title: Characteristics and chemical compositions of propolis from Ethiopia.
abstract: BACKGROUND
  Propolis is a sticky material mixed by honeybees to utilize it in protecting their hives from infection by bacteria and fungi. The therapeutic properties of propolis are due to its chemical composition with bio-active compounds; therefore, researchers are interested in studying its chemical constituents and biological properties. The main objective of this study is to determine the chemical compositions, characteristics and relative concentrations of organic compounds in the extractable organic matter of propolis samples collected from four different areas in Ethiopia.
  
  
  RESULTS
  The propolis samples were extracted with a mixture of dichloromethane and methanol and analyzed by gas chromatography-mass spectrometry (GC-MS).The results showed that the total extract yields ranged from 27.2% to 64.2% (46.7 ± 19.1%). The major compounds were triterpenoids (85.5 ± 15.0% of the total extracts, mainly α-, β-amyrins and amyryl acetates), n-alkanes (5.8 ± 7.5%), n-alkenes (6.2 ± 7.0%,), methyl n-alkanoates (0.4 ± 0.2%), and long chain wax esters (0.3 to 2.1%).
  
  
  CONCLUSIONS
  The chemical compositions of these propolis samples indicate that they are potential sources of natural bio-active compounds for biological and pharmacological applications.
authors.affiliation: Chair of Green Energy Research, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia ; College of Earth, Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon 97331 USA ; Department of Earth and Environmental Sciences, Faculty of Science, Sana'a University, Sana'a, Yemen.
authors.forename: Ahmed I
authors.initials: AI
authors.lastname: Rushdi
authors.affiliation: Bee Research Unit, Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia.
authors.forename: Nuru
authors.initials: N
authors.lastname: Adgaba
authors.affiliation: Bee Research Unit, Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia.
authors.forename: Noofal I M
authors.initials: NI
authors.lastname: Bayaqoob
authors.affiliation: Bee Research Unit, Plant Protection Department, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Al-Khazim
authors.affiliation: Chair of Green Energy Research, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia ; Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 USA.
authors.forename: Bernd I T
authors.initials: BI
authors.lastname: Simoneit
authors.affiliation: Chair of Green Energy Research, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia.
authors.forename: Aarif H
authors.initials: AH
authors.lastname: El-Mubarak
authors.affiliation: Chair of Green Energy Research, College of Food and Agriculture Sciences, King Saud University, P. O. Box 2460, Riyadh, 11451 Saudi Arabia.
authors.forename: Khalid F
authors.initials: KF
authors.lastname: Al-Mutlaq
keywords: Ethiopia; GC-MS; Propolis; Triterpenoids