Pharmacokinetics, intestinal absorption and microbial metabolism of single platycodin D in comparison to Platycodi radix extract

Lancemaside A from Codonopsis lanceolata: Studies on Antiviral Activity and Mechanism of Action against SARS-CoV-2 and Its Variants of Concern

Several plant-derived natural products with anti-SARS-CoV-2 activity have been evaluated for the potential to serve as chemotherapeutic agents for the treatment of COVID-19. Codonopsis lanceolata (CL) has long been used as a medicinal herb in East Asian countries to treat inflammatory diseases of the respiratory system but its antiviral activity has not been investigated so far. Here, we showed that CL extract and its active compound lancemaside A (LA) displayed potent inhibitory activity against SARS-CoV-2 infection using a pseudotyped SARS-CoV-2 entry assay system. We demonstrated that this inhibitory effect of LA was due to the alteration of membrane cholesterol and blockade of the membrane fusion between SARS-CoV-2 and host cells by filipin staining and cell-based membrane fusion assays. Our findings also showed that LA, as a membrane fusion blocker, could impede the endosomal entry pathway of SARS-CoV-2 and its variants of concern (VOCs), including Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2), and Omicron (B.1.1.529), in Vero cells with similar of IC₅₀ values ranging from 2.23 to 3.37 μM as well as the TMPRSS2-mediated viral entry pathway in A549 cells overexpressing ACE2 and TMPRSS2 with IC₅₀ value of 3.92 μM. We further demonstrated that LA could prevent the formation of multinucleated syncytia arising from SARS-CoV-2 spike protein-mediated membrane fusion. Altogether, the findings reported here suggested that LA could be a broad-spectrum anti-SARS-CoV-2 therapeutic agent by targeting the fusion of viral envelope with the host cell membrane.

Distribution, biotransformation, pharmacological effects, metabolic mechanism and safety evaluation of Platycodin D：A comprehensive review

Platycodonis Radix (Jiegeng), the dried root of Platycodon grandiflorum, is a traditional herb used as both medicine and food. Its clinical application for the treatment of cough, phlegm, sore throat, pulmonary and respiratory diseases has been thousands of years in China. Platycodin D is the main active ingredient in Platycodonis Radix, which belongs to the family of pentacyclic triterpenoid saponins because it contains an oleanolane type aglycone linked with double sugar chains. Modern pharmacology has demonstrated that Platycodin D displays various biological activities, such as analgesics, expectoration and cough suppression, promoting weight loss, anti-tumor and immune regulation, suggesting that Platycodin D has the potential to be a drug candidate and an interesting target as a natural product for clinical research. In this review, the distribution and biotransformation, pharmacological effects, metabolic mechanism and safety evaluation of Platycodin D are summarized to lay the foundation for further studies.

Safety evaluation of fermented Platycodon grandiflorus (Jacq.) A.DC. extract: Genotoxicity, acute toxicity, and 13-week subchronic toxicity study in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Platycodon grandiflorus (Jacq.) A.DC. is a well-known traditional herbal medicine administered for bronchitis and inflammatory diseases. Especially, anti-inflammatory effect of fermented P. grandiflorus (Jacq.) A.DC. extract (FPGE) was higher than that of P. grandiflorus (Jacq.) A.DC. extract. However, toxicological information for FPGE is lacking.

AIM OF THE STUDY

In this study, we establish a toxicological profile for FPGE by testing genotoxicity, acute and 13-week subchronic toxicity.

MATERIALS AND METHODS

FPGE was evaluated with bacterial reverse mutation, chromosome aberration, and micronucleus test. For the acute- and 13-week subchronic toxicity tests, FPGE was administered orally at doses of 0, 750, 1500, and 3000 mg/kg in SD rats.

RESULTS

The results of the genotoxic assays indicated that FPGE induced neither mutagenicity nor clastogenicity. The acute toxicity test showed that FPGE did not affect animal mortality, clinical signs, body weight changes, or microscopic findings at ≤ 3000 mg/kg. The approximate lethal dose (ALD) of FPGE in SD rats was >3000 mg/kg. For the 13-week subchronic toxicity assay, no FPGE dose induced any significant change in mortality, clinical signs, body or organ weight, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination in either SD rat sex. The rat no observed adverse effects level (NOAEL) for FPGE was set to 3000 mg/kg.

