Philippine tsaang gubat (Ehretia microphylla Lam) and ampalaya (Momordica charantia L.) leaf extracts lack amoebicidal activity in vitro

Background@#Amoebiasis is a global health problem affecting poor regions in the world. Few drugs such as metronidazole are available to treat this disease; unfortunately, it is associated with several serious side effects. Tsaang gubat and ampalaya have been used by traditional healers from different cultures to treat dysentery.@*Objective@#The aim of this research was to provide evidence to validate the use of tsaang gubat and ampalaya leaf extracts for dysentery by determining their anti-amoebic activity.@*Methods@#The tsaang gubat and ampalaya leaves were sourced from the University of the Philippines at Los Baños and processed into a lyophilized aqueous extract. Anti-amoebic activity was determined in an in vitro assay using Entamoeba histolytica HK-9 strain against 10 dose levels (18-10,000 μg/mL). The amoeba and leaf extracts were incubated for 24, 48, and 72 hours. The trophozoites were stained with Trypan blue and dispensed into chambers of a Neubauer hemocytometer. The live trophozoites (unstained) were counted under a binocular microscope. The MIC and IC50 were determined. Metronidazole and DMSO served as positive and negative controls, respectively.@*Results@#Tsaang gubat and ampalaya leaves failed to show anti-amoebic activity and even had increased growth of amoeba at all dose levels. The IC50 of tsaang gubat and ampalaya leaf extracts were >500 μg/mL at 24, 48, and 72 hours. Metronidazole was able to eradicate the amoeba parasite at 24 and 72 hours, while exposure to DMSO did not result in inhibition nor death of the parasite.@*Conclusion@#Tsaang gubat and ampalaya aqueous leaf extracts did not exhibit any anti-amoeba activity.

Characterization of the Population Demographics and the MSP-1 Block 2 Allele Gene Frequencies of <i>P. falciparum</i> Infected Individuals in Davao, Philippines

<i>Plasmodium falciparum</i> is one of the causative agents of malaria in humans. This parasite causes the most severe forms of the disease. In order to combat the disease, it is important to have knowledge about the parasite and its interaction with its host. In this study, we profiled 74 patients admitted to hospital in Tagum, Davao, Philippines who were confirmed to be infected with <i>P. falciparum</i>. We correlated the age, sex and parasite load with malaria severity and show that among these, only sex is correlated with disease severity in this population. In addition, we profiled the MSP-1 block 2 allele distribution in the population and found that the most abundant allele form was K1, followed by MAD20. The RO33 allele form was the rarest allele in this population.

Evaluation of blood preservation methods in the performance of the WHO in vitro micro-test for Plasmodium falciparum in the field

In vitro drug susceptibility testing of <I>Plasmodium falciparum</I> must be conducted immediately after collecting a sample of the patient‘s blood; otherwise the parasites may weaken and the culture fail. Collecting blood samples from individuals in areas far from the field station or clinic where in vitro testing is conducted requires a reliable method of sample preservation during transportation. We examined and compared three different methods used to preserve blood samples in endemic areas in the Philippines. The three methods are as follows: the on-site method (test is conducted soon after blood sampling), flask culture method (sample is taken to the laboratory in a culture flask with medium) and EDTA tube method (sample is taken to the laboratory in a blood collection tube). The WHO <I>in vitro</I> micro-test for susceptibility of <I>P. falciparum</I> to chloroquine was performed using an AnaeroPack® system and a portable thermostat incubator. Evaluation of the three methods was based on schizont maturation, ease of handling, and risk of contamination during the test. The on-site and flask culture methods, but not the EDTA tube method, were effective for keeping the parasites viable. Furthermore, schizont maturation appeared better with the flask method than with the on-site method, especially in the control wells (drug-free wells). In addition, it was easier to perform the flask method than the on-site method. No contamination was observed using any of the methods. The results of the study suggest that the flask culture method is the most effective and useful way to preserve blood samples for the in vitro test and, moreover, that it aids in providing detailed field evidence of drug-resistant malaria.