Analysis by UPLC-MS-QTOF and antifungal activity of guava (Psidium guajava L.)

Psidium guajava L. hydroethanolic extract as endodontic irrigant: phytochemical analysis, antioxidant activity, antimicrobial action and biocompatibility

Background

The search for novel antimicrobial agents in Endodontics is constant to overcoming persistent infections. Psidium guajava L. is a medicinal plant little explored in Endodontics. The aim of this study was to produce hydroethanolic extract of P. guajava L. and to evaluate its phytochemical composition, antimicrobial and antibiofilm action against standard and clinical strains of Enterococcus faecalis and Candida albicans, and cytotoxicity and genotoxicity on human keratinocyte cultures (HaCaT cells). The findings provide new insights into the potential of P. guajava as an alternative endodontic antimicrobial agent, contributing to the development of more effective and biocompatible therapeutic strategies.

Methods

P. guajava hydroethanolic extract was produced using young leaves of guajava and extracted using absolute ethanol and ultrapure water in a ratio (30 g:100 mL). The solid soluble, total flavonoid and total phenols content were determined. The chemical composition was determined via high-performance liquid chromatography (HPLC) analysis, then the free radical suppressive activity was assessed by determining the IC50 value, indicating the concentration required to eliminate 50% of free radicals. Later, the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) of the extract was evaluated against the strains using clinical and laboratory standards institute (CLSI) guidelines (M27-S4 and M7-A9). Then, the antibiofilm activity was evaluated via MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. Finally, the cytotoxicity of the extract was evaluated via Alamar Blue assay, and the genotoxicity via micronucleus assay on human keratinocyte cultures (HaCaT cells). Data were analyzed using ANOVA and Tukey's test or Kruskal-Wallis and Dunn's test.

Results

The soluble solids content in the extract was 3.35%. Using the quercetin standard curve, the total flavonoid concentration was 0.130 ± 0.110 mg/mL. In addition, using standard curve for phenolic acids, the total phenolic concentration was 1.770 ± 1.540 mg/mL. HPLC analysis revealed peaks of rutin, quercetin and kaempferol as major flavonoids in the P. guajava L. extract. The extract demonstrated notable antioxidant activity, with an IC50 value of 10.39 µg/mL. The MMC values ranged 1.04-8.37 mg/mL. The extract at 8.37 mg/mL was effective in reducing the biofilms of standard and clinical strains of E. faecalis and C. albicans after 10 min. Cytotoxicity analysis revealed that all tested concentrations exhibited relatively low toxicity toward HaCaT cells. Genotoxicity assessment via the micronucleus assay indicated minimal DNA damage at all tested concentrations. Overall, P. guajava L. hydroethanolic extract at 8.37 mg/mL is the most effective concentration in reducing the biofilm of the standard and clinical strains of E. faecalis and C. albicans, while maintaining biocompatibility with HaCaT cultures.

Costa M, Avelar-Gonzalez FJ, Moreno-Flores AC, Vazquez-Pedroza E, Arreola-Guerra JM, González-Gámez M. Guava Leaf Extract Exhibits Antimicrobial Activity in Extensively Drug-Resistant (XDR) Acinetobacter baumannii

Currently, a global health crisis is being caused by microbial resistance, in which Acinetobacter baumannii plays a crucial role, being considered the highest-priority microorganism by the World Health Organization (WHO) for discovering new antibiotics. As a result, phytochemicals have emerged as a potential alternative to combat resistant strains, since they can exert antimicrobial activity through various mechanisms and, at the same time, represent a more natural and safe option. This study analyzes the antimicrobial effects of guava leaf extract in ten clinical isolates of extensively drug-resistant (XDR) A. baumannii, using the agar diffusion technique and the microdilution method to determine the minimum inhibitory concentrations (MICs). Additionally, possible improvements in antimicrobial activity after the purification of polyphenolic compounds and potential synergy with the antibiotic gentamicin are examined in this research. Moreover, the effect of the plant extract in cell line A549 derived from lung tissue was also evaluated. The extract exhibited antimicrobial activity against all the strains studied, and the purification of polyphenols along with the combination with gentamicin improved the extract activity. The presence of the plant extract induced morphological changes in the lung cells after 24 h of exposure. Therefore, Psidium guajava L. leaf extract is a potential antimicrobial agent.

