Factors Influencing Oral Bioavailability of Thai Mango Seed Kernel Extract and Its Key Phenolic Principles

Potent Antifungal Activity of Penta-O-galloyl-β-d-Glucose against Drug-Resistant Candida albicans, Candida auris, and Other Non-albicans Candida Species

Among fungal pathogens, infections by drug-resistant Candida species continue to pose a major challenge to healthcare. This study aimed to evaluate the activity of the bioactive natural product, penta-O-galloyl-β-d-glucose (PGG) against multidrug-resistant (MDR) Candida albicans, MDR Candida auris, and other MDR non-albicans Candida species. Here, we show that PGG has a minimum inhibitory concentration (MIC) of 0.25-8 μg mL-1 (0.265-8.5 μM) against three clinical strains of C. auris and a MIC of 0.25-4 μg mL-1 (0.265-4.25 μM) against a panel of other MDR Candida species. Our cytotoxicity studies found that PGG was well tolerated by human kidney, liver, and epithelial cells with an IC50 > 256 μg mL-1 (>272 μM). We also show that PGG is a high-capacity iron chelator and that deletion of key iron homeostasis genes in C. albicans rendered strains hypersensitive to PGG. In conclusion, PGG displayed potent anti-Candida activity with minimal cytotoxicity for human cells. We also found that the antifungal activity of PGG is mediated through an iron-chelating mechanism, suggesting that the compound could prove useful as a topical treatment for superficial Candida infections.

Pentagalloyl Glucose: A Review of Anticancer Properties, Molecular Targets, Mechanisms of Action, Pharmacokinetics, and Safety Profile

Pentagalloyl glucose (PGG) is a natural hydrolyzable gallotannin abundant in various plants and herbs. It has a broad range of biological activities, specifically anticancer activities, and numerous molecular targets. Despite multiple studies available on the pharmacological action of PGG, the molecular mechanisms underlying the anticancer effects of PGG are unclear. Here, we have critically reviewed the natural sources of PGG, its anticancer properties, and underlying mechanisms of action. We found that multiple natural sources of PGG are available, and the existing production technology is sufficient to produce large quantities of the required product. Three plants (or their parts) with maximum PGG content were Rhus chinensis Mill, Bouea macrophylla seed, and Mangifera indica kernel. PGG acts on multiple molecular targets and signaling pathways associated with the hallmarks of cancer to inhibit growth, angiogenesis, and metastasis of several cancers. Moreover, PGG can enhance the efficacy of chemotherapy and radiotherapy by modulating various cancer-associated pathways. Therefore, PGG can be used for treating different human cancers; nevertheless, the data on the pharmacokinetics and safety profile of PGG are limited, and further studies are essential to define the clinical use of PGG in cancer therapies.

Screening bioactive compounds from Danggui-shaoyao-san for treating sodium retention in nephrotic syndrome using bio-affinity ultrafiltration

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui-shaoyao-san (DSS), a representative formula of Traditional Chinese Medicine (TCM) for promoting blood circulation and diuresis (Huo-Xue-Li-Shui) therapy, has been used to clinically nephrotic syndrome (NS) and relieve nephrotic edema.

AIM OF THE STUDY

To explore the effects and mechanisms of DSS in improving sodium retention and to identify the bioactive compounds from DSS.

MATERIALS AND METHODS

DSS prescriptions were disassembled into Yangxue-Huoxue (YXHX) and Jianpi-Lishui (JPLS). A nephrotic rat model was induced with puromycin aminonucleoside (PAN), and the effects on urinary sodium excretion, urinary plasmin(gen) content, and plasmin activity of DSS, YXHX, and JPLS extracts were assessed. The inhibitory effects on urokinase-type plasminogen activator (uPA) and plasmin activity of extracts were evaluated in vitro. Bio-affinity ultrafiltration and high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (BAU-UPLC-Q/TOF-MS) were used to rapidly screen and qualitatively analyze the uPA/plasmin affinity compounds from DSS extract. Additionally, uPA/plasmin inhibition assays and molecular docking were used to verify the activity and affinity mechanisms of the potential bioactive compounds.

