• Journal of the Society of Cosmetic Scientists of Korea
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• v.34 no.3
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• pp.233-244
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• 2008

In this study, the antioxidative effects, inhibitory effects on elastase and tyrosinase, and component analysis of Psidium guajava leaf extracts were investigated. The free radical (1,1-diphenyl-2-picrylhydrazyl, DPPH) scavenging activities $(FSC_{50})$ of extract/fractions of Psidium guajava leaf were in the order: 50% ethanol extract $(7.05{\mu}g/mL)$ < ethyl acetate fraction $(3.36{\mu}g/mL)$ < deglycosylated flavonoid aglycone fraction $(3.24{\mu}g/mL)$. Reactive oxygen species (ROS) scavenging activities $(OSC_{50})$ of some Psidium guajava leaf extracts on ROS generated in $Fe^{3+}-EDTA/H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The order of ROS scavenging activities were 50% ethanol extract $(OSC_{50},\;2.17{\mu}g/mL)$ < ethyl acetate fraction $(0.64{\mu}g/mL)$ < deglycosylated flavonoid aglycone fraction $(3.39{\mu}g/mL)$. Aglycone fraction showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of Psidium guajava leaf on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The Psidium guajava leaf extracts suppressed photohemolysis in a concentration dependent manner $(1{\sim}10{\mu}g/mL)$, particularly deglycosylated flavonoid aglycone fraction exhibited the most prominent celluar protective effect ${\tau}_{50}\;107.5min\;at\;1{\mu}g/mL)$. Aglycone fraction obtained from the deglycosylation reaction of ethyl acetate fraction among the Psidium guajava leaf extracts, showed 1 band in TLC and 1 peak in HPLC experiments (360 nm). One component was identified as quercetin. TLC chromatogram of ethyl acetate fraction of Psidium guajava leaf extract revealed 5 bands and HPLC chromatogram showed 5 peaks, which were identified as quercetin 3-O-gentobioside (10.32%) , quercetin 3-O-${\beta}$-D-glucoside (isoquercitin, 13.30%), quercetin 3-O-${\beta}$-D-galactoside (hyperin, 11.34%), quercetin 3-O-${\alpha}$-L-arabinoside (guajavarin, 19.70%), quercetin 3-O-${\beta}$-L-rhamnoside (quercitrin, 45.33%) in the order of elution time. The inhibitory effect of Psidium guajava leaf extracts on tyrosinase were investigated to assess their whitening efficacy. Finally, their anti-elastase activities were measured to predict the anti-wrinkle efficacy in the human skin. Inhibitory effects $(IC_{50})$ on tyrosinase of some Psidium guajava leaf extracts was 50% ethanol extract $(149.67{\mu}g/mL)$ < ethylacetate fraction $(30.67{\mu}g/mL)$ < deglycosylated aglycone fraction $(17.10{\mu}g/mL)$. Inhibitory effects $(IC_{50})$ on elastase of some Psidium guajava leaf extracts was 50% ethanol extract $(6.60{\mu}g/mL)$ < deglycosylated aglycone fraction $(5.66{\mu}g/mL)$ < ethylacetate fraction $(3.44{\mu}g/mL)$. These results indicate that extract/fractions of Psidium guajava leaf can function as antioxidants in bioloigcal systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. And component analysis of Psidium guajava leaf extract and inhibitory activity on elastase of the aglycone fraction could be applicable to new functional cosmetics for smoothing wrinkles.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.254-262
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• 2018

It was intended to check a possibility of activity of Psidium guajava leaf extract as anti-oxidant and anti-inflammatory material. Total polyphenol and total flavonoid content of Psidium guajava leaf extract was checked. Cream having inhibitory effect on inflammation through toxicity and NO production inhibition in RAW 264.7 cell was manufactured, and skin safety was evaluated. It was confirmen that total polyphenol and flavonoid content of Psidium guajava leaf extract was 126.4 mg/g and 223.17 mg/g respectively, which was high content. According to the results of checking toxicity through cell viability in RAW 264.7 cell, cytotoxicity was not shown. And NO production indicating inflammatory disease was inhibited concentration-dependently. According to the results of carrying out single patch test after manufacturing the cream containing the Psidium guajava leaf extract, skin irritation did not occur for 24 h to put patch on skin or for 24 h after removing the patch. Putting these results together, it was verified that there was possibility of application as raw materials for cosmetics, which would have anti-oxidant activity owing to the high polyphenol and flavonoid content of Psidium guajava leaf extract and anti-inflammatory material through NO production inhibition.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.296-304
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• 2017

