Glycyrrhizin Inhibits SARS-CoV-2 Entry into Cells by Targeting ACE2.

Coronavirus Disease 2019 (COVID-19) is a highly infectious and pathogenic disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Early in this epidemic, the herbal formulas used in traditional Chinese medicine (TCM) were widely used for the treatment of COVID-19 in China. According to Venn diagram analysis, we found that Glycyrrhizae Radix et Rhizoma is a frequent herb in TCM formulas against COVID-19. The extract of Glycyrrhizae Radix et Rhizoma exhibits an anti-SARS-CoV-2 replication activity in vitro, but its pharmacological mechanism remains unclear. We here demonstrate that glycyrrhizin, the main active ingredient of Glycyrrhizae Radix et Rhizoma, prevents the coronavirus from entering cells by targeting angiotensin-converting enzyme 2 (ACE2). Glycyrrhizin inhibited the binding of the spike protein of the SARS-CoV-2 to ACE2 in our Western blot-based assay. The following bulk RNA-seq analysis showed that glycyrrhizin down-regulated ACE2 expression in vitro which was further confirmed by Western blot and quantitative PCR. Together, we believe that glycyrrhizin inhibits SARS-CoV-2 entry into cells by targeting ACE2.

An-jun-ning, a traditional herbal formula, attenuates spontaneous withdrawal symptoms via modulation of the dopamine system in morphine-dependent rats.

BACKGROUND: The dopamine system, which is involved in drug dependence, can be damaged by opioid abuse. However, current clinical medicines cannot reverse these damages in the brain, which are believed to be a key reason for the high relapse rate after abstinence treatment. This study aimed to investigate the effects of An-jun-ning (AJN), a commercial traditional Chinese medicine formula used for the treatment of opioid addiction, on the dopamine system in morphine-dependent rats and to explore the possible mechanism underlying its therapeutic effects. METHODS: The morphine dependence model was obtained through injections of morphine at increasing doses for 8 days. The AJN pre-treatment group was administered AJN 30 min before each morphine administration, and the AJN post-treatment groups were treated with AJN for 10 days after withdrawal. Spontaneous withdrawal symptoms (wet dog shakes, and episodes of writhing) were observed after withdrawal. Autoradiography study and/or immunohistochemical staining were used to examine the levels of dopamine transporter (DAT), dopamine D2 receptor (D2R) and tyrosine hydroxylase (TH). RESULTS: (1) Pre-treatment with AJN attenuates wet dog shakes and episodes of writhing to approximately 50% or less of those observed in the morphine group (p < 0.01). (2) AJN post-treatment dose-dependently reduced the number of wet dog shakes (p < 0.01), and the episodes of writhing (p < 0.01). (3) Pre-treatment with AJN effectively interdicted the morphine-induced decreases in the levels of DAT, D2R, and TH in the striatum (p < 0.01) such that they remained at nearly normal levels. (4) Post-treatment with AJN restored DAT and D2R to the normal levels (p < 0.01) and the level of TH to 87% of normal in the striatum. CONCLUSIONS: AJN can effectively alleviate opioid withdrawal symptoms and preserve or restore the DAT, D2R, and TH levels in the striatum. The mechanism underlying the effect of AJN on withdrawal symptoms may be related to the modulation of the dopamine system by AJN. These results suggest that AJN may help to prevent relapse in opioid dependence treatment.

Brucine suppresses ethanol intake and preference in alcohol-preferring Fawn-Hooded rats.

AIM: Brucine (BRU) extracted from the seeds of Strychnos nux-vomica L is glycine receptor antagonist. We hypothesize that BRU may modify alcohol consumption by acting at glycine receptors, and evaluated the pharmacodynamic profiles and adverse effects of BRU in rat models of alcohol abuse. METHODS: Alcohol-preferring Fawn-Hooded (FH/Wjd) rats were administered BRU (10, 20 or 30 mg/kg, sc). The effects of BRU on alcohol consumption were examined in ethanol 2-bottle-choice drinking paradigm, ethanol/sucrose operant self-administration paradigm and 5-d ethanol deprivation test. In addition, open field test was used to assess the general locomotor activity of FH/Wjd rats, and conditioned place preference (CPP) was conducted to assess conditioned reinforcing effect. RESULTS: In ethanol 2-bottle-choice drinking paradigm, treatment with BRU for 10 consecutive days dose-dependently decreased the ethanol intake associated with a compensatory increase of water intake, but unchanged the daily total fluid intake and body weight. In ethanol/sucrose operant self-administration paradigms, BRU (30 mg/kg) administered before each testing session significantly decreased the number of lever presses for ethanol and the ethanol intake, without affecting the number of sucrose (10%) responses, total sucrose intake, and the number of lever presses for water. Acute treatment with BRU (30 mg/kg) completely suppressed the deprivation-induced elevation of ethanol consumption. Treatment with BRU (10, 20, and 30 mg/kg) did not alter locomotion of FH/Wjd rats, nor did it produce place preference or aversion. CONCLUSION: BRU selectively decreases ethanol consumption with minimal adverse effects. Therefore, BRU may represent a new pharmacotherapy for alcoholism.

Traditional Chinese medicine for treatment of alcoholism: from ancient to modern.

Alcohol has long been used as a daily beverage in China and around the world. It is a medicinal substance with various biological activities. In fact, alcohol has played an important role in the development of traditional Chinese medicine (TCM), within which it is considered as the earliest exhilarant and anaesthetic. Yet, as a substance with great potency of misuse and addiction, the consumption of alcohol can lead to serious damage to individual health and the society. Over the past 20 years, alcohol abuse or alcoholism has become an increasing social problem in China along with the rapid economic development. China, the country of origin for TCM, has accumulated abundant clinical experience in the treatment of alcoholism with its ancient medicine. In the present research, we have summarized clinical and primary studies concerning various remedies of TCM for alcohol abuse, including herbal components (such as Kudzu/Pueraria Lobata, Pediculus melo, Hypericumpperforatum L.), decoctions and acupuncture.

Effects of l-tetrahydropalmatine on locomotor sensitization to oxycodone in mice.

AIM: Recent studies have shown that l-tetrahydropalmatine (l-THP), an active component of Corydolis yanhusuo, can inhibit the development of the conditional place preference induced by opioid receptor agonists, but the effects of l-THP on locomotor sensitivity induced by opioid receptor agonists have not been documented. In the present study, the effects of l-THP on locomotor sensitization to oxycodone, which is an opioid receptor agonist, were studied. METHODS: Mice treated daily for 7 d with 5 mg/kg oxycodone and challenged with the same dose after 5 days of washout showed locomotor sensitization. In order to study the effects of l-THP on locomotor sensitization induced by oxycodone, l-THP was administered at doses of 6.25, 12.5, and 18.75 mg/kg, 40 min prior to treatment of oxycodone. RESULTS: l-THP per se did not affect the locomotor activity at the doses of 6.25, 12.5, and 18.75 mg/kg, but could antagonize the hyperactivity induced by oxycodone (5 mg/kg). Co-administration of l-THP (18.75 mg/kg), 40 min prior to oxycodone, could inhibit the development of sensitization to oxycodone. In addition, l-THP (6.25, 12.5, and 18.75 mg/kg, i.g.) dose-dependently prevented the expression of oxycodone sensitization. CONCLUSION: These results suggested that l-THP could attenuate the locomotor-stimulating effects of oxycodone and inhibit the development and expression of oxycodone behavioral sensitization.