Metabolomic Comparison of Guava (Psidium guajava L.) Leaf Extracts Fermented by Limosilactobacillus fermentum and Lactiplantibacillus plantarum and Their Antioxidant and Antiglycation Activities.

Probiotic fermentation of plant-based materials can lead to the generation of various bioactive substances via bacterial metabolites and the biotransformation of phenolic compounds. We compared the metabolic differences between fermentation by Limosilactobacillus fermentum KCTC15072BP (LFG) and fermentation by Lactiplantibacillus plantarum KGMB00831 (LPG) in guava leaf extract (0%, 0.5%, and 2% (w/v))-supplemented medium via non-targeted metabolite profiling. By performing multivariate statistical analysis and comparing the different guava leaf extract groups, 21 guava-derived and 30 bacterial metabolites were identified. The contents of guava-derived glucogallin, gallic acid, and sugar alcohols were significantly higher in LFG than they were in LPG. Similarly, significantly higher contents of guava-derived pyrogallol, vanillic acid, naringenin, phloretin, and aromatic amino acid catabolites were obtained with LPG than with LFG. LFG led to significantly higher antioxidant activities than LPG, while LPG led to significantly higher antiglycation activity than LFG. Interestingly, the fermentation-induced increase in the guava-leaf-extract-supplemented group was significantly higher than that in the control group. Thus, the increased bioactivity induced by guava fermentation with the Lactobacillaceae strain may be influenced by the synergistic effects between microbial metabolites and plant-derived compounds. Overall, examining the metabolic changes in plant-based food fermentation by differentiating the origin of metabolites provides a better understanding of food fermentation.

Probiotic Yogurt Supplemented with Lactococcus lactis R7 and Red Guava Extract: Bioaccessibility of Phenolic Compounds and Influence in Antioxidant Activity and Action of Alpha-amylase and Alpha-glucosidase Enzymes.

The industry has increasingly explored the development of foods with functional properties, where supplementation with probiotics and bioactive compounds has gained prominence. In this context, the study aimed to evaluate the influence of in vitro biological digestion on the content of phenolic compounds, antioxidant activity, and inhibition of α-amylase and α-glucosidase activities of probiotic yogurt supplemented with the lactic acid bacteria Lactococcus lactis R7 and red guava extract (Psidium cattleianum). A yogurt containing L. lactis R7 (0.1%) and red guava extract (4%) was characterized for the content of phenolic compounds, antioxidant activity, and potential for inhibition of digestive enzymes after a simulated in vitro digestion process. After digestion, the caffeic and hydroxybenzoic acids remained, and sinapic acid only in the last digestive phase. Antioxidant activity decreased during digestion by 28.93, 53.60, and 27.97% for DPPH, nitric oxide and hydroxyl radicals, respectively, and the inhibition of the α-amylase enzyme decreased only 4.01% after the digestion process. α-glucosidase was more efficient in intestinal digestion, demonstrating an increase of almost 50% in probiotic yogurt with red guava extract before digestion. Possibly, the phenolics change their conformation during digestion, generating new compounds, reducing antioxidant activity, and increasing the inhibitory activity of α-glucosidase digestive enzymes. It was concluded that the probiotic yogurt formulation supplemented with red guava extract could interfere with the concentration of phenolic compounds and the formation of new compounds, suggesting a positive and effective inhibition of the digestive enzymes, even after the digestive process.

Psidium guajava: An Insight into Ethnomedicinal Uses, Phytochemistry, and Pharmacology.

