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Dragon fruit oligosaccharide (DFO) has a prebiotic property which improves gut health by selectively stimulating the colonic microbiota. Altering microbiota composition may affect intestinal motility. However, no study has been done to understand the DFO effects on gut motor functions. This research thus aimed to investigate the DFO effects on mice colons compared to the prebiotic fructo-oligosaccharide (FOS) and probiotic bifidobacteria. The mice in this study received distilled water; 100, 500, and 1000 mg/kg DFO; 1000 mg/kg FOS; or 109 CFU Bifidobacterium animalis daily for 1 week and some treatments for 2 weeks. Gastrointestinal transits were analysed and motility patterns, smooth muscle (SM) contractions and morphological structures of the colons were assessed. Administration of FOS, 500 and 1000 mg/kg DFO significantly increased fecal output when compared to the control group. In mice treated with FOS and bifidobacteria, gut transit time was reduced, while upper gut transit was increased in comparison to DFO groups. Spatiotemporal maps of colonic wall motions showed that DFO increased the number of colonic non-propagation contractions and fecal pellet velocity, consistent with the results from groups treated with FOS and bifidobacteria. DFO also increased the amplitude and duration of colonic SM contractions. Histological stains showed normal epithelia, crypts, goblet cells, and SM thickness in all groups. In conclusion, DFO increased colonic SM contractions without morphological change and acted as a bulk-forming and stimulant laxative to increase fecal output and intestinal motility. Thus, DFO as a dietary supplement may promote gut health and correct gastrointestinal motility disorders.
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Biomedicine & Pharmacotherapy
journal homepage: www.elsevier.com/locate/biopha
Prebiotic oligosaccharides from dragon fruits alter gut motility in mice
Pissared Khuituan
a,
, Sakena K-da
a,b
, Kanrawee Bannob
a,b
, Fittree Hayeeawaema
a
,
Saranya Peerakietkhajorn
b
, Chittipong Tipbunjong
c
, Santad Wichienchot
d
,
Narattaphol Charoenphandhu
e
a
Department of Physiology, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
b
Department of Biology, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
c
Department of Anatomy, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
d
Interdisciplinary Graduate School of Nutraceutical and Functional Food, Prince of Songkla University, Songkhla, Thailand
e
Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
ARTICLE INFO
Keywords:
Dragon fruit oligosaccharide
Colonic contractility
Colonic smooth muscle
Gut transit time
ABSTRACT
Dragon fruit oligosaccharide (DFO) has a prebiotic property which improves gut health by selectively stimu-
lating the colonic microbiota. Altering microbiota composition may aect intestinal motility. However, no study
has been done to understand the DFO eects on gut motor functions. This research thus aimed to investigate the
DFO eects on mice colons compared to the prebiotic fructo-oligosaccharide (FOS) and probiotic bidobacteria.
The mice in this study received distilled water; 100, 500, and 1000 mg/kg DFO; 1000mg/kg FOS; or 10
9
CFU
Bidobacterium animalis daily for 1 week and some treatments for 2 weeks. Gastrointestinal transits were ana-
lysed and motility patterns, smooth muscle (SM) contractions and morphological structures of the colons were
assessed. Administration of FOS, 500 and 1000 mg/kg DFO signicantly increased fecal output when compared
to the control group. In mice treated with FOS and bidobacteria, gut transit time was reduced, while upper gut
transit was increased in comparison to DFO groups. Spatiotemporal maps of colonic wall motions showed that
DFO increased the number of colonic non-propagation contractions and fecal pellet velocity, consistent with the
results from groups treated with FOS and bidobacteria. DFO also increased the amplitude and duration of
colonic SM contractions. Histological stains showed normal epithelia, crypts, goblet cells, and SM thickness in all
groups. In conclusion, DFO increased colonic SM contractions without morphological change and acted as a
bulk-forming and stimulant laxative to increase fecal output and intestinal motility. Thus, DFO as a dietary
supplement may promote gut health and correct gastrointestinal motility disorders.
1. Introduction
The imbalance of enteric microbiota aects various gastrointestinal
(GI) functions including motility and may result in inammatory bowel
disease (IBD), irritable bowel syndrome (IBS), diarrhea, or constipation
[13]. Microbial populations in the GI tract have been maintained in a
balanced state by probiotics and prebiotics [4,5]. Probiotics, such as
bidobacteria and lactobacilli, are live microbes that are benecial to
human and animal GI health. Probiotics modulate intestinal motility,
reducing both diarrhea and constipation [68]. Despite their benets,
probiotics have limitations for patients who suer from acute
pancreatitis or allergies. Heat and acid may destroy probiotics and they
are dicult to process in some foodstus[9,10]. An alternative ap-
proach to selective modication of the composition and activity of the
intestinal microbiota is dietary supplementation with prebiotics.
Prebiotics are non-digestible food ingredients that enter the colon
without being altered by digestion and absorption. They can serve as a
source of nutrition for benecial bacteria in the colon. Prebiotics not
only promote specic changes to the composition and/or activities of
the GI microbiota; they also induce microbial competition and reduce
populations of undesirable bacteria [11,12]. The major products of
prebiotic fermentation in the colon are short chain fatty acids (SCFAs)
https://doi.org/10.1016/j.biopha.2019.108821
Received 28 December 2018; Received in revised form 20 March 2019; Accepted 26 March 2019
Abbreviations: BW, body weight; CFU, colony-forming unit; DFO, dragon fruit oligosaccharide; DP, degree of polymerization; DW, distilled water; FOS, fructo-
oligosaccharide; GI, gastrointestinal; GIMM, gastrointestinal Motility Monitor; GOS, galacto-oligosaccharides; HE, Hematoxylin-eosin; HPLC, high performance liquid
chromatography; IBD, inammatory bowel disease; IBS, irritable bowel syndrome; MW, molecular weight; PAS, periodic acid-Schi; SCFAs, short chain fatty acids;
SM, smooth muscle
Corresponding author at: Department of Physiology, Faculty of Science, Prince of Songkla University, 15 Karnjanavanich Rd., Hat Yai, Songkhla 90110 Thailand.
E-mail address: pissared.k@psu.ac.th (P. Khuituan).
Biomedicine & Pharmacotherapy 114 (2019) 108821
0753-3322/ © 2019 The Authors. Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/BY-NC-ND/4.0/).
T
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that include acetate, propionate, and butyrate. SCFAs are energy
sources for colonic epithelial cells and play roles in electrolyte trans-
port, cell dierentiation, cell growth, and colonic motility [13,14]. The
best known prebiotics are fructo-oligosaccharides (FOS), galacto-oli-
gosaccharides (GOS), and inulin [1518]. Other non-digestible oligo-
saccharides, such as some prebiotic-rich fruits and vegetables, have also
been tested for prebiotic properties.