CONCLUSIONS

The present study empirically demonstrated that FPGE has a safe preclinical profile and indicated that it could be safely integrated into health products for atopic dermatitis treatment.

Platycodin D enhances LDLR expression and LDL uptake via down-regulation of IDOL mRNA in hepatic cells

The root of Platycodon grandiflorum (PG) has long been used as a traditional herbal medicine in Asian country. Platycondin D (PD), triterpenoid saponin that is a main constituent of PG, exhibits various biological activities such as anti-inflammatory, anti-oxidant, anti-diabetic, and anti-cancer effects. A previous study showed that PD had cholesterol-lowering effects in mice that develop hypercholesterolemia, but the underlying molecular mechanisms have not been elucidated during the last decade. Here, we demonstrated that both PG and PD markedly increased levels of cell surface low-density lipoprotein receptor (LDLR) by down-regulation of the E3 ubiquitin ligase named inducible degrader of the LDLR (IDOL) mRNA, leading to the enhanced uptake of LDL-derived cholesterol (LDL-C) in hepatic cells. Furthermore, cycloheximide chase analysis and in vivo ubiquitination assay revealed that PD increased the half-life of LDLR protein by reducing IDOL-mediated LDLR ubiquitination. Finally, we demonstrated that treatment of HepG2 cells with simvastatin in combination with PG and PD had synergistic effects on the improvement of LDLR expression and LDL-C uptake. Together, these results provide the first molecular evidence for anti-hypercholesterolemic activity of PD and suggest that PD alone or together with statin could be a potential therapeutic option in the treatment of atherosclerotic cardiovascular disease.

Bioactive platycodins from Platycodonis Radix: Phytochemistry, pharmacological activities, toxicology and pharmacokinetics

Platycodonis Radix, the root of Platycodon grandiflorum (Jacq.) A. DC., is a well-known edible herbal medicine. It is a common vegetable used for the preparation of side dish, kimchi, dessert, and tea. Besides, it has been used to treat respiratory disease including cough, excessive phlegm, and sore throat for a long history. In the past decades, the bioactive components and the pharmacological activities of Platycodonis Radix have been widely investigated. Thereinto, platycodins, the oleanane-type triterpenoid saponins were demonstrated to be the main bioactive components in Platycodonis Radix, and more than 70 platycodins have been identified up to date. This paper mainly reviewed the phytochemistry, pharmacological activities (apophlegmatic, anti-tussive, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, immunomodulatory, cardiovascular protective, and hepatoprotective activities, etc.), toxicology and pharmacokinetics of platycodins isolated from Platycodonis Radix, aiming to promote further investigation on therapeutic potential of these platycodins.

Biocatalysis of Platycoside E and Platycodin D3 Using Fungal Extracellular β-Glucosidase Responsible for Rapid Platycodin D Production

Platycodi radix (i.e., Platycodon grandiflorum root) products (e.g., tea, cosmetics, and herbal supplements) are popular in East Asian nutraceutical markets due to their reported health benefits and positive consumer perceptions. Platycosides are the key drivers of Platycodi radixes' biofunctional effects; their nutraceutical and pharmaceutical activities are primarily related to the number and varieties of sugar side-chains. Among the various platycosides, platycodin D is a major saponin that demonstrates various nutraceutical activities. Therefore, the development of a novel technology to increase the total platycodin D content in Platycodi radix extract is important, not only for consumers' health benefits but also producers' commercial applications and manufacturing cost reduction. It has been reported that hydrolysis of platycoside sugar moieties significantly modifies the compound's biofunctionality. Platycodi radix extract naturally contains two major platycodin D precursors (platycoside E and platycodin D3) which can be enzymatically converted to platycodin D via β-d-glucosidase hydrolysis. Despite evidence that platycodin D precursors can be changed to platycodin D in the Platycodi radix plant, there is little research on increasing platycodin D concentrations during processing. In this work, platycodin D levels in Platycodi radix extracts were significantly increased via extracellular Aspergillus usamii β-d-glucosidase (n = 3, p < 0.001). To increase the extracellular β-d-glucosidase activity, A. usamii was cultivated in a culture media containing cellobiose as its major carbon source. The optimal pH and temperature of the fungal β-d-glucosidase were 6.0 and 40.0 °C, respectively. Extracellular A. usamii β-d-glucosidase successfully converted more than 99.9% (w/v, n = 3, p < 0.001) of platycoside E and platycodin D3 into platycodin D within 2 h under optimal conditions. The maximum level of platycodin D was 0.4 mM. Following the biotransformation process, the platycodin D was recovered using preparatory High Performance Liquid Chromatography (HPLC) and applied to in vitro assays to evaluate its quality. Platycodin D separated from the Platycodi radix immediately following the bioconversion process showed significant anti-inflammatory effects from the Lipopolysaccharide (LPS)-induced macrophage inflammatory responses with decreased nitrite and IL-6 production (n = 3, p < 0.001). Taken together, these results provide evidence that biocatalysis of Platycodi radix extracts with A. usamii may be used as an efficient method of platycodin D-enriched extract production and novel Platycodi radix products may thereby be created.