The purpose of this study was to investigate the applicability of the Psidium guajava leaf extract as a whitening functional cosmetic material. We measured DPPH radical scavenging activity, intracellular ROS, cytotoxicity in B16F10 melanoma cells and cytoprotective effect on ultraviolet A, in vitro tyrosinase inhibitory effect and melanin biosynthesis inhibitory effect. The antioxidative effect was confirmed through high DPPH radical scavenging activity and intracellular ROS activity inhibition measurement of the Psidium guajava leaf extract. The survival rate of B16F10 melanoma cells was more than 98% at all concentrations, and the cytoprotective effect from ultraviolet ray A was found to increase in a concentration-dependent manner. In addition, in vitro tyrosinase activity inhibitory effect of 10% and melanin biosynthesis inhibitory effect of 20% were observed. Through less toxicity for B16F10 melanoma cell, high antioxidant activity, inhibition of tyrosinase activity and melanin biosynthesis inhibitory effect, we confirmed the possibility of developing the Psidium guajava leaf extract as a whitening functional cosmetic material with a safe and excellent whitening effect.

• The Korean Journal of Food And Nutrition
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• v.32 no.1
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• pp.33-40
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• 2019

The purpose of this study was to evaluate the antioxidant and hepatocyte protective effects of guava (Psidium guajava L.) leaves cultivated in Korea. The contents of the total polyphenol of the extract was 271.57 mg gallic acid equivalent (GAE)/g residue. Antioxidant activities of leaf extract were evaluated by examining the free radical scavenging ability. 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and ${\alpha}-{\alpha}$-diphenyl-${\beta}$-picrylhydrazyl (DPPH) free radical scavenging activities of the extract were 1133.23 mg trolox equivalent antioxidant capacity (TEAC)/g residue and 721.68 mg TEAC/g residue, respectively. The hepatocyte protective effect of guava leaf extract was examined in HepG2 cells. Against tert-butyl hydroperoxide (TBHP), the viability of HepG2 cells were increased by the treatment of leaf extract. In addition, guava leaf extract led to the inhibition of reactive oxygen species (ROS) generated in HepG2 cells. The leaf extract increased the activity of glutathione (GSH), glutathione reductase (GR), and glutathione peroxidase (GPx) against oxidative stress. These results suggested that guava leaves might be regarded as a potential source natural antioxidant and a hepatoprotective material.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.43-53
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• 2019

The anticancer activity of guava (Psidium guajava L.) leaf extract (GLE) occurs via the induction of apoptosis in cancer cells. However, the mechanism behind GLE-induced apoptosis in the human hepatocellular carcinoma cell line HepG2 remains unclear. In the present study, we investigated the apoptotic effects and mechanism of action of GLE in cultured HepG2 cells. The results showed that GLE induced reactive oxygen species (ROS) synthesis and disrupted the mitochondrial membrane potential (${\Delta}{\Psi}m$). Moreover, GLE increased the expression of apoptotic pathway proteins, such as the cleaved forms of caspase-3, -8, and -9; the translocation of Bax and cytochrome c (cyt-c) from the mitochondria to the cytosol; and the downregulation of Bcl-2. In addition, p53 protein expression was increased upon GLE treatment. These observations indicate that the GLE-induced apoptosis in HepG2 cells is mediated by mitochondrial ROS generation, followed by caspase activation and cyt-c release, suggesting that GLE may be a promising candidate for the development of novel drugs for the treatment of liver cancers.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.266-271
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• 2023

The antioxidant capacity of the Psidium guajava leaf extracted with EtOH and their MeOH fractions using column chromatography were evaluated by 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid radical scavenging assays, total phenolic and flavonoid content, and Superoxide dismutase (SOD) assay. To determine its utility as a functional material, the crude extract was fractionated by flash column chromatography on ODS using a stepwise elution with combinations of MeOH/H₂O and then all the fractions were also investigated. In the results of antioxidant activities, the 40% and 60% MeOH fractions show the meaningful values, and then the two fractions were selected to examine the isolation and identification of the major constituents via HPLC and nuclear magnetic resonance. Further purification led to isolation of two quercetin derivatives; quercitrin (1) and isoquercetin (2). Through SOD assay, some methanol fractions via column chromatography and isolated compounds showed improved antioxidant activities compared to the extract.

• Korean Journal of Food Science and Technology
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• v.38 no.5
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• pp.679-683
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• 2006

The effects of dried and fermented guava (Psidium guajava L.) leaf extracts on blood glucose levels were investigated in low-dose streptozotocin(STZ)-induced diabetic mice. Fermented guava leaf extract (500 mg/kg/day) significantly decreased the fasting blood glucose levels after 2-4 weeks of treatment and improved the impaired glucose tolerance in STZ-induced diabetic mice. On the other hand, dried guava leaf extract lowered the blood glucose levels and improved glucose tolerance two weeks after treatment, but exacerbated STZ-induced high blood glucose levels three and four weeks after treatment. Histological and immunohistochemical observation showed that fermented guava leaf extract treatment improved STZ-induced pancreatic beta-cell damage, but dried guava leaf extract did not affect the damage to the beta-cells. These results suggest that fermented guava (Psidium guajava L.) leaf extracts improve the hyperglycemia by protecting the pancreatic beta-cells hom damage in STZ-induced diabetic mice.