Dragon fruit oligosaccharide (DFO) is extracted and puried from
dragon fruit or pitaya. This fruit is native to Central and South America
and has gained popularity worldwide. It is now grown across South East
Asia [1921]. The fruit is rich in β-carotene, lycopene, vitamin E and
essential fatty acids and exhibits antioxidant and anti-inammatory
activities [2224]. Both red pitaya with white-esh (Hylocereus undatus)
and red pitaya with red-esh (Hylocereus polyrhizus) have been reported
as a source of DFO found in its esh and peel [25,26]. In an articial
colon, DFO was resistant to hydrolysis by articial human gastric juice
and α-amylase and stimulated the growth of lactobacilli and bido-
bacteria [25,27]. Although the prebiotic properties of DFO are quite
evident from in vitro studies, the prebiotic eects of DFO on GI func-
tions, especially intestinal motility, have not been conrmed in an in
vivo model.
When managing the balance of the intestinal microbiota to improve
intestinal motility disorders such as constipation and diarrhea, it is
useful to know the eective dose and duration of prebiotic intake.
Therefore, the present study aimed to investigate the in vivo eects of
DFO in male ICR mice. The mice were supplemented with DFO for 1
and 2 weeks. Responses of interest were fecal output, intestinal transit,
evacuation time, colonic motility patterns, colonic pellet propulsion
velocity, proximal and distal colonic circular and longitudinal SM
contractions, and colonic morphological changes.
2. Materials and methods
2.1. Animals
This study was approved and guided by the Animal Ethics
Committee of the Prince of Songkla University, Thailand (Project li-
cense number MOE0521.11/799). Adult male ICR/Mlac mice (Mus
musculus; 5 weeks old, weighing 2025 g) were obtained from National
Laboratory Animal Center, Mahidol University and housed at Southern
Laboratory Animal Facility, Prince of Songkla University. The animals
were housed four per cage and kept under standard environmental
conditions at 23 to 27 °C, with 50 to 55% humidity under a 12-hour
light/12-hour dark cycle. They were fed standard commercial food
pellets (Perfect Companion Group Co., Ltd., Thailand) with ltered
water ad libitum.
2.2. Chemicals and equipment
Reference prebiotic and probiotic supplements were FOS (Sigma-
Aldrich, St. Louis, MO, USA) and Bidobacterium animalis (FD-DVS nu-
trish
®
BB-12
®
) (Chr. Hansen Holding A/S, Hoersholm, Denmark). Krebs
solution was composed as follows (in mM): 119 NaCl, 2.5 CaCl
2
, 4.5
KCl, 2.5 MgSO
4
, 25 NaHCO
3
, 1.2 KH
2
PO
4
, and 11.1 D-glucose [28,29]
(all purchased from Merck, Co., Ltd., Darmstadt, Germany) and the
working solution was made fresh on the day of the experiment. The
Gastrointestinal Motility Monitor (GIMM) System for ex vivo study of
colonic propulsive motility was purchased from Catamount Research
and Development, St. Albans, VT.
2.3. Extraction and purication method of DFO (briey)
White-eshed dragon fruits (Hylocereus undatus (Haw) Britt. and
Rose) were grown on and purchased from a certied organic, GAP
(good agricultural practice) contract fruit farm in Hat Yai, Songkhla,
Thailand. The fruits were selected from one batch to ensure consistency
of chemical composition, particularly oligosaccharide content. The
fruits were washed and separated into esh and peel parts. The esh
and peel parts were chopped into small pieces, nely ground and ex-
tracted using pectinase enzyme in a 50 L reactor [30]. We analyzed the
sugar content of white-eshed dragon fruit - mostly glucose, fructose
and some oligosaccharides - by high performance liquid chromato-
graphy (HPLC) in a previous study [25]. The low molecular weight
(MW) fraction, glucose and fructose, which does not have prebiotic
properties, was removed biologically by two-step yeast (Saccharomyces
cerevisiae) cultivation. Yeast cells were then removed by ltration and
centrifugation. The puried DFO extract was concentrated by eva-
poration and spray dried to obtain DFO powder. The DFO powder was
stored at 20 °C to ensure stability and was used for all experiments.
The MW distribution of the mixed oligosaccharides was conrmed by
mass spectrometry. There were four components of 716, 700, 490 and
474 Da with relative percentages of 100, 68, 45 and 21, respectively
[25]. Therefore, the degree of polymerization (DP) of mixed DFO is 34,
which is in the same range as some FOSs. The dietary composition of
DFO is listed in Supplemental Table S1.
2.4. Experimental design, surgical procedure and tissue preparation
After a week of acclimatization, groups of animals had their diet
variously supplemented by gavage once per day. Six groups were sup-
plemented for a week with 0.2 mL distilled water (DW) (vehicle con-
trol) or with DFO at 100, 500, or 1000 mg/kg, or with FOS at 1000 mg/
kg or with bidobacteria at 10
9
CFU. Three groups were supplemented
for two weeks with DW or with 500 mg/kg DFO or with 1000 mg/kg
FOS. An overview of the experimental procedure over 21 days is pro-
vided in Supplemental Fig. S1. Body weight (BW), food and water in-
takes, and fecal pellet outputs of all mice were recorded every day. The
colonic propulsive motility functions of the animals were analyzed ex
vivo. Animals were anesthetized by intraperitoneal injection of 70 mg/
kg Thiopental sodium (Anesthal
®
) so the abdominal cavity could be
rapidly dissected. The colon was sectioned whole from the cecum to the
rectum and placed with contents in oxygenated (5% CO
2
and 95% O
2
)
ice-cold Krebs solution (pH 7.4 with an osmolality of 289292 mmol/kg
H
2
O). To study the eects of DFO on colonic propulsive motility, the
whole colon was mounted horizontally in a 50 mL GIMM organ bath
containing oxygenated Krebs solution at 37 °C. To study SM con-
tractility, the colon was divided into two sections. The proximal colon
was sectioned 3 cm distal to the cecum and the distal colon 3 cm
proximal to the rectum. The two segments were transversely sectioned
into lengths of 1 cm. To study longitudinal SM contraction, 1 cm seg-
ments were suspended in the organ bath longitudinally. To study cir-
cular SM contraction, 1 cm segments were opened along the mesenteric
border and the muscular layer was separated. The muscular layer was
opened out to form a strip and then suspended so that contractions
occurred vertically in a 20 mL organ bath containing Krebs solution.
2.5. Fecal pellet output, gut transit and evacuation time assay
During treatments, fecal pellets evacuated over a six-hour period
were counted and hourly averages calculated. To determine fecal water
content, feces were weighed, dried at 100 °C for 30 min and weighed
again. The fecal water content (%) was calculated by ((wet weight dry
weight)/wet weight) × 100%. To measure total gut transit time, the
mice were fed an Evan-blue marker meal (5% Evan-blue in 1.5% me-
thyl cellulose; 0.1 mL (i.g.)) and were observed every 10 min until the
rst blue pellet was expelled. Evacuation time was measured by using a
bead expulsion test. A 3-mm glass bead was inserted through the anus
2 cm into the colon using a petroleum jelly-lubricated plastic tip and
time was measured until the bead was expelled. For upper gut transit
measurement, the mice received a charcoal meal and 60 min later
charcoal transit (%) was calculated by (the distance of charcoal meal/
total length of the small intestine) × 100%. These methodologies were
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performed and modied according to previously described methods
[31,32].