RESULTS

In vivo, DSS, YXHX, and JPLS prevented sodium retention in nephrotic rats. DSS and YXHX treatment decreased urinary plasmin activity but did not alter urinary plasmin(ogen) concentration, and their extracts showed strong uPA and plasmin inhibitory activity in vitro. These results suggested that uPA and plasmin are direct targets of DSS and YXHX in intervening NS sodium retention. Using BAU-UPLC-Q/TOF-MS, gallic acids, methyl gallate, albiflorin, and 1,2,3,4,6-O-pentagalloylglucose (PGG) were screened as uPA or plasmin affinity compounds. Among them, PGG was found to be a uPA and plasmin dual inhibitor, with an IC₅₀ of 6.861 μM against uPA and an IC₅₀ of 149.0 μM against plasmin. The molecular docking results of PGG with uPA and plasmin were consistent with the verification results.

CONCLUSION

Intervening in sodium retention by inhibiting uPA-mediated plasmin generation and plasmin activity in the kidneys could be possible mechanisms for DSS, as indicated by the results in PAN-induced nephrotic rats. We conclude that PGG is a potential bioactive compound responsible for the effect of DSS on natriuresis.

Therapeutic potential of mangiferin against kidney disorders and its mechanism of action: A review

There is a swing in research developments concerning the utilization of natural products as effective pharmacotherapeutic agents due to their comparatively lower toxicities than synthetic compounds. Among natural products, mangiferin is a natural C-glucosyl xanthonoid polyphenol with remarkable pharmacological activities. Emerging evidence indicates the therapeutic benefits of mangiferin against various kidney disorders, including renal injury, diabetic nephropathy, renal fibrosis, hyperuricemic nephropathy, and lupus nephritis, in experimental animal models. The mangiferin induced antioxidant response resulting in vital functions, such as protection against renal inflammation, inhibits renal cell apoptosis, activates autophagy, causes immunomodulation, regulates renal urate transporters and modulates cell signalling pathways. The purpose of this review provide a brief overview of the in vitro/in vivo reno-protective effect of mangiferin and the underlying mechanism(s) in protecting against kidney disorders. Understanding the pharmacological actions of mangiferin is prominence due to its excellent therapeutic potential in managing kidney disorders. Thus, in addition to this review, in-silico molecular docking is performed against nuclear factor kappa B (NF-κB) and soluble epoxide hydrolase (sEH) to study the mechanism of action of mangiferin. It is believed that mangiferin is a safe reno-protective molecule. The observed positive effects are attributed to the inhibition of inflammation caused by NF-κB and sEH upregulation and oxidative stress activation. Studies on the efficacy and safety of mangiferin in clinical trials are further warranted to confirm its medicinal potential as therapeutic agent for kidney disorders in humans.

Tannins as Hemostasis Modulators

The hemostasis system is often affected by complications associated with cardiovascular diseases, which results in thromboembolic events. Compounds of plant origin and plant extracts are considered as a promising source of substances that could modulate the functioning of the hemostasis system and thus reduce the risk of thromboembolism. Among them, tannins, which are plant-origin compounds with potential effects in hemostasis, deserve a special mention. This paper describes the hemostasis-modifying ability of three groups of tannins, namely ellagitannins, gallotannins, and procyanidins. The review highlights the desirable as well as undesirable influence of tannins on specific components of hemostasis, namely platelets, coagulation system, fibrinolysis system, and endothelium, and the multidirectional effect of these compounds on the thrombotic process. Studies performed under normal and pathological conditions such as diabetes or hypercoagulation are described, and the pathophysiology-dependent action of tannins is also highlighted. Most of the studies presented in the paper were performed in vitro, and due to the low bioavailability of tannins more studies should be conducted in the future to understand their actual activity in vivo.