BACKGROUND: Psidium guajava (guava) is widely distributed in tropical and subtropical regions and adapted to various environmental conditions. Guava is an important economic fruit widely used as food and folk medicine. It contains flavonoids, alkaloids, tannins, triterpenoids, reducing sugars, essential oils, carotenoids, polyphenols, etc. The presence of triterpenoid acids such as guavacoumaric, ursolic, jacoumaric, guajavanoic, guavenoic, and Asiatic acids helps to develop novel drugs against various diseases. It is used traditionally for medicinal purposes, mainly for antioxidant, antimicrobial, antispasmodic, antidiabetic, anticancer, antiallergy, anti-inflammatory, and hepato-protective properties. OBJECTIVE: The systematic literature study aims to summarize its botanical description, phytochemicals, pharmacological activities, and clinical trials. This review focuses on the plant's chemical composition and scientific approaches to human welfare. METHODS: A systematic literature search was done on Psidium guajava through previous literature and online databases such as Google Scholar, Pubmed, Science Direct, etc., to explain its ethnomedicinal uses, phytochemistry, and pharmacological applications. RESULTS: Previous literature studies of Psidium guajava suggest it can serve as antioxidant, antimicrobial, antispasmodic, antidiabetic, anticancer, anti-allergy, anti-inflammatory, and hepatoprotective effects. Successful clinical trials performed on the plant extracts against infantile rotaviral enteritis and infectious gastroenteritis showed future directions to work with the plant for clinical applications. CONCLUSION: In this review, an attempt is made to show all literature studied, especially in phytochemistry, pharmacology, clinical trials and uses as traditional folk medicine around the world. The leaves have been used by folklore over the years to treat various ailments such as skin ulcers, diarrhoea, vaginal irritation, cough, conjunctivitis, etc. Further studies are required to explore more therapeutic remedies and to develop new medicines for future perspectives.

Larvicidal and Fungicidal Activity of the Leaf Essential Oil of Five Myrtaceae Species.

Myrtaceae is one of the most diverse and abundant botanical families, exhibiting wide diversity in the chemical composition of essential oils (EOs). EOs have various biotechnological applications such as controlling the populations of organisms that negatively impact humans. This study aimed to extract EOs from Myrtaceae species, chemically characterize them, and evaluate their larvicidal and fungicidal effects. EOs were extracted from the leaves of Eugenia brasiliensis, Eugenia uniflora, Psidium cattleyanum, Psidium guajava, and Syzygium cumini by hydrodistillation for 3 h and characterized by chromatographic analysis. Larvaes of Aedes aegypti and colonies of Fusarium oxysporum were subjected to increasing EO concentrations to determine the larvicidal and fungicidal potential. The EOs of Eugenia and Psidium species are primarily composed of sesquiterpenes (>80 %), whereas S. cumini EO is rich in monoterpenes (more than 60 %). The Eugenia species had similar amounts of oxygenated monoterpenes, which may explain their higher larvicidal potential compared to other species, with CL50 of 86.68 and 147.46 PPM, respectively. In addition to these two study species, S. cumini showed a high inhibition of fungal growth, with more than 65 % inhibition. We demonstrated that the actions of five EOs from Myrtaceae with different biological activities are associated with chemical diversity.

Evaluation of 28-day repeated doses oral toxicity of essential oil from Psidium glaziovianum Kiaersk leaves on various biological parameters in Swiss mice.

Only a small number of the many medicinally important species in the genus Psidium L. have had their safety assessed. Psidium glaziovianum, a plant native to Brazil, is reported to exert antinociceptive and anti-inflammatory effects; however, there are no apparent reports of long-term safety following administering of repeated doses. The aim of this study was to examine the effects of 28-day oral of treatment at 250, 500 or 1,000 mg/kg Psidium glaziovianum essential oil (PgEO) on behavioral and physiological parameters in male and female Swiss mice. First, PgEO was chemically characterized by gas chromatography mass spectrometry (GC-MS). The following parameters were examined: motor activity, body temperature, blood glucose, urine, hematology, biochemistry, histology, and oxidative stress. Characterization of PgEO revealed 48 components which were dominated by sesquiterpenes 1,8-cineol (24.29%), α-pinene (19.73%) and ß-pinene (17.31%). Data showed that PgEO treatment in mice increased activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) without markedly affecting body weight, hematological or biochemical parameters, as well as water or food consumption. Administration of PgEO in repeated daily dosages over 28 days did not significantly alter exploratory or locomotor activities. Based upon our findings, PgEO administration daily for 28 days, exhibited low toxicity and absence of effects on the nervous system. Data demonstrated that PgEO produced hypoglycemic and antioxidant actions which need to be considered in safety assessment.

