Benifits of Black Garlic Extract

Abstract (For information about Garlife™-Black Garlic Extract)

Black garlic is a functional food produced from fresh garlic (Allium sativum L.) via fermentation with the whole bulbs or peeled cloves in a chamber in which temperature (60–90°C) and humidity (70–90%) are regulated for a period of time. Black garlic possesses an abundant amount of antioxidant compounds such as polyphenols, flavonoids, tetrahydro-β-carboline derivatives, and organosulfur compounds, including S-allyl-cysteine and S-allyl-mercaptocysteine, as compared with fresh garlic. Note that fermentation not only alters the nutrition components and sensory attributes but also enhances the bioactivity of black garlic. A growing body of evidences demonstrating therapeutic effects of black garlic, including anticancer, anti-obesity, immunomodulatory, hypolipidemic, antioxidant, hepatoprotective, and neuroprotective effects, have been reported in the last few decades. This book chapter provides a literature review of therapeutic effects of black garlic from fundamental to clinical studies that can be used by food and nutrition experts, researchers, and scientists to improve people’s health and wellness.

3.1 Anticancer effect of black garlic

Cancer, which has been regarded as one of leading cause of death in worldwide, is a type of disease related with uncontrolled or abnormal growth of cells or tissues in our bodies. With the growing number of the evidences reported for anticancer effect of black garlic in recent decades, some researchers suggested that black garlic could be used as a dietary product for preventing and treating cancers from gastric cancer to leukemia. The mechanism of anticancer effects of black garlic in different types of cancer diseases is various comprising of the induction of apoptosis, stopping the cell cycle, and inhibition of tumor growth and invasion. In 2011, Wang and collaborators suggested that aqueous extract of black garlic could inhibit proliferation and triggered the apoptosis of SGC-7901 cells, a human gastric cancer cell line, with dose-dependent manner. The authors also observed the inhibitory effect of black garlic on the growth of tumor in tumor-bearing mice [16]. Moreover, black garlic has the anti-invasive effect and prevents tumor metastasis in human gastric carcinoma AGS cells through the increase of tightness of tight junction as well as the downregulation of matrix metalloproteinases (MMP)-2 and metalloproteinases-9, which play a role as mediators of metastasis and invasiveness [17]. The anticancer effect of black garlic on colon cancer cell line also has been demonstrated. Moreover, treatment with alcoholic extract of black garlic could upregulate PTEN and downregulate Akt/pAkt expression, the members of phosphatidylinositol 3-kinase protein kinase B (PI3K/Akt) signal transduction pathway, leading to the modulation of p70S6K1 protein, induction of apoptosis, and arresting of the cell cycle of HT29 human colon cancer cell line [18]. Park and collaborators have reported that hexane extract of black garlic could reduce the cell viability of U937 cells, human histiocytic lymphoma. It has been found that hexane extract of black garlic exhibited induction of both intrinsic and extrinsic pathways through the alteration of the expression of apoptosis-relating proteins. They found that black garlic upregulates death receptor (DR)-4 and Fas ligand, increases Bax/Bcl-2 ratio, as well as induces the truncation of Bid protein, which involves not only endogenous mitochondrial pathway but also death receptor-mediated apoptotic pathway [19]. Some authors also proved that black garlic could inhibit cell growth and enhance sensitization of Lewis cells, lung cancer cell line, against ionizing radiation [20].

3.2 Benefit effect on dyslipidemia and anti-obesity

Obesity is a threatening problem to public health in Western and developed countries which causes several metabolic syndromes and chronic diseases. Obesity can be prevented by a combination of physical activity and healthy diet balance between energy intake and expenditure. Note that several functional foods such as γ-oryzanol, butyric acid, legumes, bromelain, peas, lentil, fabas beans, conjugated linoleic acid, diacylglycerols, purified black raspberries, apples, bilberries, sea buckthorn, etc. have been indicated as preventing and/or treating obesity agents via several mechanisms including the induction of satiation, decreasing of appetite, regulation of lipid metabolism, and thermogenesis [21]. Among them, black garlic is known as a prominent lipid and weight-lowering ingredient. In 2015, Ha and collaborators showed that the diet supplemented with 1.5% black garlic extract could only reduce weight but also decrease kidney and epididymal fat in high-fat model [22]. Moreover, black garlic extract attenuates dyslipidemia induced by high-fat diet. In Ha’s work, the authors observed the lowering effect of black garlic on the plasma level of total lipid, total cholesterol, and triglyceride. On the contrast, high-density lipoprotein cholesterol (HDL) of black garlic group was higher than high-fat diet group. Of note, treatment with black garlic reduces both glucose and insulin in plasma levels in high-fat diet. One of the explanations for the anti-obesity effect of black garlic is that black garlic could ameliorate diet-induced obesity through downregulation of transcription factors and enzymes related with fat and cholesterol syntheses such as sterol regulatory element-binding protein-1c (SREBP-1c), acetyl-coA carboxylase (ACC), fatty acid synthase (FAS), glucose-6-phosphate dehydrogenase (G6PDH), hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, and acyl-CoA cholesterol acyltransferase (ACAT) or fatty acid oxidation rate via increase of the expression of carnitine palmitoyltransferase-1 (CPT-1), a key enzyme related with lipolysis and fatty acid breakdown [22]. Furthermore, Chen and collaborators also recommended that the anti-obesity effect of methanol extract of black garlic could be related with regulation of lipogenesis, adipokine biosynthesis, fatty acid oxidation, fatty acid and glucose transport, and lipolysis i

By Gia-Buu Tran, Tan-Viet Pham and Ngoc-Nam Trinh

Submitted: October 31st 2018Reviewed: February 7th 2019Published: March 29th 2019

DOI: 10.5772/intechopen.85042

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Over 20years experience of garlic research & production

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Freeze Dried and low-temp manufacturing process keep all compounds original & active

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100% No Irradiation

100% No ETO treatment