SEARCH · PubMed Health

Results for “Psidium”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed2005

The antimicrobial activities of Psidium guajava and Juglans regia leaf extracts to acne-developing organisms.

This study aims to present the in vitro inhibitory effect of Psidium guajava and Juglans regia leaf extracts on the main developer of acne lesions, Propionibacterium acnes (P. acnes), and other organisms that are isolated from acne lesions. Thirty-eight subjects (males and females) who had various types of acne were enrolled in the study. The contents of the acne lesions were cultured and the frequency of P. acnes (alone and with Staphylococci spp.) was 47%, whereas the frequencies for Staphylococcus aureus and Staphylococcus epidermidis were 13% and 24%, respectively. The antimicrobial activities of Psidium guajava and Juglans regia leaf extracts, determined by disk diffusion method (zone of inhibition), were compared to tea tree oil (TTO), doxycycline and clindamycin antibiotics. The zones of inhibition due to the Psidium guajava and Juglans regia leaf extracts ranged from 15.8-17.6 mm against P. acnes, 11.3-15.7 mm against S. aureus and 12.9-15.5 mm against S. epidermidis, respectively. These zones of inhibition were significantly higher than those of TTO and equivalent in case of Staphylococci spp., but less in case of P. acnes, to those obtained from doxycycline or clindamycin. It can be concluded that Psidium guajava and Juglans regia leaf extracts may be beneficial in treating acne especially when they are known to have anti-inflammatory activities.

Acne Vulgaris↗

PubMed2000

[Effects of psidium components on cytokine productions in helper T cells and type-I allergy].

Psidium genus Myrtaceae (Psidium) is known to be a chinese medicine with an anti-allergy effect. In the present study, to identify active components in Psidium and investigate mechanisms of its anti-allergy effect, effects of several components isolated from Psidium on cytokine production in helper T cell subtypes, Th1 and Th2 cells, were studied. All components, except methyl gallate, suppressed cytokine production in both Th1 and Th2 cells. Then, effects of methyl gallate on IgE production in a model mouse with type I allergy were studied. Methyl gallate suppressed IgE production in the mouse. Only methyl gallate selectively suppressed Th2-cytokine production.

Animals↗

PubMed2003

The anti-adherence effect of Piper betle and Psidium guajava extracts on the adhesion of early settlers in dental plaque to saliva-coated glass surfaces.

The aqueous extracts of Piper betle and Psidium guajava were prepared and tested for their anti-adherence effect on the adhesion of early plaque settlers (Strep. mitis, Strep. sanguinis and Actinomyces sp.). The saliva-coated glass surfaces were used to simulate the pellicle-coated enamel surface in the oral cavity. Our results showed that the anti-adherence activities of Piper betle and Psidium guajava extracts towards the bacteria were different between the bacterial species. Psidium guajava was shown to have a slightly greater anti-adherence effect on Strep. sanguinis by 5.5% and Actinomyces sp. by 10% and a significantly higher effect on Strep. mitis (70%) compared to Piper betle. The three bacterial species are known to be highly hydrophobic, and that hydrophobic bonding seemed to be an important factor in their adherence activities. It is therefore suggested that the plant extracts, in expressing their anti-adherence activities, could have altered the hydrophobic nature of the bonding between the bacteria and the saliva-coated glass surfaces.

Actinomyces↗

PubMed2005

[Study on the hypoglycemic activity of different extracts of wild Psidium guajava leaves in Panzhihua Area].

