Impact of harvesting time and geographical region on total phenolics, flavonoids and antioxidant activity of olive (Olea ferruginea Royle) leaves, district Zhob
Paper Details
Impact of harvesting time and geographical region on total phenolics, flavonoids and antioxidant activity of olive (Olea ferruginea Royle) leaves, district Zhob
Abstract
Study area of district Zhob is well known for its naturally occurring population of Olea ferruginea .There was emerging need to unveil status of pharmaceutically active compounds in leaves of this locally used abundant species. Present study was conducted to evaluate influence of some geological parameters and harvesting time on concentration of few secondary metabolites and antioxidant activity of leaves extracted in different solvents.Sites selection was made by dividing the area with dense population of olives in north and south facing slopes. During 2017, leaves were collected from three altitudes at each slope 600 feet apart during four harvesting stages (vegetative, green fruiting, purple fruiting and black dried fruiting stage) Leaves were shade dried and extracted in three solvents (i.e. acetone, water and 80% ethanol) for quantification of total phenolic contents (TPC), total flavonoid content (TFC) and antioxidant activity (AA) on UV-VIS spectrophotometer by following standard protocols. TPC was significantly high at southern slopes (total mean value 23.73 mg/g) and AA at northern slope (with total mean 41.78%) respectively. Altitude had no significant impact on secondary metabolites and antioxidant activity except for DPPH radical scavenging activity that decreased at the mid altitude (38.19%).TPC, TFC and AA were significantly higher at black (27.99mg/g), green (27.11mg/g) and purple fruiting stage (42.44%) respectively. Solvents also had significant effects on TPC that showed high levels in acetone extracts (23.65mg/g) whereas TFC (42.49mg/g) and AA (42.46%) were higher in leaves extracted in 80% ethanol. Study aids to choose suitable location, harvesting time and extraction solvent to obtain maximum polyphenols and enhance antioxidant activity of Olea ferruginea leaves.
Cantlon JE. 1953. “Vegetation and microclimates on north and south slopes of Cushetunk Mountain, New Jersey.” Ecological Monographs 23(3), 241-270.
Dewanto V. 2002. “Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity.” Journal of agricultural and food chemistry 50(10), 3010-3014.
Folin O, Denis W. 1912. “On phosphotungstic-phosphomolybdic compounds as color reagents.” Journal of Biological Chemistry 12(2), 239-243.
Ghimire B. 2010. “Regeneration of Pinus wallichiana AB Jackson in a trans-Himalayan dry valley of north-central Nepal.” Himalayan Journal of Sciences 6(8), 19-26.
Kirkpatrick J. 1988. “Vegetation-radiation relationships in the wet-dry tropics: granite hills in northern Australia.” Vegetatio 76(3), 103-112.
Kutiel P, Lavee H. 1999. “Effect of slope aspect on soil and vegetation properties along an aridity transect.” Israel Journal of Plant Sciences 47(3), 169-178.
Lee OH, Lee BY. 2010. “Antioxidant and antimicrobial activities of individual and combined phenolics in Olea europaea leaf extract.” Bioresource technology 101(10), 3751-3754.
Måren IE. 2015. “Facing north or south: Does slope aspect impact forest stand characteristics and soil properties in a semiarid trans-Himalayan valley?” Journal of arid environments 121, 112-123.
Paudel S, Vetaas OR. 2014. “Effects of topography and land use on woody plant species composition and beta diversity in an arid Trans-Himalayan landscape, Nepal.” Journal of Mountain Science 11(5), 1112-1122.
Shank R, Noorie E. 1950. “Microclimate vegetation in a small valley in eastern Tennessee.” Ecology 11, 531-539.
Sudjana AN. 2009. “Antimicrobial activity of commercial Olea europaea (olive) leaf extract.” International journal of antimicrobial agents 33(5), 461-463.
Vetaas OR. 1992. “Gradients in field‐layer vegetation on an arid misty mountain plateau in the Sudan.” Journal of Vegetation Science 3(4), 527-534.
Waterman PG, Mole S. 1994. Analysis of phenolic plant metabolites, Blackwell Scientific Oxford District Development Profile 2011. july 18th 2012. Zhob. Prepared by planning and Development Department, Government of Balochistan, Quetta (in collaboration with) UNICEF United Nationn Children’s fund provincial office in Balochistan, Quetta, p 81.
Ayeesha Masood, Abdul Kabir Khan Achakzai, Rasool Baksh Tareen, Misbah Manzoor, Shaista Anjum, Tariq Ismail, Asad Ullah, 2019. Impact of harvesting time and geographical region on total phenolics, flavonoids and antioxidant activity of olive (Olea ferruginea Royle) leaves, district Zhob. Int. J. Biosci., 15(4), 350-358.
Copyright © 2019 by the Authors. This article is an open access article and distributed under the terms and conditions of the Creative Commons Attribution 4.0 (CC BY 4.0) license.