ABSTRACT
Title
Antiproliferative activity of aged extracts of some Italian Allium species
Authors
C. Nencini1, S. Apollinari2, P. Correale2, L. Micheli1
1“Giorgio Segre” Pharmacology Section
2Associazione Culturale Federico II
Dept. of Neurological, Neurosurgical and Behavioural Sciences, University of Siena.
1“Giorgio Segre” Pharmacology Section
2Associazione Culturale Federico II
Dept. of Neurological, Neurosurgical and Behavioural Sciences, University of Siena.
Abstract
Garlic (Allium sativum L.) has been used from centuries for treating numerous diseases, its consumption has been related to reduce risk of several common cancers, except for breast and prostate cancers which are associated with hormonal and reproductive factors (1). Some garlic constituents have shown to alter activation of carcinogens and to cause growth inhibition of tumor cells through induction of cell cycle arrest or apoptosis, or inhibition of angiogenesis (2). Also extracts of fresh garlic that are aged over a prolonged period (up to 20 months) to produce aged garlic extract (AGE) have shown to suppress cancer growth (3).
In our precedent studies we have demonstrated that three Allium spontaneous species endemic for Italian flora: Allium neapolitanum Cyr., Allium roseum L, and Allium subhirsutum L. were often resulted more active than A. sativum (4-7).
To investigate further on these species, aged extracts of leaves and bulbs of A. neapolitanum, A. roseum, A. subhirsutum, and garlic were tested in vitro for evaluating antiproliferative activity by MTT assay on five human cancer cell lines.
Colorectal adenocarcinoma cells (WiDr, HT29, and C22.20 cell lines), larynx cells (Ep.2 cell lines) were grown as a monolayer culture in RPMI, while lung cells (A549 cell lines) were grown as a monolayer culture in DMEM, both medium were supplemented with 10% fetal bovine serum, 100 units/ml penicillin, 100 µg/ml streptomycin, 2mM L-glutamine. Cells were maintained at 37°C in a humidified 5% CO2 atmosphere. The aged extracts of Allium species were dissolved in dimethyl sulfoxide 10%, diluted in growth medium at concentrations ranging 100-500 μg/ml and incubated for 72 hours. MTT (Tetrazolium blue) colorimetric assays was used to evaluate the reduction of cell viability in presence or absence of the extract.
In general among all the assayed species the aged extracts obtained from leaves and bulbs of Allium roseum showed the best lytic activity, inducing a weak dose-independent lytic activity on HT 29 cells and Ep.2, while these two extracts were found to have a good dose-dependent cytotoxicity against the WiDr cells (70.76% and 62.05% cell inhibition respectively at 500 µg/ml, P<0.02). Moreover, even the aged extracts obtained from leaves and bulbs of Allium subhirsutum showed anti-proliferative effect at 500 µg/ml causing 41.55% and 45.47% of WiDr cell inhibition respectively (P<0.05). None of the tested extracts caused a significant cytotoxicity when added to the cell lines A549, and C22.20.
Allium roseum certainly showed interesting antiproliferative activity and deserves further study in this area. This study yet showed that the wild-type species of Allium are more active and efficacious in respect to garlic bulbs.
References
In our precedent studies we have demonstrated that three Allium spontaneous species endemic for Italian flora: Allium neapolitanum Cyr., Allium roseum L, and Allium subhirsutum L. were often resulted more active than A. sativum (4-7).
To investigate further on these species, aged extracts of leaves and bulbs of A. neapolitanum, A. roseum, A. subhirsutum, and garlic were tested in vitro for evaluating antiproliferative activity by MTT assay on five human cancer cell lines.
Colorectal adenocarcinoma cells (WiDr, HT29, and C22.20 cell lines), larynx cells (Ep.2 cell lines) were grown as a monolayer culture in RPMI, while lung cells (A549 cell lines) were grown as a monolayer culture in DMEM, both medium were supplemented with 10% fetal bovine serum, 100 units/ml penicillin, 100 µg/ml streptomycin, 2mM L-glutamine. Cells were maintained at 37°C in a humidified 5% CO2 atmosphere. The aged extracts of Allium species were dissolved in dimethyl sulfoxide 10%, diluted in growth medium at concentrations ranging 100-500 μg/ml and incubated for 72 hours. MTT (Tetrazolium blue) colorimetric assays was used to evaluate the reduction of cell viability in presence or absence of the extract.
In general among all the assayed species the aged extracts obtained from leaves and bulbs of Allium roseum showed the best lytic activity, inducing a weak dose-independent lytic activity on HT 29 cells and Ep.2, while these two extracts were found to have a good dose-dependent cytotoxicity against the WiDr cells (70.76% and 62.05% cell inhibition respectively at 500 µg/ml, P<0.02). Moreover, even the aged extracts obtained from leaves and bulbs of Allium subhirsutum showed anti-proliferative effect at 500 µg/ml causing 41.55% and 45.47% of WiDr cell inhibition respectively (P<0.05). None of the tested extracts caused a significant cytotoxicity when added to the cell lines A549, and C22.20.
Allium roseum certainly showed interesting antiproliferative activity and deserves further study in this area. This study yet showed that the wild-type species of Allium are more active and efficacious in respect to garlic bulbs.
References
- Galeone C et al. Am J Clin Nutr. 2006;84:1027-1032
- Milner JA. J Nutr. 2006;136(3S):827S-831S
- Li T et al. Cancer Chemother Pharmacol. 2009;63:873-880
- Nencini C et al. Phytother Res. 2007;21:874-878
- Nencini C et al. J Med Food. 2010;13:329-335
- Nencini C et al. Int J Food Sci Nutr. 2010;61:433-439
- Nencini C et al. Plant Food Hum Nutr. 2011;DOI 10.1007/s11130-010-0204-2