Comparative pharmacokinetics between madecassoside and asiaticoside presented in a standardised extract of Centella asiatica, ECa 233 and their respective pure compound given separately in rats

Investigating pharmacokinetic profiles of Centella asiatica using machine learning and PBPK modelling

Physiologically based pharmacokinetic (PBPK) modeling serves as a valuable tool for determining the distribution and disposition of substances in the body of an organism. It involves a mathematical representation of the interrelationships among crucial physiological, biochemical, and physicochemical parameters. A lack of the values of pharmacokinetic parameters can be challenging in constructing a PBPK model. Herein, we propose an artificial intelligence framework to evaluate a key pharmacokinetic parameter, the intestinal effective permeability (Peff). The publicly available Peff dataset was utilized to develop regression machine learning models. The XGBoost model demonstrates the best test accuracy of R-squared (R2, coefficient of determination) of 0.68. The model is then applied to compute the Peff of asiaticoside and madecassoside, the parent compounds found in Centella asiatica. Subsequently, PBPK modeling was conducted to evaluate the biodistribution of the herbal substances following oral administration in a rat model. The simulation results were evaluated and validated, which agreed with the existing in vivo studies in rats. This in silico pipeline presents a potential approach for investigating the pharmacokinetic parameters and profiles of drugs or herbal substances, which can be used independently or integrated into other modeling systems.

Amelioration of age-related cognitive decline and anxiety in mice by Centella asiatica extract varies by sex, dose and mode of administration

Background: A water extract (CAW) of the Ayurvedic plant Centella asiatica administered in drinking water has been shown to improve cognitive deficits in mouse models of aging and neurodegenerative diseases. Here the effects of CAW administered in drinking water or the diet on cognition, measures of anxiety and depression-like behavior in healthy aged mice are compared. Methods: Three- and eighteen-month-old male and female C57BL6 mice were administered rodent AIN-93M diet containing CAW (0, 0.2, 0.5 or 1% w/w) to provide 0, 200 mg/kg/d, 500 mg/kg/d or 1,000 mg/kg/d CAW for a total of 5 weeks. An additional group of eighteen-month-old mice were treated with CAW (10 mg/mL) in their drinking water CAW for a total of 5 weeks to deliver the same exposure of CAW as the highest dietary dose (1,000 mg/kg/d). CAW doses delivered were calculated based on food and water consumption measured in previous experiments. In the fourth and fifth weeks, mice underwent behavioral testing of cognition, anxiety and depression (n = 12 of each sex per treatment group in each test). Results: Aged mice of both sexes showed cognitive deficits relative to young mice while only female aged mice showed increased anxiety compared to the young female mice and no differences in depression were observed between the different ages. CAW (1,000 mg/kg/d) in the drinking water improved deficits in aged mice in learning, executive function and recognition memory in both sexes and attenuated the increased measures of anxiety observed in the aged female mice. However, CAW in the diet only improved executive function in aged mice at the highest dose (1,000 mg/kg/d) in both sexes and did so less robustly than when given in the water. There were no effects of CAW on depression-like behavior in aged animals regardless of whether it was administered in the diet or the water. Conclusions: These results suggest that CAW can ameliorate age-related changes in measures of anxiety and cognition and that the mode of administration is important for the effects of CAW on resilience to these age-related changes.

Sub-chronic oral toxicity of a water-soluble extract of Centella asiatica (Centell-S) in Wistar rats

BACKGROUND

Centell-S, a water-soluble extract from Centella asiatica, is predominantly composed of madecassoside and asiaticoside, exceeding 80% w/w. Pursuing its development as an herbal medicinal product, Centell-S underwent sub-chronic toxicity assessment adhering to OECD GLP 408 standards.

METHODS

In a study involving 100 Wistar rats, varying doses of Centell-S (50, 200, or 800 mg/kg/day) or a vehicle control were administered orally over 90 days. To evaluate Centell-S's safety profile, assessments included clinical observations, health examinations, clinical biochemistry analyses, and detailed anatomical pathology evaluations were conducted.

RESULTS

Over the 90 days of treatment, the administration of Centell-S did not lead to any fatalities in the test animals. Clinical observations did not reveal any signs indicative of toxic effects. Notably, an increase in total white blood cell and lymphocyte counts was observed in both sexes, yet these levels returned to normal following a two-week discontinuation period post-treatment.

CONCLUSIONS

Under the specific conditions of the OECD GLP 408, Repeated Dose 90-day Oral Toxicity Study in Rodents, the no observed adverse effect level (NOAEL) of Centell-S was 800 mg/kg/day. These findings are promising for the continued development of Centell-S as a phytopharmaceutical for clinical applications.

