5 research outputs found
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Antioxidant properties of three aromatic herbs (rosemary, thyme and lavender) in oil-in-water emulsions
Lipid oxidation is the major form of deterioration in foods because it decreases food quality and nutritional value, and may have negative health implications. Selected aromatic plant extracts from leaves, flowers and stems of rosemary, thyme and lavender were investigated for their antioxidant activity. The total polyphenol content was determined by the Folin-Ciocalteu assay and the antioxidant capacity was determined by the Trolox equivalent antioxidant capacity, 1,1-diphenyl-2-picrylhydrazyl, oxygen radical absorbance capacity and ferric-reducing antioxidant power assays. For all four antioxidant assays, the extracts from thyme flowers, lavender leaves and thyme leaves had the highest antioxidant activity, followed by rosemary stems, rosemary leaves, and lavender stems, and the lavender flowers and thyme stems had the lowest antioxidant activity. The antioxidant activity was correlated with the polyphenol content, although minor deviations were observed. In oil-in-water emulsion, extracts from rosemary leaves and thyme leaves were most effective at retarding oxidation followed by the rosemary stems and thyme flowers. Extracts from thyme flowers and lavender leaves were less effective in the emulsion than predicted by the homogeneous antioxidant assays. This study demonstrated the potential use of plants extract as substitutes for synthetic antioxidants
Carnosic Acid Modulates Akt/IKK/NF-jB Signaling by PP2A and Induces Intrinsic and Extrinsic Pathway Mediated Apoptosis in Human Prostate Carcinoma PC-3 Cells
This study investigates the efficacy of carnosic
acid (CA), a polyphenolic diterpene, isolated from the plant
rosemary (Rosemarinus officinalis), on androgen-independent
human prostate cancer PC-3 cells. CA induced antiproliferative
effects in PC-3 cells in a concentration- and
time-dependent manner, which was due to apoptotic
induction as evident from flow-cytometry, DNA laddering
and TUNEL assay. Apoptosis was associated with the
activation of caspase-8, -9, -3 and -7, increase in Bax:Bcl-2
ratio, release of cytochrome-c and decrease in expression
of inhibitor of apoptosis (IAP) family of proteins. Apoptosis
was attenuated upon pretreatment with specific
inhibitors of caspase-8 (Z-IETD-fmk) and caspase-9 (ZLEHD-
fmk) suggesting the involvement of both intrinsic
and extrinsic apoptotic cascades. Further, apoptosis resulted
from the inhibition of IKK/NF-jB pathway as evident
from decreased DNA binding activity, nuclear translocation
of p50 and p65 and IjBa phosphorylation. The downregulation
of IKK/NF-jB was associated with inhibition of
Akt phosphorylation and its kinase activity with a concomitant
increase in the serine/threonine protein phosphatase
2A (PP2A) activity. Pharmacologic inhibition of PP2A
by okadaic acid and calyculin A, significantly reversed
CA-mediated apoptotic events in PC-3 cells indicating that
CA induced apoptosis by activation of PP2A through
modulation of Akt/IKK/NF-jB pathway. In addition, CA
induced apoptosis in another androgen refractory prostat cancer DU145 cells via intrinsic pathway as evidenced
from the activation of caspase 3, cleavage of PARP,
increase in Bax:Bcl-2 ratio and cytochrome-c release.
Carnosic acid, therefore, may have the potential for use in
the prevention and/or treatment of prostate cancer