AbstractThe aim of this work was to evaluate in vitro antiradical scavenging activity of propolis from Nkambe (North-West, Cameroon). The polyphenol content of the acetone extract was evaluated using the Folin-Ciocalteu reagent as 0.166±0.008 gGAE/100 gRM. Antiradical scavenging activity of hexane and acetone extracts was carried out on DPPH using ascorbic acid as standard. The results showed that the extracts possess antiradical activity with IC50 of 141 μg/mL and 267 μg/mL for acetone and hexane extracts, respectively. The column chromatography separation on silica gel of the hexane fractionyielded compounds 1 to 3. The structures of these compounds were elucidated by NMR and mass spectrometry data as Lupenone (1), a mixture of α and ß-Amyrin (2) and lastly Hexatriacontanoic acid (3) which was described for the first time from propolis.
A new abietane-type diterpenoid, rubesanolidic acid (1), alongside six known compounds including β-sitosterol (2), lupeol (3), betulenic acid (4) ursolic acid (5), β-sitosterol 3-O-β-D-glucopyranoside (6) and stigmasterol 3-O-β-D-glucopyranoside (7) were isolated from the roots of Burkea africana through column chromatography. Their structures were elucidated from spectroscopic analyses (UV, IR, MS, 1D and 2D NMR) data and by comparison with data from previous studies. The extract and compounds were tested for their α-amylase inhibition. The extract was more active than the isolated compounds with a percentage inhibition of 51.0±2.5 % at 400 µg/mL and was the only sample showing above 50% inhibition at this dose. Amongst the isolated compounds and at the dose of 400 µg/mL, the new diterpenoid Rubesanolidic acid exibited the highest percentage inhibition of α-amylase of 38.2±2.0% while β-sitosterol showed the lowest inhibition of 9.6±0.5%. The results indicate that B. africana is a potential source of antidiabetic compounds.
Cancers are pathologies mainly resulting from both the inability of cells to control their divisions and by the loss of mechanisms of programmed cell death. Notably, they are a leading cause of death worldwide and there are continuous increases in the incidence and mortality rates. In 2018, the global cancer burden was estimated at 18.1 million new cases and 9.6 million deaths. It is estimated that there will be 21 million new cancer cases and 17 million cancer deaths per year by 2030 (Siegel et al., 2016).Developing drug-resistant cancer in patients is a major obstacle in both conventional chemotherapeutics
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