Leshweni Jeremiah Jeremia Shai

Dr. Leshweni Jeremiah Jeremia Shai

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Research Focus & Metrics

Academic Career Length

17Years (2010-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 May 2015 in BMC Complementary and Alternative Medicine
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Journal Article
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SASalmon A. Adebayo
Salmon A. Adebayo
JDJean Paul Dzoyem
Jean Paul Dzoyem
LSLeshweni Jeremiah Jeremia Shai
Leshweni Jeremiah Jeremia Shai
JEJacobus Eloff
Jacobus Eloff
Inflammation is a common risk factor in the pathogenesis of conditions such as infections, arthritis, type 2 diabetes mellitus, obesity and cancer. An ethnobotanical survey of medicinal plants used traditionally to treat inflammation and related disorders such as pain, arthritis and stomach aches in southern Africa led to the selection of 25 plant species used in this study. The antioxidant activities of acetone extracts were determined by measuring the free radical scavenging activity and ferric reducing ability, respectively. The anti-inflammatory activities of the extracts were determined by measuring the inhibitory effect of the extracts on the activities of the pro-inflammatory enzyme, lipoxygenase and inducible nitric oxide synthase. Extracts of Peltophorum africanum had good antioxidant activity with IC50 values of 4.67 ± 0.31 μg/mL and 7.71 ± 0.36 μg/mL compared to that of the positive control ascorbic acid (2.92 ± 0.14 μg/mL and 13.57 ± 0.44 μg/mL), using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and 2,2′-azinobis (3-ethylbenzthiazoline-6-sulphonic acid (ABTS) methods, respectively. The metabolism of linoleic acid to leukotriene derivatives by 15-lipoxygenase (15-LOX) was also inhibited by the crude acetone extracts of Peltophorum africanum (IC50 = 12.42 μg/mL), Zanthoxylum capense (IC50 = 14.92 μg/mL) compared to the positive control quercetin (IC50 = 8.75 μg/mL). There was a poor correlation between the flavonoid content and 15-LOX inhibition by the extracts (R2 = 0.05), indicating that flavonoids are not involved in LOX inhibition. Extracts of Clausena anisata, at a concentration of 6.25 μg/mL inhibited nitric oxide production by RAW 264.7 macrophage cell lines in vitro by 96 %. The extracts of Zanthoxylum capense were the least cytotoxic (IC50 > 1000 μg/mL) when the extract toxicity was determined against Vero (African green Monkey) kidney cell lines. Some plant species used traditionally to treat pain have reasonable anti-inflammatory activity and flavonoids are probably not involved in this process.

12 September 2020 in Foods
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MTMapula Rebahlotse Tshidzumba
Mapula Rebahlotse Tshidzumba
APAnh Dao Phan
Anh Dao Phan
LSLeshweni Jeremiah Jeremia Shai
Leshweni Jeremiah Jeremia Shai
Yasmina SultanbawaYasmina Sultanbawa
Yasmina Sultanbawa
Dharini SivakumarDharini Sivakumar
Dharini Sivakumar
Cowpea is a well-known nutrition rich African leafy vegetable that has potential to sustain food and nutrition insecurity in sub-Saharan Africa. Consumption of cowpea legumes is associated with reduced risk of type 2 diabetes mellitus. Therefore, the present study was designed to evaluate the (i) variation in phenolic metabolites in seven cowpea cultivars (VOP1, VOP2, VOP3, VOP4, VOP5, VOP7, and VOP8 using UHPLC coupled with high resolution Q-TOF-MS technique, (ii) in vitro antioxidant activity using ferric reducing/antioxidant capacity (FRAP) assay (iii) in vitro anti-diabetic effects and (iv) composition of carotenoids and amino acids of theses cowpea cultivars. The results of this study demonstrated that gentisic acid 5-O-glucoside, quercetin 3-(2G-xylosylrutinoside) and Quercetin 3-glucosyl-(1->2)-galactoside were highest in VOP1 VOP4 and VOP5, respectively. High inhibition (>50%) of α-glucosidase and α-amylase activities was shown by the leaf extracts (50 and 25 mg/mL) of VOP1 and VOP4. Cowpea cultivars VOP1 and VOP4 demonstrated the highest gene expression levels of regulation of glucose transporter GLUT4 in C2C12 skeletal muscle cells, similar to insulin. A positive correlation exited between the phenolic components and the inhibitory effect of antidiabetic enzymes and FRAP activity. Cytotoxic effect was not detected in vitro in any cowpea cultivar. Lutein (124.6 mg/100 g) and all-trans-beta-carotene (92.6 mg/100 g) levels were highest in VOP2 and VOP1, respectively. Cowpea cultivars VOP3 and VOP4 showed potential to fulfil the daily requirements of essential amino acids. Thus, based on this information, cowpea (leaves) genotypes/cultivars can be selected and propagated for the further development of supplementary foods or functional food ingredients.

