Anthelmintic Activity and Cytotoxic Effects of Compounds Isolated from the Fruits of Ozoroa insignis Del. (Anacardiaceae)

Ozoroa insignis Del. is an ethnobotanical plant widely used in traditional medicine for various ailments, including schistosomiasis, tapeworm, and hookworm infections. From the so far not investigated fruits of Ozoroa insignis, the anthelmintic principles could be isolated through bioassay-guided isolation using Caenorhabditis elegans and identified by NMR spectroscopic analysis and mass spectrometric studies. Isolated 6-[8(Z)-pentadecenyl] anacardic (1), 6-[10(Z)-heptadecenyl] anacardic acid (2), and 3-[7(Z)-pentadecenyl] phenol (3) were evaluated against the 5 parasitic organisms Schistosoma mansoni (adult and newly transformed schistosomula), Strongyloides ratti, Heligmosomoides polygyrus, Necator americanus, and Ancylostoma ceylanicum, which mainly infect humans and other mammals. Compounds 1–3 showed good activity against Schistosoma mansoni, with compound 1 showing the best activity against newly transformed schistosomula with 50% activity at 1µM. The isolated compounds were also evaluated for their cytotoxic properties against PC-3 (human prostate adenocarcinoma) and HT-29 (human colorectal adenocarcinoma) cell lines, whereby compounds 2 and 3 showed antiproliferative activity in both cancer cell lines, while compound 1 exhibited antiproliferative activity only on PC-3 cells. With an IC50 value of 43.2 µM, compound 3 was found to be the most active of the 3 investigated compounds.

Gambaran Profil dan Infeksi Cacing Usus pada Pekerja di Tiga Rumah Potong Hewan Provinsi Riau

Background: Intestinal worm infestation is still a health problem in Indonesia that is often neglected. This disease is chronic in nature and is strongly influenced by factors of environmental hygiene and sanitation. Slaughterhouses are places where animals in the form of cows, goat/ sheep and pigs are slaughtered to be distributed to meat sellers or to reataurants. This study aims to determine the profil description and incidence of intestinal worm infestations in workers in three slaughterhouses in Riau Province.Methods: This study was a cross-sectional descriptive study in August – October 2020 in three slaughterhouses in Riau Province ( Pekanbaru, Duri and Dumai city). Stool examination was carried out using the Kato Katz Method at the Parasitology Laboratory Medical Faculty, Universitas Riau. Result: Do A total 37 workers who were examined found 35 men, age range 21 – 30 yo as much as 38% with latest education 46% was high school, length of work 1 – 5 years as much as 57% and as much as 41% have normal nutriotional status. Six workers found positive for intestinal worm infections (16%), there were three hookworm infections and one each to Trichuris trichiura, Oxyuris vermicularis and Hymenolepis diminuta.Conclusion : There were still intestinal worm infections among workers in the three slaughterhouses. Intestinal worm infection usually occurs in children and rarely occurs in adults and if it occurs in adults this may be due to poor hygiene and sanitation of the slaughterhouse workers.

Morphological and Molecular Diagnosis of Necator americanus and Ancylostoma ceylanicum Recovered from Villagers in Northern Cambodia

Human hookworm infections caused by adult <i>Ancylostoma</i> spp. and <i>Necator americanus</i> are one of the most important tropical diseases. We performed a survey of intestinal helminths using the Kato-Katz fecal examination technique targeting 1,156 villagers residing in 2 northern provinces (Preah Vihear and Stung Treng) of Cambodia in 2018. The results revealed a high overall egg positive rate of intestinal helminths (61.9%), and the egg positive rate of hookworms was 11.6%. Nine of the hookworm egg positive cases in Preah Vihear Province were treated with 5-10 mg/kg pyrantel pamoate followed by purging with magnesium salts, and a total of 65 adult hookworms were expelled in diarrheic stools. The adult hookworms were analyzed morphologically and molecularly to confirm the species. The morphologies of the buccal cavity and dorsal rays on the costa were observed with a light microscope, and the nucleotide sequences of mitochondrial cytochrome <i>c</i> oxidase subunit 1 (<i>cox</i>1) gene were analyzed. The majority of the hookworm adults (90.7%) were <i>N. americanus</i>, whereas the remaining 9.3% were <i>Ancylostoma ceylanicum</i>, a rare hookworm species infecting humans. The results revealed a high prevalence of hookworm infections among people in a northern part of Cambodia, suggesting the necessity of a sustained survey combined with control measures against hookworm infections.

