Papers by Olugbenga Popoola
A thesis submitted in partial fulfilment of the requirements for the degree of
Polycyclic Aromatic Compounds, Apr 27, 2022
Plants
Chromatographic fractionation of a methanol extract of Helichrysum rutilans afforded seven known ... more Chromatographic fractionation of a methanol extract of Helichrysum rutilans afforded seven known compounds. The isolated compounds were identified as 5,7,8-trihydroxy-3,6-dimethoxyflavone-8-O-2-methyl-2-butanoate (C-1), 5,7-dihydroxy-3,6,8-trimethoxyflavone (C-2), 5-hydroxy-3,6,7,8-tetramethoxyflavone (C-3), 5-hydroxy-3,6,7-trimethoxyflavone (C-4), ent-kaurenoic acid (C-5), ent-kauran-18-al (C-6), and 15-α-hydroxy-(-)-ent-kaur-16-en-19-oic acid (C-7). Compounds C-1–C-4 demonstrated high antioxidant capacities on ORAC hydroxyl radical (2.114 ± 4.01; 2.413 ± 6.20; 1.924 ± 16.40; 1.917 ± 3.91) × 106; ORAC peroxyl radical (3.523 ± 3.22; 2.935 ± 0.13; 2.431 ± 8.63; 2.814 ± 5.20) × 103 µMTE/g; and FRAP (1251.45 ± 4.18; 1402.62 ± 5.77) µMAAE/g, respectively. Moderate inhibitory activities against Fe2+-induced lipid peroxidation were observed for C-1–C-4 as IC50 values of 13.123 ± 0.34, 16.421 ± 0.92, 11.64 ± 1.72, 14.90 ± 0.06 µg/mL, respectively, while their respective anti-tyrosinase act...
Molecules, 2015
Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chr... more Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chromatographic methods including semi-preparative HPLC afforded three new (1-3) and six known (4-10) acylphloroglucinols alongside a known dialcohol triterpene (11). The structures of the isolated compounds were characterized accordingly as 1-benzoyl-3 (3-methylbut-2-enylacetate)-phloroglucinol (helinivene A, 1), 1-benzoyl-3 (2S-hydroxyl-3methylbut-3-enyl)-phloroglucinol (helinivene B, 2), 8-(2-methylpropanone)-3S,5,7-trihydroxyl-2,2-dimethoxychromane (helinivene C, 3), 1-(2-methylbutanone)-4-O-prenyl-phloroglucinol (4), 1-(2-methylpropanone)-4-O-prennyl-phloroglucinol (5), 1-(butanone)-3-prenyl-phloroglucinol (6), 1-(2-methylbutanone)-3-prenyl-phloroglucinol (7), 1-butanone-3-(3-methylbut-2-enylacetate)phloroglucinol (8), 1-(2-methylpropanone)-3-prenylphloroglucinol (9), caespitate (10), and 3β-24-dihydroxyterexer-14-ene (11). Excellent total antioxidant capacities were demonstrated by helinivenes A and B (1 and 2) when measured as oxygen radicals absorbance capacity (ORAC), ferric-ion reducing antioxidant power (FRAP), trolox equivalent absorbance capacity (TEAC) and including the inhibition of Fe 2+-induced lipid peroxidation (IC50 = 5.12 ± 0.90; 3.55 ± 1.92) µg/mL, while anti-tyrosinase activity at IC50 = 35.63 ± 4.67 and 26.72 ± 5.05 µg/mL were also observed for 1 and 2, respectively. This is the first chemical and in vitro biological study on H. niveum. These findings underpin new perspectives for the
Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chr... more Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chromatographic methods including semi-preparative HPLC afforded three new (1-3) and six known (4-10) acylphloroglucinols alongside a known dialcohol triterpene (11). The structures of the isolated compounds were characterized accordingly as 1-benzoyl-3 (3-methylbut-2-enylacetate)-phloroglucinol (helinivene A, 1), 1-benzoyl-3 (2S-hydroxyl-3methylbut-3-enyl)-phloroglucinol (helinivene B, 2), 8-(2-methylpropanone)-3S,5,7-trihydroxyl-2,2-dimethoxychromane (helinivene C, 3), 1-(2-methylbutanone)-4-O-prenyl-phloroglucinol (4), 1-(2-methylpropanone)-4-O-prennyl-phloroglucinol (5), 1-(butanone)-3-prenyl-phloroglucinol (6), 1-(2-methylbutanone)-3-prenyl-phloroglucinol (7), 1-butanone-3-(3-methylbut-2-enylacetate)phloroglucinol (8), 1-(2-methylpropanone)-3-prenylphloroglucinol (9), caespitate (10), and 3β-24-dihydroxyterexer-14-ene (11). Excellent total antioxidant capacities were demonstrated by helinivenes A and B (1 and 2) when measured as oxygen radicals absorbance capacity (ORAC), ferric-ion reducing antioxidant power (FRAP), trolox equivalent absorbance capacity (TEAC) and including the inhibition of Fe 2+-induced lipid peroxidation (IC50 = 5.12 ± 0.90; 3.55 ± 1.92) µg/mL, while anti-tyrosinase activity at IC50 = 35.63 ± 4.67 and 26.72 ± 5.05 µg/mL were also observed for 1 and 2, respectively. This is the first chemical and in vitro biological study on H. niveum. These findings underpin new perspectives for the
A thesis submitted in partial fulfilment of the requirements for the degree of
Biomedical Journal of Scientific and Technical Research, 2020
This work is licensed under Creative Commons Attribution 4.0 License AJBSR.MS.ID.001571.
