Antioxidant and Anticholinesterase Potential of Two Nigerian Bitter Yams Using a Simulated Gastrointestinal Digestion Model and Conventional Extraction

Salawu, Sule Ola,Ajiboye, Praise Blessing,Akindahunsi, Akintunde Afolabi,Boligon, Aline Augusti The Korean Society of Food Science and Nutrition 2017 Preventive Nutrition and Food Science Vol.22 No.2

The purpose of this study was to evaluate the antioxidant and anticholinesterase activities of yellow and white bitter yams from South Western Nigeria using methanolic extraction and simulated gastrointestinal digestion models. The phenolic compounds in the bitter yam varieties were evaluated by high performance liquid chromatography with a diode array detector (HPLC-DAD). The total phenolic content of the bitter yams was measured by the Folin-Ciocalteu method, reductive potential by assessing the ability of the bitter yam to reduce $FeCl_3$ solution, and the antioxidant activities were determined by the 2,2-diphenyl-1-picrylhydrazyl radical ($DPPH^{\cdot}$) scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation ($ABTS^{{\cdot}+}$) scavenging activity, nitric oxide radical ($NO^{\cdot}$) scavenging ability, hydroxyl radical scavenging ability, and ability to inhibit $Fe^{2+}$-induced lipid oxidation. The HPLC-DAD analysis revealed the presence of some phenolic compounds in the studied bitter yam varieties, with varying degree of quantitative changes after cooking. The antioxidant indices (total phenolic content, total flavonoid content, reducing power, $DPPH^{\cdot}$ scavenging activity, $ABTS^{{\cdot}+}$ scavenging activity, and $NO^{\cdot}$ scavenging activity) were higher in the simulated gastrointestinal digestion model compared to the methanolic extract, with the in vitro digested cooked white bitter yam ranking higher. Similarly, the in vitro digested yams had a higher inhibitory action against lipid oxidation compared to the methanolic extracts, with the cooked white bitter yam ranking high. The methanolic extracts and in vitro enzyme digests showed no acetylcholinesterase inhibitory abilities, while methanolic extracts and the in vitro enzyme digest displayed some level of butyrylcholinesterase inhibitory activities. Therefore the studied bitter yams could be considered as possible health supplements.

A PHOTOVOLTAIC WATER PUMPING SYSTEM FOR IRRIGATION

SALAWU, R. I.,GIWA, H. A. T. 慶熙大學校 材料科學技術硏究所 1989 材料科學技術硏究論集 Vol.2 No.-

A converter-coupled photovoltaic system using transistor switching unit is presented. This type of converter-coupled is exceptionally useful for pumping applications employing the cage motor as the pump driver (as in most submersible pumps). The Unit consists of a 200W silicon photovoltaic array, a 220W separately-excited converter, and a 210W centrifugal pump. The system performance, though limited by the size of the panels available, is shown to be satisfactory. The measured results compare favourably with simulated ones.

SOLAR ENERGY APPLICATIONS IN SUB-SAHARA AFRICA

SALAWU, R. I. 慶熙大學校 材料科學技術硏究所 1989 材料科學技術硏究論集 Vol.2 No.-

Protective Effect of Some Tropical Vegetables Against CCl4 -Induced Hepatic Damage

S.O. Salawu,A.A. Akindahunsi 한국식품영양과학회 2007 Journal of medicinal food Vol.10 No.2

Antioxidant and Anticholinesterase Potential of Two Nigerian Bitter Yams Using a Simulated Gastrointestinal Digestion Model and Conventional Extraction

Sule Ola Salawu,Praise Blessing Ajiboye,Akintunde Afolabi Akindahunsi,Aline Augusti Boligon 한국식품영양과학회 2017 Preventive Nutrition and Food Science Vol.22 No.2