Protective effects of madecassoside, a triterpenoid from Centella asiatica, against oxidative stress in INS-1E cells

Progressive decline in β cell function and reduction in the β cell mass is important in type 2 diabetes. Here, we tested the hypothesis that madecassoside's previously demonstrated in vivo protective effects on the β cell in experimental diabetes were exerted directly. We investigated the effects of madecassoside in protecting a β cell line (INS-1E) against a variety of agents. INS-1E cells were treated with madecassoside in the presence of high glucose (HG), a cytokine mixture, hydrogen peroxide (H2O2), or streptozotocin (STZ). HG, the cytokine mixture, H2O2 and STZ each produced a significant decrease in cell viability; this was significantly reversed by madecassoside. Pre-treatment with madecassoside reduced the number of apoptotic cells induced by HG, the cytokine mixture, H2O2, and STZ, and concentration-dependently reduced ROS production. Madecassoside also significantly enhanced glucose-induced insulin secretion. The results suggest that madecassoside's in vivo effects are exerted directly on the β cell.

Permeation of Phytochemicals of Selected Psychoactive Medicinal Plants across Excised Sheep Respiratory and Olfactory Epithelial Tissues

The intranasal route of drug administration offers an opportunity to bypass the blood-brain barrier and deliver compounds directly into the brain. Scientific evidence exists for medicinal plants (e.g., Centella asiatica and Mesembryanthemum tortuosum) to treat central nervous system conditions such as anxiety and depression. The ex vivo permeation of selected phytochemicals (i.e., asiaticoside and mesembrine) has been measured across excised sheep nasal respiratory and olfactory tissue. Permeation studies were conducted on individual phytochemicals and C. asiatica and M. tortuosum crude extracts. Asiaticoside exhibited statistically significantly higher permeation across both tissues when applied alone as compared to the C. asiatica crude extract, while mesembrine permeation was similar when applied alone or as M. tortuosum crude extract. Permeation of all the phytocompounds was similar or slightly higher than that of the drug atenolol across the respiratory tissue. Permeation of all the phytocompounds was similar to or slightly lower than that of atenolol across the olfactory tissue. In general, the permeation was higher across the olfactory epithelial tissue than across the respiratory epithelial tissue and therefore showed potential for direct nose-to-brain delivery of the selected psychoactive phytochemicals.

A review of pharmacokinetic and pharmacological properties of asiaticoside, a major active constituent of Centella asiatica (L.) Urb

ETHNOPHARMACOLOGICAL RELEVANCE

Centella asiatica (L.) Urb., a potential medicinal plant, is widely used in orient traditional medicine. Its major active constituents include asiaticoside (AS), madecassoside (MS), asiatic acid and madecassic acid. Thereinto, AS is a pentacyclic triterpenoid saponin with a variety of pharmacological effects including antitumor, neuroprotective and wound healing effects.

AIM OF THE STUDY

In this review, we summarize the pharmacokinetics, safety and pharmacological properties of AS.

MATERIALS AND METHODS

We gathered information about AS from articles published up to 2022 and listed in Google scholar, PubMed, Web of Science, Elsevier, and similar databases. The keywords used in our search included "asiaticoside", "Centella asiatica", "pharmacokinetics", "nerve", "cancer", "skin", etc. RESULTS: AS appeared to degrade through a first-order reaction and had low biotoxicity. However, the pharmacokinetic properties of AS differed according to species. AS is highly blood-brain-barrier permeable without any harmful side effect. It has a variety of pharmacological effects including anti-neural inflammation and anti-cancer properties, as well as protective properties for the skin, cardiovascular system, and pulmonary system.

CONCLUSION

This review comprehensively summarized current information regarding the pharmacokinetic and pharmacological properties of AS, and supported the pharmaceutical value of this compound. Future research should focus on improving bioavailability of AS and conducting clinical assessment.

Bioenhancing effects of piperine and curcumin on triterpenoid pharmacokinetics and neurodegenerative metabolomes from Centella asiatica extract in beagle dogs

