Quantification of capsaicin by LC–ESI–MS/MS
An LC-ESI-MS/MS method through MRM was developed for the
selective detection and quantification of 1 and 3 at 11.22 and
12.35 min in the extract (Fig. 3). The selectivity and sensitivity of
(MRM) LC-ESI-MS/MS relies on the application of MRM in which
each ionized compound gives a distinct precursor-to-product ion
transition that is diagnostic for the presence of a particular comtRpound in an extract. Comparison of the chromatograms of blank
and spiked standard substance indicated no significant interference
at the retention times of the investigated compounds. In the
optimized method, chromolith RP18e monolithic type column
(50 4.6 mm) was used for optimal separation of 1 and 3. The
presence of 1 and 3 was successfully detected by mass fragmentography
using two MRM transitions. Standards were injected using
LC without column (through union) controlled by Mass-Hunter
workstation software ver. B.04.00, for qualitative optimization.
Chromatograms of MRM transition mass of m/z 306.1?137.0
and 273.0?257.8 were taken as quantifier and transition mass
of m/z 306.1?170.1 and 273.0?229.9 were taken as qualifier
for 1 and 3 respectively as shown in Fig. 4. As seen in figure-4, ions
peaks were sufficiently separated and, 1 and 3 were present in all
the samples. The quantified values of 1 and 3 were found to be
8.30 lg/L and 2.31 mg/L, respectively. In comparison to 1, 3 was
found to be present in higher concentration in all the extracts.
Notably, the present method reports for the first time use of chromolith
C-18 column and (MRM) LC-ESI-MS/MS for the separation
and quantification of capsaicin. The developed multimode LC-ESIMS/
MS method can easily be utilized as a fast and sensitive analytical
tool for analysis of 1 and 3 in the presence of other possible
constituents.
Biological Activity
Compound 3 showed significant antiproliferative activity
against different human cancer cell lines (Table 2) in which human
promyelocytic leukemia, HL-60 cells were found to be the most
sensitive with IC50 value of 85 lM. Therefore, we chose the HL-
60 cell line for further studies on 3.
Phase contrast microscopy and Hoechst 33,258 staining
Apoptosis induction by 3 was checked through phase contrast
microscopy and Hoechst staining. The apoptotic bodies were
significantly visible in cells treated with 200 lM concentration of
3 for 72 h (Fig. 5A and B). Compound 3 at 200 lM concentration
caused cell wall deformation, shrinkage of cell size, nuclear condensation
and formation of scattered apoptotic bodies as shown
by white arrows in Fig. 5A and B, while the nuclei of untreated cells
are healthy and round in shape. The number of apoptotic bodies increased
with increased concentration of 3 in HL-60 cells.
Measurement of mitochondrial membrane potential
Rhodamine-123 uptake into mitochondria is driven by mitochondrial
transmembrane potential (Wmt). Loss of Wmt leads to
depolarization of mitochondrial membranes and mitochondrial
dysfunctions leads to cell death. Compound 3 induced loss of mitochondrial
membrane potential (MMP) in HL-60 cells in a dose
dependant manner (Fig. 5C). The loss of mitochondrial membrane
potential also releases several pro-apoptotic factors that activate
caspases and finally induces apoptosis
Quantification of capsaicin by LC–ESI–MS/MSAn LC-ESI-MS/MS method through MRM was developed for theselective detection and quantification of 1 and 3 at 11.22 and12.35 min in the extract (Fig. 3). The selectivity and sensitivity of(MRM) LC-ESI-MS/MS relies on the application of MRM in whicheach ionized compound gives a distinct precursor-to-product iontransition that is diagnostic for the presence of a particular comtRpound in an extract. Comparison of the chromatograms of blankand spiked standard substance indicated no significant interferenceat the retention times of the investigated compounds. In theoptimized method, chromolith RP18e monolithic type column(50 4.6 mm) was used for optimal separation of 1 and 3. Thepresence of 1 and 3 was successfully detected by mass fragmentographyusing two MRM transitions. Standards were injected usingLC without column (through union) controlled by Mass-Hunterworkstation software ver. B.04.00, for qualitative optimization.Chromatograms of MRM transition mass of m/z 306.1?137.0and 273.0?257.8 were taken as quantifier and transition massof m/z 306.1?170.1 and 273.0?229.9 were taken as qualifierfor 1 and 3 respectively as shown in Fig. 4. As seen in figure-4, ionspeaks were sufficiently separated and, 1 and 3 were present in allthe samples. The quantified values of 1 and 3 were found to be8.30 lg/L and 2.31 mg/L, respectively. In comparison to 1, 3 wasfound to be present in higher concentration in all the extracts.Notably, the present method reports for the first time use of chromolithC-18 column and (MRM) LC-ESI-MS/MS for the separationand quantification of capsaicin. The developed multimode LC-ESIMS/MS method can easily be utilized as a fast and sensitive analyticaltool for analysis of 1 and 3 in the presence of other possibleconstituents.Biological ActivityCompound 3 showed significant antiproliferative activityagainst different human cancer cell lines (Table 2) in which humanpromyelocytic leukemia, HL-60 cells were found to be the mostsensitive with IC50 value of 85 lM. Therefore, we chose the HL-60 cell line for further studies on 3.Phase contrast microscopy and Hoechst 33,258 stainingApoptosis induction by 3 was checked through phase contrastmicroscopy and Hoechst staining. The apoptotic bodies weresignificantly visible in cells treated with 200 lM concentration of3 for 72 h (Fig. 5A and B). Compound 3 at 200 lM concentrationcaused cell wall deformation, shrinkage of cell size, nuclear condensationand formation of scattered apoptotic bodies as shownby white arrows in Fig. 5A and B, while the nuclei of untreated cellsare healthy and round in shape. The number of apoptotic bodies increasedwith increased concentration of 3 in HL-60 cells.Measurement of mitochondrial membrane potentialRhodamine-123 uptake into mitochondria is driven by mitochondrialtransmembrane potential (Wmt). Loss of Wmt leads todepolarization of mitochondrial membranes and mitochondrialdysfunctions leads to cell death. Compound 3 induced loss of mitochondrialmembrane potential (MMP) in HL-60 cells in a dosedependant manner (Fig. 5C). The loss of mitochondrial membranepotential also releases several pro-apoptotic factors that activatecaspases and finally induces apoptosis
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