Herbicide and Cytogenotoxic Activity of Inclusion Complexes of Psidium gaudichaudianum Leaf Essential Oil and ß-Caryophyllene on 2-Hydroxypropyl-ß-cyclodextrin.

The present investigation aimed to develop inclusion complexes (ICs) from Psidium gaudichaudianum (GAU) essential oil (EO) and its major compound ß-caryophyllene (ß-CAR), and to evaluate their herbicidal (against Lolium multiflorum and Bidens pilosa) and cytogenotoxic (on Lactuca sativa) activities. The ICs were obtained using 2-hydroxypropyl-ß-cyclodextrin (HPßCD) and they were prepared to avoid or reduce the volatility and degradation of GAU EO and ß-CAR. The ICs obtained showed a complexation efficiency of 91.5 and 83.9% for GAU EO and ß-CAR, respectively. The IC of GAU EO at a concentration of 3000 µg mL-1 displayed a significant effect against weed species B. pilosa and L. multiflorum. However, the ß-CAR IC at a concentration of 3000 µg mL-1 was effective only on L. multiflorum. In addition, the cytogenotoxic activity evaluation revealed that there was a reduction in the mitotic index and an increase in chromosomal abnormalities. The produced ICs were able to protect the EO and ß-CAR from volatility and degradation, with a high thermal stability, and they also enabled the solubilization of the EO and ß-CAR in water without the addition of an organic solvent. Therefore, it is possible to indicate the obtained products as potential candidates for commercial exploration since the ICs allow the complexed EO to exhibit a more stable chemical constitution than pure EO under storage conditions.

Analytical assessment of modulated electric flux triggered degradation of chlorfenapyr and deltamethrin pesticides in guava fruits.

The purpose of this study was to explore the new effective method and investigate the dissipation of chlorfenapyr and deltamethrin (DM) pesticides used in the treatment of guava fruit from tropical and sub-tropical areas of Pakistan. Five different solutions of varying concentrations of pesticides were prepared. This study involved the in-vitro and in-vivo analysis of modulated electric flux-triggered degradation as an efficient method for the safer degradation of selected pesticides. The Taser gun was used as a tool for providing different numbers of electrical shocks of million voltages to the pesticides present in guava fruit at different temperatures. The degraded pesticides were extracted and analyzed by High-performance liquid chromatography (HPLC). The HPLC chromatograms verified that significant dissipation of pesticides took place when these were exposed to 9 shocks at 37 °C, which proved the efficiency of this degradation method. More than 50% of the total spray of both pesticides was dissipated. Thus, modulated electrical flux-triggered degradation is one of the effective methods for pesticide degradation.

Chemical composition, antinociceptive and anti-inflammatory effects in mice of the essential oil of Psidium cattleyanum Sabine leaves.

ETHNOPHARMACOLOGICAL RELEVANCE: One of the native species of the genus most often mentioned by traditional people is Psidium cattleyanum Sabine, which is used mostly to treat disorders of the respiratory, genitourinary, and digestive systems. These symptoms are mainly treated by the decoction of the leaves. Additionally, there are gaps in the in vivo and toxicity investigations of this species. AIM OF THE STUDY: The aim of this study was evaluate antinociceptive and anti-inflammatory potential of essential oil from P. cattleyanum leaves in vivo. MATERIALS AND METHODS: Gas chromatography-mass spectrometry (GC/MS) was used to examine the essential oil of P. cattleyanum. The acute toxicity test was then done with a 2000 mg/kg dosage. The oil at 50, 100, and 200 mg/kg orally, as well as the reference medications Morphine 10.0 mg/kg IP and/or Indomethacin 20.0 mg/kg IP, were tested using nociception (abdominal writhing, formalin, and tail immersion) and inflammatory models (paw edema and peritonitis). RESULTS: The phytochemical assay showed a high concentration of ß-caryophyllene (46.68%) and α-caryophyllene (10.81%). In the in vivo assays, P. cattleyanum essential oil proved to be an important antinociceptive agent, reaching 76.96% inhibition of abdominal writhing with acetic acid and 67.12% in the formalin assay. An increase in latency time in the tail test was also reported. In the test with carrageenan, the oil showed significant inhibition compared to the control. A decrease in the migration of leukocytes was also reported in the group treated with P. cattleyanum, reaching 60.49% at the dose of 200 mg/kg. CONCLUSIONS: The essential oil from the leaves of P. cattleyanum has anti-inflammatory and antinociceptive action and has potential for application in the pharmaceutical and food industry.