OBJECTIVE: To illuminate the role of water-soluble, 650 ml/L edible alcohol and 950 ml/L edible alcohol-soluble extracts of wild Psidium guajava leaves in Panzhihua Area in decreasing blood glucose. METHODS: High-level blood glucose models were made by use of male Kunming mice given intraperitoneal injection of glucose, subcutaneous injection of adrenaline and intraperitoneal injection of streptozotocin (STZ), respectively. Blood glucose concentration was measured after oral administration (gastrogavage) of the soluble extracts of Psidium guajava leaves, respectively. Body weight and organ morphology were observed, and organ index was obtained. The All available indexes were statistically analyzed in comparing the study groups and control group. RESULTS: three extracts resisted the rise of blood glucose level induced by exogenous glucose and adrenaline to various degrees. The extracts of water, 650 ml/L alcohol and 950 ml/L alcohol significantly decreased the blood glucose level in STZ-induced diabetic mice by 36.3%, 33.5% and 31.3% respectively. Furthermore, among three extracts, water-soluble extract showed little influence on the growth of mice. CONCLUSION: The water-soluble, 650 ml/L edible alcohol and 950 ml/L edible alcohol-soluble extracts of wild Psidium guajava leaves in Panzhihua area may have different hypoglycemic potential.

Animals↗

PubMed2005

Antidiabetic effects of extracts from Psidium guajava.

During a screening of medicinal plants for inhibition of protein tyrosine phosphatase1B (PTP1B), an extract from Psidium guajava (Myrtaceae) leaves exhibited significant inhibitory effect on PTP1B. Thus, its antidiabetic effect on Lepr(db)/Lepr(db) mice was evaluated. Significant blood glucose lowering effects of the extract were observed after intraperitoneal injection of the extract at a dose of 10mg/kg in both 1- and 3-month-old Lepr(db)/Lepr(db) mice. In addition, histological analysis of the liver from the butanol-soluble fraction treated Lepr(db)/Lepr(db) mice revealed a significant decrease in the number of lipid droplets compared to the control mice. Taken together, it was suggested that the extract from Psidium guajava leaves possesses antidiabetic effect in type 2 diabetic mice model and these effect is, at least in part, mediated via the inhibition of PTP1B.

Age Factors↗

PubMed2004

Chemical constituents from the leaves of Psidium guajava.

Five constituents including one new pentacyclic triterpenoid guajanoic acid (1) and four known compounds beta-sitosterol (2), uvaol (3), oleanolic acid (4), and ursolic acid (5) have been isolated from the leaves of Psidium guajava. The new constituent 1 has been characterized as 3beta-p-E-coumaroyloxy-2alpha-methoxyurs-12-en-28-oic acid through 2D NMR techniques and chemical transformations. This is the first report of isolation of compound 3 from the genus Psidium.

Magnetic Resonance Spectroscopy↗

PubMed2006

Effects of two medicinal plants Psidium guajava L. (Myrtaceae) and Diospyros mespiliformis L. (Ebenaceae) leaf extracts on rat skeletal muscle cells in primary culture.

Crude decoction, aqueous and ethanolic extracts of two medicinal plants (Psidium guajava and Diospyros mespiliformis), widely used in the central plateau of Burkina Faso to treat many diseases were evaluated for their antagonistic effects on caffeine induced calcium release from sarcoplasmic reticulum of rat skeletal muscle cells. These different extracts showed a decrease of caffeine induced calcium release in a dose dependent manner. Comparison of the results showed that Psidium guajava leaf extracts are more active than extracts of Diospyros mespiliformis and that crude decoctions show better inhibitory activity. The observed results could explain their use as antihypertensive and antidiarrhoeal agents in traditional medicine, by inhibiting intracellular calcium release.

Animals↗

PubMed2006

The effect of Piper betle and Psidium guajava extracts on the cell-surface hydrophobicity of selected early settlers of dental plaque.

The adhesion of early settlers of dental plaque to the tooth surface has a role in the initiation of the development of dental plaque. The hydrophobic surface properties of the bacteria cell wall are indirectly responsible for the adhesion of the bacteria cell to the acquired pellicle on the tooth surfaces. In this study, the effect of aqueous extract of two plants (Psidium guajava and Piper betle) on the cell-surface hydro-phobicity of early settlers of dental plaque was determined in vitro. Hexadecane, a hydrocarbon was used to represent the hydrophobic surface of the teeth in the oral cavity. It was found that treatment of the early plaque settlers with 1 mg/ml extract of Psidium guajava reduced the cell-surface hydrophobicity of Strep. sanguinis, Strep. mitis and Actinomyces sp. by 54.1%, 49.9% and 40.6%, respectively. Treatment of these bacteria with the same concentration of Piper betle however, showed a comparatively lesser effect (< 10%). It was also observed that the anti-adhesive effect of the two extracts on the binding of the early plaque settlers to hexadecane is concentration dependent.