Exploring Medicinal Plants for Antimicrobial Activity and Synergistic Effects With Doxycycline Against Bacterial Species

Medicinal plants are rich sources of bioactive compounds with diverse pharmacological properties, including antimicrobial activities. This study aimed to assess the antibiofilm potential of methanol and ethanol extracts from nine selected medicinal plants, as well as their synergistic effects with doxycycline against Bacillus strains. Standard procedures were employed to determine the phytochemical composition, total phenolic, and flavonoid contents of the extracts. The antibacterial activity was evaluated using the broth microdilution method, while biofilm formation was assessed via the microtiter plate method. Antibiofilm activity was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium-bromide (MTT) assay. Combination studies were conducted using the checkerboard microdilution method. All extracts contained phenols, flavonoids, steroids, triterpenes, and anthraquinones. The methanolic extract of Psidium guajava exhibited the highest total phenolic and flavonoid contents (90.48 ± 0.55 mg GAE/g), while the ethanolic extract of Olax subscorpioidea showed the highest flavonoid content (6.48 ± 0.33 mg QE/g). Ethanol extracts of Eucalyptus globulus and Psidium guajava and methanolic extract of Syzygium jambos demonstrated significant antibacterial activity against Bacillus anthracis 34F2 Sterne strains, with a MIC value of 64 μg/mL. Biofilm formation in Bacillus strains was notably enhanced in the presence of glucose. The methanolic extract of O. subscorpioides exhibited the highest biofilm imbibition (85%), while Picralima nitida methanolic extract showed the most effective biofilm eradication (79%). The combination of Solanum torvum ethanol extract with doxycycline displayed synergistic effects against biofilm formation inhibition and eradication in all tested Bacillus strains. Taken together, Solanum torvum ethanol extract shows promise for developing new combination antibacterial therapies.

α-Glucosidase inhibitory activities of constituents from Psidium guajava leaves

Psidium guajava is a plant of the Myrtaceae with various pharmacological activity. In this study, the water extract and the isolated compounds from guava leaves were evaluated for in vitro α-glucosidase inhibition using spectrophotometric method. Ellagic acid, quercetin, quercetin-3-O-glucuronide, avicularin, isoquercitrin, and quercetin-3-galactoside showed α-glucosidase inhibitory activity, and their IC50 value were 25.0, 41.0, 53.5, 46.9, 60.0 and 72.1 μg/mL, respectively compared with the positive control acarbose (IC50 49.2 μg/mL). This study could provide a theoretical basis for the application of Psidium guajava in the treatment of hyperglycemia.

New polyvinyl alcohol/gellan gum-based bioplastics with guava and chickpea extracts for food packaging

Plastic is a fossil-based synthetic polymer that has become an essential material in our daily life. Plastic pollution resulting from the accumulation of plastic objects has become problematic for our environment. Bioplastic can be a biodegradable environmentally friendly alternative for the synthetic plastic. In this paper, bioplastics based on polyvinyl alcohol (PVA)/gellan gum (GG) blend have been produced in three different compositions and their chemical structure, mechanical, morphological and thermal properties have been studied. Glycerol has been used as a plasticizer. To add extra features to the PVA/GG bioplastic, Psidium guajava (guava) leaves, GL, and chickpea, CP, extracts have been added to the PVA/GG (30/70) blend. Water and aqueous ethanol have been used in the extraction of GL and CP, respectively. The addition of the plant's extracts enhanced the tensile properties of the PVA/GG bioplastic. Weathering acceleration tests have been carried out to examine the degradation of the prepared bioplastics. Cytotoxicity studies revealed that the prepared bioplastic is safe to be used in food packaging applications. Water and oxygen permeability for the new PVA/GG bioplastic have also been studied. The addition of the plant extracts (GL and CP extracts) increased the oxygen and water permeability to different extents. Bioplastic life cycle assessment (LCA) and CO2 emissions in comparison to fossil-based plastic have been investigated. From all the results, PVA/GG based bioplastic proved to be a degradable, safe and effective alternative for fossil-based plastics in food packaging applications.

Molecular Cloning, Heterologous Expression, Purification, and Evaluation of Protein-Ligand Interactions of CYP51 of Candida krusei Azole-Resistant Fungal Strain

Due to the increasing prevalence of fungal diseases caused by fungi of the genus Candida and the development of pathogen resistance to available drugs, the need to find new effective antifungal agents has increased. Azole antifungals, which are inhibitors of sterol-14α-demethylase or CYP51, have been widely used in the treatment of fungal infections over the past two decades. Of special interest is the study of C. krusei CYP51, since this fungus exhibit resistance not only to azoles, but also to other antifungal drugs and there is no available information about the ligand-binding properties of CYP51 of this pathogen. We expressed recombinant C. krusei CYP51 in E. coli cells and obtained a highly purified protein. Application of the method of spectrophotometric titration allowed us to study the interaction of C. krusei CYP51 with various ligands. In the present work, the interaction of C. krusei CYP51 with azole inhibitors, and natural and synthesized steroid derivatives was evaluated. The obtained data indicate that the resistance of C. krusei to azoles is not due to the structural features of CYP51 of this microorganism, but rather to another mechanism. Promising ligands that demonstrated sufficiently strong binding in the micromolar range to C. krusei CYP51 were identified, including compounds 99 (Kd = 1.02 ± 0.14 µM) and Ch-4 (Kd = 6.95 ± 0.80 µM). The revealed structural features of the interaction of ligands with the active site of C. krusei CYP51 can be taken into account in the further development of new selective modulators of the activity of this enzyme.