The purpose of this study was to evaluate the antioxidant and anticholinesterase activities of yellow and white bitter yams from South Western Nigeria using methanolic extraction and simulated gastrointestinal digestion models. The phenolic compounds in the bitter yam varieties were evaluated by high performance liquid chromatography with a diode array detector (HPLC-DAD). The total phenolic content of the bitter yams was measured by the Folin-Ciocalteu method, reductive potential by assessing the ability of the bitter yam to reduce FeCl₃ solution, and the antioxidant activities were determined by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·) scavenging activity, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS<SUP>·+</SUP>) scavenging activity, nitric oxide radical (NO<SUP>·</SUP>) scavenging ability, hydroxyl radical scavenging ability, and ability to inhibit Fe<SUP>2+</SUP>-induced lipid oxidation. The HPLC-DAD analysis revealed the presence of some phenolic compounds in the studied bitter yam varieties, with varying degree of quantitative changes after cooking. The antioxidant indices (total phenolic content, total flavonoid content, reducing power, DPPH<SUP>·</SUP> scavenging activity, ABTS<SUP>·+</SUP> scavenging activity, and NO<SUP>·</SUP> scavenging activity) were higher in the simulated gastrointestinal digestion model compared to the methanolic extract, with the in vitro digested cooked white bitter yam ranking higher. Similarly, the in vitro digested yams had a higher inhibitory action against lipid oxidation compared to the methanolic extracts, with the cooked white bitter yam ranking high. The methanolic extracts and in vitro enzyme digests showed no acetylcholinesterase inhibitory abilities, while methanolic extracts and the in vitro enzyme digest displayed some level of butyrylcholinesterase inhibitory activities. Therefore the studied bitter yams could be considered as possible health supplements.

Mineral Elements Bio-Accessibility and Antioxidant Indices of Blanched Basella rubra at Different Phases of in vitro Gastrointestinal Digestion

Sule Ola Salawu,Bukola Eugenia Olukemi,Ikuosho Charity Asikhia,Akintunde Afolabi Akindahunsi 한국식품영양과학회 2018 Preventive Nutrition and Food Science Vol.23 No.1

The present investigation was designed to evaluate the mineral element bio-accessibility and antioxidant indices of blanched Basella rubra at different phases of simulated in vitro digestion (oral, gastric, and intestinal). The phenolic composition of processed vegetable was determined using high-performance liquid chromatography (HPLC)-diode-array detection method. Mineral composition, total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), and total antioxidant activity (TAA) of the in vitro digested blanched and raw vegetable were also determined. HPLC analysis revealed the presence of some phenolic compounds, with higher levels (mg/g) of polyphenols in raw B. rubra (catechin, 1.12; p-coumaric acid, 6.17; caffeic acid, 2.05) compared with the blanched counterpart, with exeption of chlorogenic acid (2.84), that was higher in blanched vegetable. The mineral content (mg/100 g) showed a higher value in enzyme treated raw vegetable compared to their blanched counterparts, with few exceptions. The results revealed a higher level of some of the evaluated minerals at the intestinal phase of digestion (Zn, 6.36/5.31; Mg, 5.29/8.97; Ca, 2,307.69/1,565.38; Na, 5,128/4,128.21) for raw and blanched respectively, with the exception of Fe, K, and P. The results of the antioxidant indices of in vitro digested B. rubra revealed a higher value at the intestinal phase of in vitro digestion, with raw vegetal matter ranking higher (TPC, 553.56 mg/g; TFC, 518.88 mg/g; FRAP, 8.15 mg/g; TAA, 5,043.16 μM Trolox equivalent/g) than the blanched counterpart. The studied vegetable contains important minerals and antioxidant molecules that would be readily available after passing through the gastrointestinal tract and could be harnessed as functional foods.

Specific Domain Pattern of ε-Fe₂O₃ Thin Films Grown on Yttrium-Stabilized Zirconia (100) as a Nucleation Site for α-Fe₂O₃

Viet, Vu Quoc,Adeyemi, Salawu Yusuff,Son, Won Huyk,Rhyee, Jong-Soo,Lee, Nam-Suk,Kim, Heon-Jung American Chemical Society 2018 Crystal Growth & Design Vol.18 No.6