Actinomyces↗

PubMed2002

Triterpenoids from Psidium guajava leaves.

Three pentacyclic triterpenoids including one new guajavanoic acid (2) and two known obtusinin (1) and goreishic acid I (3) have been isolated from the leaves of Psidium guajava. The new constituent 2 has been characterized as 2alpha-hydroxy-3beta-p-E-coumaroyloxyurs-12, 18-dien-28-oic acid through 1H-NMR and 13C-NMR (broad band and DEPT). This is the first report of isolation of compound 1 and 3 from the genus Psidium.

Chromatography, Thin Layer↗

PubMed1994

Quercetin glycosides in Psidium guajava L. leaves and determination of a spasmolytic principle.

The traditional herbal remedy from Psidium guajava leaves has been medically proposed in Mexico as effective treatment of acute diarrhea. A methanolic leaf extract was subjected to a bioassay-guided isolation of spasmolytic constituents. Six fractions were separated on a polyvinylpolypyrrolidine (PVPP) column using a water methanol-gradient. The fraction containing flavonols inhibited peristalsis of guinea pig ileum in vitro. A trace of quercetin aglycone together with five glycosides was isolated from this active fraction and identified as quercetin 3-O-alpha-L-arabinoside (guajavarin); quercetin 3-O-beta-D-glucoside (isoquercetin); quercetin 3-O-beta-D-galactoside (hyperin); quercetin 3-O-beta-L-rhamnoside (quercitrin) and quercetin 3-O-gentobioside. Biological activity of each pure compound was studied in the same bioassay. Obtained results suggest that the spasmolytic activity of the Psidium guajava leaf remedy is mainly due to the aglycone quercetin, present in the leaf and in the extract mainly in the form of five flavonols, and whose effect is produced when these products are hydrolyzed by gastrointestinal fluid.

Animals↗

PubMed2004

Antioxidant power of phytochemicals from Psidium guajava leaf.

Dried ground leaves of Psidium guajava L. (guava) were extracted by water and aqueous ethyl alcohol 50% (1:10) ratio, and the total phenolic content in the extracts was determined spectrophotometrically according to Folin- Ciocalteu's phenol method and calculated as gallic acid equivalent (GAE). Remarkably high total phenolic content 575.3 +/-15.5 and 511.6+/-6.2 mg of GAE/g of dried weight material (for ethanol guava leaf extracts and water guava leaf extracts, respectively) were obtained. The antioxidant activity of lyophilized extracts was determined at ambient temperature by means of a 2,2-diphenyl-1-picrylhydryzyl (DPPH*) colorimetry with detection scheme at 515 nm. The activity was evaluated by the decrease in absorbance as the result of DPPH* color change from purple to yellow. The higher the sample concentration used, the stronger was the free radical-scavenging effect. The results obtained showed that ascorbic acid was a substantially more powerful antioxidant than the extracts from guava leaf. On the other hand, the commercial guava leaf extracts and ethanol guava leaf extracts showed almost the same antioxidant power whereas water guava leaf extracts showed lower antioxidant activity. The parameter EC(50) and the time needed to reach the steady state to EC(50) concentration (T(EC(50))) affected the antiradical capacity of the sample. The antioxidant efficiency (AE) has been shown to be a more adequate parameter for selecting antioxidants than the widely used EC(50). This study revealed that guava leaf extracts comprise effective potential source of natural antioxidants.

Antioxidants↗

PubMed2004

Influence of storage environment, surface coating, and individual shrink wrapping on quality assurance of guava (Psidium guajava) fruits.