2.6. Measurement of ex vivo colonic motility
A GIMM organ bath, lined with Sylgard, was placed on top of lu-
minance plates to silhouette colonic segments and continuously per-
fused with Krebs solution at 10 mL/min. The segment was pinned in situ
at both oral and caudal ends of its length. Before recording, the segment
was allowed to equilibrate in Krebs solution for 30 min without ushing
out fecal pellets. Pellet movement was recorded for 30 min using a
video camera connected to a computer running GIMM software (2
times/individual). Spatiotemporal maps of motility were constructed
from recordings acquired from individual runs. In each video frame, the
image of the colonic segment was converted to a silhouette. The dia-
meter at each point along the entire length was calculated and con-
verted into a grey-scale. The contracted diameters (intestinal contrac-
tion) were coded as white and the relaxed diameters (intestinal
dilation) as black. The total number of spontaneous contractions was
dened as the sum of the number of non-propagation contractions and
the number of propagation contractions over 30 min. Non-propagation
contractions were dened as those contractions that failed to move the
pellet forward. The velocity of fecal pellet propulsion through the
whole colon was determined only in the propagation contraction pat-
tern and was performed using the fecal pellet tracking method in the
GIMM software, in which the pellet is digitally darkened and tracked
from the oral end to the caudal end. Fecal pellet velocity was calculated
and displayed in mm/second.
2.7. Measurement of in vitro smooth muscle contractility
The distal end of the colonic segment was tied to an organ holder
while the proximal end was secured with a silk thread to an isometric
force transducer (Model FT03, Grass, USA) and stretched passively
under a load of 500 mg. The signal output of mechanical activity, am-
plied and digitized via a Bridge Amp and PowerLab
®
System (AD
Instruments, Australia), was stored on a computer for subsequent
analysis using LabChart7 program software. Signals were acquired and
analyzed twice per individual. Following the 30 min equilibration
period, the spontaneous contractions representing basal activity in the
colonic SM were recorded for 5 min. To stimulate contraction, carba-
chol (Tocris Bioscience, Bristol, UK) was added to the Krebs solution in
the organ bath in a cumulative fashion. The concentrations progressed
from 0.1 to 1 to 10 μM without washing between concentrations. The
amplitude, duration, and frequency of contractions of each colonic
segment were calculated. The mean amplitude (in mg) was calculated
as the average of peak to peak dierences over 5 min and was expressed
as a percentage of the values recorded in the presence of 1 μM CCh
(maximal contraction). The frequency and duration were respectively
expressed as the number of contractions per minute (times/min) and
the mean of contraction times (in seconds) recorded in a 5-min period.
Fig. 1. Eects of one-week and two-week dietary supplementation with DFO on the number of fecal pellets and time of evacuation in mice. Mice were treated with (A
and B) 0.2 mL DW, DFO (100, 500, and 1000 mg/kg, p.o.), FOS (1000 mg/kg, p.o.), and bidobacteria (10
9
CFU, p.o.) for a week, then with (C and D)0.2 mL DW,
DFO (500 mg/kg, p.o.) and FOS (1000 mg/kg, p.o.) for two weeks. Each bar of the data represents means ± SEM (n = 46).
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2.8. Histological study
Colonic segments were xed in 10% formalin solution, embedded in
paran, and sectioned every 7 μm. The sections were deparanized
with xylene and rehydrated in serial graded ethanol. Hematoxylin-eosin
(HE) and Periodic acid-Schi(PAS) staining were performed according
to the standard protocols, and tissues were observed by light micro-
scopy. SM thickness was measured with image J software.
2.9. Statistical analysis
Results obtained from this study were expressed as means ± SEM
with n in parentheses denoting the number of animals. Data were
analyzed using the statistical program GraphPad Prism 5.0 (GraphPad
Software Inc., San Diego, California, USA). Comparison among multiple
groups was made using one-way analysis of variance test followed by
the Bonferroni post hoc test. The determination of sample size was
computed using the MINITAB Statistical Analysis Package (Minitab 16,
Minitab Inc., Pennsylvania, USA). The level of signicance for all sta-
tistical tests was P< 0.05.
3. Results
3.1. Eects of DFO on body weight, food and water intakes, and fecal pellet
output
There was no signicant change in BW, food intake, or water intake
in mice whose diet was supplemented by the vehicle control or all doses
of DFO for one and two weeks (Supplemental Figs. S2 and S3). The
mean fecal pellet number for all the DFO-treated groups did not sig-
nicantly dier from that for the control group (Fig. 1A and C). How-
ever, signicant dierences were found in mean fecal pellet wet weight.
Among the group supplemented with 500 and 1000 mg/kg DFO for a
week, mean fecal pellet wet weight increased by 2.3 times compared to
the vehicle control and among the group that received 500 mg/kg DFO
for two weeks, the weight increase was 2 times. These increases in
mean fecal pellet wet weight were similar to the eect of supple-
mentation with the reference prebiotic, 1000 mg/kg FOS (Fig. 2A and
C). The increases in fecal mass occurred despite the similarity in food
intakes between the experimental groups and the control group. We
concluded that the change was induced by DFO. The changes in fecal
mass among two DFO-treated groups support the supposed prebiotic
eects of DFO put forward in our previous study [25]. However, fecal
water content was not signicantly dierent in any of the groups
(Fig. 2B and D).
Fig. 2. Eects of one-week and two-week dietary supplementation with DFO on fecal pellet weight and fecal water content in mice. Mice were treated with (A and B)
0.2 mL DW, DFO (100, 500, and 1000 mg/kg, p.o.), FOS (1000 mg/kg, p.o.), and bidobacteria (10
9
CFU, p.o.) for a week, then (C and D)0.2 mL DW, DFO (500 mg/
kg, p.o.) and FOS (1000 mg/kg, p.o.) for two weeks. Each bar of the data represents means ± SEM (n = 6 10). *P< 0.05 and **P<0.01 compared to vehicle
control group (DW).
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3.2. Eects of DFO on evacuation time and gut transit
Marker meals were used to demonstrate the action of DFO on upper
gut and total gut transit time. The total gut transit time of the vehicle
control was approximately 230 min. Among the groups supplemented
with DFO at 1000 mg/kg for a week and 500mg/kg for two weeks, this
time was reduced by approximately 30%. These reduced times were
similar to the total gut transit times observed in the groups treated with
the reference prebiotic and the reference probiotic (Fig. 3A and C).
Upper gut transit, dened as the proportion of the small intestinal
length transited by a charcoal meal, was 56.03 ± 2.80% among the
mice supplemented with DW (vehicle control) for a week and
61.01 ± 4.40% among the mice supplemented with DW for two weeks.
These values signicantly increased in every experimental group except
the group treated with DFO at 100 mg/kg for a week (Fig. 3B and D).
However, compared to the control group, evacuation time slightly in-
creased among mice treated for one week with DFO at 100 and 500 mg/
kg but decreased among other groups supplemented for one week.
Evacuation time was not signicantly dierent compared to the control
group among mice treated with 500 mg/kg of DFO for two weeks
(Fig. 1B and D).