Since ancient times, plants with medicinal properties possessing no or little toxicological poten... more Since ancient times, plants with medicinal properties possessing no or little toxicological potentials have been relevant for the treatment of several diseases and healing purposes. Medicinal plants serve as important therapeutic agents and valuable resources for manufacturing numerous modern and traditional medicines. Many developing nations still rely on herbal remedies as their mainstay of health-care. This review study is aimed to report the trado-medicinal values of some ethnobotanical plants commonly used in traditional formulations as well as the scientific investigations of these plants for their acclaimed use in traditional practices. Essential phytochemicals and bioactive compounds of these plants are also reviewed.
Sustainable Food Production
The article reports the amino acid composition of Nigerian beef jerky meat called Kilishi. Kilish... more The article reports the amino acid composition of Nigerian beef jerky meat called Kilishi. Kilishi is consumed dry, hence determination was on dry weight basis. Sample was purchased in Ado-Ekiti, Nigeria. Amino acid values were highest for non-essential amino acid in Glu (14.3 g100g-1) whereas from essential amino acid it was Lys (8.69 g100g-1). Other high value amino acids were (in g100g-1): Asp (8.85), Leu (7.68), Arg (6.02), Ile (4.08), Trp (1.02), Cys (1.18) and His (2.40). P-PER1,2,3 values were superior at values of 2.52 – 2.70. EAAI1 (soybean standard) was 1.23 and EAAI2 (egg standard) was 94.5 with corresponding BV of 91.3. Lys/Trp was very high at 8.55 and Met/Trp was 2.38. Values of TNEAA was 52.1 g100g-1 (57.7%) and TEAA was 38.2 g100g-1(42.3%). In the egg score comparison Ser (0.461) was the limiting amino acid (LAA) with protein corrected digestibility value of 0.338; in provisional EAA scoring pattern, LAA was Val (0.882) and corrected version was 0.742; in pre-school ...
Revista de Chimie
The study determined the levels of heavy metals in some selected cosmetic products, commonly mark... more The study determined the levels of heavy metals in some selected cosmetic products, commonly marketed in Nigeria, and assessed their possible potential human health risks. The health risk assessment was patterned according to the model of the United States Environmental Protection Agency (USEPA). The heavy metals concentrations ranged from 0.043 0.027 (Pb) - 1.89 1.04 (Fe) with the concentration order: Fe]Cu]Zn]Mn]Cr]Cd]Pb. The total daily intake for all the metals were generally below maximum tolerable daily intake (MTDI). The estimated hazard index, hazard quotient and cancer risks were all within allowable level. The study indicated that users of the studied products are less susceptible to any significant health (carcinogenic or non-carcinogenic) risk.
The Natural Products Journal
Background: Antioxidant and antityrosinase activities of medicinal plants, together with their va... more Background: Antioxidant and antityrosinase activities of medicinal plants, together with their various health benefits have received attention in recent times. However, with wide ethnobotanical uses of Phyllanthus amarus, data on in-vitro skin depigmentation activity and cytotoxicity, as well as its impact on mediators of Reactive Oxygen Species (ROS) are still lacking. This present study is, therefore, designed to evaluate its tyrosinase inhibitory action, antioxidant potentials and cytotoxic activities. Methods: In this study, quantitative determination of polyphenols, flavanol, flavonol, flavonoids, Oxygen Reducing Antioxidant Capacity (ORAC), Trolox Equivalent Antioxidant Capacity (TEAC) were performed on the extracts of P amarus. Also, tyrosinase inhibitory efficacy of the hexane, methanol and aqueous extracts of Phyllanthus amarus were evaluated using ELISA-based methods. Cytotoxicity studies were done with mouse Sertoli (TM4) cells, using MTT assay and cell counts. Results: T...