Self-Emulsifying Micellization of Crude Extracts from Apple (Malus domestica cv. Anna), Plum (Prunus domestica cv. Satsuma), and Guava (Psidium guajava L.) Fruits.

Micellar microemulsions are thermodynamically stable self-emulsifying systems that have been used to successfully improve the low oral bioavailability of several bioactive phytochemicals, such as antioxidant polyphenols. However, most studies have reported the micellization of single-compounds or purified chemical fractions; thus, the stability, phytochemical-loading efficiency, and bioactivity of complex crude extracts remain largely unexplored. In this study, we evaluated the effects of micellar emulsification of tropical apple (Malus domestica cv. Anna), plum (Prunus domestica cv. Satsuma), and guava (Psidium guajava L.) extracts regarding particle size and stability, polyphenol-loading efficiency, antioxidant capacity, and cytotoxic activity in human and murine cells. Simple food-grade extraction protocols were implemented to obtain apple, plum, and guava extracts. Total polyphenols, flavonoids, and antioxidant activity (DPPH) were determined in the fruit extracts, and their polyphenol profile was further characterized by liquid chromatography (HPLC-DAD). The dried extracts were mixed into a food-grade, self-emulsifying system, and their cytotoxicity in human and murine cell lines was compared. Our research showed that complex fruit matrixes were successfully emulsified into thermodynamically stable polysorbate-based nanometric micelles with uniform size distribution and consistent pH stability, with potential applications in food and biomedical industries.

Analysis of inhibition of guava (Psidium guajava l.) leaf polyphenol on the protein oxidative aggregation of frozen chicken meatballs based on structural changes.

This study compared the effects of guava leaf polyphenol (GLP) on the aggregation and structural changes of myofibrillar proteins (MPs) from chicken meatballs, frozen for 6 months, with that of tea polyphenol (TP). The high antioxidation ability of 450 mg/L GLP was manifested by changes in 1, 1-diphenyl-2-picrylhydrazyl (DDPH), 2, 2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, and the ferric reducing antioxidant power (FRAP) in vitro. Compared with the control, the carbonyl, disulfide bond content, particle size, zeta potential and turbidity of sample with GLP decreased by 25.9 %, 17.7 %, 18.2 %, 11.4 % and 11.7 %, respectively, while the solubility of the sample, after freezing it for 6 months, increased by 14.8 %. Meanwhile, in sustaining the structural stability of MPs, the GLP-treated group exhibited better microstructure (scanning electron microscopy, SEM), lower free amino and sulfhydryl loss, higher α-helix structure and fluorescence intensity than the control. Our results showed that GLP significantly inhibited MP aggregation, and was superior to TP in terms of its particle size, solubility, and turbidity, sulfhydryl content (P < 0.05). Overall, it was demonstrated that GLP has the potential to inhibit protein aggregation and enhance structural stability during frozen storage.

The improvement of guava (Psidium guajava) juice quality using crude multi-enzymatic extracts obtained from yeasts.