Centell-S is a water-soluble extract of Centella asiatica containing more than 80% w/w triterpenoid glycosides. Madecassoside and asiaticoside are two major components of the extract and can be converted into active metabolites, triterpenic acids in large mammal species. In this study, the pharmacokinetic profiles and metabolomic changes generated by the bioactive triterpenoids of Centell-S alone, and in combination with the bioenhancers piperine and curcumin, were investigated in beagle dogs. The test substances were orally administered over multiple doses for 7 consecutive days. At day 1 and 7 after receiving the test compounds, the level of major bioactive triterpenoids and related metabolites were measured using triple quadrupole and high-resolution accurate mass orbitrap models of LCMS to determine pharmacokinetic and metabolomic profiles, respectively. Centell-S was well tolerated, alone and in all combination groups. The combination of Centell-S and piperine significantly increased (p < 0.05) the systemic exposure of madecassoside on day 1 and asiatic acid on day 7, by approximately 1.5 to 3.0-fold of C_max and AUC values as compared to the Centell-S alone, while the addition of curcumin did not provide a significant improvement. Several metabolomic changes were observed from pre-dose to 4 h post-dose, with some biomarkers of neurodegenerative diseases including L-glutamine, lysophosphatidylcholine (17:0), taurochenodeoxycholic acid, uric acid, stearic acid, palmitic acid, and lactic acid showing good correlation with the systemic exposure of the bioactive triterpenoids (asiatic acid). Thus, the combining of piperine to Centell-S exhibits the improvement of bioactive triterpenoids which are related to the biomarkers of neurodegenerative diseases. These promising results might be useful for the development of this standardised extract to become a more effective phytomedicine for neurodegenerative diseases.

Increase water solubility of Centella asiatica extract by indigenous bioenhancers could improve oral bioavailability and disposition kinetics of triterpenoid glycosides in beagle dogs

A newly standardised extract of Centellaasiatica (Centell-S) with better water solubility than the previous standardised extract of C.asiatica (ECa 233) was developed, and pharmacokinetic profiles of bioactive triterpenoids were investigated in beagle dogs. The test substances were administered via intravenous or oral administration with single and multiple doses for 7 days. The concentrations of major bioactive triterpenoids, including madecassoside, asiaticoside, madecassic acid, and asiatic acid, in biological samples were measured by liquid chromatography–tandem mass spectrometry. The dogs in this study showed good tolerability to all test substances, based on the physical appearance and blood chemistry 24 h after dosing. The major bioactive triterpenoids found in systemic blood circulation were madecassoside, asiaticoside, and asiatic acid; the concentration of these components ranged from 1 to 10,000 µg/L after intravenous administration of 1.0 mg/kg Centell-S. Oral administration of 10 and 20 mg/kg Centell-S generated approximately twofold higher plasma levels of both madecassoside and asiaticoside compared with equivalent doses of ECa 233. In addition, there was an accumulation of triterpenoid glycosides after multiple oral administrations of Centell-S for 7 days, while triterpenic acids showed little tendency for accumulation. Beagles had good tolerability to both standardised extracts of C.asiatica, and showed a similar pattern of bioactive triterpenoids to humans. Centell-S increased oral bioavailability of major triterpenoid glycosides and can be further developed into a phytopharmaceutical product.

Anti-excitotoxicity and neuroprotective action of asiaticoside encapsulated polymeric nanoparticles in pilocarpine rodent seizure model

Asiaticoside (ASI), an ursane-type triterpenoid saponin, isolated from the memory enhancing herb Centella asiatica, is known for its neuroprotective activities. Here the anti-excitotoxicity and neuro protective effects of ASI encapsulated alginate chitosan nanoparticles (ACNPs) were evaluated in pilocarpine (PC) induced seizure in mice model. ACNPs were prepared by ionic gelation-polyelectrolyte complex method and their physicochemical characterization was carried out by TEM, SEM, DLS, XRD and FT-IR. Subsequently their encapsulation efficiency (EE), in vitro drug release, cell viability, seizure score, DNA fragmentation and mRNA expression of regulatory stress markers were evaluated. Membrane permeability of ACNPs in brain, histopathology and biological TEM and SEM analyses were also carried out. TEM of ACNPs showed spherical morphology with a particle size of 200-400 nm. DLS of ACNPs displayed an average size of 486.2 nm with polydispersity index (PDI) of 0.567 and zeta potential of -14.1 mV. ACNPs achieved high EE (> 90%) and controlled release (10%). Biological evaluation studies revealed ACNPs as non-toxic to mouse neural stem cells (mNSCs). They displayed enhanced brain permeability and attenuated seizure. Our results confirmed ACNPs as effective in crossing the brain membrane barrier and mitigating seizure severity induced by PC.

