The effects of the botanical estrogen, isoliquiritigenin on delayed spatial alternation

Toxicity overview of endocrine disrupting chemicals interacting in vitro with the oestrogen receptor

The oestrogen receptor (ER) from the nuclear receptor family is involved in different physiological processes, which can be affected by multiple xenobiotics. Some of these compounds, such as bisphenols, pesticides, and phthalates, are widespread as consequence of human activities and are commonly present also in human organism. Xenobiotics able to interact with ER and trigger a hormone-like response, are known as endocrine disruptors. In this review, we aim to summarize the available knowledge on products derived from human industrial activity and other xenobiotics reported to interact with ER. ER-disrupting chemicals behave differently towards oestrogen-dependent cell lines than endogenous oestradiol. In low concentrations, they stimulate proliferation, whereas at higher concentrations, are toxic to cells. In addition, most of the knowledge on the topic is based on individual compound testing, and only a few studies assess xenobiotic combinations, which better resemble real circumstances. Confirmation from in vivo models is lacking also.

Isoliquiritigenin Decreases Bone Resorption and Osteoclast Differentiation

SCOPE

A dose-ranging study is performed using young estrogen-depleted rats to determine whether dietary isoliquiritigenin (ILQ) alters bone metabolism and if the effects are associated with estrogen receptor signaling.

METHODS AND RESULTS

Six-week-old rats (ovariectomized at 4 weeks of age) are fed diets containing 0, 100, 250, or 750 ppm ILQ (n = 5/treatment) for 7 days. Gene expression in femur and uterus, blood markers of bone turnover, body composition, and uterine weight and epithelial cell height are determined. Because ILQ lowers bone resorption, the effect of ILQ on in vitro differentiation of osteoclasts from bone marrow of mice is assessed. Treatment resulted in a dose-dependent increases in serum ILQ but no changes in serum osteocalcin, a marker of global bone formation. Contrastingly, ILQ administration results in reduced serum CTX-1, a marker of global bone resorption, and reduces tartrate resistant acid phosphatase expression in osteoclast culture. ILQ treatment and endogenous estrogen production had limited overlap on gene expression in femur and uterus. However, uterine epithelial cell hyperplasia is observed in two of five animals treated with 750 ppm.

CONCLUSIONS

In conclusion, dietary ILQ reduces bone resorption in vivo and osteoclast differentiation in vitro, by mechanisms likely differing from actions of ovarian hormones.

Melatonin for premenstrual syndrome: A potential remedy but not ready

Premenstrual syndrome (PMS), a recurrent and moderate disorder that occurs during the luteal phase of the menstrual cycle and quickly resolves after menstruation, is characterized by somatic and emotional discomfort that can be severe enough to impair daily activities. Current therapeutic drugs for PMS such as selective serotonin reuptake inhibitors are not very satisfying. As a critical pineal hormone, melatonin has increasingly been suggested to modulate PMS symptoms. In this review, we update the latest progress on PMS-induced sleep disturbance, mood changes, and cognitive impairment and provide possible pathways by which melatonin attenuates these symptoms. Moreover, we focus on the role of melatonin in PMS molecular mechanisms. Herein, we show that melatonin can regulate ovarian estrogen and progesterone, of which cyclic fluctuations contribute to PMS pathogenesis. Melatonin also modulates gamma-aminobutyric acid and the brain-derived neurotrophic factor system in PMS. Interpreting the role of melatonin in PMS is not only informative to clarify PMS etiology but also instructive to melatonin and its receptor agonist application to promote female health. As a safe interaction, melatonin treatment can be effective in alleviating symptoms of PMS. However, symptoms such as sleep disturbance, depressive mood, cognitive impairment are not specific and can be easily misdiagnosed. Connections between melatonin receptor, ovarian steroid dysfunction, and PMS are not consistent among past studies. Before final conclusions are drawn, more well-organized and rigorous studies are recommended.

Toxicity as prime selection criterion among SARS-active herbal medications

We present here a new selection criterion for prioritizing research on efficacious drugs for the fight against COVID-19: the relative toxicity versus safety of herbal medications, which were effective against SARS in the 2002/2003 epidemic. We rank these medicines according to their toxicity versus safety as basis for preferential rapid research on their potential in the treatment of COVID-19. The data demonstrate that from toxicological information nothing speaks against immediate investigation on, followed by rapid implementation of Lonicera japonica, Morus alba, Forsythia suspensa, and Codonopsis spec. for treatment of COVID-19 patients. Glycyrrhiza spec. and Panax ginseng are ranked in second priority and ephedrine-free Herba Ephedrae extract in third priority (followed by several drugs in lower preferences). Rapid research on their efficacy in the therapy - as well as safety under the specific circumstances of COVID-19 - followed by equally rapid implementation will provide substantial advantages to Public Health including immediate availability, enlargement of medicinal possibilities, in cases where other means are not successful (non-responders), not tolerated (sensitive individuals) or just not available (as is presently the case) and thus minimize sufferings and save lives. Moreover, their moderate costs and convenient oral application are especially advantageous for underprivileged populations in developing countries.