Journal of Agricultural Chemistry and Environment
Background: The study determined the presence and concentration of persistent organochlorine pest... more Background: The study determined the presence and concentration of persistent organochlorine pesticides (OCPs) residues in cow milk from Ekiti State University Agricultural farm in Ado-Ekiti, Nigeria. The study was investigated in order to monitor consumer's exposure to these chemicals pesticides. Methods: Qualitative identification and quantification evaluation of the extracted pesticides after clean-up on silica gel were done with a Gas Chromatography coupled with an Electron Capture Detector (GC-ECD). Results: The results revealed the presence of 11 OCPs residues in the milk samples, with concentration range of 0.001-0.189 mg/l, while α-BHC, endrin, endrin aldehyde, endosulfan II, endosulfan sulphate and methoxychlor were not detected. The analysis of variance revealed no significant variation in the levels of all the analysed pesticides except dieldrin. Conclusion: The hazard indices (HIs) were significantly lower than 1 with the range of 0.00063-0.107, indicating no potential health risk.
The Natural Products Journal
Background: Over exposure to Ultra Violet (UV) radiation is one of the most significant external ... more Background: Over exposure to Ultra Violet (UV) radiation is one of the most significant external stress-inducing factors resulting into occurrence of skin pigmentation among others in human body. The biological implication of such disorders is not only limited to premature skin aging and cancer, but also resulted into economic loss of perishable agricultural products. Methods: Methanol extracts of ten (10) medicinal plants with skin health traditional history were selected for this study. The biological profile of the extracts was assessed in an in-vitro system using colorimetric assays: tyrosinase inhibition, Ferric-ion Reducing Antioxidant Power (FRAP), Trolox Equivalent Absorbance Capacity (TEAC) and Fe II-induced microsomal lipid peroxidation. Results: Representative of asteraceae such as Laggera pterodonta (S3); Ageratum conyzoides (S4) and Chromolaena odorata (S5), while Euphorbia convoluloides (S8) were found to possess good anti- tyrosinase activity (IC50 = 177.50; 125.08; 1...
Biomedical Journal of Scientific & Technical Research
Rooibos (Aspalathus linearis (Brum.f) Dahlg.), is an economic plant of South Africa known to be a... more Rooibos (Aspalathus linearis (Brum.f) Dahlg.), is an economic plant of South Africa known to be a rich source of phytochemicals, including its health beneficial polyphenols thereby ascribed a global recognition in the preparation of herbal tea. In this study, chloroform and ethanol extracts of both green and fermented rooibos were subjected to preliminary phytochemical and thin layer chromatography (TLC) using anti-tyrosinase bio-autographic screening. The most bioactive green rooibos ethanolic extract (GRE) was fractionated using a gradient of TLC-guided column chromatographic method. The constituents of the fractions obtained were identified by analytical highperformance liquid chromatography/ultra-violet detector (HPLC/UV). In vitro biological activities demonstrated by GRE/FRE (fermented rooibos ethanol extract) include: skin depigmentation (85.837 ± 1.722/58.703 ± 4.184 % at 1 mg/mL); Iron (II)-induced lipid peroxidation inhibition (59.170 ± 0.869/42.344 ± 1.655 at 1 mg/mL); ORAC and TEAC (38.653 ± 0.761/10.317 ± 2.722 and 7.320 ± 2.465/2.559 ± 3.601) µM TE/g X 103 and FRAP (6.187 ± 0.014/1.156 ± 0.220) µM AEE/g X 10 3 respectively. Most of the activities demonstrated by GRE were in competitive manner to that of the commercial skin depigmenting agent kojic acid with % inhibition of 99.179 ± 0.945 % at 1 mg/mL and that of antioxidant EGCG with 83.062 ± 0.309 % at same concentration. The results obtained propose the unfermented rooibos to have good antioxidant and tyrosinase inhibitory activity as an indication of having diverse health promoting properties, especially to alleviate the occurrence of diseases associated with oxidative stress thereby promoting its universal acceptability as both economic and medicinal plant.
Sensors
South Africa is a country with a wide variety of plants that may contain excellent anti-tyrosinas... more South Africa is a country with a wide variety of plants that may contain excellent anti-tyrosinase inhibitors. With wide applications in cosmetics, pharmaceuticals and food products, tyrosinase inhibitors have received very special attention in the recent past as a way of preventing the overproduction of melanin in epidermal layers which often over time brings detrimental effects on human skin. In this present study, a fast screening method using a cyclic voltammetry technique was applied in the evaluation of methanolic extracts of twenty-five species of plants from the Lamiaceae family for anti-tyrosinase activity. Among these plants, those that showed a fast current inhibition rate at a minimum concentration when compared to a kojic acid standard were classified as having the greatest anti-tyrosinase activity. These include Salvia chamelaeagnea, S. dolomitica, Plectranthus ecklonii, P. namaensis, and P. zuluensis. The results presented herein focused in particular on providng firs...
