Search Results (3)

This research aimed to qualitatively analyze the composition of selected extra virgin olive oils from organic and conventional farming available on the Polish market. Determination of the fatty acid profile, determination of the sterol content, and measurement of the acidic and peroxide numbers of the olive oils were performed. Moreover, the content of phenolic acids was determined using the HPLC method, and the antioxidant activity was examined using, e.g., the FRAP and DPPH methods, to establish the differences between the analyzed olive oil samples. The most abundant fatty acids in the olive oil were monounsaturated fatty acids (65.60–78.50%) with oleic acid (59.54–75.36%), saturated fatty acids (14.60–20.49%) with palmitic acid (10.93–16.45%), and polyunsaturated fatty acids (7.80–15.04%) with linoleic acid (6.24–14.34%). The phytosterol fraction consisted of β-sitosterol, campesterol, stigmasterol, clerosterol, ∆5-avenasterol, cycloartenol, 24-methylenecycloartenol, and citrostadienol, and its concentration ranged from 775.23 to 1115.70 mg/kg of the olive oils. The conventional method of olive cultivation influenced campesterol concentration in the extra virgin olive oils, and the concentration was higher in such products than in organic. Tests conducted on the reduction of iron ions (FRAP method) showed that the olive oil obtained from conventional farming (except for one product) had slightly higher antioxidant activity (0.23–0.30 μmol TE/g of olive oil) than that obtained from organic farming (0.19–0.26 μmol TE/g of olive oil). The total content of phenolic acids (oleuropein, hydroxytyrosol, and tyrosol) in the extra virgin olive oils ranged from 133.20 to 226.82 mg/kg. Full article

The cytotoxic effects and mechanism of action of clerosterol, isolated from the marine alga Codium fragile, were investigated in A2058 human melanoma cells. Clerosterol inhibited the growth of A2058 cells with an IC₅₀ of 150 µM and induced apoptotic cell death, as evidenced by DNA fragmentation, an increase in the number of sub-G₁ hypodiploid cells and the presence of apoptotic bodies. Clerosterol treatment caused the loss of mitochondrial membrane potential. Alterations in the expression of apoptosis-associated proteins in response to clerosterol treatment included upregulation of Bax, downregulation of Bcl-2 and activation of caspases 3 and 9. The pan-caspase inhibitor treatment attenuated the expression of the active form of caspases and cell death induced by clerosterol. The present results show that clerosterol exerts its cytotoxic effect in A2058 human melanoma cells by caspases-dependent apoptosis. Full article

In the search for new antiparasitic natural compounds from the medicinal plants from Cameroon, the new 22-hydroxyclerosterol, established as such on the basis of detailed chemical and spectroscopic analysis, was isolated from the hexane extract of the stem bark of Allexis cauliflora together with the known clerosterol. 22-Hydroxyclerosterol inhibited the growth of Trypanosoma brucei brucei cells with an ED₅₀ value of 1.56 μM. The compound was also established as an uncompetitive inhibitor of the glycolytic enzyme PGI of T. brucei (Ki’= 3 ± 1 μM), an uncompetitive inhibitor of mammalian rabbit muscles’ enzyme PyK (Ki’= 26 ± 3 μM) and a mixed inhibitor of PyK of Leishmania mexicana (Ki’= 65 ± 10 μM; Ki= 24 ± 5 μM). Full article