Guava (Psidium guajava) fruits of cv. L-49 with individual shrink wrapping using 9 micro LLDPE film could be successfully stored up to 12 days at ambient and 18 days in evaporative cool chamber with negligible loss in vitamin C content. The untreated fruits lose 25-30% of ascorbic acid within 1 week after harvest. Delay in senescence and metabolic activities as supported by less changes in soluble solids, sugars, acidity, respiration, and ethylene evaluation rate was also observed in individual shrink wrapped fruits in cool chamber. The spoilage of fruits by Fusarium rots was significantly less in cool chamber in individually shrink wrapped fruits followed by Sta-fresh treatment. Sta-fresh was more effective in cool chamber than ambient. Individually stored wrapped fruits scored a better value of sensory score than Sta-fresh under both the storage condition.

Antioxidants↗

PubMed2006

Kinetic analysis on the sensitivity of glucose- or glyoxal-induced LDL glycation to the inhibitory effect of Psidium guajava extract in a physiomimic system.

Experimentation with a physiomimic system and kinetic analysis exhibited four distinct reaction phases in LDL glycation despite of the type of inducer: glucose or glyoxal. LDL glycation was more sensitive to a status of hyperglycemia (such as 400 mg glucose/100 mL) as evidenced by the reaction order of 0.53. Glucose reacted intensively in the Initial Phase (reaction period 0-2h) which was identified to result from a parallel mechanism involving both the direct Schiff's product formation and the auto-oxidative cleavages. In contrast, a physiological level of glyoxal revealed merely a reaction order of only 0.09, implicitly indicating a far less sensitive glycation which can be attributed to a mechanism proceeding simply through a molecular Schiff's reaction. On treatment with Psidium guajava L. aqueous extract (PE) (0.01-0.625 mg/mL), a rather unique and significant inhibitory characteristic on LDL glycation was observed with a dose-dependent manner. We attributed such an effect of PE to its distinct abundance of polyphenolic content (165.61+/-10.39 mggallic acid equivalent (GAE)/g). Conclusively, PE is an excellent anti-LDL glycative agent whose potential therapeutic uses can be extended to the prevention of a variety of cardiovascular and neurodegenerative diseases associated with glycations.

Glucose↗

PubMed2005

2D RNA-QSAR: assigning ACC oxidase family membership with stochastic molecular descriptors; isolation and prediction of a sequence from Psidium guajava L.

Quantitative structure-activity relationship (QSAR) techniques for small molecules could be applied to nucleic acids. Unfortunately, almost all molecular descriptors are more successful at encoding branching information than sequences and/or cannot be back-projected. A solution for scaling the QSAR problem up to RNA may be to transform sequences into secondary structures first. Our group has used Markovian negentropies as molecular descriptors for drug design with preliminary results in bioinformatics [Bioinformatics 2003, 19, 2079]. However, RNA-QSAR studies on RNA molecules have not been described to date. Novel Markovian negentropies have been introduced here as molecular descriptors for 2D-RNA structures. An RNA-QSAR study of the ACC proteins from different plants has been carried out. The QSAR recognizes 19/20 sequences (95.0%) within the ACC family and 12/17 (70.6%) of the control group sequences. The model has a high Matthews' regression coefficient (C = 0.68). Overall cross-validation average accuracies were 14 out of 15 for ACC sequences (93.3%) and 10 out of 13 for control sequences (76.9%). Finally, ACC oxidase family membership was assigned to a new sequence isolated for the first time in this work from Psidium guajava L. A backprojection map for this sequence identifies the left stem (40%) and the main stem (45%) as highly important substructures. Results of an nBLAST experiment are consistent with this finding and indicate a high conservation score (>70) for left stem and main stem; whereas major loop, right stem, cap and major loop right half were hardly conserved.

Amino Acid Oxidoreductases↗

PubMed2006

Ozone-induced foliar injury in saplings of Psidium guajava 'Paluma' in São Paulo, Brazil.