Molecules, 2013
The ethno-medicinal approach to drug discovery represents one of the most important sources of ne... more The ethno-medicinal approach to drug discovery represents one of the most important sources of new and safe therapeutic agents to the challenges confronting modern medicine and daily life. Many of the traditionally important medicinal plants contain active molecules or ones that serve as precursors to biosynthesised secondary metabolites to which the biological activity could be attributed. Marrubiin is one such compound and is a potential valuable compound which exists in high concentrations in many traditionally important Lamiaceae species which have demonstrated excellent pharmacological properties with commendably high safety margins. Marrubiin's attributes include a low turnover, high stability and little catabolism, which are core characteristics required for therapeutic compounds and nutraceuticals of economic importance. In addition, marrubiin is considered a potential substrate for potent active compounds viz; marrubiinic acid, and marrubenol. The contribution of marrubiin to drug discovery thus needs to be put into prospective due to its ready availability, high potential applications and ease of modification. In this short review we highlight the most important chemical and pharmacological aspects reported on marrubiin since it was discovered.
Chinese Chemical Letters, 2014
ABSTRACT The novel coordination structures of europium and terbium chloride-picolinamide complexe... more ABSTRACT The novel coordination structures of europium and terbium chloride-picolinamide complexes (EuCl3·(C6H6N2O)2·5H2O, Eu-pa and TbCl3·(C6H6N2O)2·5H2O, Tb-pa) are reported. The crystal structures in the solid state are characterized by X-ray single crystal diffraction, FTIR, Raman, FIR, THz and Luminescence spectroscopy. In the crystal structures, the pyridyl nitrogen and carbonyl oxygen atoms in picolinamide are coordinated to the metal ions to form a five-membered ring structure. The experimental results indicate the similar coordination structures of Eu and Tb-pa complexes and the changes of hydrogen bonds and conformation of the ligands induced by complexation. The results provide models for the coordination structures of lanthanide ions with ligands having amide groups.
Molecules, 2015
Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chr... more Phytochemical investigation of aerial parts of Helichrysum niveum (H. niveum) using different chromatographic methods including semi-preparative HPLC afforded three new (1-3) and six known (4-10) acylphloroglucinols alongside a known dialcohol triterpene (11). The structures of the isolated compounds were characterized accordingly as 1-benzoyl-3 (3-methylbut-2-enylacetate)-phloroglucinol (helinivene A, 1), 1-benzoyl-3 (2S-hydroxyl-3-methylbut-3-enyl)-phloroglucinol (helinivene B, 2), 8-(2-methylpropanone)-3S,5,7-trihydroxyl-2,2-dimethoxychromane (helinivene C, 3), 1-(2-methylbutanone)-4-O-prenyl-phloroglucinol (4), 1-(2-methylpropanone)-4-O-prennyl-phloroglucinol (5), 1-(butanone)-3-prenyl-phloroglucinol (6), 1-(2-methylbutanone)-3-prenyl-phloroglucinol (7), 1-butanone-3-(3-methylbut-2-enylacetate)-phloroglucinol (8), 1-(2-methylpropanone)-3-prenylphloroglucinol (9), caespitate (10), and 3β-24-dihydroxyterexer-14-ene (11). Excellent total antioxidant capacities were demonstrated by ...
Molecules (Basel, Switzerland), Jan 20, 2015
Ten flavonoid-related structures viz. heliteretifolin (1), isoxanthohumol (2), 2',4',6... more Ten flavonoid-related structures viz. heliteretifolin (1), isoxanthohumol (2), 2',4',6'-trihydroxy-3'-prenylchalcone (3), isoglabranin (4), glabranin (5), 7-methoxy-isoglabranin (6), quercetin (7), 4'-methoxyquercetin (8), 4'-methoxykaempferol (9) and mosloflavone (10) were isolated from a H. teretifolium methanolic extract and identified. One of them (compound 1) is reported for the first time from a natural source, while compounds 6, 8-10 were isolated for the first time from the genus Helichrysum. The total extract of H. teretifolium showed potent antioxidant activity. When tested for total antioxidant capacity compound 3 possesses moderate biological activity compared to 2, which displayed some of the highest TEAC values (4529.01 ± 2.44; 4170.66 ± 6.72) µM TE/g, respectively. Compounds 7 and 8 demonstrated the highest inhibitory activities on Fe2+-induced lipid peroxidation (IC50 = 2.931; 6.449 µg/mL); tyrosinase (8.092; 27.573) and elastase (43.342; 86.5...
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Papers by Olugbenga Popoola