Since ancient times, medicinal plants have been crucial in developing powerful therapeutic substances. According to current estimates, 80% of people in developing nations still rely on folk medicine to treat various common health issues. Furthermore, herbal medications are in more significant demand than ever, and their acceptance has grown over time [46, 47].
The pharmacological treatment of trichinellosis is debatable. Albendazole is one of the benzimidazoles and is the drug of choice in trichinellosis treatment. However, albendazole has been linked to various adverse medication responses, including fatalities, encephalitis, seizures, and severe drug eruptions [6, 48].
Additionally, it exhibits a weak susceptibility to migrating and encapsulated muscle larvae [49]. That might explain the urgent need for a new, secure, potent therapy to eradicate Trichinella spp. infection.
Cyperus rotundus, a worldwide herb used in conventional medicine to treat several diseases, is regarded as a plant with infinite medicinal properties validated by the scientific committee [12, 50, 51]. Moreover, C. rotundus has a wide range of safety features. The researchers documented that administering C. rotundus extract orally in rats did not induce acute toxicity, and there was no mortality or behavior changes for subacute toxicity [52].
In the current study, the in vitro anti-trichinellosis potential of the active phytoconstituents of C. rotundus aerial part 90% methanol extract and its derived fractions (EtOAc fr., pet-ether fr., and n-BuOH fr.) were determined. The fraction with the most promising effects was then used to evaluate the in vivo therapeutic effects of C. rotundus.
The preliminary phytochemical screening tests are valuable for investigating the bioactive plant secondary metabolites [53]. C. rotundus 90% MeOH extract, and its derived fractions included high quantities of flavonoids, phenols, sterols, and triterpenoids, which had different pharmacological properties. The previous phytochemical surveys on the different parts of C. rotundus documented the presence of sesquiterpenes, phenylpropanoids, phenolics, alkaloids, flavonoids, and iridoids in rich amounts [12, 19]. These secondary metabolites played an insignificant role in the growth of the plant. However, they were essential for various defense mechanisms against the harmful effects of UV radiation, herbivore, and microbial attack [54].
Phenolics and flavonoids are the major groups of secondary metabolites, especially in plants, and have been considered responsible for various pharmacological activities [55]. Phenolic and flavonoids represent one of the most diverse groups of natural compounds. Therefore, the 90% MeOH ext. of C. rotundus and its derived fractions were analyzed for total phenolic and flavonoid contents in this study. The findings showed that C. rotundus' EtOAc fr. had a higher concentration of phenols and flavonoids than its n-BuOH fr., 90% MeOH ext., and pet-ether fr. It was reported that the concentration of phenolic compounds in plants depended on environmental factors such as light, temperature, and soil salinity. Furthermore, the solubility of phenolic compounds is governed by the kind of extraction and solvent polarity [56]. The previous reports stated that the 70% ethanol extract of dried rhizomes of C. rotundus had a total phenolic content value of 73.27 ± 4.26 mg catechin equivalents/g of dried rhizome extract [57]. In addition, the different extracts of C. rotundus (hexane, petroleum ether, ethyl acetate, chloroform, 70% acetone, 70% ethanol, 70% methanol, and water) were quantitatively analyzed for TPC and TFC. The TPC of the different extracts ranged from 0.0358 ± 0.002 to 118.924 ± 5.946 μg GAE/mg dry extract, and the TFC ranged from 7.196 ± 0.359 to 200.654 ± 10.032 μg quercetin equivalent (QE)/mg dry extract [58]. Other findings showed that the TPC of C. rotundus extracts (70% ethanol, MeOH, and water) ranged from 70.75 ± 4.48 to 254.50 ± 5.26 μg GAE/mg extract. In comparison, the TFC ranged from 51.23 ± 2.62 to 164.34 ± 3.75 μg catechin equivalents (CE)/mg extract [59]. Thus, our investigation proved that the Egyptian C. rotundus extracts had a significant number of phenolics and flavonoids, which could contribute to its promising medicinal properties.
The LC–ESI–MS analysis of the 90% MeOH extract of C. rotundus in negative ion mode revealed the presence of polyphenolic compounds, including phenolic acids, flavonoids (C-glycosyl and O-glycosyl), and organic acids. A detailed description of these identified compounds can be found in the Supplementary data file.
Moreover, to the best of our knowledge, some of these compounds were detected in C. rotundus for the first time, for example, compounds 3, 4, 9, 11, 12, 14, 16, 20, and 24, which encourages us to do further chromatographic isolation for these bioactive ingredients.