3.3. Eects of DFO on colonic motility
Since gut transit time decreased after supplementation with DFO, it
is possible that DFO could increase gut motility. In the spatiotemporal
maps, two patterns of motility were observed. The initial pattern was
the propagation or peristaltic contractions, motility induced by food
pellets. In the group treated with 1000 mg/kg DFO for a week, the
pellets were pushed at 0.6 mm/s (Fig. 4D) by aboral propagation. This
fecal pellet velocity was a signicant increase compared to the control
group. Meanwhile, administration of 500 mg/kg DFO and 1000 mg/kg
FOS for two weeks also increased fecal pellet velocity, but not as sig-
nicantly (Fig. 5D). The results suggested that the reference prebiotics
and probiotics had similar or even greater eects than DFO, with the
exception of 1000 mg/kg FOS treatment for a week (Fig. 4D). The
second pattern of motility consisted of shallow circular muscle con-
tractions separated by short phases of relaxation. Because the con-
tractions pushed the pellets forward and backward (non-propagation
contraction or segmentation), the contraction velocity could not be
calculated. By comparison with the vehicle control, a signicant in-
crease in the total number of contractions (Fig. 4A) was observed after
treatment with 1000 mg/kg DFO for a week. The contribution to this
total increase was especially noticeable in the non-propagation pattern
(Fig. 4B). This response was similar to the results of the week long
treatments with the reference prebiotic and probiotic (Fig. 4A and B).
However, the number of propagation contractions was not signicantly
dierent (Fig. 4C). Similarly, two weeks of treatment with 500 mg/kg
DFO and 1000 mg/kg FOS yielded a signicant increase in the total
number of contractions and non-propagation contractions but not
propagation pattern contractions (Fig. 5AC). Spatiotemporal maps of
these colonic motility patterns can be found in Supplemental Figs. S4
and S5.
3.4. Eects of DFO supplementation for one week on proximal and distal
colonic circular and longitudinal SM contractions
The mean amplitude of contraction of the circular SM from proximal
colon segments from the control group was 30.27 ± 4.99%. Among all
the other groups, the mean amplitude increased. These increases ranged
Fig. 3. Eects of one-week and two-week
dietary supplementation with DFO on Evan-
blue total gut transit time and charcoal meal
upper gut transit in mice. Mice were treated
with (A and B)0.2 mL DW, DFO (100, 500 and
1000 mg/kg, p.o.), FOS (1000 mg/kg, p.o.),
and bidobacteria (10
9
CFU, p.o.) for a week,
then (C and D)0.2 mL DW, DFO (500 mg/kg,
p.o.) and FOS (1000 mg/kg, p.o.) for two
weeks. (A and C) Each bar of the total gut
transit time represents the mean of the total gut
transit time (min) ± SEM (n = 46). (B and D)
Each bar of the upper gut transit represents the
mean of the percentage of the small intestine
length traveled by the charcoal plug ± SEM
(n = 711). *P< 0.05, **P< 0.01 and
***P< 0.001 compared to vehicle control
group (DW).
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from 37.00 ± 7.67%, for the group treated with 100 mg/kg DFO for a
week, to 92.63 ± 5.16 after 7-day treatment with 10
9
CFU bido-
bacteria. After supplementation for a week with 500 and 1000 mg/kg
DFO, the contraction amplitude was signicantly higher than that of
the control group. This result was similar to the result for prebiotic FOS
(Fig. 6A). The representative traces of the contractions of proximal
colonic circular SM of mice treated with DW, DFO, FOS, and bido-
bacteria for 7 days were shown in Supplemental Fig. S6. In the long-
itudinal SM proximal colon segments, the mean amplitude of contrac-
tion of the control group was 36.27 ± 7.79% but, after every 7-day
treatment the mean amplitudes of contractions increased. These in-
creases were especially signicant in the groups supplemented with
1000 mg/kg of DFO (70.55 ± 8.31%) and 10
9
CFU bidobacteria
(79.21 ± 8.98). Treatment with 1000 mg/kg FOS did not signicantly
enhance the amplitude of contraction in longitudinal SM (Fig. 6A). The
representative traces of the contractions of proximal colonic long-
itudinal SM of mice treated for 7 days were shown in Supplemental Fig.
S7. The mean frequency of the spontaneous contractions in both cir-
cular and longitudinal SM proximal colon segments in any experimental
group was not signicantly dierent from the control group (Fig. 6C).
In contrast, the durations of contraction in longitudinal SM were sig-
nicantly longer in the groups treated with 1000 mg/kg DFO and bi-
dobacteria than they were in the control group. Meanwhile, supple-
mentation with 1000 mg/kg FOS signicantly increased the duration of
contraction only in the circular SM (Fig. 6E). We also investigated the
eect of DFO on the contraction of the distal colonic SM (Supplemental
Fig. S8 and S9). In both circular and longitudinal SM segments
(Fig. 6B), the mean amplitude of contractions signicantly increased,
compared to the control group, only in the group treated with bido-
bacteria. Similarly, the mean frequency of spontaneous contractions in
both circular and longitudinal SM showed no signicant change in re-
sponse to DFO and FOS when compared to the results from the control
groups (Fig. 6D). The duration of contractions of circular muscle sig-
nicantly increased in the groups treated with 1000 mg/kg of DFO and
bidobacteria, whereas the contraction duration of longitudinal muscle
increased in the groups treated with 1000 mg/kg FOS and bido-
bacteria (Fig. 6F).
3.5. Eects of DFO supplementation for two weeks on proximal and distal
colonic circular and longitudinal SM contractions
After treatment with 500 mg/kg of DFO and 1000 mg/kg of FOS for
two weeks, the amplitude of proximal colonic contractions was sig-
nicantly higher than the amplitude of the control group in both cir-
cular and longitudinal SM (Fig. 7A). DFO and FOS increased the fre-
quency of circular SM contractions when compared to the control group
(Fig. 7C) and also increased the duration of contractions in longitudinal
SM (Fig. 7E). The representative traces of the contractions of proximal
Fig. 4. Eects of a week of dietary supplementation with DFO on the number of contractile responses for 30 min in the entire colon. Mice were treated with 0.2 mL
DW, DFO (100, 500 and 1000 mg/kg, p.o.), FOS (1000 mg/kg, p.o.), and bidobacteria (10
9
CFU, p.o.) for a week: (A) Number of total contractions, (B) Number of
non-propagation contractions, (C) Number of propagation contractions, and (D) Velocity of fecal pellet propulsion through whole colon. Data are means ± SEM
(n = 5). *P< 0.05, **P< 0.01 and ***P< 0.001 compared to control group (DW).
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colonic circular and longitudinal SM of mice treated with DW, DFO, and
FOS for 14 days were shown in Supplemental Fig. S10 and S11. In the
distal colon, in the groups treated with 500 mg/kg DFO and 1000 mg/
kg FOS, the amplitude of contractions in circular SM was signicantly
higher than the amplitude of the control group. The amplitude of
contractions in longitudinal SM showed no change (Fig. 7B). In contrast
to the amplitude, no signicant dierence was measured in the fre-
quency of contractions after administration of DFO and FOS (Fig. 7D).
The duration of contractions of the longitudinal SM of DFO- and FOS-
treated mice was signicantly longer than the control group (Fig. 7F).
The representative traces of the contractions of distal colonic circular
and longitudinal SM of mice treated for 14 days were shown in Sup-
plemental Fig. S12 and S13.
3.6. Eects of DFO on colonic smooth muscle histology
To determine whether DFO increased the thickness of the colonic
SM, the histological characteristics of the colonic wall were determined.
