In vitro antiplasmodial activity, cytotoxicity, and gas chromatography - flame ionization detector metabolites fingerprint of extracts and fractions from Tetrorchidium didymostemon.

BACKGROUND: Tetrorchidium didymostemon is used as an antimalarial remedy in southern Nigeria. OBJECTIVE(S): This study was aimed at providing scientific validation for the use of T. didymostemon in the treatment of malaria in Nigeria. MATERIALS AND METHODS: Plasmodium falciparum 3D7 (Pf3D7) strain was cultured and maintained in fresh O+ human erythrocytes. Standard methods were used to evaluate in vitro antiplasmodial activity, cytotoxic effect on Vero cell line, phytochemical screening, and antioxidant capacity. Gas Chromatography - Flame Ionization Detector (GC-FID) metabolite fingerprinting of the most potent fraction was carried out. RESULTS: The methanol leaf extract had higher antiplasmodial activity (IC50Pf3D7 = 25 ± 0.21 µg/mL) in comparison with the stem bark extract (SBE) (IC50Pf3D7 = 50 ± 0.94 µg/mL). The n-hexane fraction of the leaf extract had the best antiplasmodial activity (IC50Pf3D7 = 3.92 ± 0.46 µg/mL) and selectivity index. This was followed by the dichloromethane (IC50Pf3D7 = 12.5 ± 1.32 µg/mL), ethyl acetate (IC50Pf3D7 = 35.0 ± 4.80 µg/mL), and hydromethanol fraction which was inactive (IC50Pf3D7 > 100 µg/mL). All extracts and fractions were not toxic on Vero cell line (CC50 > 1000 µg/mL). The n-hexane and dichloromethane fractions had the highest amount of phytochemicals. GC-FID analysis revealed high amounts of kaempferol, α-pinene, camphor, humulene, azulene, and ß-caryophyllene in the n-hexane fraction. CONCLUSION: The results of our study validate the traditional use of T. didymostemon in the treatment of malaria in southern Nigeria. They also suggest that the phytoconstituent(s) responsible for the antiplasmodial activity of this plant may be more extractable in non-polar solvents.

Evaluating the impact of COVID-19 pandemic lockdown on education in Nigeria: Insights from teachers and students on virtual/online learning.

BACKGROUND: As in many countries worldwide, due to the COVID-19 pandemic lockdown, higher institutions in Nigeria closed in March 2020 and only began reopening in October of the same year. As a result of the lockdown, some higher institutions had to quickly move from the traditional face-to-face teaching method to virtual learning. This study aimed to investigate the impact of COVID-19 lockdown on education in Nigeria and also provide recommendations that may be useful in developing remote teaching contingency strategies. Five-point Likert-scale questionnaire targeting students and teachers separately was designed to get feedbacks from both students and teachers on their experiences, issues and successes. The questionnaires were divided into five categories: virtual classrooms, course learning outcomes, alternative method of assessment, impact of online teaching and satisfaction. RESULTS: A total of 703 students and 60 teachers from five different local universities participated in this study. All participants (> 50%) had difficulties with Internet connection. Students (67%) as well as teachers (59%) agree that they had limited interactions with one another and this negatively influence student's satisfaction (p < 0.01). While students were split on the most appropriate method of assessment, teachers (63%) believe assignments and oral examinations are more suitable for online teaching. Many teachers (66%) admitted that it was difficult assessing students' abilities and performance. Some students (> 40%) were concerned about the number of assignments given. Most teachers (84%) believe there is an increase in tendency for examination malpractice when assessment was conducted virtually. Students had significantly (p < 0.05) higher marks in all courses during online assessment compared to previous session involving face-to-face teaching. About 83% of teachers admitted it was difficult explaining complex scientific concepts. CONCLUSION: Based on the results of this study, we provided recommendations to help educational institutions in Nigeria develop remote teaching contingency strategies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s42269-021-00538-6.

Evaluation of the Phenolic Content, Antioxidant and Antimicrobial Activities of Oil and Non-Oil Extracts of Citrus sinensis (L.) Osbeck Seeds.