Psidium guajava L.: From byproduct and use in traditional Mexican medicine to antimicrobial agent

Mexico is one of the largest guava producers in the world, so it has access to a huge amount of waste and byproducts obtained after the industrial processing of the fruit. This review discusses the potential recovery of this residue for its application as an antimicrobial agent, considering the phytochemical composition, the bioactivity reported in-vivo and in-vitro, and the toxicology of the plant. Nowadays there is a growing demand for more natural and safer products, so the use of guava extracts is an interesting initiative, especially due to its availability in the country, its wide variety of traditional uses, and its phytochemical profile. This review highlights the importance and potential antimicrobial use of this plant in today's world.

Psidium guajava L. An Incalculable but Underexplored Food Crop: Its Phytochemistry, Ethnopharmacology, and Industrial Applications

Psidium guajava L. (guava) is a small tree known for its fruit flavor that is cultivated almost around the globe in tropical areas. Its fruit is amazingly rich in antioxidants, vitamin C, potassium, and dietary fiber. In different parts of the world, this plant holds a special place with respect to fruit and nutritional items. Pharmacological research has shown that this plant has more potential than just a fruit source; it also has beneficial effects against a variety of chronic diseases due to its rich nutritional and phytochemical profile. The primary goal of this document is to provide an updated overview of Psidium guajava L. and its bioactive secondary metabolites, as well as their availability for further study, with a focus on the health benefits and potential industrial applications. There have been several studies conducted on Psidium guajava L. in relation to its use in the pharmaceutical industry. However, its clinical efficacy and applications are still debatable. Therefore, in this review a detailed study with respect to phytochemistry of the plant through modern instruments such as GC and LC-MS has been discussed. The biological activities of secondary metabolites isolated from this plant have been extensively discussed. In order to perform long-term clinical trials to learn more about their effectiveness as drugs and applications for various health benefits, a structure activity relationship has been established. Based on the literature, it is concluded that this plant has a wide variety of biopharmaceutical applications. As a whole, this article calls for long-term clinical trials to obtain a greater understanding of how it can be used to treat different diseases.

Hypoglycemic effect and toxicity of the dry extract of Eugenia biflora (L.) DC. leaves

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Eugenia biflora (Myrtaceae) are traditionally used by Amazonian populations for the control of diabetes. However, their chemical composition has not yet been described and pharmacological evidence has not been reported.

OBJECTIVE

This study aimed to identify the chemical constituents and evaluate the hypoglycemic and toxic effect of the dry extract of the E. biflora leaves (DEEB).

MATERIALS AND METHODS

DEEB, obtained by infusion, was analyzed using LC-HRMS and NMR, whose the catechin flavonoid was quantified using NMR. The antidiabetic effect of DEEB was evaluated according to its inhibition of the enzymes α-amylase and α-glucosidase, as well as the content of total phenols, free radical scavengingand antiglycation activities, and its in vitro cell viability. Oral maltose tolerance and chronic multiple dose tests (28 days) in streptozotocin-induced diabetic mice (STZ) were performed. The hypoglycemic effect and toxicity of this extract were evaluated in the multiple dose assay. Biochemical parameters, hemolysis, and levels of the thiobarbituric acid reactive species in the liver were investigated and histopathological analyses of the kidneys and liver were performed.

RESULTS

Eight phenolic compounds were identified, with catechin (15.5 ± 1.7 mg g-1) being the majority compound and a possible chemical marker of DEEB. The extract showed inhibition activity of the enzyme α-glucosidase. Chronic administration of DEEB (50 mg/kg of body weight) reduced glucose levels in diabetic animals, similar to acarbose; however, DEEB (100 and 200 mg/kg bw) caused premature death of mice by D22 of the treatment. Our data indicate that one of the mechanisms of toxicity in DEEB may be related to the aggravation of oxidative stress in the liver. This histopathological study indicated that DEEB failed to minimize the progression of the toxicity of diabetes caused by STZ.