Guava juice is cloudy and viscous, which hinders filtration, decreases yield, and causes the loss of quality after its processing and during storage. This study aimed to evaluate enzymatic treatment effects using crude multi-enzymatic extracts (CME) obtained from Rhodotorula mucilaginosa, Rhodotorula orizycola, and Pseudozyma sp. produced by submerse fermentation in the extraction of juice guava. Mixtures of 100 ml of guava pulp and multi-enzymatic extracts proposed by Doehlert planning were incubated under constant agitation at 150 rpm and 50°C, and a Doehlert design was applied as a multivariate optimization strategy. The optimal conditions using the multi-enzymatic extract were: 0.4% (v/v) of CME for 131 min for the multi-enzymatic treatment using Pseudozyma sp.; 3.0% (v/v) of CME for 154 min using the R. mucilaginosa CME; and 5.0% (v/v) of CME for 90 min using R. oryzicola. The maximum viscosity reduction values for the juices treated with the CME of yeasts were 10.33%, 86.38%, and 13.33% for the juices treated with the CME of Pseudozyma sp., R. mucilaginosa, and R. orizycola, respectively. The physical-chemical properties were improved after treatment with CMEs, yielding a reduction of clarity, increase of total soluble solids and reducing sugars, and decreasing the acidity (pH) for all treatments with enzymatic extracts of all strains. The yeasts studied showed a potential for CME production to be applied to juice, improving the quality of the juice, and R. mucilaginosa was the most prominent yeast due to most significant reduction of viscosity in guava juice.

Macroporous adsorptive resin-assisted enrichment of polyphenol from Psidium guajava leaves improved its in vitro antioxidant and anti-hemolytic properties.

Phytochemical analyses of guava leaf extracts, commonly applied in traditional medicine, revealed the presence of several bioactive polyphenols. In this study, we optimized the enrichment of total polyphenol from Guava leaf ethanolic extract (GEE) using six macroporous adsorptive resins (MAR) including AB8, D101, X5, ADS17, S400, and AD7. Also investigated are the contributions of adsorption time, extract concentration, pH, elution time, and eluent ethanol concentrations on the polyphenol enrichment potential of MAR. The antioxidant and anti-hemolytic properties of the crude and polyphenol-rich extracts were determined. Our results indicate that treatment of GEE extract with AB8 MAR at a concentration of 15 mg GEE/g resin, adsorption time of 45 min, elution time of 40 min, and eluent ethanol concentration of 50% (v/v) improved the flavonoids and phenol concentration of GEE by 2 and 2.5 folds respectively. The DPPH radical scavenging, ferric reducing ability of the plasma (FRAP), anti-hemolytic and anti-peroxidation activity of the resultant polyphenol-rich extracts improved by 1.5, 1.6, 1.4, and 1.88 folds respectively, when compared to the crude extract. Our work shows that the MAR-assisted enrichment operation is a rapid, feasible, and economical strategy for enriching bioactive polyphenols from guava leaf extracts.

Phytochemical profiling, antidiabetic, antitumoral and cytotoxic potential of Psidium cattleianum Afzel. ex Sabine leaves of red variety.

In this study, phytochemical profiling, and antidiabetic, antitumoral and cytotoxic potential of aqueous extracts of leaves of red variety of Psidium cattleianum Afzel. ex Sabine were investigated. The extracts were obtained using a cellulase complex. The total phenolic compounds (TPC) were determined, and the individual phenolic compounds were quantified by HPLC-ESI-MS/MS. For the TPC, the amounts varied from 85.91 to 106.33 mg EAG g-1. Eighteen compounds have been identified. The compounds with the highest concentrations were gallic acid, quercetin and protocatechuic acid. Antidiabetic activity was obtained through α-amylase and α-glucosidase inhibition tests. The extract inhibited 17.94% of α-amylase activity and 73.34% of α-glucosidase activity. The antitumoral activity in cells of cutaneous melanoma (SK-MEL-28) and the cytotoxic activity was determined in peripheral blood mononuclear cells (PBMC). The cellular migration was determined for cells SK-MEL-28. Antitumoral effects on cells SK-MEL-28 were observed and the absence of cytotoxicity on the PBMCs.