<P>This study examined the phase competition and critical thickness of ε-Fe<SUB>2</SUB>O<SUB>3</SUB> in epitaxial ε-Fe<SUB>2</SUB>O<SUB>3</SUB> thin films grown on a (100)-oriented yttrium-stabilized zirconia (YSZ) substrate using a pulsed laser deposition technique. The maximum critical thickness was found to be ∼20 nm for a single phase of ε-Fe<SUB>2</SUB>O<SUB>3</SUB> at the optimal laser spot size without impurities. Above this critical thickness, (00l)-oriented α-Fe<SUB>2</SUB>O<SUB>3</SUB> begins to appear along with ε-Fe<SUB>2</SUB>O<SUB>3</SUB>, eventually dominating in the thicker samples. These results suggest that the stability of ε-Fe<SUB>2</SUB>O<SUB>3</SUB> films are influenced by the appearance of a specific domain pattern, which becomes a favorable nucleation site for α-Fe<SUB>2</SUB>O<SUB>3</SUB>. The ε-Fe<SUB>2</SUB>O<SUB>3</SUB> films grown on the YSZ (100) substrate have a larger saturation moment than ε-Fe<SUB>2</SUB>O<SUB>3</SUB> grown on SrTiO<SUB>3</SUB> (111), and its coercive field approaches 1/4 of the maximum coercive field of ε-Fe<SUB>2</SUB>O<SUB>3</SUB> nanoparticles.</P><P>Plane view of ε-Fe<SUB>2</SUB>O<SUB>3</SUB> and α-Fe<SUB>2</SUB>O<SUB>3</SUB> unit cells on a YSZ (001) substrate oriented along the <I>c</I>-direction. Edge structure of two ε-Fe<SUB>2</SUB>O<SUB>3</SUB> domains sharing a horizontal line is a possible nucleation site for α-Fe<SUB>2</SUB>O<SUB>3</SUB>. Formation of this structure limits stable growth of ε-Fe<SUB>2</SUB>O<SUB>3</SUB> on the YSZ (001)</P> [FIG OMISSION]</BR>

Formation of CaCO3 from calcium sources with different anions in single process of CO2 capture-mineralization

문대현,Arti Murnandari,Omotayo Salawu,이찬우,이원희,김영은,박기태,이지은,Jun Eo,정순관,윤민혜 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.10

The single process CO2 capture-mineralization approach integrates methods of CO2 absorption using aqueous solvents and mineral carbonation technology to not only remove carbon dioxide quickly, but also to simultaneously produce precipitated calcium carbonate (PCC). To develop a more sustainable process, it is important to extract calcium from inexpensive raw materials such as industrial by-products. The extractant has a significant effect on the quality of the calcium carbonate produced because it determines the anion paired with the calcium cation. In this work, several calcium sources with different anions (Propionate, Acetate, Nitrate and Chloride) were applied in the single process CO2 capture-mineralization method, and their influence on the polymorph of the obtained CaCO3 was investigated. The CaCO3 produced with inorganic calcium sources predominantly exhibited a calcite structure, while the CaCO3 produced with organic calcium sources had a structure in which vaterite and calcite coexist. This result was in good agreement with our DFT calculations, which indicated the adsorption energy of the organic anions (Propionate and Acetate) were lower than the inorganic anions on the surface of vaterite. Except for chloride with its non-polar nature, in most cases, there was a strong correlation between the polymorph and the adsorption energy calculated for each surface. A mechanism for the polymorph CaCO3 formation in our single process CO2 capture-mineralization method was proposed after observing crystal formation at low concentration.

HPLC-DAD Phenolic Profiling and In Vitro Antioxidant Activities of Three Prominent Nigerian Spices

Olufunmilayo Sade Omoba,Aderonke Ibidunni Olagunju,Sule Ola Salawu,Aline Augusti Boligon 한국식품영양과학회 2019 Preventive Nutrition and Food Science Vol.24 No.2

Spices and herbs have antioxidant, anti-inflammatory, and anti-microbial properties, amongst others. These characteristics are attributable to their composition, such as high polyphenol and flavonoid contents that are responsible for their antioxidative properties. Methanolic extracts of Ocimum basilicum (OB), Xylopia aethiopica (XA), and Piper guineensis (PG) were evaluated to profile their phenolic compounds and in vitro antioxidant properties. High performance liquid chromatography with diode-array detection phenolic compounds profiling revealed that quercetin, quercitrin, and isoquercitrin are the most prevalent phenolic compound in OB, XA, and PG, respectively. All the extracts possessed good antioxidant activity. XA showed the highest total phenolic content of 29.50 ㎎ gallic acid equivalents/g, a total flavonoid content of 21.17 ㎎ quercetin equivalents/g, 2,2-diphenyl-1-picrylhydrazyl and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging abilities of 29% and 88.23%, respectively, and a nitric oxide scavenging activity of 44.13 ㎎/g. Thus, the XA methanolic extract demonstrated a high content of phenolic compounds and significant antioxidative properties, with prospective potency to prevent oxidative damage and promote better cardiovascular health.