The seeds of Citrus sinensis (L.) Osbeck (sweet orange) are waste products usually discarded. They may however contain phytochemicals that have potent bioactivities. In this study, the phenolic content, and antioxidant and antimicrobial activities of oil and non-oil (solid) extracts of C. sinensis seeds were evaluated using standard protocols. The seed oil contained significantly (P>0.05) higher contents of total phenol and total flavonoid when compared to the solid extract. However, the non-oil extract contained significantly (P<0.05) higher tannin contents than the seed oil. Ferric reducing antioxidant potential was not significantly different between both extracts. The antimicrobial activities of both extracts revealed that the seed oil possesses better antibacterial activities compared to the non-oil extract. The antifungal test revealed that the seed oil significantly inhibited the growth of Candida albicans (20 mm zone of inhibition at a concentration of 200 µg/mL), however, it did not inhibit the growth of Aspergillus niger and Penicillum sp. The minimum inhibitory concentration values against the bacterial and fungal strains were similar for both extracts in the range of 50∼100 µg/mL. Minimum bactericidal concentration and minimum fungicidal concentration values ranged from 100∼200 µg/mL for both extracts. The results in this study indicate that C. sinensis seed oil and non-oil extracts possess antioxidant, and antibacterial and antifungal properties that may be differentially exploited in the development of antimicrobial agents.

Sub-acute toxicity study of methanol extract of Tetrorchidium didymostemon leaves using biochemical analyses and gene expression in Wistar rats.

Tetrorchidium didymostemon is widely used by traditional medicine practitioners to manage and treat several diseases. Despite its known ethnomedicinal uses, there are no scientific studies on the toxic effects of this plant. This study was performed to evaluate the potential toxicity of methanol extracts Tetrorchidium didymostemon leaves through sub-acute oral administration in rats. Twenty four (24) male albino rats (Wistar strain) of average weight 150 ± 20 g were randomly divided into 4 groups of 6 rats each. Group 1 was the control while groups 2, 3 and 4 were administered 100, 300 and 600 mg/kg body weight of the plant extracts respectively for 14 consecutively days. The extract did not induce any treatment related changes in body weight, organ/body weight ratio, biochemical parameters (aspartate transaminase, alanine transaminase, total protein, albumin, creatinine and urea), oxidative stress indices (malondialdehyde, superoxide dismutase and reduced glutathione) and histopathology (liver and kidney) of the treated groups when compared to the control. However, at 600 mg/kg body weight dose, the extract caused a significant (p < 0.05) decrease in hemoglobin level, packed cell volume and the expression of albumin gene of rats. Similarly, at 300 and 600 mg/kg body weight, the extract also caused a non-significant (p > 0.05) decrease in red blood cell count. Furthermore, the extract at 100 and 300 mg/kg body weight induced a significant (p < 0.05) increase in the expression of tumor necrosis factor - alpha and kidney injury molecule - 1 (KIM-1) genes. Catalase gene expression especially in the kidney was up-regulated in the groups administered the extract. Our study suggests that oral administration of T. didymostemon leaves extract is relatively safe. However, there is need for caution due to the observed changes in hematological profile, up-regulation of KIM-1 genes as well as down regulation of albumin gene.

Therapeutic failure after regimen with artemether-lumefantrine combination therapy: a report of three cases in Benin City, Nigeria.

Artemisinin-based combination therapy (ACT) is recommended by the World Health Organization for the treatment of uncomplicated malaria. Currently, there appears to be a downward trend in the efficacy of ACT in some parts of sub-Saharan Africa because some patients have been positive for Plasmodium parasite 3 days after artemether-lumefantrine treatment. We reported three cases of possible parasite resistance to artemether-lumefantrine therapy. All subjects had complete parasite clearance when treated with other antimalarial drugs. This observation necessitates the urgent need to re-evaluate artemether-lumefantrine medication in Nigeria since it is one of the most commonly used ACT drug.

Therapeutic failure after regimen with artemether-lumefantrine combination therapy: a report of three cases in Benin City, Nigeria

Abstract Artemisinin-based combination therapy (ACT) is recommended by the World Health Organization for the treatment of uncomplicated malaria. Currently, there appears to be a downward trend in the efficacy of ACT in some parts of sub-Saharan Africa because some patients have been positive for Plasmodium parasite 3 days after artemether-lumefantrine treatment. We reported three cases of possible parasite resistance to artemether-lumefantrine therapy. All subjects had complete parasite clearance when treated with other antimalarial drugs. This observation necessitates the urgent need to re-evaluate artemether-lumefantrine medication in Nigeria since it is one of the most commonly used ACT drug.