Influence of honey on the gastrointestinal metabolism and disposition of glycyrrhizin and glycyrrhetic acid in rabbits

Recent advances in glycyrrhizin metabolism, health benefits, clinical effects and drug delivery systems for efficacy improvement; a comprehensive review

BACKGROUND

Glycyrrhizin (GL) is a major active constituent of licorice root (Glycyrrhiza glabra) that is considered one of the oldest and most frequently employed botanicals in Chinese medicine and worldwide, with most effects attributed to its rich GL content. Structurally, GL a triterpene saponin that is widely used as a flavoring agent in foodstuffs and cosmetics, and also proposed for various clinical applications with a myriad of health benefits. Pharmacological and biological activities of GL include antiviral, anti-inflammatory, antioxidant, and anticancer activities (in vitro and in vivo). Currently, there is no comprehensive review on GL biological effects and its action mechanisms.

PURPOSE

This review summarizes GL pharmacological actions from a molecular biology perception, presented on its metabolism and side effects based on in vitro, in vitro and clinical studies. Moreover, the potential of GL as a nanomedicine delivery system is also summarized. The progress in drug delivery research using GL presented herein is expected to provide a theoretical basis for developing other novel drugs formulations.

METHODS

A systematic review was carried out in several electronic databases (Science Direct, SpringerLink, CNKI, PubMed, Web of Science, Elsevier, and Scopus), using the following key words: glycyrrhizin "AND" bioactivity "OR" clinic "OR" therapeutic "OR" drug delivery. This search included manuscripts published between 1989 and 2021.

RESULTS

126 researches were selected and summarized in this review. The analysis of these studies indicated that GL has antiviral activity against different viruses. Further, GL efficiently suppressed the respiratory manifestations associated with COVID-19 by reducing the expression of angiotensin converting enzyme 2 (ACE2) that employed by the virus as an entry point. Otherwise, GL was found to induce antioxidant, anti-inflammatory, immune-modulatory, and anticancer activity. Besides, diminution the particle size of GL to nanometer size significantly augments their action and biodistribution.

CONCLUSION

This article summarizes the pharmacological actions of GL. The potential of GL as a nanomedicine delivery system is also presented. Nevertheless, most studies reported provide no deep insight of GL health effects warranting for more future studies to elucidate its action mechanism and potential therapeutic benefits through preclinical and clinical trials.

Investigate the effect of honey on the absorption of seven active ingredients from wu-tou decoction in rats

Wu-tou decoction has been used as a traditional Chinese medicine prescription for thousands of years. It is composed of five herbs, namely, Radix Aconiti Preparata, Ephedrae Herba, Astragali Radix, Glycyrrhiza Radix and Paeoniae Radix Alba. In addition, the original prescription also contains honey, but in modern research, the existence of honey is commonly ignored. To investigate the effect of absorption in rats after oral wu-tou decoction within or without honey. In this research, a rapid and sensitive UPLC-MS/MS method was investigated to the quantitative analysis of ephedrine, pseudoephedrine, paeoniflorin, calycosin-7-glucoside, glycyrrhizic acid, liquiritin and benzoylmesaconine in rat plasma after single and continuous oral decoctions. The results of pharmacokinetic parameters showed that C_max , CL/F, AUC_0-t and AUC_0-∞ in the honey group were significantly increased than those in the non-honey group except for ephedrine, pseudoephedrine. It obtained the same trend regardless of single or continuous oral administration. The research showed that honey could promote the absorption of some effective components in wutou decoction in rats, enhance bioavailability, and provide a theoretical basis for the scientific and rational compatibility of the original prescription.

Effects of processing adjuvants on traditional Chinese herbs

Processing of Chinese medicines is a pharmaceutical technique that transforms medicinal raw materials into decoction pieces for use in different therapies. Various adjuvants, such as vinegar, wine, honey, and brine, are used in the processing to enhance the efficacy and reduce the toxicity of crude drugs. Proper processing is essential to ensure the quality and safety of traditional Chinese medicines (TCMs). Therefore, sound knowledge of processing principles is crucial to the standardized use of these processing adjuvants and to facilitate the production and clinical use of decoction pieces. Many scientific reports have indicated the synergistic effects of processing mechanisms on the chemistry, pharmacology, and pharmacokinetics of the active ingredients in TCMs. Under certain conditions, adjuvants change the content of active or toxic components in drugs by chemical or physical transformation, increase or decrease drug dissolution, exert their own pharmacological effects, or alter drug pharmacokinetics. This review summarizes various processing methods adopted in the last two decades, and highlights current approaches to identify the effects of processing parameters on TCMs.