CONCLUSIONS

This study demonstrated the hypoglycemic potential of E. biflora leaves. However, the prolonged use of this tea can be harmful to its users due to its considerable toxicity, which needs to be better investigated.

Kaempferol: A flavonoid with wider biological activities and its applications

Kaempferol and its derivatives are naturally occurring phytochemicals with promising bioactivities. This flavonol can reduce the lipid oxidation in the human body, prevent the organs and cell structure from deterioration and protect their functional integrity. This review has extensively highlighted the antioxidant, antimicrobial, anticancer, neuroprotective, and hepatoprotective activity of kaempferol. However, poor water solubility and low bioavailability of kaempferol greatly limit its applications. The utilization of advanced delivery systems can improve its stability, efficacy, and bioavailability. This is the first review that aimed to comprehensively collate some of the vital information published on biosynthesis, mechanism of action, bioactivities, bioavailability, and toxicological potential of kaempferol. Besides, it provides insights into the future direction on the improvement of bioavailability of kaempferol for wide applications.

Chemical Constituents and Biological Activities of Croton heliotropiifolius Kunth

Croton heliotropiifolius Kunth (Euphorbiaceae), whose occurrence has already been registered in the most varied Brazilian biomes, is commonly found in the Chapada do Araripe, Ceará. The species is traditionally used to treat fungal, parasitic, and degenerative diseases. This study investigated the chemical composition and pharmacological potential (antioxidant, antifungal, antiparasitic, and cytotoxic) of an aqueous extract obtained from the roots of C. heliotropiifolius. Following a qualitative phytochemical screening, the chemical constituents were identified by ultra-efficiency liquid chromatography coupled witha quadrupole/time-of-flight system (UPLC-QTOF). The antioxidant potential was verified by thin-layer chromatography (TLC). The direct and combined antifungal activity of the extract against opportunistic Candida strains was investigated using the microdilution method. The minimal fungicidal concentration (MFC) was determined by subculture, while the modulation of the morphological transition (fungal virulence) was evaluated by light microscopy. The in vitro antiparasitic activity was analyzed using epimastigotes of Trypanosoma cruzi and promastigotes of Leishmania braziliensis and Leishmania infantum, while cytotoxicity was determined in cultures of mouse fibroblasts. The phytochemical analysis identified the presence of acids, terpenes, flavonoids, lignans, and alkaloids. Among these constituents, the presence of polar and non-polar phenolic compounds with known antioxidant action was highlighted. While the extract showed clinically ineffective antifungal effects, it could enhance the effectiveness of fluconazole, in addition to inhibiting the morphological transition associated with increased virulence in Candida strains. Although the extract showed low cytotoxicity against fibroblasts, it also had weak antiparasitic effects. In conclusion, Croton heliotropiifolius is a source of natural products with antifungal and antioxidant potential.

Study of the capacity of the essential oil of Lantana montevidensis to modulate the action of fluconazole on Candida albicans and Candida tropicalis strains

In recent decades, fungal infections have been increasing, as well as the indiscriminate use of large-scale antifungal. The objective of the present study was to characterize the chemical components of L. montevidensis leaf essential oil (EOLm) and evaluate its antifungal potential and fluconazole modulating activity against Candida strains. The essential oil was obtained by hydrodistillation and its chemical components were determined by Gas Chromatography coupled to Mass Spectrometry. The antifungal activity was determined by the microdilution method to determine the minimum inhibitory concentration. The modulatory activity of fluconazole by the oil (EOLm) was evaluated against the four Candida strains. Our results demonstrated a predominance of β-Caryophyllene (34.96%) and Germacrene D (25.49%), while (E)-Caryophyllene (0.08%) and δ-Cadinene (0.13%) were the minor constituents. For the antifungal activity, it was evidenced that the EOLm did not inhibit the growth of Candida albicans (CA LM 77 and CA INQS 40006) and Candida tropicalis (CT INCQS 40042 and CT LM 23), but, potentiated the effect of fluconazole in particular against C. tropicalis, although the FIC index indicates indifferent modulation for all strains tested. This study strongly suggests that administration of the fluconazole in combination with plant essential oils can provide a new opportunity to improve the outcome of the drug effect.

Chemical composition and protective effect of guava (Psidium guajava L.) leaf extract on piglet intestines

BACKGROUND

Dietary intervention is an important approach to improve intestinal function of weaned piglets. Phytogenic and herbal products have received increasing attention as in-feed antibiotic alternatives. This study investigated the chemical composition of guava leaf extract (GE) by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Meanwhile, we investigated the effects of dietary supplementation with GE on diarrhea in relation to immune responses and intestinal health in weaned piglets challenged by enterotoxigenic Escherichia coli (ETEC).