Pharmacometric analysis of tribendimidine mono- and combination therapies to achieve high cure rates in patients with hookworm infections

To treat hookworm infections, pharmacotherapy has been only moderately successful and drug resistance is a threat. Therefore, novel treatment options including combination therapies should be considered, in which tribendimidine could play a role. Our aims were to (i) characterize the pharmacokinetics of tribendimidine's metabolites in adolescents receiving tribendimidine monotherapy, or a combination with ivermectin or oxantel pamoate, (ii) evaluate possible drug-drug interactions (DDI), (iii) link exposure to response, aiming to (iv) identify a treatment strategy associated with high efficacy, i.e. >90% cure rates (CRs), utilizing model-based simulations. A population pharmacokinetic model was developed for tribendimidine's primary and secondary metabolites dADT and adADT in 54 hookworm-positive adolescents, with combination therapy evaluated as possible covariate. Subsequently, an exposure-response analysis was performed utilizing CRs as response markers. Simulations were performed to identify a treatment strategy to achieve >90% CRs. A two-compartmental model best described metabolite disposition. No pharmacokinetic DDI was identified with ivermectin or oxantel pamoate. All participants receiving tribendimidine plus ivermectin were cured. For the monotherapy and combination with oxantel pamoate arm, Emax models adequately described the correlation between dADT exposure and probability to be cured, with a required exposure to achieve 50% of maximum effect of 39.6 and 15.6 nmol/mL*h, respectively. Based on our simulations an unrealistically high monotherapy tribendimidine dose would be necessary to achieve CRs >90%, while combination therapy with ivermectin would meet this desired target product profile. Further clinical studies should be launched to develop this combination for the treatment of hookworm and other helminth infections.

Population pharmacokinetics and exposure-response analysis of tribendimidine to improve treatment for children with hookworm infection

Tribendimidine has been successful in treating hookworm infections and may serve as alternative to albendazole should resistance arise. Our aims were to (i) characterize the pharmacokinetics (PK) of tribendimidine's primary metabolite deacetylated amidantel (dADT) and secondary metabolite, acetylated derivative of amidantel (adADT) in school-aged children and adolescents, (ii) link exposure to efficacy against hookworm, and (iii) evaluate whether tribendimidine pharmacotherapy in children could be further improved. First, a population PK model was developed based on dried-blood-spot samples collected in 155 school-aged children and adolescents with hookworm infections, following tribendimidine doses ranging from 100-400 mg. Second, an exposure-response analysis was conducted to link the active metabolite dADT to cure rates (CRs) and egg reduction rates (ERRs). Third, simulations were performed to identify a treatment strategy associated with >90% CRs. A two-compartmental model with transit compartments describing observed delay in absorption adequately described PK data of dADT and adADT. Allometric scaling was included to account for growth and development. The absorption rate was 56% lower with 200-mg tablets compared with 50 mg tablets, while the extent of absorption remained unaffected. The identified Emax models linking dADT exposure to ERRs and CRs showed shallow curves, as increasing exposure leads to marginal efficacy increase. Combination therapy should be considered as a 12-fold higher dose would be needed to achieve 95% ERRs and CRs >90% with tribendimidine alone. Further studies are warranted to evaluate safety of higher tribendimidine doses and combination therapies with other anthelmintic agents to improve treatment strategy for children with hookworm infection.

A Randomized Controlled Trial to Investigate Safety and Variability of Egg Excretion After Repeated Controlled Human Hookworm Infection

Background Controlled human hookworm infections could significantly contribute to the development of a hookworm vaccine. However, current models are hampered by low and unstable egg output, reducing generalizability and increasing sample sizes. This study aims to investigate the safety, tolerability, and egg output of repeated exposure to hookworm larvae. Methods Twenty-four healthy volunteers were randomized, double-blindly, to 1, 2, or 3 doses of 50 Necator americanus L3 larvae at 2-week intervals. Volunteers were monitored weekly and were treated with albendazole at week 20. Results There was no association between larval dose and number or severity of adverse events. Geometric mean egg loads stabilized at 697, 1668, and 1914 eggs per gram feces for the 1 × 50L3, 2 × 50L3, and 3 × 50L3 group, respectively. Bayesian statistical modeling showed that egg count variability relative to the mean was reduced with a second infectious dose; however, the third dose did not increase egg load or decrease variability. We therefore suggest 2 × 50L3 as an improved challenge dose. Model-based simulations indicates increased frequency of stool sampling optimizes the power of hypothetical vaccine trials. Conclusions Repeated infection with hookworm larvae increased egg counts to levels comparable to the field and reduced relative variability in egg output without aggravating adverse events. Clinical Trials Registration NCT03257072.