OBJECTIVE: It is of great interest to identify the oxidation products of sesamol that may be beneficial to humans. This study was undertaken to identify the oxidation products of sesamol and investigate their antioxidant and cytotoxic activities.
MATERIALS AND METHODS: Using the ferricyanide oxidation approach, four oxidation products of sesamol (2, 3, 20 & 21) have been identified. Structural elucidation of these compounds was established on the basis of their detailed NMR spectroscopic analysis, mass spectrometry and x-ray crystallography. Additionally, a formation mechanism of compound 20 was proposed based on high-resolution mass spectrometry-fragmentation method. The antioxidant activities of these compounds were determined by the DPPH, FRAP, and ABTS assays. The in vitro antiproliferative activity of these compounds was evaluated against a panel of human cancer cell lines as well as non-cancerous cells.
RESULTS: Two oxidation products of sesamol were found to contain an unusual methylenedioxy ring-opening skeleton, as evidenced by spectroscopic and x-ray crystallographic data. Among all compounds, 20 displayed impressive antiproliferative activities against a panel of human cancer cell lines yet remained non-toxic to noncancerous cells. The antioxidant activities of compound 20 are significantly weaker than sesamol as determined by the DPPH, FRAP, and ABTS assays.
CONCLUSION: The oxidation products of sesamol could be a valuable source of bioactive molecules. Compound 20 may be used as a potential lead molecule for cancer studies.
METHODS: The cytotoxic effect of hydromethanolic extract of A. crispa and its solvents partitions (ethyl acetate and aqueous extracts) against breast cancer cells were evaluated by using MTT assay. The cells were treated with concentration of extracts ranging from 15.63 μg/mL- 1000 μg/mL for 72 h. The quantification of phenolic and flavonoid contents of the extracts were carried out to determine the relationship between of phytochemical compounds responsible for cytotoxic and antioxidative activities. The antioxidant capacity was measured by DPPH and ABTS free radical scavenging assay and expressed as milligram (mg) Trolox equivalent antioxidant capacity per 1 g (g) of tested extract.
RESULTS: The hydromethanolic and ethyl acetate extracts showed moderate cytotoxic effect against MCF-7 with IC50 values of 57.35 ± 19.33 μg/mL, and 54.98 ± 14.10 μg/mL, respectively but aqueous extract was inactive against MCF-7. For MDA-MB-231, hydromethanolic, ethyl acetate and aqueous extracts exhibited weak cytotoxic effects against MDA-MB-231 with IC50 values more than 100 μg/mL. The plant revealed high total phenolic content, total flavonoid and antioxidant capacity.
CONCLUSION: The response of different type of breast cancer cell lines towards A. crispa extract and its partitions varied. Accordingly, hydromethanolic and ethyl acetate extracts appear to be more cytotoxic to oestrogen receptor (ER) positive breast cancer than oestrogen receptor (ER) negative breast cancer. However, aqueous extract appears to have poor activity to both types of breast cancer. Besides that, hydromethanolic and ethyl acetate extracts exhibit higher TPC, TFC and antioxidant capacity compared to aqueous extract. Synergistic effect of anticancer and antioxidant bioactives compounds of A. crispa plausibly contributed to the cytotoxic effects of the extract.
METHODS: The phenolic compounds of PKC were obtained by solvent extraction and the product rich in phenolic compounds was labeled as phenolic-enriched fraction (PEF). This fraction was evaluated for its phenolic compounds composition. The antioxidant activity of PEF was determined by using 1,1-diphenyl-2-picryl-hydrazil scavenging activity, ferric reducing antioxidant power, inhibition of ß-carotene bleaching, and thiobarbituric acid reactive substances assays. The cytotoxicity assay and molecular biomarkers analyses were performed to evaluate the cytoprotective effects of PEF towards aflatoxin B1 (AFB1)-induced cell damage.
RESULTS: The results showed that PEF contained gallic acid, pyrogallol, vanillic acid, caffeic acid, syringic acid, epicatechin, catechin and ferulic acid. The PEF exhibited free radical scavenging activity, ferric reducing antioxidant power, ß-carotene bleaching inhibition and thiobarbituric acid reactive substances inhibition. The PEF demonstrated cytoprotective effects in AFB1-treated chicken hepatocytes by reducing the cellular lipid peroxidation and enhancing antioxidant enzymes production. The viability of AFB1-treated hepatocytes was improved by PEF through up-regulation of oxidative stress tolerance genes and down-regulation of pro-inflammatory and apoptosis associated genes.
CONCLUSIONS: The present findings supported the proposition that the phenolic compounds present in PKC could be a potential cytoprotective agent towards AFB1 cytotoxicity.
METHODS: In the current study, the crude methanol and fractionated extract of the rhizomes of Alpinia pahangensis were investigated for their antioxidant activity using four different assays namely, the DPPH scavenging activity, superoxide anion scavenging, β-carotene bleaching and reducing power assays whilst their phenolic contents were measured by the Folin-Ciocalteu's method.In vitro neutral red cytotoxicity assay was employed to evaluate the cytotoxic activity against five different cancer cell lines, colon cancer (HCT 116 and HT-29), cervical cancer (Ca Ski), breast cancer (MCF7) and lung cancer (A549) cell lines, and one normal cell line (MRC-5). The extract that showed high cytotoxic activity was further investigated for its chemical constituents by GC-MS (gas chromatography-mass spectrometry) analysis.
RESULTS: The ethyl acetate fraction showed the strongest DPPH radical scavenging (0.35 ± 0.094 mg/ml) and SOD activities (51.77 ± 4.9%) whilst the methanol extract showed the highest reducing power and also the strongest antioxidant activity in the β-carotene bleaching assays in comparison to other fractions. The highest phenolic content was found in the ethyl acetate fraction, followed by the crude methanol extract, hexane and water fractions. The results showed a positive correlation between total phenolic content with DPPH radical scavenging capacities and SOD activities. The hexane fraction showed potent cytotoxic effect against KB, Ca Ski and HCT 116 cell lines with IC₅₀ of 5.8 ± 0.1 and 9.1 ± 2.0 ug/ml, respectively. The major components of hexane fraction analysed by GC-MS analysis were mostly methyl esters.
CONCLUSIONS: The current study suggests that the methanol extract and ethyl acetate fraction of A. pahangensis is a potential source of natural antioxidant for protective as well as prevention of life-threatening diseases. The hexane fraction of A. pahangensis may have the potential to be developed into therapeutic option for treating cancer.