• 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.

• 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.

• 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.

• 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.

• 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.

• 한국식품영양과학회지
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• 제38권12호
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• pp.1773-1778
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• 2009

본 연구는 인공합성보존료를 대체할 수 있는 천연보존료의 개발을 위한 방안으로 대표적인 세균성 식중독 미생물로서 그람 음성균인 Escherichia coli O157:H7과 Salmonella Typhimurium, 그리고 그람 양성균인 Staphylococcus aureus와 Listeria monocytogenes에 대한 항균 특성을 조사하였다. 구아바 가지와 잎의 메탄올과 에탄올 추출물 S. aureus의 생육을 저해하였으며, 아울러 가지와 잎의 아세톤 추출물은 200 ppm 농도의 첨가에서 식중독 원인균 S. aureus균을 전혀 자라지 못하는 결과를 확인하였다. 이러한 결과는 구아바 잎과 가지의 추출물에 그람 양성균에 대한 높은 항균활성이 있음을 의미하며, 구아바 가지를 항균력을 가지는 소재로 이용될 수 있음을 시사한다.