• 한국식품영양학회지
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• 제32권1호
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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.

• 한국식품저장유통학회지
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• 제14권6호
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• pp.605-610
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• 2007

구아바 잎을 이용한 가공제품개발의 기초자료를 마련하고자 구아바 잎을 발효, 증숙 및 볶음 처리하여 품질특성을 살펴보았다. 그 결과 총 페놀성 화합물 함량의 경우 볶음 처리한 것이 높게 나타났으며, tyrosinase 저해활성 및 전자공여능은 증숙 처리한 것이 우수한 것으로 나타났다. 또한 전반적인 기호도에 있어서는 발효 및 증숙 처리한 것이 우수한 것으로 나타났다. 한편 데침 및 증숙 처리 시간에 따른 품질특성을 살펴본 결과, 총 페놀성 화합물 함량, tyrosinase 저해활성 및 전자공여능은 처리시간이 길어질수록 전반적으로 감소하는 경향이었으며, 증숙 처리한 것이 데침 처리한 것에 비해 우수한 것으로 나타났다. 데침 및 증숙 처리된 구아바 잎의 관능검사 결과, 통계적으로 유의적인 차이가 없었으나, 구아바 잎의 떫은맛으로 인해 전반적으로 관능평점이 낮게 나타났다. 따라서 구아바 잎을 사용한 가공제품 개발에서는 떫은맛을 감소시킬 수 있는 방안의 연구가 필요한 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권6호
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• pp.886-895
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• 2013

This study was conducted to explore the antioxidant potential and functional value of guava (Psidium guajava L.) powder in muscle foods. Guava powder was used as a source of antioxidant dietary fibre in sheep meat nuggets at two different levels i.e., 0.5% (Treatment I) and 1.0% (Treatment II) and its effect was evaluated against control. Guava powder is rich in dietary fibre (43.21%), phenolics (44.04 mg GAE/g) and possesses good radical scavenging activity as well as reducing power. Incorporation of guava powder resulted in significant decrease (p<0.05) in pH of emulsion and nuggets, emulsion stability, cooking yield and moisture content of nuggets while ash and moisture content of emulsion were increased. Total phenolics, total dietary fibre (TDF) and ash content significantly increased (p<0.05) in nuggets with added guava powder. Product redness value was significantly improved (p<0.05) due to guava powder. Textural properties did not differ significantly except, springiness and shear force values. Guava powder was found to retard lipid peroxidation of cooked sheep meat nuggets as measured by TBARS number during refrigerated storage. Guava powder did not affect sensory characteristics of the products and can be used as source of antioxidant dietary fibre in meat foods.

• 한국조리학회지
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• 제19권3호
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• pp.248-258
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• 2013

본 연구에서는 쌀가루에 구아바 분말을 0%, 10%, 20%, 30%를 첨가하여 쿠키로 제조한 후 품질특성을 살펴보았다. 구아바 분말을 첨가한 쌀 쿠키의 수분함량은 $5.90{\pm}0.12{\sim}6.02{\pm}0.13$이었다. 구아바 분말을 첨가한 쌀 쿠키의 L 값과 b 값은 구아바 분말 첨가량이 증가함에 따라 유의적으로 감소하는 경향을 보였다(p<0.05). 구아바 분말을 첨가한 쌀 쿠키의 경우 구아바 분말의 첨가량이 증가할수록 퍼짐성은 작아지고 구아바 분말 쌀 쿠키의 경도는 유의적으로 증가하는 경향을 보였다(p<0.05). 구아바 분말을 첨가하지 않은 대조구보다 색(color), 맛(taste), 향(flavor), 조직감(texture), 전체적인 기호도(overall acceptability), Top grain score에 있어서 구아바 분말 20% 첨가구가 전반적으로 높게 평가되어 구아바 분말을 첨가한 쌀 쿠키 제조 시 구아바 분말 20%를 첨가하는 것이 가장 바람직할 것으로 사료된다.

• 한국약용작물학회지
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• 제20권2호
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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.