Isoliquiritigenin, an Orally Available Natural FLT3 Inhibitor from Licorice, Exhibits Selective Anti-Acute Myeloid Leukemia Efficacy In Vitro and In Vivo

Licorice is a medicinal herb widely used to treat inflammation-related diseases in China. Isoliquiritigenin (ISL) is an important constituent of licorice and possesses multiple bioactivities. In this study, we examined the selective anti-AML (acute myeloid leukemia) property of ISL via targeting FMS-like tyrosine kinase-3 (FLT3), a certified valid target for treating AML. In vitro, ISL potently inhibited FLT3 kinase, with an IC₅₀ value of 115.1 ± 4.2 nM, and selectively inhibited the proliferation of FLT3-internal tandem duplication (FLT3-ITD) or FLT3-ITD/F691L mutant AML cells. Moreover, it showed very weak activity toward other tested cell lines or kinases. Western blot immunoassay revealed that ISL significantly inhibited the activation of FLT3/Erk1/2/signal transducer and activator of transcription 5 (STAT5) signal in AML cells. Meanwhile, a molecular docking study indicated that ISL could stably form aromatic interactions and hydrogen bonds within the kinase domain of FLT3. In vivo, oral administration of ISL significantly inhibited the MV4-11 flank tumor growth and prolonged survival in the bone marrow transplant model via decreasing the expression of Ki67 and inducing apoptosis. Taken together, the present study identified a novel function of ISL as a selective FLT3 inhibitor. ISL could also be a potential natural bioactive compound for treating AML with FLT3-ITD or FLT3-ITD/F691L mutations. Thus, ISL and licorice might possess potential therapeutic effects for treating AML, providing a new strategy for anti-AML.

Enhancement of Oral Bioavailability and Anti-hyperuricemic Activity of Isoliquiritigenin via Self-Microemulsifying Drug Delivery System

The aim of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) for enhancement of the oral bioavailability of isoliquiritigenin (ISL) as well as evaluate its in vivo anti-hyperuricemic effect in rats. The ISL-loaded self-microemulsifying drug delivery system (ISL-SMEDDS) was comprised of ethyl oleate (EO, oil phase), Tween 80 (surfactant), and PEG 400 (co-surfactant). The ISL-SMEDDS exhibited an acceptable narrow size distribution (44.78 ± 0.35 nm), negative zeta potential (- 10.67 ± 0.86 mV), and high encapsulation efficiency (98.17 ± 0.24%). The in vitro release study indicated that the release rates of the formulation were obviously higher in different release media (HCl, pH 1.2; PBS, pH 6.8; double-distilled water, pH 7.0) compared with the ISL solution. The oral bioavailability of the ISL-SMEDDS was enhanced by 4.71 times in comparison with the free ISL solution. More importantly, ISL-SMEDDS significantly reduced uric acid level by inhibiting xanthine oxidase (XOD) activity in the model rats. Collectively, the prepared ISL-SMEDDS proved to be potential carriers for enhancing the solubility and oral bioavailability of ISL, as well as ameliorating its anti-hyperuricemic effect.

Licorice root components mimic estrogens in an object location task but not an object recognition task

This study investigated the efficacy of components of licorice root to alter performance on two different recognition tasks, a hippocampus-sensitive metric change in object location (MCOL) task and a striatum-sensitive double object recognition (DOR) task. Isoliquiritigenin (ISL), licorice root extract (LRE), and whole licorice root powder (LRP) were assessed. Young adult female rats were ovariectomized (OVX) and exposed to ISL, LRE or LRP at 0.075%, 0.5% or 5% respectively in the diet. An estradiol group was included as a positive control based on our prior findings. Rats were allowed to explore two objects for three 5-min study trials (separated by 3-min intervals) before a fourth 5-min test trial where the objects were moved closer together (MCOL task) or replaced with two new objects (DOR task). Rats typically habituate to the objects across the three study trials. An increase in object exploration time in the test trial suggests the rat detected the change. Estradiol improved MCOL performance and impaired DOR performance, similar to previously shown effects of estradiol and other estrogens, which tend to improve learning and memory on hippocampus-sensitive tasks and impair striatum-sensitive cognition. LRP had no effect on recognition while exposure to ISL and LRE improved MCOL performance. Exposure to ISL, LRE and LRP failed to attenuate DOR, contrary to effects of estradiol shown here and to previous reports in young-adult OVX rats. These findings suggest components of licorice root may prove to be effective therapies targeting memory enhancement without unintended deleterious cognitive effects.