Anti-oxidative and cholinesterase inhibitory effects of leaf extracts and their isolated compounds from two closely related Croton species

A comparative evaluation of the antioxidant and acetylcholinesterase inhibitory activity of the leaf extracts of Croton gratissimus and Croton zambesicus (subgratissimus) and compounds isolated from the extracts was carried out to determine their potential and suitability or otherwise as a substitute for each other in the management of oxidative and neurodegenerative conditions. Different antioxidant assays (DPPH, FRAP, β-carotene-linoleic and the lipid peroxidation models) and the microplate assay for acetylcholinesterase (AChE) inhibition were carried out separately to study the activities of the crude leaf extracts and four solvent fractions from each of the two Croton species. Bioassay guided fractionation was used to target antioxidant constituents of the crude extracts and ethyl acetate fractions of 20% aqueous methanol extract of C. gratissimus on silica gel and Sephadex LH-20 columns resulted in the isolation of kaempferol-3-O-β-6''(p-coumaroyl) glucopyranoside (tiliroside, 2), apigenin-6-C-glucoside (isovitexin, 3) and kampferol (4). The extract of C. zambesicus yielded quercetin-3-O-β-6''(p-coumaroyl) glucopyranoside-3'-methyl ether (helichrysoside- 3'-methyl ether, 1), kaempferol-3-O-β-6''(p-coumaroyl) glucopyranoside (tiliroside, 2) and apigenin-6-C-glucoside (isovitexin, 3). Three of the isolated compounds and their different combinations were also included in the bioassays. In all the assays performed, the antioxidant capacity and AChE inhibitory effects of C. zambesicus extracts were weaker than those of C. gratissimus. This suggests that C. gratissimus may not be substituted by C. zambesicus, despite the similarity in some of their constituents. Generally, the combinations made from the isolated compounds showed better activities in most of the assays compared to the individual isolated compounds. This suggests mechanisms such as synergism and/or additive effects to be taking place. This study established low, moderate and high antioxidant activities as well as AChE inhibitory effects by the crude extracts, fractions, compounds and compound combinations. This means some of the extracts, isolated compounds and compound combinations could be useful in the management of neurodegenerative conditions and serve as sources of natural neurodegenerative agents.

Medienart:

E-Artikel

Erscheinungsjahr:

2013

Erschienen:

2013

Enthalten in:

Zur Gesamtaufnahme - volume:18

Enthalten in:

Molecules (Basel, Switzerland) - 18(2013), 2 vom: 01. Feb., Seite 1916-32

Sprache:

Englisch

Beteiligte Personen:

Ndhlala, Ashwell R [VerfasserIn]
Aderogba, Mutalib A [VerfasserIn]
Ncube, Bhekumthetho [VerfasserIn]
Van Staden, Johannes [VerfasserIn]

Links:

Volltext

Themen:

01YAE03M7J
1,1-diphenyl-2-picrylhydrazyl
4Y8F71G49Q
9KJL21T0QJ
Antioxidants
Beta Carotene
Biological Products
Biphenyl Compounds
Cholinesterase Inhibitors
DFD3H4VGDH
E1UOL152H7
Free Radical Scavengers
Iron
Journal Article
Linoleic Acid
Malondialdehyde
Phospholipids
Picrates
Plant Extracts
Research Support, Non-U.S. Gov't
Thiobarbituric Acid Reactive Substances

Anmerkungen:

Date Completed 09.07.2013

Date Revised 21.10.2021

published: Electronic

Citation Status MEDLINE

doi:

10.3390/molecules18021916

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM224716050