23 December 2024 in Analytical Methods
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OFOmobosede Oluwatoyin Fashedemi
Omobosede Oluwatoyin Fashedemi
OOOkoroike C. Ozoemena
Okoroike C. Ozoemena
SPSiwaphiwe Peteni
Siwaphiwe Peteni
AHAderemi Bashiru Haruna
Aderemi Bashiru Haruna
LSLeshweni Jeremiah Jeremia Shai
Leshweni Jeremiah Jeremia Shai
Kenneth Ikechukwu OzoemenaKenneth Ikechukwu Ozoemena
Kenneth Ikechukwu Ozoemena
This review evaluates various point-of-care (POC) methodologies for HPV detection and highlights the current advancements in POC diagnostic devices.

9 March 2019 in Electrocatalysis
Verified
Journal Article
Closed access
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OOOkoroike C. Ozoemena
Okoroike C. Ozoemena
LSLeshweni Jeremiah Jeremia Shai
Leshweni Jeremiah Jeremia Shai
TMTobile Maphumulo
Tobile Maphumulo
Kenneth Ikechukwu OzoemenaKenneth Ikechukwu Ozoemena
Kenneth Ikechukwu Ozoemena


1 January 2017 in Asian Pacific Journal of Tropical Medicine
Verified
Journal Article
Open access
SASalmon A. Adebayo
Salmon A. Adebayo
LSLeshweni Jeremiah Jeremia Shai
Leshweni Jeremiah Jeremia Shai
JEJacobus Eloff
Jacobus Eloff
To investigate the anti-inflammatory activity of different fractions and glutinol (isolated compound), using nitric oxide synthase and cyclooxygenase (COX) inhibition as an indication of anti-inflammatory activity. Anti-inflammatory activity was evaluated using an in vitro assay determining the inhibition of the activity of pro-inflammatory enzyme model. Cyclooxygenases and inducible nitric oxide synthase are crucial enzymes involved in the pathogenesis of many chronic inflammatory conditions. Sub-fraction F3.3 that was derived from n-hexane fraction of PA leaves significantly inhibited (P = 0.01) the catalytic activity of COX-2 (IC50 = 0.67 μg/mL) better than isolated compound, glutinol (IC50 = 1.22 μg/mL), compound 2 (CP2) (IC50 = 1.71 μg/mL) and sub-fraction F3.3.0 (IC50 = 1.30 μg/mL). A similar trend was observed in investigation of the inhibition of nitric oxide synthesis in RAW 264.7 cells by F3.3, glutinol, CP2 and F3.3.0. Inducible COX-2 and inducible nitric oxide synthase are among potent signalling enzymes that exacerbate inflammation. Bioactive sub-fractions (F3.3 and F3.3.0) derived from the n-hexane fraction of PA had good anti-inflammatory activity, and the isolated compound, and glutinol may be useful as a template for the development of new anti-inflammatory drugs.