|Oncol Rep. 2014 Jan;31(1):298-304. |
|Combination of liquiritin, isoliquiritin and isoliquirigenin induce apoptotic cell death through upregulating p53 and p21 in the A549 non-small cell lung cancer cells.[Pubmed: 24247527]|
|Liquiritin, Isoliquiritin and isoliquirigenin are the active polyphenols present in Glycyrrhiza uralensis which has been used for the treatment of cancer and its complications.
METHODS AND RESULTS:
The present study was conducted to evaluate the cytotoxicity and antitumor activity of liquiritin, Isoliquiritin and isoliquirigenin on human non-small lung cancer cells including apoptosis-induction, inhibition of apoptotic pathways and to explore the underlying mechanism. Lactate dehydrogenase assays, FITC Annexin V staining assay were performed to evaluate cellular cytotoxicity and apoptosis activity. The results showed that pretreatment with these polyphenols induced apoptosis in A549 cells. Liquiritin, Isoliquiritin and isoliquirigenin significantly increased cytotoxicity of, and upregulated p53 and p21 and downregulated the apoptotic pathways. Furthermore, it inhibited cell cycle at the G2/M phase. Western blot analysis showed it significantly decreased the protein expression of PCNA, MDM2, p-GSK-3β, p-Akt, p-c-Raf, p-PTEN, caspase-3, pro-caspase-8, pro-caspase-9 and PARP, Bcl-2 in a concentration-dependent manner while the protein expression of p53, p21 and Bax was increased. In addition, Akt pathway was downregulated.
These findings suggest that liquiritin, Isoliquiritin and isoliquirigenin inhibited the p53-dependent pathway and showed crosstalk between Akt activities. These active polyphenols can be an alternative agent for the treatment of lung cancer.
|Molecules. 2016 Feb 19;21(2):237. |
|Antifungal Activity of Isoliquiritin and Its Inhibitory Effect against Peronophythora litchi Chen through a Membrane Damage Mechanism.[Pubmed: 26907232 ]|
METHODS AND RESULTS:
This study investigated the antifungal activity and potential antifungal mechanism(s) of Isoliquiritin against P. litchi Chen, one of the main litchi pathogens. The antifungal activity of Isoliquiritin against P. litchi Chen had been proven in a dose-dependent manner through in vitro (mycelial growth and sporangia germination) and in vivo (detached leaf) tests. Results revealed that Isoliquiritin exhibited significant antifungal activity against the tested pathogens, especially, P. litchi Chen, with a minimum inhibitory concentration of 27.33 mg/L. The morphology of P. litchi Chen was apparently changed by Isoliquiritin through cytoplasm leakage and distortion of mycelia. The cell membrane permeability of the P. litchi Chen increased with the increasing concentration of Isoliquiritin, as evidenced by a rise in relative electric conductivity and a decrease in reducing sugar contents. These results indicated that the antifungal effects of Isoliquiritin could be explained by a membrane lesion mechanism causing damage to the cell membrane integrity leading to the death of mycelial cells.
Taken together, Isoliquiritin may be used as a natural alternative to commercial fungicides or a lead compound to develop new fungicides for the control of litchi downy blight.
|Biol Pharm Bull. 1995 Oct;18(10):1382-6. |
|Inhibitory effect of isoliquiritin, a compound in licorice root, on angiogenesis in vivo and tube formation in vitro.[Pubmed: 8593441]|
|A water extract of licorice root inhibits granuloma angiogenesis in adjuvant-induced chronic inflammation (Phytother. Res., 5, 195. 1991).
METHODS AND RESULTS:
The present study has investigated the effects of licorice-derived compounds on granuloma angiogenesis. Isoliquiritin (0.31-3.1 mg/kg), a licorice-derived flavonoid, inhibited the carmine content of granuloma tissue 50-fold greater than licorice extract. Glyeyrrhizin (20-80 mg/kg), a licorice-derived saponin, inhibited carmine content with a weak potency. The licorice extract (0.01-1 mg/ml) also inhibited tube formation from vascular endothelial cells in a concentration-dependent manner. From the chemical structure-activities of used licorice-derived flavonoids (0.1-100 microM), their potencies for anti-tube formation were in the order isoliquiritigenin > Isoliquiritin > liquiritigenin >> Isoliquiritin-apioside. Glycyrrhizin (0.1-100 microM) and glycyrrhetinic acid (0.1-10 microM) increased tube formation. A glycyrrhizin (82 micrograms/ml)-induced increase in tube formation was inhibited by Isoliquiritin. The combined effect of a mixture of 82 micrograms/ml glycyrrhizin and 4.2 micrograms/ml Isoliquiritin, a similar concentration ratio to their yield ratio in the licorice extract, corresponded to the effect of 100 micrograms/ml extract.
In conclusion, the anti-angiogenic effect of licorice extract depended on the anti-tube formation effect of Isoliquiritin.