Obesity is recognized globally as a major mortality risk factor
due to its involvement in other metabolic complications like insulin
resistance, type 2 diabetes mellitus, and several cancers. It is linked
with consumption of excessive calories and their less expenditure.
Different strategies (diet control, pharmacological interventions,
and surgery) have been tried to treat obesity. However, these strategies
cannot permanently cure obesity, which was evident by
bodyweight regain with above treatments. Literature suggests
that probiotics play a major role in the management of obesity
and associated diseases. According to World Health Organization,
probiotics are defined as “live micro-organisms which when
administered in adequate amounts confer health benefits on the
host”. Role of probiotic organisms on carbohydrate and lipid metabolism
has been extensively studied and discussed below. However,
contradictory results have been reported in the context of probiotics
role in obesity that observed no effect on body weight and feed
intake (Ji et al., 2012; Kumar et al., 2012). Administration of probiotics
in the form of fermented milk, lyophilized cells, dahi (Indian
traditional fermented milk) and yogurt in clinical and animal
models have been studied for their anti-obesity effects. Oral administration
of different lactobacilli strains viz., PL60, PL62, and GG to a
high-fat diet (HFD) fed mice shown a decrease in the body weight
gain, visceral fat and hepatic enzymes (Lee et al., 2006, 2007). In our
study, dahi prepared by using the probiotic strain Lactobacillus casei
NCDC19 had shown positive effects in the obesity management in
mice model (Rather et al., 2014). Moreover, combination of several
probiotics (Streptococcus Thermophilus, Bifidobacterium, and Lactobacillus)
also showed reduction in the body weight gain via short
chain fatty acid (butyrate) production by stimulating glucagon
like peptide in leptin deficient obese mice (Yadav et al., 2013). Similarly,
significant results have been reported with probiotic strains
such as Lactobacillus gasseri SBT2055 (Kadooka et al., 2010, 2013;
Ogawa et al., 2014), Bifidobacterium bifidum W23, Bifidobacterium
lactis W51, Enterococcus faecium W54, Lactobacillus acidophilus
W22, Lactobacillus brevis W63 and Lactococcus lactis W58 in human
subjects (Lamprecht et al., 2012). While, contradictory results were
also observed in this area and these results might be due to strain
dependent, type of diet and different animal models (Ji et al.,
2012; Kumar et al., 2012). In the recent past, research was focused
towards cocktail of herbs and prebiotics with probiotics to treat
metabolic complications. Dietary incorporation of prebiotic
galacto-oligosaccharides (GOS) and whey protein isolate in HFD
fed mice resist the increase in blood glucose levels, insulin resistance
and liver glycolytic enzymes (Kavadi et al., 2017) whereas
herbal ingredients such as Aloe vera (AV) and Gymnema sylvestre
(GS) supplementation to HFD fed animals had similar results
(Pothuraju et al., 2016a,b). Studies addressing the role of herbs
and their active ingredients as alternative therapies for the treatment
of obesity and its associated metabolic diseases are also
reviewed (Pothuraju et al., 2014, 2016a,b). A comprehensive understanding
obtained from all these studies indicates that administration
of prebiotics alone is not a good criterion to treat obesity
effectively. Probiotic bacteria can efficiently proliferate and survive
in the presence of prebiotics that acts as a selective substrate for
these organisms in the colon (Singh et al., 2012). In our previous
study, among the different strains of Lactobacillus rhamnosus
screened for potential probiotic attributes (acid/bile tolerance,
cell surface hydrophobicity, and anti-microbial activity), NCDC17
strain have been reported to potential probiotic properties. In addition,
a significant stimulation of the growth of NCDC17 was
observed when cultured in the presence of prebiotic almond (2%
w/v) as compared to inulin (Singh et al., 2012). In another study,
we have used AV and NCDC 19 as a synbiotic combination to study
its effects on angiotensin-converting enzyme (ACE) activity. Addition
of AV powder (0.5 and 1% w/v) to NCDC 19 exhibited a significant
increase in ACE activity (Basannavar et al., 2014). In a recent
finding, administration of AV and GS alone or in combination
with NCDC 17 and Lactobacillus Plantarum NCDC 625 to HFD fed
mice resulted in significant reduction in body weight gain, glucose
levels, insulin resistance along with proinflammatory makers (TNFa
and IL-6) (Pothuraju et al., 2015, 2016a,b). These results could be
related to one or more of the possible mechanisms viz. increased
pancreatic insulin secretion by AV; binding of gymnemic acids present
in GS glucose receptor, which might have prevented its intestinal
absorption (Pothuraju et al., 2015) or else prevention of lipid
absorption by phytosterols found in the herbs. In addition, active
components present in herbs may act as energy source for the
growth of probiotic microorganisms, which further led to antiobese
effects. However, the exact molecular mechanisms involved
in anti-obese effects of prebiotics/herbal ingredients and probiotics
is yet to known and should be a future target to treat the metabolic
disorders.