13.7.1 Obesity and Weight Loss
Dietary supplements are available to promote weight loss. Several groups of researchers evaluated the safety and efficacy of KGM, a water-soluble fibre supplement, for achieving weight loss in overweight and obese individuals (Chen et al., 2003; Keithley et al., 2013). More recently, Zalewski et al. (2014) systematically evaluated the effects of KGM on body weight (BW) and body mass index (BMI) in otherwise healthy obese or overweight children and adults. The results concluded that short-term KGM may help to reduce BW and BMI.
13.7.2 Diabetes Management
Despite significant achievements in treatment modalities and preventive measures, the prevalence of diabetes has risen exponentially in the last decade. Moreover, an increasing number of people are using dietary and herbal supplements, even though there is a general lack of evidence for their safety and efficacy. KGM has been considered as potentially emerging alternative therapies for type 2 diabetes. KGM is useful in improving diabetes control, reducing associated risk factors such as hyperlipidemia and hypertension, and ameliorating insulin resistance (Chearskul et al., 2007; Estiasih et al., 2012; Harijati et al., 2011; Vuksan et al., 2001). Moreover, KGM showed hypoc-holesterolemic effects. Gallaher et al. (2002) studied the effect of both chitosan and KGM in 21 overweight normo-cholesterolemic subjects (11 males and 10 females). They were fed 2.4 g/day of a supplement containing equal amounts of chitosan and GM. The results showed that the serum total, HDL and LDL cholesterol concentrations, were significantly lower in the final period compared to the initial period. However, the serum triacylglycerol concentration did not change between periods. Therefore, KGM restricts the diffusion of glucose into the blood from the gut (Poddar etal, 2014).
13.7.3 Probiotic Properties
The colon of healthy humans contains a diverse bacterial population. The colon is dominated by strict anaerobes including Bacteroides spp., Clostridium, Bifidobacterium spp., Atopobium spp., and peptococci. Facultative anaerobes occur less in numbers and include lactobacilli, enterococci, streptococci and Enterobacteriaceae. Yeasts occur in much lower numbers. Among the bacteria, lactobacilli and bifidobacteria are the most significant organisms in terms of human health. The growth of these bacteria is stimulated specifically by prebiotics (Al-Ghazzewi et al., 2012; Connolly et al., 2010; Liebman and Al-Wahsh, 2011). Glucomannans hydrolyzate (GMH) acts as a prebiotic by stimulating selectively the growth of gut-friendly bacteria and serving as valuable functional food. Like other polysaccharides, the polymers can be depolymerized with acids and enzymes (Al-Ghazzewi et al., 2014; Bateni et al., 2013; Elamir et al., 2008).
13.7.4 Effects on Immune System
Administration of pulverized KGM prevented the development of allergic rhinitis-like symptoms and the increase of plasma immunoglobulin E (IgE) and G (IgG) levels in mice (Onishi et al., 2007; Tester and Al-Ghazzewi, 2013). In this context, Suzuki et al. (2009) reported that consuming hydrolyzed KGM can help to prevent atopic diseases by suppressing IgE production in mice. More recently, Onitake et al. (2014) investigated the role of pulverized konjac glucomannan (PKGM) in intestinal immunity in a mouse model of oxazolone (OXA)-induced colitis.
13.7.5 Processing for Drug Delivery
In recent year, cases of colonic diseases are increasing. Researches have found abundant microflora in the colon and amounts of drugs, which are colon-specific absorbable. The colon specific drug delivery is an important and new therapeutic entity due to controlled drug delivered to its site of action (in sufficient amounts) at the appropriate rate (Singh et al., 2012). The natural polysaccharides such as chitosan, guar gum, inulin, konjac glucomannan (KGM) and locust bean gum are usually used to prepare and study controlled drug delivery system. They are biodegradable in the colon and have good gel-forming abilities (Patel-Parul et al., 2012; Yu and Xiao, 2008). KGM are involved in many other types of applications, such as encapsulation, controlled release, etc. More recently, KGM has also been used in controlled drug delivery systems (Alvarez-Mancenido et al., 2006; Alonso-Sande et al., 2009; Mrsny, 2012; Zhang et al., 2014).
13.7.6 Other Activities
Dey et al. (2010) investigated the effects of methanolic extracts of the tuber of Amorphophallus paeoniifolius for its antihelmintic activity against Pheretima posthuma and Tubifex tubifex. Moreover, Sahu et al. (2009) evaluated the anti-oxidant property of various fractions of Amorphophallus tubers, such as hexane, chloroform, ethyl acetate, alcohol and hydro alcohol by in vitro methods like ferrous ion-induced lipid peroxidation, reducing power, total anti-oxidant activity, DPPH and nitric oxide scavenging activity. The in-vitro antioxidant activity guided fractionation of the tuber revealed that the alcoholic fractions showed more activity as compared to chloroform, ethyl acetate and hexane fractions.
13.8 Summary and Future Perspectives
From the aforementioned content, Amorphophallus have broad application prospects in many fields. The unique rheological and gelling properties of EFY starch and flour are widely employed to emulsify and stabilize the products for the food, drinks, cosmetic and pharmaceutical industries. Nowadays, it is well-known that EFY powder is mostly used as a health food. However, KGM is still a promising polysaccharide as an excipient for controlled drug delivery systems with relatively low cost and desired properties. Moreover, KGM is a very promising bioactive material for drug nanocarrier systems, since its amphiphilic structure can incorporate diverse biomolecules, potentially providing novel nanostructure drug delivery systems. EFY is increasingly attracting attention in different pharmaceutical applications, such as promote immune system, control agents for diabetes, maintaining blood cholesterol levels, coating material, and skeleton material for tissue engineering applications.
However, for application as pharmaceutical excipients, its characteristic parameters have not been assured to give a guidance for further study and applications. These will be challenging and heavy works for future standard use. With deepening of research, a general conclusion is that EFY will be a promising and versatile choice for the preparation of food and pharmaceutical applications. More modifications on EFY can be done and advanced formulations can be developed for better applications.
References
Akesowan, A. (2002) Effect of salt and added water (ice) contents on the yield, physical and sensory properties of low-fat Moo Yo containing a Konjac gel. The Journal of Agricultural Sciences, 35: 63–73.