Psidium guajava 'Paluma' was evaluated under field conditions as a tropical bioindicator species of ozone (O(3)). Three exposures of 90 days each were performed (June 21, 2004-March 19, 2005). In each one of them, saplings of 'Paluma' (n=30) were exposed to ambient air at a site in São Paulo (Brazil) with high ozone concentrations, and in a greenhouse with charcoal-filtered air. Ozone-like visible foliar injuries were observed during the winter, spring and summer exposures, when AOT40 reached 6166ppbh, 3504ppbh and 4828ppbh, respectively. No injuries were observed in the plants kept under filtered air. The injuries consisted in red stippling on adaxial leaf surfaces. They did not cover the veins and appeared first in older leaves, becoming more intense as the exposure period increased. Injury incidence, severity, and the cumulative exposure threshold at injury onset varied among the exposure periods. AOT40 explained partly the incidence, severity and leaf injury index LII (r(2)=0.52, 0.39, 0.38, respectively, p=0.002). The results confirm the potential of the species as an O(3)-sensitive bioindicator.

Air Pollutants↗

PubMed2006

Psidium guajava 'Paluma' (the guava plant) as a new bio-indicator of ozone in the tropics.

Psidium guajava 'Paluma' saplings were exposed to carbon filtered air (CF), ambient non-filtered air (NF), and ambient non-filtered air+40ppb ozone (NF+O(3)) 8h per day during two months. The AOT40 values at the end of the experiment were 48, 910 and 12 895ppbh(-1), respectively for the three treatments. After 5 days of exposure (AOT40=1497ppbh(-1)), interveinal red stippling appeared in plants in the NF+O(3) chamber. In the NF chamber, symptoms were observed only after 40 days of exposure (AOT40=880ppbh(-1)). After 60 days, injured leaves per plant corresponded to 86% in NF+O(3) and 25% in the NF treatment, and the average leaf area injured was 45% in NF+O(3) and 5% in the NF treatment. The extent of leaf area injured (leaf injury index) was explained mainly by the accumulated exposure of ozone (r(2)=0.91; p<0.05).

Brazil↗

PubMed2006

Novel 2D maps and coupling numbers for protein sequences. The first QSAR study of polygalacturonases; isolation and prediction of a novel sequence from Psidium guajava L.

The development of 2D graph-theoretic representations for DNA sequences was very important for qualitative and quantitative comparison of sequences. Calculation of numeric features for these representations is useful for DNA-QSAR studies. Most of all graph-theoretic representations identify each one of the four bases with a unitary walk in one axe direction in the 2D space. In the case of proteins, twenty amino acids instead of four bases have to be considered. This fact has limited the introduction of useful 2D Cartesian representations and the corresponding sequences descriptors to encode protein sequence information. In this study, we overcome this problem grouping amino acids into four groups: acid, basic, polar and non-polar amino acids. The identification of each group with one of the four axis directions determines a novel 2D representation and numeric descriptors for proteins sequences. Afterwards, a Markov model has been used to calculate new numeric descriptors of the protein sequence. These descriptors are called herein the sequence 2D coupling numbers (zeta(k)). In this work, we calculated the zeta(k) values for 108 sequences of different polygalacturonases (PGs) and for 100 sequences of other proteins. A Linear Discriminant Analysis model derived here (PG=5.36.zeta1-3.98.zeta3-42.21) successfully discriminates between PGs and other proteins. The model correctly classified 100% of a subset of 81 PGs and 75 non-PG proteins sequences used to train the model. The model also correctly classified 51 out of 52 (98.07%) of proteins sequences used as external validation series. The uses of different group of amino acids and/or axes orientation give different results, so it is suggested to be explored for other databases. Finally, to illustrates the use of the model we report the isolation and prediction of the PG action for a novel sequence (AY908988) isolated by our group from Psidium guajava L. This prediction coincides very well with sequence alignment results found by the BLAST methodology. These findings illustrate the possibilities of the sequence descriptors derived for this novel 2D sequence representation in proteins sequence QSAR studies.

Algorithms↗

PubMed2004

Antifungal activity of fruit pulp extract from Psidium sartorianum.

The methanol extract of the fruit pulp of Psidium sartorianum was evaluated against seven Candida spp. and nine other fungal strains that are human pathogens. The extract showed a significant activity against seven Trichophyton species. Candida species were insensitive.

Antifungal Agents↗