• Journal of the Korean Applied Science and Technology
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• v.37 no.1
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• pp.56-65
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• 2020

This study attempted to review the possibility of Psidium guajava leaf extract as a cosmetics ingredient by measuring antioxidant activity through ABTS radical scavenging activity, cytotoxicity in RAW 264.7 macrophages, ROS generation-inhibiting effects through DCF-DA assay and antimicrobial activity, and the results found the followings: The Psidium guajava leaf extract revealed excellent ABTS radical scavenging activity. In RAW 264.7 macrophages, no cytotoxicity was found. The ROS generation in the cells was reduced in a dose-dependent manner. The antimicrobial activities were observed in the following strains: S. aureus, E. coli, C. albicans and P. acnes. In terms of minimum inhibitory concentration (MIC) on each strain, which ranged from 0.25 to 1 mg/mL, C. albican was the lowest, followed by E. coli, S. aureus and P. acnes. The above results confirmed the effects of Psidium guajava leaf extract: antioxidant activity, inhibition of ROS generation in the cells, antimicrobial effects on skin flora which causes inflammation. Therefore, it appears that the extract would be available as a cosmetics ingredient which is free of toxins and side effects.

• Korean Journal of Medicinal Crop Science
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• v.20 no.2
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• pp.94-100
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• 2012

Guava ($Psidium$ $guajava$) contain a great deal of polyphenol compound and work on the treatment of $Diabetes$ $mellitus$ effectively. In this study, the bioactivities of aqueous extract (GLEx) of guava leaf were investigated. Total phenolic contents of GLEx was 266.9 mg tan/g. The effects of GLEx on digestive enzymes, ${\alpha}$-amylase, maltase and sucrase were investigated. $IC_{50}$ values of GLEx against ${\alpha}$-amylase, maltase and sucrase were 0.65 mg/$m{\ell}$, 2.0 mg/$m{\ell}$ and 3.5 mg/$m{\ell}$ respectively. The effect of GLEx on oral glucose tolerance test (OGTT) was performed in normal ICR mouse, control (dstilled water) and GLEx (aqueous extract of Guava leaf) were co-administered orally with glucose, showed reducing effect on the blood glucose level. The guava is likely to useful for prevention or improvement of hyperglycemia by lowering the blood glucose level and inhibiting glycoside hydrolase activity.

• Korean journal of food and cookery science
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• v.26 no.2
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• pp.171-179
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• 2010

The objectives of this study were to investigate the antioxidative activity of crackers made with a guava(Psidium guajava Linn.) leaf extract harvested in Korea. Guava leaf extraction using boiling water showed significantly higher antioxidative activities than extracting using 70% ethanol based on the higher total phenolic contents, FRAP, and ABTS assays(p<0.05). The crackers containing 1% guava leaf extract, and 0.075% BHT were stored at $63^{\circ}C$ for 7 days for the Schaal oven test, and the oxidative stability(AV, POV), antioxidative activity(DPPH, FRAP, ABTS assay), and sensory evaluation were compared. The crackers containing 1% guava leaf extract were found to have a higher oxidative stability than the control due to a lower acid value and peroxide value after 7 days of storage. The antioxidative activities of the crackers containing 1% guava leaf extract was the highest after 7 days as determined in the DPPH and ABTS assay, and was lower than crackers containing 0.075% BHT after 4 days as assessed by the FRAP assay. In the sensory evaluation, the crackers containing the 1% guava leaf extract had the highest scores in terms of taste, texture, and overall palatability than others at increasing storage time. As a result, the addition of 1% guava leaf extract harvested in Korea increased the antioxidative effect as well as the sensory acceptability of crackers.

• Fashion & Textile Research Journal
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• v.13 no.5
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• pp.778-789
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• 2011

The natural dyeing of silk fabrics with guava leaf extract was investigated. Mixed components of flavonoid and tannin seem to be the components of guava leaf extract. The temperature and time for dyeing of silk fabrics with guava leaf extract were $40^{\circ}C$ and $90^{\circ}C$ for eighty minutes, respectively. The dyeing equilibrium was shown at the fourth time of repeated dyeing. The highest K/S value was recorded at pH 3. Fe-mordanted fabrics showed the highest K/S value. High K/S values were shown in the post-mordanting of dyed fabrics at $40^{\circ}C$ and the pre-mordanting of dyed fabrics at $90^{\circ}C$. After repeated dyeing and mordanting, various color change occurred with mordant treatment. Surface colors were changed to YR color in alkaline water extract and to Y color in acidic water and ethanol extract, respectively. The washing fastness was level 3-4 for Sn-mordanted fabrics and level 4 for Fe-mordanted fabrics, and the dry cleaning fastness also showed very excellent result with level 4-5. The rubbing fastness was satisfactory with level 3-4. The light fastness was above level 4 only when Fe-mordanting was conducted, and the rest of dyed fabrics was not fast enough. In the antibacterial activity, the powder of guva leaf extract showed 99.9% of high antibacterial activity and Staphylococcus aureus showed 99.6% in dyed fabric. All dyed fabrics showed higher deodorization and UV protection rate than control fabric.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.12
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• pp.1702-1710
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• 2017