Influence of extrusion process on the release of phenolic compounds from mango (Mangifera indica L.) bagasse-added confections and evaluation of their bioaccessibility, intestinal permeability, and antioxidant capacity

Extruded polyphenol-rich by-products like mango bagasse (MB) could be used to manufacture functional confections. However, few reports have assessed the extrusion impact on MB polyphenols within a food matrix. This research aimed to evaluate the impact of extrusion on the bioaccessibility, intestinal permeability, and antioxidant capacity of phenolic compounds (PC) from non-extruded and extruded MB-added confections (EMBC and MBC, respectively). The inhibition of 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl radicals and in silico approaches were used to evaluate the antioxidant capacity. MBC displayed the highest gastric bioaccessibility (%) of xanthones and flavonoids, whereas selective release of gallic acid, mangiferin, and quercetin glucoside was shown for EMBC. Lower PC' apparent permeability coefficients were found in EMBC compared to MB (0.11 to 0.44-fold change, p < 0.05). EMBC displayed the highest antioxidant capacity by the DPPH method for the non-digestible fraction, being mangiferin the highest in silico contributor (-4 kcal/mol). Our results showed that the extrusion process helps release selective phenolics from MBC, which increases their bioaccessibility and intestinal permeability.

Gastrointestinal metabolism of monomeric and polymeric polyphenols from mango (Mangifera indica L.) bagasse under simulated conditions

Mango bagasse (MB) is an agro-industrial by-product rich in bioactive polyphenols with potential application as a functional ingredient. This study aimed to delineate the metabolic fate of monomeric/polymeric MB polyphenols subjected to simulated gastrointestinal digestion. The main identified compounds by LC/MS-TOF-ESI were phenolic acids [gallic acid (GA) and derivates, and chlorogenic acid], gallotannins and derivatives [di-GA (DA) and 3GG-to-8GG], benzophenones [galloylated maclurins (MGH, MDH)], flavonoids [Quercetin (Quer) and (QuerH)] and xanthones [mangiferin isomers]. The bioaccessibility depended on the polyphenols' structure, being Quer, 5G to 8G the main drivers. The results suggested that the gastrointestinal fate of MB polyphenols is mainly governed by benzophenones and gallotannins degalloylation and spontaneous xanthone isomerization in vitro to sustain GA bioaccessibility.

A review of the phytochemical, pharmacological, pharmacokinetic, and toxicological evaluation of Quercus Infectoria galls

ETHNOPHARMACOLOGICAL RELEVANCE

Quercus Infectoria galls (QIG) have a long history of use in traditional Chinese medicine and traditional Uyghur medicine for the treatment of diarrhea, hemorrhage, skin disease, and many other human ailments. Medicinal applications of QIG have become increasingly popular in Greece, Asia Minor, Syria, and Iran.

AIM OF THE REVIEW

The present paper reviewed the ethnopharmacology, phytochemistry, analytical methods, biological activities, metabolism, pharmacokinetics, toxicology, and drug interactions of QIG to assess the ethnopharmacological uses, explore its therapeutic potential, and identify future opportunities for research.

MATERIALS AND METHODS

Information on QIG was gathered via the Internet (using Google Scholar, Baidu Scholar, Elsevier, ACS, Pubmed, Web of Science, CNKI, and EMBASE) and libraries. Additionally, information was also obtained from local books and PhD and MS dissertations.

RESULTS

QIG has played an important role in traditional Chinese medicine. The main bioactive metabolites of QIG include tannins, phenolic acids, flavonoids, triterpenoids, and steroids. Scientific studies on the QIG extract and its components have shown its wide range of pharmacological activities, such as cholinesterase- and monoamine oxidase-inhibitory, antitumor, anti-hypertension, antidiabetic, antimicrobial, insecticidal, antiparasitic, antioxidant, and anti-inflammatory.

CONCLUSIONS

The ethnopharmacological, phytochemical, pharmacological, and analytical methods of QIG were highlighted in this review, which provides information for future studies and commercial exploration. QIG has a huge potential for pharmaceutical and nutraceutical applications. Moreover, comprehensive toxicity studies of this plant must be conducted to ensure its safety. Additional investigations are recommended to transmute the ethnopharmacological claims of this plant in folklore medicines into scientific rationale-based information. Research on pharmacokinetics studies and potential drug interactions with standard-of-care medications is still limited, which calls for additional studies particularly on humans. Further assessments and clinical trials should be performed before it can be integrated into medicinal practices.

