Protein Profiling And Bioactivity Study Of Protein Extracted From Gynura Procumbens (Lour.) Merr.
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Date
2015-06
Authors
CHAW SEN, HEW
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Abstract
Gynura procumbens (Lour.) Merr. is a traditional medicinal plant for treatments of
high cholesterol, high blood pressure, diabetes and cancer. Studies on the small
molecule compounds of the plants have shown that the leaves of G. procumbens
possess anti-hyperglycaemic, anti-hyperlipidaemic, anticancer and anti-inflammatory
activities. Despite the extensive studies on this plant, to date, there is no report on its
protein content. Thus, the objectives of the study were to profile the protein content
of G. procumbens, whereby the differentially expressed proteins between stem,
mature leaf and young leaf of the plant were compared; and the bioactivities of the
raw and fractionated protein were evaluated. A gel-based proteomic was established
and used to analyse the protein content of the leaves of G. procumbens. Amongst the
valuable plant defence proteins detected were peroxidase, thaumatin-like proteins,
harpin binding protein 1 and miraculin. Various types of protein categories were
identified in the protein extracted from G. procumbens which include the high
abundance proteins in mature leaf consisted of proteins involved energy and
metabolism, which tally with the role of the mature leaf as the energy generator for
the entire plant. The expression of proteins also varied among plants collected from
different geographical areas. No antimicrobial activity was detected while poor
antioxidant activity was observed in the crude protein extract. On the other hand, the
extract exerted LDH cytotoxicity with EC50 value of 760 μg/mL (w/v) after 48 hours
treatment on MDA-MB-231, a breast cancer cell line. Active protein fraction SNF11/
12 obtained from gel filtration fractionation inhibited the growth of MDA-MB-
231 at EC50 value of 3.8 μg/mL (w/v). The mRNA expressions of proliferation
markers, Ki67 and PCNA were reduced significantly (p<0.05) in the MDA-MB-23
cells treated with SN-F11/12. The expression of an invasion marker, CCL2, was also
reduced in the treated MDA-MB-231 cells. Twelve proteins were identified in the
SN-F11/12 by mass spectrometry analysis. Further investigation on SN-F11/12 is
needed to evaluate its usefulness as a chemotherapeutic drug. This study showed that
G. procumbens has some commercial valuable proteins and the protein fraction, SNF11/
12 demostrated anti-cancer property. The proteomes of stem, mature leaf and
young leaf were successfully developed and provided a platform for further research.
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Keywords
Protein Profiling And Bioactivity Study Of Protein Extracted , From Gynura Procumbens (Lour.) Merr