Absence of Plasmodium falciparum artemisinin resistance gene mutations eleven years after the adoption of artemisinin-based combination therapy in Nigeria.

BACKGROUND: The occurrence of artemisinin resistance (ART)-associated polymorphism of Plasmodium falciparum K13-propeller (pfk13) gene before and after the introduction of artemisinin-based combination therapy (ACT) in two regions of Nigeria was investigated in this study. Regular surveillance is necessary to make a definite conclusion on the emergence and pattern of possible resistance to ART. METHODS: This cross-sectional study was carried out in the Southwestern and Southeastern geopolitical zones of Nigeria. A total of 150, 217, and 475 participants were enrolled for the study in the Southwest (2004_Group A), Southwest (2015_Group B), and southeast (2015_Group C), respectively. Blood samples were collected from the study participants for DNA extraction and a nested PCR for P. falciparum identification. Samples that were positive for P. falciparum were genotyped for the pfk13 gene using the Sanger sequencing method. The single nucleotide polymorphisms were analysed using the Bioedit software. RESULTS: A total of 116, 125, and 83 samples were positive for P. falciparum, respectively for the samples collected from the Southwest (2004 and 2015) and southeast (2015). Parasite DNA samples collected from febrile children in 2004 (Group A; n = 71) and 2015 (Group B; n = 73) in Osogbo Western Nigeria and 2015_Group C (n = 36) in southeast Nigeria were sequenced successfully. This study did not observe mutations associated with the in vitro resistance in southeast Asia, such as Y493H, R539T, I543T, and C580Y. Two new polymorphisms V520A and V581I were observed in two samples collected in Osogbo, Southwest Nigeria. These two mutations occurred in the year 2004 (Group A) before the introduction of ACT. Six mutations were identified in 17% of the samples collected in southeast Nigeria. One of these mutations (D547G) was non-synonymous, while the remaining (V510V, R515R, Q613Q, E688E, and N458N) were synonymous. Also, one (2%) heterozygote allele was identified at codon 458 in the 2015 (Group C) samples. CONCLUSIONS: None of the mutations observed in this study were previously validated to be associated with ART resistance. These results, therefore, suggest that artemisinin is likely to remain highly effective in treating malaria in the study areas that are malarious zone.

Antiulcer Effects of Methanol Extract of Euphorbia hirta and Honey Combination in Rats.

Stomach ulcer is an endemic gastrointestinal disorder which constitutes a major public health problem all over the world. Stomach ulcer results when there is an imbalance between the protective factors (mucus and bicarbonate) and aggressive factors (acid and pepsin) in the stomach. Dried powdered leaves and stem of the phytomedicine Euphorbia hirta (E. hirta) (1000 g) was extracted with methanol using a soxhlet apparatus. The evaluation of the phytochemical constituents of E. hirta and acute toxicity (to ascertain the safety of using the phytomedicine over a short period of time) was carried out. The antiulcer and gastroprotective effects of crude extract of E. hirta combined with honey in rats were evaluated. The study model using 0.6 M HCl model of ulceration was used to evaluate the antiulcer and gastroprotective activities of the phytomedicine. The soxhlet extraction of E. hirta gave a yield of 54.5 g of crude extract (5.45%). Phytochemical screening of E. hirta showed that the extract contains alkaloids, tannins, saponins, glycosides, flavonoids, and unsaturated steroids. Acute toxicity studies showed that LD50 was greater than 5000 mg/kg. The study showed that the crude extract of E. hirta at 200 mg/kg when administered alone had 54% inhibition of ulceration while when administered together with honey increased to 94% inhibition of ulceration, but honey alone had 89.47% inhibition of ulceration. This implied that E. hirta when combined with honey had a synergistic effect and enhanced the inhibition of ulceration, and this could be seen by the protection of the gastric mucosa. The study of the phytomedicine E. hirta combined with honey revealed that the phytomedicine has antiulcer activities against 0.6 M HCl-induced gastric ulcer in rats. This therefore validates usage and claim by the Igbo people of the southeastern part of Nigeria that the phytomedicine of E. hirta combined with honey has good antiulcer potential.