There was no evidence that consumption of 500 mg/kg DFO over the
two week period had irritated the colonic mucosa. The morphology of
the simple squamous epithelium was normal. The number of goblet
cells present in the mucosal layer was comparable to the numbers
present in FOS- and DW-treated groups (Fig. 8A, arrows). Regarding the
muscular layer, there was no signicant dierence in the thickness of
the SM layer in the DFO-treated group compared to both FOS- and DW-
treated groups (Fig. 8B).
4. Discussion
The present study of mice found that dietary supplementation with
DFO accelerated upper gut transit, which reduced travel time of the
content to the colon and also reduced total gut transit time. This result
is consistent with the results from the reference FOS- and bido-
bacteria-treated groups and supplementation with short-chain FOS and
products containing Lactobacillus or Bidobacterium species also re-
duced intestinal transit time in human adults [33,34]. Reduced in-
testinal transit time was reported in malabsorptive states and diarrhea
symptoms [35]. However, in this study, the BW of DFO-treated groups
did not change compared to the control group and no diarrheal feces
were observed. DFO is a non-digestible, fermentable, and soluble short-
chain carbohydrate. When consumed, around 50% of DFO is estimated
to reach the colon. The rest is hydrolyzed by salivary and pancreatic α-
amylases (16%), gastric juice (2.5%), and small intestinal brush-border
enzymes (30%). In the intestine, this soluble ber has an appreciable
water holding capacity that increases fecal mass. However, the water
holding capacity of DFO is known to be less than that of other bers,
such as wheat ber [36]. Fecal pellet wet weight signicantly increased
in DFO- and FOS-treated groups in this study, compared to the control
group. However, the percentages of fecal water content were not sig-
nicantly dierent. These results are consistent with the nding of a
previous study that fecal water content in dogs was not inuenced by
FOS treatment [37].
Increased colonic content stimulated peristaltic or propagation
Fig. 5. Eects of DFO dietary supplementation for two weeks on the number of contractile responses for 30 min in the entire colon. Mice were treated with 0.2 mL
DW, DFO (500 mg/kg, p.o.) and FOS (1000 mg/kg, p.o.) for two weeks: (A) Number of total contractions, (B) Number of non-propagation contractions, (C) Number
of propagation contractions, and (D) Velocity of fecal pellet propulsion through whole colon. Data are means ± SEM (n = 56). *P< 0.05 compared to control
group (DW).
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contractions and also accelerated intestinal transit [38]. Peristaltic
contraction reduced the colonic diameter without occluding the lumen.
Thus, these movements did not empty the proximal colon in a single
sweep but rather slowly pushed small amounts of content into the distal
colon. Even though the propagation pattern of the DFO-treated groups
was not signicantly dierent when compared to the control group, a
trend of increase was observed and fecal pellet velocity signicantly
increased after one week of treatment with 1000 mg/kg DFO. The eect
of DFO on propagation pattern was comparable to the result obtained
from bidobacteria but not the result of FOS, which enhanced only the
non-propagation pattern. Distention by natural fecal pellets was a major
trigger for neurally mediated colonic propulsion [39,40]. Thus, it could
reasonably be suggested that peristaltic contractions in the colon were
the result of a distension-triggered motor pattern generator mediated by
the enteric nervous system [41].
In addition to distending the colonic wall by volume, DFO might
alter bowel motility by changing the colonic environment. In vitro
studies showed that bacterial fermentation of oligosaccharides in-
creased production of SCFAs, lowering colonic pH [4244]. The lower
pH stimulated the growth of lactobacilli and bidobacteria and sup-
pressed the growth of harmful bacteria [43]. Increasing fermentation
by-products such as gas and SCFAs could increase stool bulk and also
stimulate gut motility [45]. There are many conicting studies about
the eects of prebiotics and probiotics on GI motility. Some of these
studies suggested that these supplements increased intestinal motility,
while others concluded the opposite [4648]. Ingestion of Lactobacillus
reuteri reduced the amplitude of colonic contractions at both constant
and increased luminal pressure, which is required to induce phasic
contractions in rats [46]. On the other hand, the administration of
fermented milk prepared with Lactobacillus casei enhanced colonic
propulsive contraction and defecation rate in pigs [47]. Another study
proposed that healthy newborns fed with breast milk had softer stools
Fig. 6. Eects of a week of DFO supplementation on spontaneous (A, C and E) proximal and (B, D and F) distal colonic circular and longitudinal SM contractions in
mice. Mice were treated with 0.2 mL DW, DFO (100, 500 and 1000 mg/kg, p.o.), FOS (1000 mg/kg, p.o.), and bidobacteria (10
9
CFU, p.o.) for a week. Values are
means ± SEM (n = 10) and are expressed as (A and B) a percentage of the maximum amplitude of contraction, (C and D) contractions/min, and (E and F) the
duration of contractions in seconds. *P< 0.05, **P< 0.01 and ***P< 0.001 compared to vehicle control group (DW).
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and higher stool frequency than newborns fed with bovine milk. GOS
and FOS supplementation reduced stool consistency but increased stool
frequency [48]. In agreement with previous studies, we found that DFO
accelerated gut transit by increasing intestinal motility, fecal pellet
velocity, and also the number of colonic contractions, especially non-
propagation pattern contractions.
Non-propagation or segmenting contractions cause mixing and local
circulation of contents. This pattern may slow gut transit to counteract
the strong eect of DFO on peristaltic contraction. Therefore, in this
study, no adverse eects from DFO supplementation, such as diarrhea
or malabsorption, were observed. Normally the anal canal is closed by
internal anal sphincter contraction. When the rectum is distended, the
internal sphincter relaxes by reex. Rectal distention elicits a sensation
that signals the urge for defecation, which is prevented by the external
anal sphincter. The contraction of the external sphincter is maintained
by reex activation through dorsal roots in the sacral spinal cords. Since
there was no signicant dierence in evacuation time in this study, we
concluded that DFO and the other treatments in this study did not aect
neural control over defecation.
Delayed motility or transit of colonic contents may lead to con-
stipation. There is a direct correlation between increased dietary bers
or prebiotics, increased colonic intraluminal bulk, and enhanced co-
lonic transit or motility. Many studies reported that prebiotics improve
health in a similar way to probiotics but are cheaper, safer, and easier to
incorporate into the diet. However, excessive intake of short-chain
carbohydrates can cause undesirable side eects, such as atulence,
bloating, rumbling, cramps, and liquid stools, which are all caused by
gas formation and the osmotic eects of certain fermentation products.
Fortunately, 1000 mg/kg/day or less of DFO was usually well-tolerated
by the mice in our study.
Colonic SM contractions are organized to allow optimal absorption
of water and electrolytes, net aboral movement of contents, and the
Fig. 7. Eects of two-week dietary supplementation with DFO on spontaneous (A, C and E) proximal and (B, D and F) distal colonic circular and longitudinal SM
contractions in mice. Mice were treated with 0.2 mL DW, DFO (500 mg/kg, p.o.) and FOS (1000 mg/kg, p.o.) for two weeks. Values are means ± SEM (n = 8) and
are expressed as (A and B) a percentage of the amplitude of maximum of contraction, (C and D) contractions/min and (E and F) the duration of contraction in
seconds. *P< 0.05 and **P< 0.01 compared to vehicle control group (DW).
