of gavage with papaya latex (117 μmol of active papaya latex supernatant for 4 days), the H. contortus worm burdens were reduced by 98%. Repeated treatment, daily for 4 days, was more effective than a single dose, but efficacy was not enhanced by concurrent treatment with the antacid cimetidine.

CONCLUSIONS

Our results provide support for the idea that cysteine proteinases derived from papaya latex may be developed into novel anthelmintics for the treatment of lumenal stages of gastro-intestinal nematode infections in sheep, particularly those parasitizing the abomasum.

Physiological and morphological effects of genistein against the liver fluke, Fasciola hepatica

A study has been carried out to determine the activity of genistein against adult liver fluke, Fasciola hepatica. Flukes were incubated in vitro in genistein at a concentration of 0.27 mg/ml (=1 mM). They ceased to move after 3 h, at which point the experiment was terminated and the specimens prepared for examination by scanning and transmission electron microscopy. Surface changes to the flukes comprised swelling and blebbing, especially in the posterior region of the flukes, and there was particular disruption to the spines, accompanied by some spine loss. Fine structural changes to the tegumental syncytium indicated an accelerated release of secretory bodies at the surface, but a reduction in their production within the cell bodies. Autophagic activity was evident in the tegumental cells, a phenomenon that was also observed in the gastrodermal cells. Disruption to the testis and vitelline follicles was severe, with an apparent block in the normal developmental sequence of the spermatogenic and vitelline cells, respectively. Shell protein production by the vitelline cells was also disrupted. In separate experiments, somatic muscle strips were exposed to concentrations of genistein ranging from 1 microm to 1 mm. There were statistically significant increases in the frequency and/or amplitude of muscle contractions at concentrations of 10 microm, 100 microm and 1 mm. The results suggest that genistein is capable of causing severe morphological and neuromuscular disruption to adult flukes in vitro over a short time-span.

Triclabendazole progress report, 2005–2009: an advancement of learning?

Triclabendazole (TCBZ) remains the drug of choice for treating infections of the liver fluke,Fasciola hepaticain livestock and has become the main drug used to treat human cases of the disease as well. Cases of resistance in livestock continue to be reported, suggesting that the problem is increasing. In order to address the problem, there is a need for better understanding of drug action. A ‘state-of-play’ review on different aspects of TCBZ activity was published by the present author in 2005. The main purpose of the current review is to assess what progress has been made in the past four years towards understanding the main aspects of drug activity, including drug pharmacokinetics and pharmacodynamics and an understanding of the mechanism(s) of resistance. Also, what advances have been made in identifying alternative compounds and using drug combinations to enhance TCBZ activity. Stemming from a number ofin vivostudies, it has become evident that fluke isolates of differing sensitivity to TCBZ differ in some of their biological parameters, and information on this interesting phenomenon will be presented. An update on the use of TCBZ for human fascioliasis is also given. The review will indicate what progress has been made, but will also highlight areas that remain inadequately understood and require greater research focus.

Developing novel anthelmintics from plant cysteine proteinases

Intestinal helminth infections of livestock and humans are predominantly controlled by treatment with three classes of synthetic drugs, but some livestock nematodes have now developed resistance to all three classes and there are signs that human hookworms are becoming less responsive to the two classes (benzimidazoles and the nicotinic acetylcholine agonists) that are licensed for treatment of humans. New anthelmintics are urgently needed, and whilst development of new synthetic drugs is ongoing, it is slow and there are no signs yet that novel compounds operating through different modes of action, will be available on the market in the current decade. The development of naturally-occurring compounds as medicines for human use and for treatment of animals is fraught with problems. In this paper we review the current status of cysteine proteinases from fruits and protective plant latices as novel anthelmintics, we consider some of the problems inherent in taking laboratory findings and those derived from folk-medicine to the market and we suggest that there is a wealth of new compounds still to be discovered that could be harvested to benefit humans and livestock.