RESULTS

In total, 323 characterized compounds, which including 91 phenolic compounds and 232 other compounds were identified. Animal experiment results showed that the supplementation of 50-200 mg kg^-1 of GE in the diet could reduce diarrhea incidence, increase activities of superoxide dismutase, glutathione peroxidase and total anti-oxidant capacity in the serum (P < 0.05), decrease the levels of interleukin 1β, interleukin 6 and tumor necrosis factor α in the serum or jejunum mucosa (P < 0.05), and increase villus height and villus height to crypt depth ratio (P < 0.05) in the jejuna of piglets challenged by oral ETEC compared with negative control group (NC). Meanwhile, diet supplementation with 50-200 mg kg^-1 GE reduced the levels of D-lactate, endothelin-1 and diamine oxidase in the serum, and increased the expression of zonula occludens-1, Claudin-1, Occludin and Na⁺ /H⁺ exchanger 3 (P < 0.05) in the jejuna mucosa of piglets challenged by ETEC compared with the NC.

CONCLUSIONS

These results suggested that GE could attenuate diarrhea and improve intestinal barrier function of piglets challenged by ETEC. © 2020 Society of Chemical Industry.

Immunomodulatory potential of extracts, fractions and pure compounds from Phyllanthus amarus and Psidium guajava on striped catfish (Pangasianodon hypophthalmus) head kidney leukocytes

This study aimed to identify major phytochemical constituents, as well as compare the immunomodulatory effects of Psidium guajava L. and Phyllanthus amarus Schun and Thonn crude ethanol extracts and their fractions on striped catfish (Pangasianodon hypophthalmus) head kidney leukocytes (HKLs). Moreover, pure constituents were also investigated for their effects on those cells: hypophyllanthin, identified as a major constituent of P. amarus crude extracts and its hexane fraction; corosolic acid, ursolic acid, and oleanolic acid, identified in P. guajava crude extract, ethyl acetate and dichloromethane fractions; with other terpenic derivatives, as well as guajaverin and avicularin, identified with other flavonoids by LC-UV-MS in the crude P. guajava extract and its ethyl acetate fraction. Cell viability, respiratory burst assay (RBA), nitric oxide synthase (NOS) and lysozyme activity in HKLs were analyzed after 24 h stimulation with each extract (10, 20 and 40 μg/mL) or pure compound (7.5, 15 and 30 μM). Our results show that the hexane fraction of both plant extracts inhibited the viability of HKLs, while several other fractions enhanced the cell viability. All P. guajava fractions at all or some concentration considerably enhanced the RBA production in HKLs. Similarly, NOS production was also significantly increased by some or all concentrations of P. guajava dichloromethane and ethyl acetate fractions. However, the NOS production was dose-dependently inhibited in HKLs treated with Pa ethyl acetate and both plants aqueous fractions at 10 or 10 and 40 μg/mL respectively. The lysozyme activity in cells treated with P. guajava crude extracts and all its organic solvent fractions were stronger than those in P. amarus treatments. Pure compounds including corosolic acid, guajaverin, ursolic acid, hypophyllanthin inhibited the HKLs viability according to concentration and type of compound. All pure compounds except avicularin significantly stimulated, at certain or all concentrations, the RBA production and/or the lysozyme activity in HKLs. The NOS production was significantly reduced in HKLs treated with oleanolic acid (30 μM) and hypophyllanthin (7.5 μM) while its level was increased by hypophyllanthin at 30 μM. These results highlighted that the crude ethanol extracts of P. guajava and P. amarus, their fractions and some of their pure components at certain concentrations can potentially act as immunomodulators, and could be considered as valuable candidates in fishery sciences.

Current Aspects in the Biology, Pathogeny, and Treatment of Candida krusei, a Neglected Fungal Pathogen

Fungal infections represent a constant and growing menace to human health, because of the emergence of new species as causative agents of diseases and the increment of antifungal drug resistance. Candidiasis is one of the most common fungal infections in humans and is associated with a high mortality rate when the fungi infect deep-seated organs. Candida krusei belongs to the group of candidiasis etiological agents, and although it is not isolated as frequently as other Candida species, the infections caused by this organism are of special relevance in the clinical setting because of its intrinsic resistance to fluconazole. Here, we offer a thorough revision of the current literature dealing with this organism and the caused disease, focusing on its biological aspects, the host-fungus interaction, the diagnosis, and the infection treatment. Of particular relevance, we provide the most recent genomic information, including the gene prediction of some putative virulence factors, like proteases, adhesins, regulators of biofilm formation and dimorphism. Moreover, C. krusei veterinary aspects and the exploration of natural products with anti-C. krusei activity are also included.