Major chemical carcinogens and health exposure risks in some therapeutic herbal plants in Nigeria.

People of all ages and genders utilize herbal medicine to treat varieties of problems all around the world. The accumulation of Cd and Cr in therapeutic herbs (Adansonia digitata, Psidium guajava, and Carica papaya) can lead to a variety of health complications. These leaf extracts are used to treat varieties of ailments, including cancer, in the northern Nigerian states of Borno, Jigawa, and Kano. The researchers employed high-resolution continuous source atomic absorption spectrometry. The statistical parameters such as mean, range, minimum and maximum were computed along with one-way analysis of variance (ANOVA) to assess activity concentrations of Major Chemical Carcinogens (MCCs) in the herb extracts from the three states. The result demonstrated substantial statistical variation in the concentration of Chromium between groups with C. papaya (F = 190.683, p = 0.000), P. guajava (F = 5.698, p = 0.006), A. digitata (F = 243.154, p = 0.000). The post hoc test revealed that the C. papaya and A. digitata observed concentrations were statistically significant across the three states (p = 0.000). It was observed that there is no statistically significant difference between concentrations of the extracts between Kano and Borno states for P. guajava (p = 0.686). For Cd, the one-way ANOVA showed significant statistically variation in the concentration between groups with C. papaya (F = 77.393, p = 0.000), P. guajava (F = 4.496, p = 0.017), A. digitata (F = 69.042, p = 0.000). The post hoc test with multiple comparisons revealed that the activity concentration of all extracts was statistically significant across the three states (p<0.05). The target risk quotient (THQ) for Cd was more than unity in A. digitata and C. papaya, except for P. guajava from Borno State. The probable cancer risk was observed for consumption of plant extracts as a result of Cr and Cd.

Intraspecific C-value variation and the outcomes in Psidium cattleyanum Sabine essential oil.

Polyploidy, a numerical alteration of the karyotype, is one of the most important mechanisms in plant speciation and diversification, but could also be detected among populations, the cytotypes. For example, Psidium cattleyanum, a polyploid complex, has chromosome numbers ranging from 2n=3x=33 to 2n=12x=132. Polyploidization causes an increase in DNA content, and both modifications may cause alteration in plant growth, physiology, and epigenetics. Based on this possibility, here we aim to verify the influence of the polyploidization on the production of P. cattleyanum essential oil chemotypes. Differences in the DNA contents, as a proxy to different ploidies, were observed and three distinct chemotypes were identified through the chromatographic profile analysis. The Psidium cattleyanum DNA content and qualitative and quantitative characteristics of the essential oils presented a positive relationship. Plants with higher DNA contents presented higher levels of oil production, which was mostly composed of hydrogenated sesquiterpenes, while plants with lower DNA contents produced lower amount of oil, which was mostly composed of hydrogenated monoterpenes. Based on the importance of essential oils, polyploid plants, which present higher DNA content, are recommended as possible matrices for the propagation of new plants with the potential to produce major compounds of agronomic and pharmacological interest.

Volatile Dimethyl Disulfide from Guava Plants Regulate Developmental Performance of Asian Citrus Psyllid through Activation of Defense Responses in Neighboring Orange Plants.