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Fig. 8. Histological cross-section images (Conventional H&E and PAS staining) of (A) mouse colon paran sections and (B) colonic SM thickness of DFO-treated
mice. Mice were orally administered with 0.2 mL DW, DFO (500 mg/kg)or FOS (1000 mg/kg)for two weeks. Arrows in an upper row and a middle row in (A)
represent epithelium and number of goblet cells, respectively; a lower row shows thickness of muscular layer; scale bar =20 μm.
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storage and orderly evacuation of feces. The muscularis layers display
two distinct motility patterns: propagated peristaltic contractions,
which involve the coordinated contractions of the longitudinal and
circular SM; and non-propagated segmentation contractions, which
mainly involve the circular muscle layer. This study showed that DFO
treatment for a week increased the force and duration of contractions in
both circular and longitudinal SM in the proximal colon but only in-
creased the duration of circular SM contractions in the distal colon.
After two weeks of treatment with DFO, the contraction frequency of
circular SM had increased in the proximal but not the distal colon.
Short-chain carbohydrates, including DFO, are very rapidly fermented
in the terminal ileum and proximal colon to produce SCFAs. Therefore,
SM in the proximal colon should be aected much more than SM in the
distal colon [36]. However, the underlying mechanisms that control the
eects of DFO on colonic SM contraction are still unknown.
Recent research found that specic SCFAs, such as butyrate, in-
creased cholinergic-mediated colonic circular SM contractions in rats
[49]. Hurst and co-workers also reported that butyrate, acetate, and
propionate in the colonic lumen have dierent eects on proximal and
distal colonic contractions and that these eects were dependent on
chain length. The net eect of SCFAs on contraction depended on the
balance of SCFAs produced when gut microbiota ferment non-digestible
carbohydrates [14]. The occurrence of contractions is always inu-
enced by slow wave activity in the colonic SM cell membrane. The
contractions, however, are initiated by a spike in potential activity,
which occurs when slow waves reach the electrical threshold. Thus,
slow wave frequency sets the maximum frequency of contractions. The
force and duration of muscle contractions are directly related to the
amplitude and frequency of spike potential. The spike potential oc-
currence depended heavily on neuronal and hormonal activities as well
as local chemical agents, but slow waves were extremely regular [50].
Aligned with our results, the eects of DFO might regulate the amount
of spiking but less so the threshold of the slow wave. Therefore, DFO
aects mostly the strength and duration of contractions rather than the
frequency.
Coordinated intestinal circular and longitudinal SM contractions
produce caudal propulsion of luminal contents via peristalsis. Excitatory
factors such as SCFAs from the bidogenic eect and distention from
the osmotic eect may act on free fatty acid and stretch receptors at the
intestinal epithelia. They stimulate 5-hydroxytryptamine, which acti-
vates CGRP-containing neurons, a series of interneurons, and motor
neurons to release acetylcholine, tachykinin, or substance P orad to the
luminal stimulus. These neurotransmitters cause circular SM contrac-
tions and longitudinal SM relaxation. Vasoactive intestinal peptide and
nitric oxide are released to the luminal stimulus and stimulate circular
SM relaxation and longitudinal SM contractions [50].
Some studies conrmed that prebiotic supplements or SCFAs could
change the colonic structure. Butyrate, for example, exerted a trophic
eect in colonocytes. However, in the present study, DFO did not show
trophic eects on the gut wall nor change SM thickness. Previous stu-
dies also reported that a high ber diet increased both secretory activity
and numbers of mucin-secreting goblet cells in the colon of rats [51].
Conversely, our study showed no DFO eect on either epithelium or
goblet cell numbers. Since intestinal mucin in colonic mucosa plays a
cytoprotective role against a variety of luminal hazards, and since
goblet cell numbers were altered during intestinal infections, based on
general criteria in histomorphological scores for intestinal inamma-
tion, changes in epithelial or mucosal architecture did not result from
consumption of DFO [52,53]. These ndings may conrm the safety of
this product as a supplement.
Taken together, these data suggest that in addition to desirable
prebiotic properties [25], DFO also acts as a bulk-forming laxative
which absorbs water from the intestinal lumen to increase fecal mass
(osmotic eect) as well as a stimulant laxative that increases intestinal
motility in mice. We also showed an association between DFO ingestion
and alteration to colonic SM contractility. These ndings conrm that
DFO may be suitable to supplement prebiotic/probiotic/symbiotic
products and laxative products. DFO may also be a promising nutri-
tional therapy for GI motility disorders such as constipation and IBS.
Nevertheless, further investigation is required to identify the under-
lying mechanisms responsible for changes in GI motility induced by diet
or gut bacteria.
Disclosure
None of the authors had conicts of interest throughout the study
process.
Authorship contributions
The authorsresponsibilities:
P.K., S.P., C.T., S.W., and N.C. - conceptualized and designed re-
search;
P.K., S.K., K.B., F.H., and C.T. - conducted research;
S.W. - provided essential reagents;
P.K., S.K., K.B., F.H., and C.T. - analyzed data;
P.K., C.T. and N.C. - wrote the paper;
P.K. - reviewed nal content;
All authors: reviewed and approved nal version of the manuscript.
Acknowledgements
This work was supported by a grant from Thailand Research Fund
(P.K., grant number MRG5980042), (N.C. is a TRF Senior Research
Scholar, grant number TRF; RTA6080007). The authors are grateful for
Publication Clinic of Prince of Songkla University and Mr. Thomas
Coyne for providing assistance in proofreading and providing feedback
on the manuscript.
Appendix A. Supplementary data
Supplementary material related to this article can be found, in the
online version, at doi:https://doi.org/10.1016/j.biopha.2019.108821.
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... For small intestinal transit, mice were gavage fed a 0.3 mL charcoal meal containing 10% w/v charcoal in 5% w/v gum arabic at 30 min before euthanasia. The euthanized mice were dissected, and transit (%) was calculated from the following equation [37]: ...
... The concentrations of carbachol progressed from 0.1 to 1 to 10 µM, without washing between increments. The amplitude of contraction (g) and frequency of contraction (times/min) were recorded with the PowerLab ® System (AD Instruments, New South Wales, Australia) and analyzed with LabChart7 program software [20,37]. ...
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Constipation is a symptom that is widely found in the world’s population. Various dietary supplementations are used to relieve and prevent constipation. Seaweed is widely used for its health benefits. In this study, we aimed to investigate the effects of Sargassum plagiophyllum extract (SPE) on functions of the gastrointestinal tract and gut microbiota. The results show that SPE pretreatment increased the frequency of gut contraction, leading to reduce gut transit time. SPE pretreatment also significantly increased the secretion of Cl− and reduced Na+ absorption, increasing fecal water content in constipated mice (p < 0.05). In addition, the Bifidobacteria population in cecal contents was significantly higher in constipated mice pretreated with 500 mg/kg SPE for 14 days than in untreated constipated mice (p < 0.05). Our findings suggest that SPE can prevent constipation in loperamide-induced mice. This study may be useful for the development of human food supplements from S. plagiophyllum, which prevent constipation.
... The administration of prebiotics has been reported to relieve constipation in patients by increasing stool frequency and improving stool consistency [2]. The possible mode of action may be alteration of gut motility due to stimulation of the colonic microbiota [3]. A known medicinal plant, brown seaweed (e.g. ...
... In a study of constipation in rats, pretreatment with SPE shortened gastrointestinal transit time, which in turn alleviated reductions in the numbers of goblet cells [11]. In ICR mice, the consumption of prebiotic extracts of dragon fruit stimulated gut motility [3]. These results suggested that SPE pretreatment increased the frequency of defecation and prevented the loss of goblet cells in constipated rats, which in turn protected the intestinal epithelium. ...
Article
Purpose: To evaluate the toxicity of the dried seaweed, Sargassum plagiophyllum, extract (SPE) pretreatment in constipated mice.Methods: The dried seaweed powder was mixed with distilled water and extracted by autoclave at 121°C. Antioxidant activity of the extract was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Human normal colon cells were pretreated with SPE at 0 - 100 μg/mL for 24 h before challenging them with 100 μM hydrogen peroxide (H2O2). Intracellular reactive oxygen species (ROS) were quantified using 2',7'- dichlorodihydrofluorescein diacetate (H2DCFDA). Male ICR mice were pretreated for 14 consecutive days with SPE at 100, 500 and 1,000 mg/kg or lactulose at 500 mg/kg. Body weight and food intake were recorded daily. Constipation was induced with loperamide on days 12, 13 and 14 and fecal pellets evacuated over a 4-hr period. The ileum, liver, kidney, and spleen were collected for histopathological examination.Results: The IC50 for the radical scavenging capacity of SPE was 343.90 ± 4.21 μg/mL compared to 14.14 ± 0.71 μg/mL for ascorbic acid. Pretreatment with SPE was significantly reduced ROS production in human normal colon cells. Oral administration of all doses of SPE and lactulose for 14 consecutive days had no effect on food intake or body weight when compared to the normal control group. Defecation was significantly more frequent in mice pretreated with SPE at 100 mg/kg than in the constipation control group. Histopathological examination of the ileum, liver, kidney and spleen of pretreated constipated mice revealed no toxic effect from either SPE or lactulose. On the other hand, the loss of mucus-producing cells in the ileum of constipated mice was significantly lower in mice pretreated with SPE.Conclusions: These findings support the safety of SPE supplementation and may broaden itsapplication in clinical fields as an alternative drug or supplement for constipation management.
... Fecal pellet output assay, which is a simple and non-invasive means to evaluate gastrointestinal motility, was also performed based on a previous report (Khuituan et al., 2019). All mice were removed from their home cages and individually placed in clean cages for observation. ...
... Xu et al. (2020) proved that the nonapeptide DN-9 slowed the gastrointestinal transit in mice using the upper intestinal transit test and colonic bead expulsion assay. Khuituan et al. (2019) indicated that prebiotic oligosaccharides from dragon fruits altered gut motility in mice via evaluating the fecal pellets output assay over six hours. In the present research, we also found that DON induced slower upper intestinal transit and decreased the accumulated number and weight of fecal pellets. ...
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Deoxynivalenol (DON) is a prevalent Fusarium mycotoxin, occurs predominantly in the global environment, especially in cereals, animal feed and food commodities. The widespread contamination causes a serious risk to human and animal health. DON usually impairs weight gain, which is presumably from its capacity to reduce feed intake by interfering with intestinal motility. To clarify the role of smooth muscle cells (SMCs) contractility in intestinal motility and growth inhibition caused by DON, twelve weaned piglets were firstly divided into two groups to feed control or Fusarium mycotoxin-contaminated (MC) diet. Results showed that the final body weight, average daily gain and average daily feed intake were significantly reduced in piglets fed the MC diet. Exposure to the MC diet also significantly decreased the thickness of smooth muscle layer and SMCs contractile markers expression (myosin heavy chain 11, smooth muscle actin gamma 2, transgelin, calponin 1) in jejunum and ileum of piglets. Furthermore, oral DON supplementation (3 mg/kg body weight) to mice in six consecutive days could significantly inhibit the upper intestinal transit, impede normal defecation and downregulate SMCs contractile markers expression in small intestine. Finally, we generated a porcine enteric smooth muscle cell line (PISMC), and found that DON could depress its contractility by decreasing PISMC proliferation, migration and contractile markers expression. In conclusion, these findings in vivo and in vitro suggest that DON, as a common environmental toxin, can not only reduce proliferative and motile phenotype, but also decrease contractile apparatus components (contractile markers expression) in SMCs, which in turn influences SMCs contractility and then interferes with intestinal motility and growth performance.
... are exported from Southeast Asia and the Americas to Europe and other parts of Asia. The fruit offers many medicinal benefits as it contains antioxidants and is rich in fiber (Wybraniec et al. 2007;Ortíz-Hernandez and Carrillo-Salazar 2012;Tenore et al. 2012) which aids in digestion (Khuituan et al. 2019). Red peels of S. undatus and S. monacanthus are also used to extract betalain pigments in the production of dyes (Lestari 2016). ...
Article
Cultivation of dragon fruits (Selenicereus spp.) has health and commercial benefits, which are threatened by the presence of destructive diseases affecting this crop. In this study, a pathogenic isolate was obtained from a diseased stem of Selenicereus monacanthus (red peel, red flesh) in Luzon, Philippines. The causal agent of the disease was identified using combined morphological, cultural, pathogenicity, and molecular characterization. Colony and spore morphologies indicate that the pathogen belongs to the genus Colletotrichum. DNA sequences of the partial internal transcribed spacer, actin, glyceraldehyde-3-phosphate dehydrogenase, and beta-tubulin gene regions confirmed that the isolate was Colletotrichum tropicale. Anthracnose developed in S. undatus (red peel, white flesh) and S. monacanthus inoculated with C. tropicale. However, the isolate did not infect S. megalanthus (yellow peel, white flesh). To our knowledge, this is the first report of C. tropicale causing dragon fruit anthracnose. This study also provides evidence that resistance to anthracnose exists in the Selenicereus species. Because S. monacanthus and S. undatus have commercial significance, management strategies would be needed. Dragon fruit breeding programs using S. megalanthus as a source of resistance to anthracnose would be worthwhile.
... Glucose, fructose and oligosaccharides are dominant carbohydrates present in red pitaya [8]. Additionally, polysaccharides and polyphenols are well-known antioxidants and can be used for prebiotic enrichment as well as natural colourants (betanin) in food products [9,10]. Essential fatty acids, especially linoleic acid, extracted from pitaya seeds have been reported to have laxative activity on gastroenteritis [11]. ...
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Red pitaya (Hylocereus polyrhizus, red pulp with pink peel), also known as dragon fruit, is a well-known species of pitaya fruit. Pitaya seeds and peels have been reported to exhibit higher concentrations of total polyphenols, beta-cyanins and amino acid than pulp, while anthocyanins (i.e., cyanidin 3-glucoside, delphinidin 3-glucoside and pelargonidin 3-glucoside) were only detected in the pulp extracts. Beta-cyanins, phenolics and flavonoids were found to increase gradually during fruit maturation and pigmentation appeared earlier in the pulp than peel. The phytochemicals were extracted and purified by various techniques and broadly used as natural, low-cost, and beneficial healthy compounds in foods, including bakery, wine, dairy, meat and confectionery products. These bioactive components also exhibit regulative influences on the human gut microbiota, glycaemic response, lipid accumulation, inflammation, growth of microbials and mutagenicity, but the mechanisms are yet to be understood. The objective of this study was to systematically summarise the effect of red pitaya’s maturation process on the nutritional profile and techno-functionality in a variety of food products. The findings of this review provide valuable suggestions for the red pitaya fruit processing industry, leading to novel formulations supported by molecular research.