• 한국식품과학회지
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• 제38권5호
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• pp.679-683
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• 2006

저 용량 Streptozotocin(STZ)으로 유도한 제l형 당뇨 모델 생쥐에서 건조 구아바 잎과 발효 구아바 잎 에탄올 추출물의 혈당에 미치는 영향을 비교하였다. STZ로 유도된 쥐에서 발효 구아바 잎 추출물(500 mg/kg/day)은 투여 4주후에도 공복 혈당이 유의적으로 감소하였으며 내당능 장애도 개선되었음을 보여 주었다. 한편 건조 구아바 잎 추출물은 투여 후 2주 동안 공복 혈당이 낮게 나타났으며 내당능 장애도 개선되었지만 3주후부터 고혈당으로 약화되었다. 각 실험군에서 적출한 췌장 조직과 인슐린의 면역 조직 화학 분석 결과, 발효 구아바 잎 추출물은 STZ로 유도된 췌장섬 세포의 손상을 억제하는 것이 관찰되었으나 건조 구아바 잎 추출물은 베타 세포의 손상에 영향을 주지 못하였다. 본 연구 결과는 STZ로 유도된 당뇨 모델 생쥐에서 발효 구아바 잎 추출물이 췌장 베타 세포의 손상을 보호함으로서 혈당 개선 효과를 나타냄을 보여준다.

• 한국자원식물학회지
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• 제21권5호
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• pp.408-412
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• 2008

본 연구는 기능성소재 개발에 이용될 수 있는 유용한 기초자료를 얻고자 구아바 잎의 총페놀화합물의 함량, 항산화활성, tyrosinase 저해활성을 측정하였다. 1. 구이바잎 추출물의 총페놀화합물은 19.0(g/100g, D.W.)의 함량으로 강한 항산화활성을 보였다(radical 소거활성의 IC50는 $102.5{\mu}g/ml$, SOD 유사활성의 IC50는 $49.4{\mu}g/ml).$) 2. 용매분획물의 radical 소거활상을 측정한 결과, $100{\mu}g/ml$의 농도에선도 ethylacetate(G-E), butanol(G-B), 물분획(G-W)은 50% 이상의 높은 소거활성을 보였다 radical 소거 활성은 G-B>G-E>G-W 순으로 높은 활성을 보였고, 각 분획물의 농도가 증가할수록 소거능이 높아지는 경향을 나타냈다. hexane분획(G-H)의 소거활성은 보이지 않았다. 3. 용매분획별 SOD 유사활성에 대한 결과, $100{\mu}g/ml$의 농도에서 G-E, G-B, G-W는 각각 81.8, 84.7, 65.3%로 높은 활성을 나타냈으며, 각 분획물의 농도가 증가할수록 SOD 유사활성도 증가하는 경향을 나타냈다 G-H의 활성은 보이지 않았다. 4. 구아바잎의 추출물과 용매분획물의 tyrosinase저해 효과를 측정한 결과, 추출물 1mg/ml의 농도에서 60.8%의 저해효과을 보였으며, 용매분획은 G-E(65.2%), G-B(62.8%), G-W(51.6%), G-H(28.9%)의 순으로 tyrosinase 저해효과를 보였다.

• 생명과학회지
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• 제19권1호
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• pp.40-45
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• 2009

구아바(Psidium guajava L.)와 바나바(Lagerstroemia speciosa L.)는 항당뇨 효과를 갖는 대표적인 약용식물로 알려져 있다. 이들 식물은 다양한 폴리페놀(polyphenol) 성분을 함유하며 당뇨병의 치료에 효과적으로 작용한다. 따라서 본 연구는 이들 추출물을 streptozotocin (STZ)으로 당뇨를 유발한 실험쥐에 섭취시켜 항당뇨 효과를 상호 비교하였다. STZ으로 당뇨를 유발한 실험쥐에 구아바 및 바나바 잎 추출물을 섭취시킨 결과 당뇨쥐에 비해 혈당은 약 19-32%, 총콜레스테롤(total cholesterol)은 약 24-46%, 중성지방(triglyceride)은 22-67% 그리고 유리지방산(free fatty acid) 은 49-71% 감소하였고 또한 인슐린 분비와 췌장에 존재하는 베타세포의 회복도 증가되었다. 한편 구아바 추출물의 섭취가 바나바 추출물의 섭취에 비해 항당뇨 효과가 더 높았는데 그 이유는 바나바 잎에 포함된 친수성 폴리페놀(polyphenol) 성분이 에탄올 추출과정에서 대부분 추출되지 않았고 또한 추출된 코로소릭산(corosolic acid) 은 지금까지 알려진 것과는 달리 항당뇨 활성이 낮았기 때문이다.

• Nutrition Research and Practice
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• 제15권5호
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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.

• 한국식품조리과학회지
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• 제26권2호
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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.