Intercropping with guava (Psidium guajava L.) can assist with the management of Asian citrus psyllid (ACP, Diaphorina citri Kuwayama), the insect vector of the huanglongbing pathogen, in citrus orchards. Sulfur volatiles have a repellent activity and physiological effects, as well as being important components of guava volatiles. In this study, we tested whether the sulfur volatiles emitted by guava plants play a role in plant-plant communications and trigger anti-herbivore activities against ACP in sweet orange plants (Citrus sinensis L. Osbeck). Real-time determination using a proton-transfer-reaction mass spectrometer (PTR-MS) showed that guava plants continuously release methanethiol, dimethyl sulfide (DMS), and dimethyl disulfide (DMDS), and the contents increased rapidly after mechanical damage. The exposure of orange plants to DMDS resulted in the suppression of the developmental performance of ACP. The differential elevation of salicylic acid (SA) levels; the expression of phenylalanine ammonia lyase (PAL), salicylate-O-methyl transferase (SMT), and pathogenesis-related (PR1) genes; the activities of defense-related enzymes PAL, polyphenol oxidase (PPO), and peroxidase (POD); and the total polyphenol content were observed in DMDS-exposed orange plants. The emission of volatiles including myrcene, nonanal, decanal, and methyl salicylate (MeSA) was increased. In addition, phenylpropanoid and flavonoid biosynthesis, and aromatic amino acid (such as phenylalanine, tyrosine, and tryptophan) metabolic pathways were induced. Altogether, our results indicated that DMDS from guava plants can activate defense responses in eavesdropping orange plants and boost their herbivore resistance to ACP, which suggests the possibility of using DMDS as a novel approach for the management of ACP in citrus orchards.

Green Synthesis and Characterization of Cobalt Oxide Nanoparticles Using Psidium guajava Leaves Extracts and Their Photocatalytic and Biological Activities.

The advanced technology for synthesizing nanoparticles utilizes natural resources in an environmentally friendly manner. Additionally, green synthesis is preferred to chemical and physical synthesis because it takes less time and effort. The green synthesis of cobalt oxide nanoparticles has recently risen due to its physico-chemical properties. In this study, many functional groups present in Psidium guajava leaf extracts are used to stabilize the synthesis of cobalt oxide nanoparticles. The biosynthesized cobalt oxide nanoparticles were investigated using UV-visible spectroscopic analysis. Additionally, Fourier-transform infrared spectroscopy revealed the presence of carboxylic acids, hydroxyl groups, aromatic amines, alcohols and phenolic groups. The X-ray diffraction analysis showed various peaks ranging from 32.35 to 67.35°, and the highest intensity showed at 36.69°. The particle size ranged from 26 to 40 nm and confirmed the average particle size is 30.9 nm. The green synthesized P. guajava cobalt oxide nanoparticles contain cobalt as the major abundant element, with 42.26 wt% and 18.75 at% confirmed by the EDAX techniques. SEM images of green synthesized P. guajava cobalt oxide nanoparticles showed agglomerated and non-uniform spherical particles. The anti-bacterial activity of green synthesized P. guajava cobalt oxide nanoparticles was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli with a 7 to 18 mm inhibitory zone. The photocatalytic activity was evaluated using green synthesized P. guajava cobalt oxide nanoparticles and observed 79% of dye degradation. The MTT assay of P. guajava cobalt oxide nanoparticles showed an excellent cytotoxic effect against MCF 7 and HCT 116 cells compared to normal cells. The percentage of cell viability of P. guajava cobalt oxide nanoparticles was observed as 90, 83, 77, 68, 61, 58 and 52% for MCF-7 cells and 82, 70, 63, 51, 43, 40, and 37% for HCT 116 cells at the concentration of 1.53, 3.06, 6.12, 12.24, 24.48, 50, and 100 µg/mL compared to control cells. These results confirmed that green synthesized P. guajava cobalt oxide nanoparticles have a potential photocatalytic and anti-bacterial activity and also reduced cell viability against MCF-7 breast cancer and HCT 116 colorectal cancer cells.

The effect of Psidium guajava hydroalcoholic extract on reducing the expression of Resistin and TNF-α genes in articular chondrocytes of patients with knee osteoarthritis.