Objective: The study examined the effect of condensed tannins (CT) containing Ficus infectoria and Psidium guajava leaf meal mixture (LMM) supplementation on nutrient metabolism, methane emission and performance of lambs. Methods: Twenty four lambs of ~6 months age (average body weight $10.1{\pm}0.60kg$) were randomly divided into 4 dietary treatments (CT-0, CT-1, CT-1.5, and CT-2 containing 0, 1.0, 1.5, and 2.0 percent CT through LMM, respectively) consisting of 6 lambs each in a completely randomized design. All the lambs were offered a basal diet of wheat straw ad libitum, oat hay (100 g/d) along with required amount of concentrate mixture to meet their nutrient requirements for a period of 6 months. After 3 months of experimental feeding, a metabolism trial of 6 days duration was conducted on all 24 lambs to determine nutrient digestibility and nitrogen balance. Urinary excretion of purine derivatives and microbial protein synthesis were determined using high performance liquid chromatography. Respiration chamber study was started at the mid of 5th month of experimental feeding trial. Whole energy balance trials were conducted on individual lamb one after the other, in an open circuit respiration calorimeter. Results: Intake of dry matter and organic matter (g/d) was significantly (p<0.05) higher in CT-1.5 than control. Digestibility of various nutrients did not differ irrespective of treatments. Nitrogen retention and microbial nitrogen synthesis (g/d) was significantly (p<0.01) higher in CT-1.5 and CT-2 groups relative to CT-0.Total body weight gain (kg) and average daily gain (g) were significantly (linear, p<0.01) higher in CT-1.5 followed by CT-1 and CT-0, respectively. Feed conversion ratio (FCR) by lambs was significantly (linear, p<0.01) better in CT-1.5 followed by CT-2 and CT-0, respectively. Total wool yield (g; g/d) was linearly (p<0.05) higher for CT-1.5 than CT-0. Methane emission was linearly decreased (p<0.05) in CT groups and reduction was highest (p<0.01) in CT-2 followed by CT-1.5 and CT-1. Methane energy (kcal/d) was linearly decreased (p<0.05) in CT groups. Conclusion: The CT supplementation at 1% to 2% of the diet through Ficus infectoria and Psidium guajava LMM significantly improved nitrogen metabolism, growth performance, wool yield, FCR and reduced methane emission by lambs.

• Journal of Life Science
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• v.19 no.3
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• pp.334-342
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• 2009

This study investigates the effects of Psidium guajava L. leaf (Pg), Lagerstroemia speciosa L. leaf (Ls) and mixture A (Pg, Ls, Morus indica L. leaf extract, Pinus densiflora needles extract, Acanthopanax senticosus M. root extract) on streptozotocin (STZ)-diabetes rats. For four weeks, STZ-diabetes rats were fed crystallized extracts of Pg, Ls, and mixture A. Compared to the diabetic control group, extracts of Pg, Ls, and mixture A decreased glucose levels in rats by 20%, 14% and 24% respectively. These extracts also decreased the level of total cholesterol, triglyceride and free fatty acid, compared to the diabetic control group, while effectively increasing levels of insulin and high-density lipoprotein-cholesterol. These results showed that mixture A had greater antihyperglycemic, antihyperlipidemic, and insulin-increasing effects than the Pg and Ls extracts. Mixture A also showed better restoration of damaged beta cell function compared to Pg and Ls extracts. Therefore, it was proved that mixture A provides a beneficial synergistic effect when compared with Pg and Ls extracts used individually.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.317-323
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• 2012

We investigated the quality characteristics of cookies prepared after the addition of various concentration of used guava leaf powder(0%, 1%, 3%, 5%, all w/w) as a substitute for flour. In this study, as guava leaf powder concentration rose, there was a decrease in the water content level. In addition, color, spread factor, hardness and sensory evaluation of the cookies were examined. The results showed that with an increase in guava leaf powder concentration, the L value decreased significantly, while the values for a and b of cookies increased when more guava leaf power was added to cookies. The spread factor of cookies decreased, but the hardness of cookies increased significantly, as guava leaf powder concentration increased. Cookies containing 0% and 3% of guava leaf powder showed a similar sensory evaluation score in terms of color, taste and flavor of the cookies. In the case of texture and overall consumer acceptability, cookies with 3% of guava leaf powder showed the highest score.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1377-1384
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• 2007