Comparative study of bioactive constituents in crude and processed Glycyrrhizae radix and their respective metabolic profiles in gastrointestinal tract in vitro by HPLC-DAD and HPLC-ESI/MS analyses

Two HPLC methods with diode array detection (HPLC-DAD) and electrospray ionization-mass spectrometry (HPLC-ESI/MS), respectively, were developed to investigate the differences of chemical constituents and their metabolism in gastrointestinal tract in vitro between two decoctions of crude and processed Glycyrrhizae radix. Total of eleven constituents (liquiritin apioside, liquiritin, licuraside, isoliquiritin, ononin, glycyrrhizin, liquiritigenin-7,4'-diglucoside, licorice saponin A3, 22β-acetoxylglycyrrhizic acid, licorice saponin G2, and yunganoside E2) were identified in the two decoctions, whereas lower contents of these constituents were usually found in the decoction of processed Glycyrrhizae Radix. [corrected] Furthermore, these constituents were metabolized into their respective aglycons in human intestinal bacteria juice, and the metabolism ratios were all higher in processed Glycyrrhizae Radix [corrected] decoction. No change was found in artificial gastric or intestinal juice. This study revealed that the processing can alter the contents of main constituents in crude G. radix and their metabolism in gastrointestinal tract, in which intestinal bacteria play an important role in the metabolism of licorice constituents.

Biological analysis of herbal medicines used for the treatment of liver diseases

Herbal medicines have been used to treat liver disorders for thousands of years in the East and have now become a promising therapy internationally for pathological liver conditions. Biological analysis of hepatoprotective herbs is an important issue from the pharmacokinetic perspective in developing new therapeutic managements for liver disease. The biological analysis focuses on the pretreatment methods, separation and quantification of herbal medicines in biological samples. We have compiled and discuss the biological analytical method of six herbal medicines for liver protection containing Silybum marianum(silymarin), Glycyrrhiza glabra, Scutellaria baicalensis, Schisandra chinensis, Salvia miltiorrhiza and Astragalus membranaceus. This review provides a convenient reference for researchers to reduce time-consuming method optimization.

Technology for improving the bioavailability of small molecules extracted from traditional Chinese medicines

Evidence that small molecules extracted from traditional Chinese medicines (TCMs) have beneficial effects on health is increasingly being reported in the scientific literature and these compounds are now widely recognized as potential therapeutic drugs. There have been several detailed studies of the absorption, distribution, metabolism and excretion of these compounds in rats and humans. However, some active components have low bioavailability owing to their unsuitable physicochemical and biopharmaceutical characteristics, resulting in differences in vivo. The main problem in using natural products as a source of pharmaceutical lead compounds is the need to improve the bioavailability of these compounds. This review presents and discusses the current methods used for improvement and their impact on the bioavailability of some new pharmaceutical lead compounds from TCMs.

Effects of glucose, fructose and 5-hydroxymethyl-2-furaldehyde on the presystemic metabolism and absorption of glycyrrhizin in rabbits

Our previous study reported that co-administration of honey significantly increased the serum levels of glycyrrhetic acid (GA) after oral administration of glycyrrhizin (GZ) in rabbits. The components of honey are sucrose, glucose, fructose and 5-hydroxymethyl-furaldehyde (HMF). To clarify the causative component(s) in honey that altered the metabolic pharmacokinetics of GZ, rabbits were given GZ (150 mg kg(-1)) with and without glucose (5 g/rabbit), fructose (5 g/rabbit) and HMF (1 mg kg(-1)), respectively, in crossover designs. An HPLC method was used to determine concentrations of GZ and GA in serum as well as GA and 3-dehydroglycyrrhetic acid (3-dehydroGA) in faeces suspension. A noncompartment model was used to calculate the pharmacokinetic parameters and analysis of variance was used for statistical comparison. Our results indicated that the area under curve (AUC) of GA was significantly increased by 29% when HMF was coadministered, whereas the pharmacokinetics of GZ and GA were not significantly altered by coadministration of glucose or fructose. An in-vitro study, using faeces to incubate GZ and GA individually, indicated that HMF significantly inhibited the oxidation of GA to 3-dehydroGA and this may explain the enhanced GA absorption in-vivo. It was concluded that HMF is the causative component in honey that affects the presystemic metabolism and pharmacokinetics of GZ in-vivo.

Profound difference of metabolic pharmacokinetics between pure glycyrrhizin and glycyrrhizin in licorice decoction

To investigate the difference of metabolic pharmacokinetics between pure glycyrrhizin (GZ) and GZ in licorice decoction, six New Zealand White rabbits were orally given pure GZ and licorice decoction containing equivalent content of GZ in a randomized crossover design. HPLC methods were used for the quantitation of GZ and glycyrrhetic acid (GA) in serum. The results indicated that the areas under curves (AUCs) of GZ and GA after administration of licorice decoction were significantly higher than those after pure GZ. This result was contradictory with that obtained in rats. To explore the mechanism of the pharmacokinetic difference, feces of rabbits, rats, pigs and humans were used to investigate the presystemic metabolism of pure GZ and GZ in licorice decoction. The results indicated that pure GZ was hydrolyzed to GA more rapidly and to a greater extent than that in licorice decoction by various feces. In addition, when pure GZ was fermented, the metabolic profiles of GA and 3-dehydroGA in rabbit feces were quite different from other feces. In conclusion, the bioavailabilities of GZ and GA are significantly better from licorice than from pure GZ in rabbits but the presystemic metabolism of pure GZ in rabbit is rather different from that in rat, pig and human.