• Korean Journal of Plant Resources
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• v.21 no.5
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• pp.408-412
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• 2008

This research was designed to investigate the antioxidant activities and tyrosinase inhibitory effects of guava (Psidium guajava L.) leaf. Total phenol content was obtained from guava leaf extract of 19.0 (g/100g, D.W.). The crude extract exhibited significantly antioxidant activities (IC50value $102.5{\mu}g/ml$, free radical scavenging; $49.4{\mu}g/ml$, SOD like activity). The crude extract of guava leaf was fractionated into four partition layers; hexane (G-H), ethyl acetate (G-E), butanol (G-B) and water (G-W) layer. The extracts of G-E, G-B, G-W showed high radical scavenging activities of over 50% at $100{\mu}g/ml$. SOD like activities of G-E, G-B, G-W were revealed, as 81.8%, 84.7%, 65.3% at $100{\mu}g/ml$, while those of G-H did not showed the effectively. The crude extract of guava leaf showed high tyrosinase inhibitory effect as 60.8% at 1mg/ml, the measurement of G-E, G-B, G-W were 65.2%, 62.8%, 51.6% and that of G-H was not effective. These results indicate that useful bioactive substances exist in the guava leaf extracts, especially G-E, G-B. And the guava leaf has the potential of being developed into health related products.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.3
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• pp.151-157
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• 2023

Background: The potential impact of aqueous extracts from Psidium guajava leaves on the reproductive system of female rabbits was evaluated. Methods: Twenty-eight rabbits, aged five to six months were utilized. Rabbits were divided into four groups and were randomly assigned to receive one of the following oral doses of the guava leaf extracts: 0 (control group), 10, 20, or 30 mg/kg of body weight. After a treatment period of 30 days, blood was collected via jugular venipunture and the serum was extracted for the assessment of serum biochemical traits levels. The females were bred and monitored throughout their pregnancy to ascertain reproductive outcomes. Results: The results indicated that the guava leaf extract significantly increased the body weight of the rabbits during both pre- and post-pregnancy compared to the control group (p < 0.05). The litter size at three weeks post-birth, prolificity rate, FSH, LH, and protein levels were notably higher (p < 0.05) at a dose of 20 mg/kg of body weight. The viability rate three weeks post-birth increased with escalating extract doses, and the highest values were observed at doses of 20 and 30 mg/kg of body weight (p < 0.05). Conclusions: This study demonstrated that, the aqueous extract of guava leaves appears to stimulate the production of FSH, LH and enhance body weight, prolificity, and pregnancy outcomes in mammals. As such, it is suggested that a dose of 20 mg/kg body weight could be beneficial in improving the reproductive performance of female.

• Nutrition Research and Practice
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• v.15 no.5
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• pp.568-578
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• 2021

BACKGROUND/OBJECTIVES: Psidium guajava L. (guava) leaves have been shown to exhibit hypoglycemic and antidiabetic effects in rodents. This study investigated the effects of guava leaf extract on adipogenesis, glucose uptake, and lipolysis of adipocytes to examine whether the antidiabetic properties are mediated through direct effects on adipocytes. MATERIALS/METHODS: 3T3-L1 cells were treated with 25, 50, 100 ㎍/mL of methanol extract from guava leaf extract (GLE) or 0.1% dimethyl sulfoxide as a control. Lipid accumulation was evaluated with Oil Red O Staining and AdipoRed assay. Immunoblotting was performed to measure the expression of adipogenic transcription factors, fatty acid synthase (FAS), and AMP-activated protein kinase (AMPK). Glucose uptake under basal or insulin-stimulated condition was measured using a glucose analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-D-glucose. Lipolysis from fully differentiated adipocytes was measured by free fatty acids release into the culture medium in the presence or absence of epinephrine. RESULTS: Oil Red O staining and AdipoRed assay have shown that GLE treatment reduced lipid accumulation during adipocyte differentiation. Mitotic clonal expansion, an early essential event for adipocyte differentiation, was inhibited by GLE treatment. GLE inhibited the expression of transcription factors involved in adipocyte differentiation, such as peroxisome proliferator-activated receptor 𝛄 (PPAR𝛄), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein-1c (SREBP-1c). FAS expression was also decreased while the phosphorylation of AMPK was increased by GLE treatment. In addition, GLE increased insulin-induced glucose uptake into adipocytes. In lipid-filled mature adipocytes, GLE enhanced epinephrine-induced lipolysis but reduced basal lipolysis dose-dependently. CONCLUSIONS: The results show that GLE inhibits adipogenesis and improves adipocyte function by reducing basal lipolysis and increasing insulin-stimulated glucose uptake in adipocytes, which can be partly associated with antidiabetic effects of guava leaves.