New mono-ether of glycerol and triterpenes with DPPH radical scavenging activity from Cameroonian propolis

Abstract

The extracts of some propolis samples were analysed by GC-MS and then purified by column chromatography. The latter led to the isolation of a new mono-ether of glycerol, 1'-O-eicosanyl glycerol and a new triterpene, methyl-3β,27-dihydroxycycloart-24-en-26-oate together with known triterpenoids namely betulin, 3β-hydroxylanostan-9,24-dien-21-oic acid, mangiferonic acid, a mixture of ambolic acid and β-sitosterol, 3β-hydroxycycloartan-12,24(25)-diene and 27-hydroxymangiferonic acid. The DPPH radical scavenging potential of some extracts and compounds were measured. The radical scavenging activity varied from Hexane extract of Foumban propolis (IC = 5.6 mg/mL) to Methanol extract of Foumban propolis (IC = 1.07 mg/mL) for the extracts and from 3β-hydroxylanostan-9,24-dien-21-oic acid (IC = 1.22 mg/mL) to 1'-O-eicosanyl glycerol (IC = 0.93 mg/mL) for the compounds. Activities of samples were moderate as they remained closer to those of the standard antioxidants Gallic acid (IC = 0.30 mg/mL) and vitamin C (IC = 0.80 mg/mL), especially 1'-O-eicosanyl glycerol, the most active compound.

Antioxidant Variability of Propolis Collected from Different Zones in Hives

“…IC50 values calculated in this study were lower in contrast with values of these works. Talla et al (2017) compare DPPH value of Cameroonian propolis and vitamin C. The IC50 value of Cameroonian is found 0.30 mg/mL. That value is higher than our findings.…”

A New fatty acid and some triterpenoids from propolis of Nkambe (North-West Region, Cameroon) and evaluation of the antiradical scavenging activity of their extracts

“…The DPPH (1,1-diphenyl-2-picrylhydrazyl) antiradical scavenging activity of the extracts was done according to the method described elsewhere [12] with slight modifications. To 2 mL of the solution of the test sample prepared at different concentrations, 1 mL of a methanol solution of DPPH (100 μg/mL) was added.…”

“…From this, five other solution concentrations were obtained from the mother solution making a total of six solutions at six concentrations: 120, 100, 80, 60, 40 and 20 μg/mL. The test at each concentration was done in triplicates, the absorbance was mesured and the percentage inhibition calculated according to the following equation [12].…”

“…Many studies on different samples show that propolis chemical composition is difficult to standardize because it is highly dependent on a number of factors such as local flora and environmental conditions of the site of collection of resin from plants for production of propolis. This is why propolis from areas not yet studied seems to be a promising source of new bioactive molecules [12]. From different botanical and geographical origins of the world, more than 300 compounds including volatile organic compounds, flavonoid aglycones, phenolic acids and their esters, phenolic aldehydes, alcohols and ketones, sesquiterpenes, quinones, coumarins, steroids, amino acids were reported to have been isolated from propolis [8,13].…”

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“…Many papers reporting chemical composition of various propolis samples exist but chemical analysis of volatile components (essential oils) of propolis remains under-researched and since the bioactivities of propolis are related to its composition in non-volatile and volatile components, studies on essential oils of propolis becomes very necessary (Piotr et al, 2018). Though existing studies on Cameroonian propolis report predominantly triterpenes (Tamfu et al, 2016;Talla et al, 2017), no study reporting the chemical composition of essential oils of Cameroonian propolis exists to the best of our knowledge. The aim of this study is to obtain essential oil from a Cameroonian propolis sample by hydrodistillation, determine its chemical composition by gas chromatography mass spectrometry (GC-MS) and evaluate its anticholinesterase activity.…”