To save time and money, it is common practice to assess an agent’s potential anti-parasitic activity in vitro before trying in vivo research. It is not always the case that an agent’s in vivo activity will follow from its in vitro performance. This variance results from various factors, including the pharmacology and bioavailability of these drugs in the host [60].
An effective in vitro agent must be tested additionally in vivo. Therefore, we tested C. rotundus 90% MeOH ext. and its derived fractions (pet-ether fr. EtOAc fr., and n-BuOH fr.) in vitro. The in vitro studies proved that n-BuOH fr. had the most promising effects; as a result, the n-BuOH fr. treated group was subjected to SEM examination. Besides, in vivo testing was carried out for n-BuOH fr. using the murine model.
Regarding the in vitro studies for C. rotundus different extracts, the LC50 was calculated to be 156.12 µg/ml, 294.67 µg/ml, 82.09 µg/ml, and 73.16 µg/ml for 90% MeOH ext., EtOAc fr., pet-ether fr. and n-BuOH fr., respectively.
The in vitro or in vivo anti-parasitic activity of C. rotundus was documented in previous studies. The in vitro anthelmintic activity of C. rotundus against Pheretima posthuma was reported by Kasala et al. [22]. In addition, C. rotundus revealed potent activity against E. histolytica trophozoites in vitro and showed verified safety evidence for use [24].
In Trichinella spp., the cell wall includes the cuticle, hypodermis, and somatic musculature. Cuticle integrity is essential for parasite shape, protection, and nutrition and is necessary for osmoregulation [49].
In this study, electron microscopy scans demonstrated substantial adult worm destruction, loss of the normal morphology in groups treated with n-BuOH fr. and albendazole. It kept its typical appearance when incubated in the culture medium.
Transcuticular passive diffusion is the primary route by which drugs enter nematodes, followed by the worm’s surface being destroyed. Surface blebs indicated effective anti-parasitic activity because they were thought to be the worm’s replacement for its destroyed surface membrane [41, 61].
In the present research, we explored the therapeutic effect of n-BuOH fr. by administering n-BuOH fr., ABZ, and combined treatment (n-BuOH fr. and ABZ). All treated groups notably decreased the adult worm total count compared to the control-infected group. The best results were demonstrated by the group GVa, which received combined therapy and showed the best reduction of adult worms of T. spiralis with an efficacy of 91%, followed by GIIIa, which was administered albendazole with an efficacy of 88%, and GIVa that received n-BuOH fr. with a satisfactory percentage of reduction of 70%.
Concerning how drugs affect the muscle phase, a significant decrease in the mean larval count per gram muscle was reported in all treated groups. The best reduction was found in group GVb, which received combination therapy with an efficacy of 81%, followed by the mice group that received ABZ (GIIIb) with an efficacy of (76%), and the mice group that received n-BuOH fr. (GIVb), with a 65% reduction.
These findings were consistent with the results of Fahmy et al. [25], as they reported that the combined therapies of C. rotundus extract with the standard drugs (nitazoxanide and spiramycin) had the highest effectiveness against murine cryptosporidiosis and toxoplasmosis, respectively, followed by standard medications.
The albendazole effect on T. spiralis was reported in many previous studies, with a variance in efficacy [37, 47, 62, 63]. The variation in the efficacy of albendazole on intestinal and muscular phases was attributed to variance in treatment dose, time, and duration [63].
Albendazole acts mainly by inhibiting microtubule polymerization through selective binding to the parasite beta-tubulin monomer, besides having a small effect on host tubulin binding [64]. However, a study by Siriyasatien et al. [63] concluded that for the early stage of T. spiralis infection, 20 mg/kg albendazole given for 15 days was effective in treating infection in mice, while the late stage of infection was witnessed to be tolerant of albendazole. However, the duration of treatment was longer.
The result was similar to a study by McCracken [65], who documented that the Trichinella population became less susceptible to treatment when the worms matured. Comparing previous results with the results of the current study might explain the promising results found in the groups treated with the combined therapy.
In this study, the infected control group’s small intestinal sections underwent histological evaluation and revealed significant intravillous inflammatory cellular infiltration, primarily composed of lymphocytes and plasma cells. The intestinal villi showed broadening and atrophy. Besides, adult worm fragments were found in the intestinal lumen. The infected control group’s muscle tissue samples showed a massive amount of encysted T. spiralis larvae widely distributed in the sarcoplasm of muscle cells and several chronic inflammatory cells. These results agreed with that of El-Wakil et al. [41] and Dyab et al. [66]. There was an obvious reduction in damaging and inflammatory alterations in the treated groups. The group that received combination therapy had the most promising results in regaining typical architecture, having the fewest cysts with degenerating capsules, and focal pericapsular plasma-lymphocytic inflammatory cellular infiltration.