A previous study suggested that the phyto-extract mixture (PEM381) containing Camellia sinensis (leaf), Psidium guajava (leaf), and Rosa hybrida (flower) inhibited not only arachidonic acid cascade-related enzymes (5-lipoxygenase and cyclooxygenase) in vitro but also degranulation and histamine release from rat peritoneal mast cells. In this study, the same PEM381 was used to investigate its inhibitory effects on the syntheses of leukotrienes and prostaglandins as well as on serum concentration of histamine and eosinophils infiltration in type I allergic reaction-induced mice. The PEM381 could decrease concentrations of serum cysteinyl leukotrienes from mice activated by anti-DNP IgE and DNP-albumin. The concentration of serum histamine by oral administration of PEM381 (25, 50, and 100 mg/kg of body weight) in type I allergic reaction-induced mice was $395.93{\pm}190.37$ nM, $315.59{\pm}164.23$ nM, and $325.07{\pm}112.02$ nM, respectively, while that of positive control (promethazine hydrochloride 10 mg/kg of body weight) was $270.12{\pm}24.02$ nM. In addition, the PEM381 also showed inhibitory effect on the eosinophils infiltration in the nasal mucosa of mice which were sensitized with ovalbumin. However, the effect of PEM381 on the syntheses of prostaglandins seemed to be insignificant. Consequently, these results suggest that PEM381 may be useful for the prevention and treatment of type I allergy-related diseases.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.155-162
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• 2007

The purpose of this study is to investigate the anti type I allergic effects and mechanisms of the phyto extract mixture (PEM381) which contains Camellia sinensis (leaf), Psidium guajava (leaf), and Rosa hybrida (flower). PEM381 was tested for its inhibitory effects on arachidonic acid cascade related enzymes (5-lipoxygenase and cyclooxygenase), the mast cell mediated allergic reaction and passive cutaneous anaphylaxis. $IC_{50}$ value of PEM381 against 5-lipoxygenase was $14.11{\pm}0.51ppm$ while that of positive control (nordihy-droguaiaretic acid) was $0.54{\pm}0.08ppm$. PEM381 also exhibited considerable selective inhibition of cyclooxygenase-2. PEM381 could inhibit both degranulation and histamine release in a dose dependent manner from rat peritoneal mast cells activated by compound 48/80. In addition, oral administration of PEM381 showed an inhibitory effect on passive cutaneous anaphylaxis reaction activated by anti-dinitrophenyl IgE antibody in mice. These results suggest that PEM381 may be useful for the prevention and treatment of type Ⅰ allergy related diseases.

• Fashion & Textile Research Journal
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• v.14 no.2
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• pp.320-330
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• 2012

The natural dyeing of cotton fabrics with guava leaf extract was investigated. The temperature and time of dyeing are $40^{\circ}C$ and $90^{\circ}C$ for eighty minutes, respectively. In addition, the dyebath has been set at pH 5. Sn pre-mordanted fabrics showed the highest K/S value. Regardless of dyeing temperature, K/S values were high when Al, Cu, Fe-mordanted fabrics were dyed in post-mordanting and Sn-mordanted fabrics were dyed in pre-mordanting. The K/S value of dyeing fabrics could be increased with repetitive dyeing and mordanting. Compared to untreated dyed fabrics, the K/ S values of fabrics which had been treated with soybean milk, chitosan and gall nut tannin were increased. The changed surface colors of fabrics that were treated with soybean milk, chitosan and gall nut tannin were Y, YR and achromatic colors. Fabrics dyed with alkaline water extract showed reddish color. Sn-mordanted fabrics dyed with acidic water extract showed vivid yellowish color, and Cu-mordanted fabrics dyed with ethanol extract showed yellowish green color. In case of Sn-mordanted fabrics, the washing fastness was level 4. The dry cleaning fastness also showed very excellent result with level 4-5. The rubbing fastness was better in dry rubbing than in wet rubbing of the fabrics. For the light fastness, all dyed fabrics showed low fastness. For antibacterial activity, the powder of guava leaf extract and the dyed fabrics with guava leaf extract showed 99.9% of high antibacterial activity. All dyed fabrics showed higher deodorization and UV protection rate than control fabric.