Identification of Anti-.ALPHA.-Amylase Components from Olive Leaf Extracts

Komaki, Eriko; Yamaguchi, Shinya; Maru, Isafumi; Kinoshita, Mitsuhiro; Kakehi, Kazuaki; Ohta, Yasuhiro; Tsukada, Yoji

doi:10.3136/fstr.9.35

Cited by 108 publications

(92 citation statements)

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“…In this paper, we present results proving that OA is not an α-amylase inhibitor. This finding is in agreement with other published data (Hou et al, 2009;Wang et al, 2011) although there are also contradictory results supporting that OA might effectively repress this activity (Khati et al, 2013;Ali et al, 2006;Komaki et al, 2003), with quite variable IC 50 values in the range of 10 µM-2.6 mM.…”

Section: Discussionsupporting

confidence: 83%

Free radical scavenging and α-glucosidase inhibition, two potential mechanisms involved in the anti-diabetic activity of oleanolic acid

et al. 2016

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SUMMARY:This work investigates the role of oleanolic acid (OA), isolated from the olive (Olea europaea L.) leaf, as a radical scavenger and inhibitor of the hydrolyzing enzymes of dietary carbohydrates. New evidence is provided showing that OA may capture 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and peroxyl radicals, and also exert a strong and non-competitive inhibition of α-glucosidase (IC 50 10.11 ± 0.30 µM). The kinetic and spectrometric analyses performed indicate that OA interacts with this enzyme inside a hydrophobic pocket, through an endothermic and non spontaneous process of a hydrophobic nature. These are two possible mechanisms by which OA may facilitate a better control of post-prandial hyperglycaemia and oxidative stress, so contributing to preserving insulin signalling. Obesity, insulin resistance and Type 2 Diabetes Mellitus are considered the first pandemics of the 21st century. In this sense, OA might be used in future preventive and therapeutic strategies, as an ingredient in new drugs and functional foods.KEYWORDS: Anti-diabetic activity; Antioxidant; α-glucosidase inhibitor; Olea europaea; Oleanolic acid RESUMEN: La Captación de radicales libres y la inhibición de α-glucosidasa, dos posibles mecanismos involucrados en la actividad antidiabética del ácido oleanólico. Este trabajo estudia el papel del ácido oleanólico (OA), aislado de la hoja de olivo, como secuestrador de radicales libres e inhibidor de enzimas implicados en la hidrolisis de los carbohidratos de la dieta, dos mecanismos por los que el triterpeno podría mitigar la hiperglicemia postprandial y el estrés oxidativo. Se aportan nuevas evidencias que muestran que el OA puede capturar radicales ácido 2,2'-azino-bis-(3-etilbenzotiazolín)-6-sulfónico y peroxilo, y que ejerce una potente inhibición nocompetitiva de α-glucosidasa (IC 50 10.11±0.30 µM). El análisis cinético y espectrométrico llevado a cabo indica que OA interacciona con este enzima en el interior de un bolsillo hidrofóbico, mediante un proceso endotér-mico no espontáneo, de naturaleza hidrofóbica. Estos son dos posibles mecanismos por los cuales el OA puede facilitar un mejor control de la hiperglucemia postprandial y el estrés oxidativo, lo que contribuye a preservar la señalización de la insulina. La obesidad, la resistencia a la insulina y la diabetes mellitus tipo 2 se consideran la primera pandemia del siglo XXI. En este sentido, el OA podría ser utilizado en futuras estrategias preventivas y terapéuticas, como ingrediente de nuevos fármacos y alimentos funcionales. Free radical scavenging and α-glucosidase inhibition, two potential mechanisms involved in the anti-diabetic activity of oleanolic acid. Grasas Aceites 67 (3): e142. doi: http://dx