Pharmacokinetic Characterization of (Poly)phenolic Metabolites in Human Plasma and Urine after Acute and Short-Term Daily Consumption of Mango Pulp

Pharmacokinetic (PK) evaluation of polyphenolic metabolites over 24 h was conducted in human subjects (n = 13, BMI = 22.7 ± 0.4 kg/m2) after acute mango pulp (MP), vitamin C (VC) or MP + VC test beverage intake and after 14 days of MP beverage intake. Plasma and urine samples were collected at different time intervals and analyzed using targeted and non-targeted mass spectrometry. The maximum concentrations (Cmax) of gallotannin metabolites were significantly increased (p < 0.05) after acute MP beverage intake compared to VC beverage alone. MP + VC beverage non-significantly enhanced the Cmax of gallic acid metabolites compared to MP beverage alone. Pyrogallol (microbial-derived metabolite) derivatives increased (3.6%) after the 14 days of MP beverage intake compared to 24 h acute MP beverage intake (p < 0.05). These results indicate extensive absorption and breakdown of gallotannins to galloyl and other (poly)phenolic metabolites after MP consumption, suggesting modulation and/or acclimation of gut microbiota to daily MP intake.

Pentagalloyl glucose from Schinus terebinthifolia inhibits growth of carbapenem-resistant Acinetobacter baumannii

The rise of antibiotic resistance has necessitated a search for new antimicrobials with potent activity against multidrug-resistant gram-negative pathogens, such as carbapenem-resistant Acinetobacter baumannii (CRAB). In this study, a library of botanical extracts generated from plants used to treat infections in traditional medicine was screened for growth inhibition of CRAB. A crude extract of Schinus terebinthifolia leaves exhibited 80% inhibition at 256 µg/mL and underwent bioassay-guided fractionation, leading to the isolation of pentagalloyl glucose (PGG), a bioactive gallotannin. PGG inhibited growth of both CRAB and susceptible A. baumannii (MIC 64-256 µg/mL), and also exhibited activity against Pseudomonas aeruginosa (MIC 16 µg/mL) and Staphylococcus aureus (MIC 64 µg/mL). A mammalian cytotoxicity assay with human keratinocytes (HaCaTs) yielded an IC50 for PGG of 256 µg/mL. Mechanistic experiments revealed iron chelation as a possible mode of action for PGG's activity against CRAB. Passaging assays for resistance did not produce any resistant mutants over a period of 21 days. In conclusion, PGG exhibits antimicrobial activity against CRAB, but due to known pharmacological restrictions in delivery, translation as a therapeutic may be limited to topical applications such as wound rinses and dressings.

Mango (Mangifera indica L.): a magnificent plant with cancer preventive and anticancer therapeutic potential

Mangifera indica L. (mango), a long-living evergreen plant belonging to the Anacardiaceae family, has been cultivated for thousands of years in the Indian subcontinent for its excellent fruits which represent a rich source of fiber, vitamin A and C, essential amino acids, and a plethora of phytochemicals. M. indica is extensively used in various traditional systems of medicine to prevent and treat several diseases. The health-promoting and disease-preventing effects of M. indica are attributed to a number of bioactive phytochemicals, including polyphenols, terpenoids, carotenoid and phytosterols, found in the leaf, bark, edible flesh, peel, and seed. M. indica has been shown to exhibit various biological and pharmacological activities, such as antioxidant, anti-inflammatory, immunomodulatory, antimicrobial, antidiabetic, antiobesity, and anticancer effects. There are a few studies conducted that have indicated the nontoxic nature of mango constituents. However, while there are numerous individual studies investigating anticancer effects of various constituents from the mango tree, an up-to-date, comprehensive and critical review of available research data has not been performed according to our knowledge. The purpose of this review is to present a comprehensive and critical evaluation of cancer preventive and anticancer therapeutic potential of M. indica and its phytochemicals with special focus on the cellular and molecular mechanisms of action. The bioavailability, pharmacokinetics, and safety profile of individual phytocomponents of M. indica as well as current limitations, challenges, and future directions of research have also been discussed.

Pentagalloyl Glucose and Its Functional Role in Vascular Health: Biomechanics and Drug-Delivery Characteristics

Pentagalloyl glucose (PGG) is an elastin-stabilizing polyphenolic compound that has significant biomedical benefits, such as being a free radical sink, an anti-inflammatory agent, anti-diabetic agent, enzymatic resistant properties, etc. This review article focuses on the important benefits of PGG on vascular health, including its role in tissue mechanics, the different modes of pharmacological administration (e.g., oral, intravenous and endovascular route, intraperitoneal route, subcutaneous route, and nanoparticle based delivery and microbubble-based delivery), and its potential therapeutic role in vascular diseases such as abdominal aortic aneurysms (AAA). In particular, the use of PGG for AAA suppression and prevention has been demonstrated to be effective only in the calcium chloride rat AAA model. Therefore, in this critical review we address the challenges that lie ahead for the clinical translation of PGG as an AAA growth suppressor.