Drug-Herb Interactions among Thai Herbs and Anticancer Drugs: A Scoping Review

More than half of Thai patients with cancer take herbal preparations while receiving anticancer therapy. There is no systematic or scoping review on interactions between anticancer drugs and Thai herbs, although several research articles have that Thai herbs inhibit cytochrome P450 (CYP) or efflux transporter. Therefore, we gathered and integrated information related to the interactions between anticancer drugs and Thai herbs. Fifty-two anticancer drugs from the 2020 Thailand National List of Essential Medicines and 75 herbs from the 2020 Thai Herbal Pharmacopoeia were selected to determine potential anticancer drug–herb interactions. The pharmacological profiles of the selected anticancer drugs were reviewed and matched with the herbal pharmacological activities to determine possible interactions. A large number of potential anticancer drug–herb interactions were found; the majority involved CYP inhibition. Efflux transporter inhibition and enzyme induction were also found, which could interfere with the pharmacokinetic profiles of anticancer drugs. However, there is limited knowledge on the pharmacodynamic interactions between anticancer drugs and Thai herbs. Therefore, further research is warranted. Information regarding interactions between anticancer drugs and Thai herbs should provide as a useful resource to healthcare professionals in daily practice. It could enable the prediction of possible anticancer drug–herb interactions and could be used to optimize cancer therapy outcomes.

Hypoxia-Induced Neuroinflammation in Alzheimer's Disease: Potential Neuroprotective Effects of Centella asiatica

Alzheimer's disease (AD) is a neurodegenerative disorder that is characterised by the presence of extracellular beta-amyloid fibrillary plaques and intraneuronal neurofibrillary tau tangles in the brain. Recurring failures of drug candidates targeting these pathways have prompted research in AD multifactorial pathogenesis, including the role of neuroinflammation. Triggered by various factors, such as hypoxia, neuroinflammation is strongly linked to AD susceptibility and/or progression to dementia. Chronic hypoxia induces neuroinflammation by activating microglia, the resident immune cells in the brain, along with an increased in reactive oxygen species and pro-inflammatory cytokines, features that are common to many degenerative central nervous system (CNS) disorders. Hence, interests are emerging on therapeutic agents and plant derivatives for AD that target the hypoxia-neuroinflammation pathway. Centella asiatica is one of the natural products reported to show neuroprotective effects in various models of CNS diseases. Here, we review the complex hypoxia-induced neuroinflammation in the pathogenesis of AD and the potential application of Centella asiatica as a therapeutic agent in AD or dementia.

Actions and Therapeutic Potential of Madecassoside and Other Major Constituents of Centella asiatica: A Review

Centella asiatica is a popular herb well-known for its wide range of therapeutic effects and its use as a folk medicine for many years. Its therapeutic properties have been well correlated with the presence of asiaticoside, madecassoside, asiatic and madecassic acids, the pentacyclic triterpenes. The herb has been extensively known to treat skin conditions; nevertheless, several pre-clinical and clinical studies have scientifically demonstrated its effectiveness in other disorders. Among the active constituents that have been identified in Centella asiatica, madecassoside has been the subject of only a relatively small number of scientific reports. Therefore, this review, while including other major constituents of this plant, focuses on the therapeutic potential, pharmacokinetics and toxicity of madecassoside.

Immunomodulatory effect of standardized C. asiatica extract on a promotion of regulatory T cells in rats

Background

ECa 233 is a standardized extract of C. asiatica containing the triterpenoid glycosides, madecassoside to asiaticoside in the ratio of (1.5 ± 0.5):1. Anti-inflammatory activities of ECa 233 have been reported; however the immunomodulatory effects of ECa 233 on regulatory T cells, which have a pivotal role in immune regulation, has not been elucidated. Therefore, we investigated the effects of ECa 233 on regulatory T cells that may provide benefits in autoimmune and chronic inflammatory diseases.

Methods

ECa 233 was prepared as oral suspension in 0.5% carboxymethylcellulose and administered to male Wistar rats via oral gavage. The pharmacokinetics and toxicity of ECa 233 were evaluated. Splenic lymphocytes were isolated and analyzed by flow cytometry and qPCR to determine the immunomodulatory effects of ECa 233 on regulatory T cells.

Results

All rats had good tolerability to ECa 233 and other test preparations. The pharmacokinetic study showed low oral bioavailability for both triterpenoids, with the maximum plasma concentration reached at 4 h for asiaticoside and at 0.5 h for madecassoside. Multiple oral administration of ECa 233 reduced the frequency of T cells, particularly CD8 T cells in rats. ECa 233 enhanced the percentage of regulatory T cells, characterized by high expression of CD25⁺ and upregulation of FoxP3 gene.

Conclusions

The present study demonstrated that ECa 233 possesses immunosuppressive properties by enhancing regulatory T cells. These results provide in vivo evidence for the anti-inflammatory action of ECa 233, in line with previously reports, and the potential uses of ECa 233 in the treatment of chronic inflammatory and autoimmune diseases.