Knee osteoarthritis is the most common joint disease and the most important cause of disability in elderly patients. Due to the side effects of nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of osteoarthritis, the use of herbs is recommended as an alternative treatment. The guava fruit can be considered as a natural medicine due to its antioxidant and anti-inflammatory properties. In this study, the effect of Psidium guajava hydroalcoholic extract was considered on reducing the expression of the resistin gene and TNF-α gene in articular chondrocytes of patients with knee osteoarthritis. For this purpose, cartilage chondrocytes of 10 Chinese patients with knee osteoarthritis, who were indicated for arthroplasty, were used for evaluating the effect of guava fruit on the expression of these genes. Articular chondrocytes were cultured under appropriate conditions and their viability was assessed by MTT assay. To increase the level of cytokines, cells were treated with lipopolysaccharide (LPS). They were kept in an incubator with 90% humidity at 37°C for the next steps. Then, the expression of the resistin gene and TNF-α gene was investigated by RNA isolation and cDNA preparation. The results showed that the expression of the resistin gene and TNF-α gene were reduced to 56.59% and 51.86%, respectively, by hydroalcoholic extract of guava fruit. Therefore, according to the results of this study and previous researches, the hydroalcoholic extract of guava fruit (Psidium guajava) can be considered as an effective complementary and alternative treatment for osteoarthritis of the knee.

The effect of hydroalcoholic extract of Psidium guajava L. on experimentally induced oral mucosal wound in rat.

BACKGROUND: The aim of this study was to evaluate the biological effects of hydroalcoholic extract of Psidium guajava L leaves and phenytoin as a standard agent on the induced oral mucosal wound. METHODS: Hundred seventy Sprague Dawley rats were grouped in 5 clusters randomly. Oral mucosal wounds were induced in all rats except for the control group. Phenytoin and guajava leaf extract were used as a mouthwash. Twelve rats from the 5 groups were euthanized on day 7th and 10th, and 10 rats from each group were sacrificed on the 14th day. Interleukin-6 and total antioxidant capacity were determined in the serum. The tissues were evaluated for pathological and stereological assessments. Phytochemical analyses were performed on the hydroalcoholic extract of Psidium guajava L to determine the antioxidant potency. RESULTS: Total phenolic content test and DPPH analysis demonstrated the high potential of antioxidant capacity of Psidium guajava L. Decreasing IL-6 and increasing TAC were seen in the guajava hydroalcoholic extract and phenytoin groups. The difference of IL-6 between the wound treated guajava group and the wounded group was significant. The wound treated guajava group and wound treated phenytoin group on the 14th day increased the number of fibroblast cells and volume density of sub-mucosae effectively to the same thickness to be considered as a healed sub-mucosae layer. The volume density of the epithelium changes showed statistically significant different responses based on gender. CONCLUSION: In conclusion, hydroalcoholic extract of Psidium guajava L leaves might exert theraputic effects on oral mucositis.

Chemical Composition, Antibacterial, Antioxidant and Enzyme Inhibitory Activities of the Essential Oil from Leaves of Psidium guajava L.

Guava (Psidium guajava L.) leaf essential oil (GLEO) was extracted by water distillation, and its in vitro antioxidant, antidiabetic, and antibacterial properties were evaluated. Using GC/MS to determine the chemical components of GLEO, 27 constituents were identified, accounting for 74.90 % of the total oil content, among which L-caryophyllene (24.46 %), L-calamenene (10.82 %), (-)-globulol (10.69 %), and α-copaene (8.71 %) were the main components. Subsequently, the antioxidant activity of GLEO was determined by DPPH, ABTS, and ß-carotene bleaching tests. The half maximal inhibitory concentration of GLEO for three free radicals were IC50 =17.66±0.07 µg/mL, IC50 =19.28±0.03 µg/mL, and IC50 =3.17±0.01 µg/mL, respectively. Moreover, GLEO exhibited remarkable α-amylase (IC50 =13.99±0.34 µg/mL) and α-glucosidase (IC50 =5.50±1.02 µg/mL) inhibitory activities. It was effective against Streptomyces acidiscabies (MIC=1.25 µg/mL), Ralstonia solanacearum (MIC=5 µg/mL), and Erwinia carotovora subsp carotovora borgey (MIC=2.5 µg/mL), showing significant antibacterial properties. Based on the findings, given the high biological activity of GLEO, it is a biological preservative for food, medicine, and cosmetics and is valuable in natural therapy and crop disease management.