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Section: Discussionsupporting

confidence: 83%

Free radical scavenging and α-glucosidase inhibition, two potential mechanisms involved in the anti-diabetic activity of oleanolic acid

et al. 2016

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“…It was also reported that ble state in diabetes 9 . In fact, the inhibitory activity of oleuropein s aglycon and luteolin glucosides luteolin-7-O-β-glucoside and luteolin-4 -O-β-glucoside against pancreatic amylase were determined 8 . However, the antidiabetic effects of hydroxytyrosol component have not yet been investigated against α-glucosidase and α-amylase.…”

mentioning

confidence: 99%

The α-Glucosidase and α-Amylase Enzyme Inhibitory of Hydroxytyrosol and Oleuropein

et al. 2015

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“…The applicant identified two human studies (Komaki et al, 2003;de Bock et al, 2013), and three animal studies (Komaki et al, 2003;Poudyal et al, 2010;Wainstein et al, 2012) as being pertinent.…”

Section: Scientific Substantiation Of the Claimed Effectmentioning

confidence: 99%

Scientific Opinion on the substantiation of a health claim related to olive (Olea europaea L.) leaf water extract and increase in glucose tolerance pursuant to Article 13(5) of Regulation (EC) No 1924/2006

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2014

EFS2

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Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to olive (Olea europaea L.) leaf water extract and increase in glucose tolerance. The food that is the subject of the health claim, olive leaf water extract standardised by its content of oleuropein, is sufficiently characterised. The claimed effect, an increase in glucose tolerance, is a beneficial physiological effect as long as serum insulin concentrations are not disproportionately increased. One human intervention study showed an increase in glucose tolerance without disproportionate increase in insulin concentrations after daily consumption of the olive leaf water extract for 12 weeks under the conditions of use proposed by the applicant. However, the results have not been replicated in other studies, and no evidence has been provided in relation to the mechanism by which the olive leaf water extract could exert the claimed effect. The scientific evidence is insufficient to establish a cause and effect relationship between the consumption of olive leaf water extract and an increase in glucose tolerance. To avoid confusion, the original version has been removed from the EFSA Journal, but is available on request, as is a version showing all the changes made.Olive leaf water extract and increase in glucose tolerance 2 EFSA Journal 2014;12(5):3655 SUMMARYFollowing an application from Comvita New Zealand Limited, submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of the United Kingdom, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to olive leaf water extract and increase in glucose tolerance.The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The application includes a request for the protection of proprietary data.The food that is the subject of the health claim is olive (Olea europaea L.) leaf water extract standardised by its content of oleuropein. The Panel considers that the food, an olive leaf water extract (standardised by its content of oleuropein), which is the subject of the health claim, is sufficiently characterised.The claimed effect proposed by the applicant refers to "reduces the glycaemic response following carbohydrate consumption". The target population is adults willing to reduce their glycaemic response. Upon request by EFSA for clarification, the applicant indicated that the claimed effect relates to a long-term increase in glucose tolerance, which could be assessed in vivo in humans by an oral glucose tolerance test (OGTT) following chronic consumption (e.g. 12 weeks) of the food that is the subject of the health claim. The Panel considers that an increase in glucose tolerance is a beneficial physiological effect as long as serum insulin concentrations are not disproportionately increased.The applicant identified two human studies and three animal studies as...

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Identification of Anti-.ALPHA.-Amylase Components from Olive Leaf Extracts

Cited by 108 publications

References 20 publications

Free radical scavenging and α-glucosidase inhibition, two potential mechanisms involved in the anti-diabetic activity of oleanolic acid

Free radical scavenging and α-glucosidase inhibition, two potential mechanisms involved in the anti-diabetic activity of oleanolic acid

The α-Glucosidase and α-Amylase Enzyme Inhibitory of Hydroxytyrosol and Oleuropein

Scientific Opinion on the substantiation of a health claim related to olive (Olea europaea L.) leaf water extract and increase in glucose tolerance pursuant to Article 13(5) of Regulation (EC) No 1924/2006

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