A C8-Modified Graphene@mSiO2 Composites Based Method for Quantification of Gallic Acid in Rat Plasma after Oral Administration of Changtai Granule and Its Application to Pharmacokinetics

A rapid, effective extraction technique has been established for measuring the gallic acid in rat plasma by using sandwich-structured graphene/mesoporous silica composites with C₈-modified interior pore-walls as adsorbent. The unique characteristics of the graphene-silica composites excluded large molecules, like proteins, from the mesopore channels as a result of size exclusion effect, leading to a direct extraction of drug molecules from protein-rich biological samples such as plasma without any other pretreatment procedure. Followed by elution and centrifugation, the gallic acid-absorbed composites were rapidly isolated before LC-MS/MS. Serving as a reliable tool for analysis of Traditional Chinese Medicine: Changtai Granule, the newly developed method was fully validated and successfully applied in the pharmacokinetic study of gallic acid in rat plasma. Extraction recovery, matrix effect and stability were satisfactory in rat plasma. According to the results of pharmacokinetic studies, Changtai Granule exhibited greater adsorption, distribution and clearance properties of gallic acid in the treatment of ulcerative colitis. Hence, this study may offer a valuable alternative to simplify and speed up sample preparation, and be useful for clinical studies of related preparations.

Phenolic Compounds and Its Bioavailability: In Vitro Bioactive Compounds or Health Promoters?

Botanical preparations present a widespread and secular history of use. In fact, natural matrices possess a rich pool of phytochemicals, with promising biological effects. Among them, phenolic compounds have revealed to confer very important attributes to improve the well-being and longevity of worldwide population. Numerous in vitro studies have been carried out evaluating the wide spectrum of bioactivities of phenolic compounds, including its health effects, but through in vivo experiments some of these previous results cannot be properly confirmed, and considerable variations are observed. Pharmacokinetic parameters, including the assessment of bioavailability and bioefficacy of phenolic compounds, still continue to be largely investigated and considered a great hot topic among the food science and technology researchers. Thus, based on these crucial aspects, this chapter aims to provide an extensive approach about the question of the bioavailability of phenolic compounds, describing its biosynthetic routes and related mechanisms of action; to focus on the current facts and existing controversies, highlighting the importance of in vivo studies and the impact of phenolic compounds on the quality of life and longevity.

In vitro glucuronidation of methyl gallate and pentagalloyl glucopyranose by liver microsomes

Methyl gallate (MG) and pentagalloyl glucopyranose (PGG) are bioactive phenolic compounds that possess various pharmacological activities. However, the knowledge of hepatic metabolism of MG and PGG is limited. The purpose of this study was to investigate the in vitro glucuronidation of MG and PGG using liver microsomes from human (HLMs) and rats (Sprague-Dawley, SDRLMs; Wistar, WRLMs; and Gunn, GRLMs), and recombinant human uridine 5'-diphospho-glucuronosyltransferases (UGT) 1A1 and 1A9. The results demonstrated that liver microsomes catalyzed two mono-glucuronided MG (M1 and M2) formations but that UGT1A1 and 1A9 catalyzed only M1 formation. For PGG, a mono-glucuronided metabolite was mediated by liver microsomes or UGT1A9. However, a PGG glucuronide was absent in the UGT1A1 system. Additionally, all metabolites showed susceptibility to β-glucuronidases. Furthermore, the glucuronidation activities of PGG were lower than those of MG. The kinetic parameters of MG glucuronidation demonstrated that the SDRLMs and GRLMs were more similar to the HLMs than the WRLMs for the formations of M1 and M2, respectively and that the SDRLMs and HLMs preferentially contributed to M1, whereas the WRLMs and GRLMs showed the favored formation of M2. In conclusion, MG and PGG were subjectively glucuronided by liver microsomes to demonstrate species- and strain-dependent metabolism.