Understanding the Molecular Mechanisms of the Interplay Between Herbal Medicines and Gut Microbiota

Herbal medicines (HMs) are much appreciated for their significant contribution to human survival and reproduction by remedial and prophylactic management of diseases. Defining the scientific basis of HMs will substantiate their value and promote their modernization. Ever-increasing evidence suggests that gut microbiota plays a crucial role in HM therapy by complicated interplay with HM components. This interplay includes such activities as: gut microbiota biotransforming HM chemicals into metabolites that harbor different bioavailability and bioactivity/toxicity from their precursors; HM chemicals improving the composition of gut microbiota, consequently ameliorating its dysfunction as well as associated pathological conditions; and gut microbiota mediating the interactions (synergistic and antagonistic) between the multiple chemicals in HMs. More advanced experimental designs are recommended for future study, such as overall chemical characterization of gut microbiota-metabolized HMs, direct microbial analysis of HM-targeted gut microbiota, and precise gut microbiota research model development. The outcomes of such research can further elucidate the interactions between HMs and gut microbiota, thereby opening a new window for defining the scientific basis of HMs and for guiding HM-based drug discovery.

Metabolite identification and pharmacokinetic study of platycodi radix (Jiegeng) in vivo

The secondary platycosides, 3-O-β-d-glucopyranosylplatycodigenin and 3-O-β-d-glucopyranosylplatyconic acid, were qualitatively and quantitatively analyzed in vivo for the first time.

Yiqi Wenyang Fang ameliorates allergic rhinitis through inhibiting inflammatory response and promoting the expression of Foxp3

Allergic rhinitis (AR) is an inflammatory disease with a hypersensitivity response to environmental stimulus. The aim of this study was to evaluate the effect of Yiqi Wenyang Fang (YWF) on AR and investigate the underlying mechanism. A total of 48 female Sprague-Dawley rats were randomly divided into six groups (normal control, model control, YWF at low dose, YWF at median dose, YWF at high dose, and loratadine). Rats were injected with antigen for sensitization. Then, rats in the YWF groups were treated with different dose of YWF for 28 days. Loratadine was used as a positive control. Number of sneezes, degree of runny nose, nasal rubbing movements, and tissue damage were scored. The protein and mRNA expression of Foxp3 were determined by western blot and real time-PCR analysis, respectively. Flow cytometry was used to detect the number of CD4⁺CD25⁺Foxp3⁺ Treg cells. The content of interleukin (IL)-10, transforming growth factor β1 (TGF-β1), IL-13, and IL-4 in the serum were detected by enzyme-linked immunosorbent assay (ELISA). Scores of symptoms were significantly reduced and nasal mucosa damage was alleviated after YWF administration. YWF increased the expression of Foxp3, IL-10, TGF-β1, and number of CD4⁺CD25⁺Foxp3⁺ Treg cells which were reduced by antigen injection. The expression levels of IL-13 and IL-4 were increased after antigen administration while decreased after YWF treatment. YWF may ameliorate AR through inhibiting inflammatory response and promoting Foxp3 expression.