Job's tears (Coix lacryma-jobi Linn.) is commonly used as an herbal medicine. The low incidence of
cancer has been observed in the area of China where regularly consume Job's tears. The effects of preparation methods of Job's tears on anti-
cancer activities were investigated. Potent in vitro anti-proliferative, apoptotic and anti-oxidative activities of semi-purified Job's tears extracts from different preparation methods on 5 human
cancer cell lines comparing with standards and commercial product were observed.
AIM OF STUDY: The crude methanolic extracts of non-cooked, steamed and roasted Job's tears cultivars were prepared and further semi-purified by liquid-liquid extraction techniques. Both of crude and semi-purified extracts were tested for anti-proliferative, apoptotic induction, anti-oxidative activities and
phytochemicals content.
RESULTS: The highest yields of crude and-purified extracts were 4.60% and 1.46%, respectively. In
crude extracts, the steamed whole Thai Black Loei Job's tears (W-TBL-S1) extract showed the highest anti-proliferative activity in mouth epidermal
carcinoma cell (KB) at the IC50 of 43.61±0.76μg/ml (0.005 folds of
doxorubicin), whereas the roasted whole Laos White Loei Job's tears (W-LWL-R2) extract showed the highest apoptotic activity in cervical
adenocarcinoma (HeLa) at 21.52±1.50% (0.22 and 15.05 folds of
doxorubicin and commercial product, respectively). After liquid-liquid extraction, almost all of the semi-purified extracts showed increases in anti-proliferative activity.
Ethyl acetate fraction of the roasted whole Laos White Loei Job's tears (W-LWL-R2) showed the highest anti-proliferative activity in HeLa cell at the IC50 of 0.97±0.82μg/ml (7.82 and 45.39 folds of
doxorubicin and
crude extract, respectively) and apoptotic activity of 18.77±6.31% (0.19 folds of
doxorubicin). The commercial product showed no anti-proliferative activity in all cell lines but induced apoptosis in HeLa cell at 1.43±0.34%. The
butanol and
hexane soluble fractions of the roasted whole of Laos White Loei Job's tears (W-LWL-R2) showed the highest
free radical scavenging (SC50) and
metal chelating activity (MC50) of 0.31±0.06mg/ml (0.64 folds of
ascorbic acid) and 0.08±0.01mg/ml (6.37 folds of
EDTA), respectively. All
ethyl acetate fractions contain high content of
carotenoid and
tannin, whereas the
hexane soluble fraction of the roasted hull of Laos Black Loei Job's tears (H-LBL-R1) showed the highest
linoleic acid content of 8.09±0.74% w/w.
CONCLUSIONS: