Thesis Abstract

<p> </p><p>Honey has been used traditionally for ages to treat infectious diseases. Antimicrobial activity of honey is complex due to the involvement of multiple bioactive compounds. The physico-chemical and antimicrobial properties of honey varieties from <em>Apis</em>&nbsp;<em>mellifera </em>and stingless bees,<em>Hypotrigona </em>sp. (Okotobo – Igbo) and<em>&nbsp;Melipona </em>sp.(Ifufu – Igbo) were studied using International Honey Commission protocols and microbiological methods (agar-well diffusion and broth microdilution) respectively. A total of nine honey samples (3 from each) were used. The physico-chemical analyses of the honey varieties showed that the honeys had mean pH range of 3.73±0.08 – 4.24±0.20. Honey samples from <em>Hypotrigona</em>&nbsp;sp. had the highest mean moisture (17.50 ± 0.80 %), total dissolved solids (370.01 ± 22.51 ppm), hydromethylfurfural (16.58 ± 0.37 mg/kg), total acidity (35.57 ± 0.42me q/kg), protein content (16.58 ± 0.37 g/kg)and phenol content (527.41 ± 3.60 mg/kg). <em>Melipona</em>&nbsp;sp. honey had the highest average flavonoids (86.39 ± 4.69 mg/kg), total sugar (80.71 ± 1.37 % (g/100g) and reducing sugar (75.64 ± 1.99 % (g/100g) contents. There were no statistically significant differences between the mean pH, electrical conductivity and protein contents of <em>A. mellifera</em>&nbsp;and <em>Melipona</em>&nbsp;sp. honeys (<em>p</em>&lt; 0.05). Several strong correlations were observed among some of the physicochemical properties of these honey varieties. In the initial antimicrobial activity testing, <em>Hypotrigona</em>&nbsp;sp. honey samples had statistically the highest mean inhibition zones diameter (mm) against MDR <em>Staphylococcus aureus</em>&nbsp;(7.14 ± 4.11), <em>Klebsiella pneumonia</em>(7.92 ± 3.96)<em>,</em>&nbsp;<em>Pseudomonas aeruginosa </em>ATCC 25783 (9.77 ±4.58)<em>, </em>MDR<em>&nbsp;S. enterica </em>(6.96 ± 4.03),and <em>Aspergillus niger</em>&nbsp;(10.12 ± 5.51)<em>.</em>The minimum inhibitory concentrations (MICs) of the honey varieties from <em>A. mellifera, Hypotrigona</em>&nbsp;sp. and <em>Melipona</em>&nbsp;sp. ranged from 6.3 – 25.0%, 3.1 – 12.5% and 6.3 – 25.0% (v/v) respectively. There were no statistically significant differences between the mean MICs of <em>A. mellifera,</em>&nbsp;<em>Hypotrigona </em>sp. and<em>&nbsp;Melipona </em>sp.honeys against<em>&nbsp;P. aeruginosa </em>ATCC 25783 (7.64 ±2.76, 7.28 ± 4.14 and 8.33 ± 3.31 % v/v respectivel y).<em>Hypotrigona</em>&nbsp;sp. honey had the least mean MICs (4.15 ± 1.58 – 11.11 ± 2.76 % v/v) against most of the test organisms.The minimum biocidal concentration (MBC) of the honey varieties from<em>A.</em>&nbsp;<em>mellifera, Hypotrigona </em>sp. and<em>&nbsp;Melipona </em>sp. against the test organismsvaried from 6.3</p><p>– 50%, 3.1 – 25% and 12 – 50% (v/v) respectively. T here were no statistically significant differences between the mean MBCs of the honey varieties against</p><p><em>Klebsiella pneumonia</em>(<em>p </em>= 0.669)<em>,P. aeruginosa </em>ATCC 25783 (<em>p </em>= 0.977),<em>&nbsp;A. niger</em>(<em>p</em></p><p>= 0.688) and <em>C. albicans</em>&nbsp;(<em>p</em>&nbsp;= 0.168)<em>.</em>The honey varieties had exceptional levels of hydrogen peroxide-dependent activity, and non-peroxide activity against the test organisms. This research has also shown that the honey varieties varied significantly in their physicochemical and antimicrobial properties. ‘Okotobo’ and ‘ifufu’ honeys that are both not consumed as widely as regular bee honeyhave shownto contain bioactive compounds and have antimicrobial properties similar to those of regular bee honey.</p><p>&nbsp;</p> <br><p></p>

Thesis Overview

<p> </p><p><strong>1.1. &nbsp; &nbsp; &nbsp;</strong><strong>INTRODUCTION</strong></p><p>Traditional &nbsp;medicine &nbsp;has &nbsp;been &nbsp;used &nbsp;to &nbsp;treat &nbsp;infections &nbsp;since &nbsp;the &nbsp;origin &nbsp;of</p><p>mankind and honey is one of the oldest medicines considered as a remedy for microbial infections (Cooper <em>et al</em>., 2009). It was not until late 19th century that researchers discovered that honey has natural antimicrobial qualities (Zumla and Lulat, 1989). Resistance to antibiotics continues to rise and few new therapies are on the horizon, there is further increased interest in the antimicrobial potency of honey (Fahim <em>et al</em>., 2014). Previous studies showed that honey hadremarkable antimicrobial activity against fungi, bacteria,viruses and protozoa(Molan, 1992; Sherlock <em>et al</em>., 2010; Mohapatra <em>et al</em>., 2011; Fahim <em>et al</em>., 2014).</p><p>Honey is a natural sweet mixture produced by honey insects from the nectar of flowers or from living parts of plants. The insect transform the nectar into honey by combining this mixture with substances of their own. The mixture is then regurgitated, dehydrated and stored in the waxy honeycomb inside the hive to ripen and mature for further use (Iurlina and Fritz, 2005). Honey is composed mainly of carbohydrates, smaller amount of water and a great number of minor components. Sugars are the main constituents of honey, constituting of about 95%. Honey characterization is based on the determination of its chemical, physical or biological properties (Gomes <em>et al.,</em>&nbsp;2010).</p><p>Even though honey is produced worldwide, its composition and antimicrobial activity can be variable, and are dependent primarily on their botanical origin, geographical and entomological source (Maryann, 2000). Other certain external factors, such as harvesting season, environmental factors, processing and storage condition, also play important roles (Gheldof and Engeseth, 2002). Entomologically, the honey variety produced by honey bees (the genus<em>Apis</em>) is one most commonly referred to, as it is the type of honey collected by most beekeepers and consumed by most people in Nigeria. Honeys produced by other insects (stingless insects) have different properties (Sherlock <em>et al.,</em>2010).</p><p>Antimicrobial activity of honey is highly complex due to the involvement of multiple compounds and also due to large variations in the concentrations of these compounds among honeys. It depends on osmotic effect (sugar concentration), hydrogen peroxide, and low pH, as well as more recently identified compounds, methyl glyoxal and antimicrobial peptide, bee defensin-1 (Fahim <em>et al</em>., 2014).</p> <br><p></p>