Asiatic acid ameliorates obesity-related osteoarthritis by inhibiting myeloid differentiation protein-2

Obesity is related to osteoarthritis (OA). Aberrant lipid metabolism results in increased levels of free fatty acids, such as palmitate (PA), leading to inflammatory responses and excess catabolism of chondrocytes. Asiatic acid (AA), a plant anti-inflammatory compound, has been reported to exert protective effects for several diseases, but its effect on obesity-related OA is still unclear. The aim of this study is to evaluate the chondro-protective effect of AA on PA-induced human chondrocytes and a high fat diet (HFD)-fed mouse cartilage degeneration model. In vitro, the levels of the inflammatory and extracellular matrix (ECM) markers of chondrocytes after being treated with PA (500 μM) and AA (2.5-10 μM) were determined using western blotting and immunofluorescence enzyme-linked immunosorbent assay (ELISA). In vivo, after the oral administration of HFD and AA, X-ray examination, safranin O staining, and ELISA assay were conducted to evaluate cartilage calcification and degeneration and cytokine and adipokine levels in the serum of mice. AA treatment eliminated the inflammation caused by PA and extracellular matrix degradation. Mechanistically, AA blocked the stimulation of the NF-κB pathway. Analysis with co-immunoprecipitation and molecular docking indicated that the MD-2/TLR4 complex was a target of AA. In vivo, AA treatment not only prevented HFD-induced OA changes but also reduced proinflammatory cytokine and adipokine production in obese mice. AA exerted a chondroprotective effect by inhibiting the TLR4/MD-2 axis, thus showing promise for treating obesity-related OA.

Toward a better understanding of metabolic and pharmacokinetic characteristics of low-solubility, low-permeability natural medicines

Today, it is very challenging to develop new active pharmaceutical ingredients. Developing good preparations of well-recognized natural medicines is certainly a practical and economic strategy. Low-solubility, low-permeability natural medicines (LLNMs) possess valuable advantages such as effectiveness, relative low cost and low toxicity, which is shown by the presence of popular products on the market. Understanding the in vivo metabolic and pharmacokinetic characteristics of LLNMs contributes to overcoming their associated problems, such as low absorption and low bioavailability. In this review, the structure-based metabolic reactions of LLNMs and related enzymatic systems, cellular and bodily pharmacological effects and metabolic influences, drug-drug interactions involved in metabolism and microenvironmental changes, and pharmacokinetics and dose-dependent/linear pharmacokinetic models are comprehensively evaluated. This review suggests that better pharmacological activity and pharmacokinetic behaviors may be achieved by modifying the metabolism through using nanotechnology and nanosystem in combination with the suitable administration route and dosage. It is noteworthy that novel nanosystems, such as triggered-release liposomes, nucleic acid polymer nanosystems and PEGylated dendrimers, in addition to prodrug and intestinal penetration enhancer, demonstrate encouraging performance. Insights into the metabolic and pharmacokinetic characteristics of LLNMs may help pharmacists to identify new LLNM formulations with high bioavailability and amazing efficacy and help physicians carry out LLNM-based precision medicine and individualized therapies.

Pharmacological Properties, Molecular Mechanisms, and Pharmaceutical Development of Asiatic Acid: A Pentacyclic Triterpenoid of Therapeutic Promise

Asiatic acid (AA) is a naturally occurring aglycone of ursane type pentacyclic triterpenoids. It is abundantly present in many edible and medicinal plants including Centella asiatica that is a reputed herb in many traditional medicine formulations for wound healing and neuropsychiatric diseases. AA possesses numerous pharmacological activities such as antioxidant and anti-inflammatory and regulates apoptosis that attributes its therapeutic effects in numerous diseases. AA showed potent antihypertensive, nootropic, neuroprotective, cardioprotective, antimicrobial, and antitumor activities in preclinical studies. In various in vitro and in vivo studies, AA found to affect many enzymes, receptors, growth factors, transcription factors, apoptotic proteins, and cell signaling cascades. This review aims to represent the available reports on therapeutic potential and the underlying pharmacological and molecular mechanisms of AA. The review also also discusses the challenges and prospects on the pharmaceutical development of AA such as pharmacokinetics, physicochemical properties, analysis and structural modifications, and drug delivery. AA showed favorable pharmacokinetics and found bioavailable following oral or interaperitoneal administration. The studies demonstrate the polypharmacological properties, therapeutic potential and molecular mechanisms of AA in numerous diseases. Taken together the evidences from available studies, AA appears one of the important multitargeted polypharmacological agents of natural origin for further pharmaceutical development and clinical application. Provided the favorable pharmacokinetics, safety, and efficacy, AA can be a promising agent or adjuvant along with currently used modern medicines with a pharmacological basis of its use in therapeutics.