... This effect on transit time was attributed to greater speed and total number of intestinal contractions compared to control after a week of 1000 mg kg −1 d −1 of dragon fruit. 126 These results in animals show great potential for fecal bulking and transit time reduction. While red dragon fruit has not yet been studied, it is a better source of fiber and phytochemicals compared to white dragon fruit, 127 which could suggest that it could be an ...
Article
Fruits are the seed-bearing product of plants and have considerable nutritional importance in the human diet. The consumption of fruits is among the dietary strategies recommended for constipation due to its potential effects on the gut microbiota and gut motility. Dietary fiber from fruits has been the subject of research on the impact on gut microbiota, gut motility and constipation, however, fruits also contain other components that impact the intestinal luminal environment that may impact these outcomes including sorbitol and (poly)phenols. This review aims to explore the mechanisms of action and effectiveness of fruits and fruit products on the gut microbiota, gut motility and constipation, with a focus on fiber, sorbitol and (poly)phenols. In vitro, animal and human studies investigating the effects of fruits on gut motility and gut microbiota were sought through electronic database searches, hand searching and consulting with experts. Various fruits have been shown to modify the microbiota in human studies including blueberry powder (lactobacilli, bifidobacteria), prunes (bifidobacteria), kiwi fruit (Bacteroides, Faecalibacterium prausnitzii) and raisins (Ruminococcus, F. prausnitzii). Prunes, raisins and apple fiber isolate have been shown to increase fecal weight in humans, whilst kiwifruit to increase small bowel and fecal water content. Apple fiber isolate, kiwifruit, fig paste, and orange extract have been shown to reduce gut transit time, while prunes have not. There is limited evidence on which fruit components play a predominant role in regulating gut motility and constipation, or whether a synergy of multiple components is responsible for such effects.
... On the other hand, the size of the WMC is a major limita-tion for its use in mice, and to the best of our knowledge, the WMC technique has not been applied for the evaluation of murine GI transit. Currently, the most common method for the assessment of whole murine GI transit is terminal experiments in which the timing of the first appearance of non-absorbable markers, such as charcoal [9], carmine red [10][11][12][13][14][15], and Evans blue [16][17][18][19], in the stool is measured. Several recent studies have shown that fluorescence imaging with indocyanine green [20] and diagnostic imaging [21,22] are useful for measuring intestinal transit in non-terminal experiments. ...
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In vivo assessment of murine gastrointestinal (GI) motility is useful for understanding GI diseases and developing effective therapies. The establishment of noninvasive measurement methods for mice will contribute to translational research bridging basic research and clinical practice, which can be a beneficial for maintaining quality of life in humans and animals. Recent advances in noninvasive diagnostic techniques have led to this update on the application and performance of available tests in mice. In vivo imaging techniques have been developed as noninvasive methods for the assessment of murine GI motility, and many of these methods have been applied to humans. Imaging techniques, including scintigraphy and ultrasonography, are frequently used in clinical practice. Basic data obtained using methods commonly used in clinical practice may be directly translated to clinical practice and are more attractive than those obtained using invasive methods. In this review, we provide recommended methods for noninvasively investigating gastric, small intestinal, and colonic motility in mice and detail the benefits of each test.
Chapter
Changes in consumers’ eating habits reflect an increase in interest in healthier foods. Because of this there is an interest in the development of processed foods that can offer additional advantages to consumers. There are several studies regarding the incorporation of prebiotic and probiotic in dairy-based foods. However, there is a demand for nondairy products that need to be answered as people that have restrictions as milk protein allergy, lactose intolerance and strict vegetarians that cannot eat dairy products. This chapter will discuss about quality aspects, health effects and, challenges in incorporating prebiotics and probiotics in nondairy products as juices and fresh-cut fruit and vegetables.
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This review examines the nutritional and functional aspects of some representatives of the Cactaceae family, as well as its technological potential in the most diverse industrial fields. The studied species are good sources of nutrients and phytochemicals of biological interest, such as phenolic compounds, carotenoids, betalains, phytosterols, tocopherols, etc. They also have shown great potential in preventing some diseases, including diabetes, obesity, cancer, and others. As to technological applications, the Cactaceae family can be explored in the production of food (e.g., cakes, yogurts, bread, ice cream, and juices), as natural dyes, sources of pectins, water treatment and in animal feed. In addition, they have great potential for many technological domains, including food chemistry, pharmacy, biotechnology, and many others.
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Background: Feeding dogs with diets rich in protein may favor putrefactive fermentations in the hindgut, negatively affecting the animal's intestinal environment. Conversely, prebiotics may improve the activity of health-promoting bacteria and prevent bacterial proteolysis in the colon. The aim of this study was to evaluate the effects of dietary supplementation with fructooligosaccharides (FOS) on fecal microbiota and apparent total tract digestibility (ATTD) in dogs fed kibbles differing in protein content. Twelve healthy adult dogs were used in a 4 × 4 replicated Latin Square design to determine the effects of four diets: 1) Low protein diet (LP, crude protein (CP) 229 g/kg dry matter (DM)); 2) High protein diet (HP, CP 304 g/kg DM); 3) Diet 1 + 1.5 g of FOS/kg; 4) Diet 2 + 1.5 g of FOS/kg. The diets contained silica at 5 g/kg as a digestion marker. Differences in protein content were obtained using different amounts of a highly digestible swine greaves meal. Each feeding period lasted 28 d, with a 12 d wash-out in between periods. Fecal samples were collected from dogs at 0, 21 and 28 d of each feeding period. Feces excreted during the last five days of each feeding period were collected and pooled in order to evaluate ATTD. Results: Higher fecal ammonia concentrations were observed both when dogs received the HP diets (p < 0.001) and the supplementation with FOS (p < 0.05). The diets containing FOS resulted in greater ATTD of DM, Ca, Mg, Na, Zn, and Fe (p < 0.05) while HP diets were characterized by lower crude ash ATTD (p < 0.05). Significant interactions were observed between FOS and protein concentration in regards to fecal pH (p < 0.05), propionic acid (p < 0.05), acetic to propionic acid and acetic + n-butyric to propionic acid ratios (p < 0.01), bifidobacteria (p < 0.05) and ATTD of CP (p < 0.05) and Mn (p < 0.001). Conclusions: A relatively moderate increase of dietary protein resulted in higher concentrations of ammonia in canine feces. Fructooligosaccharides displayed beneficial counteracting effects (such as increased bifidobacteria) when supplemented in HP diets, compared to those observed in LP diets and, in general, improved the ATTD of several minerals.
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Background Probiotics are commonly recommended for the alleviation of constipation symptoms. The aim of this research was to determine the effects of probiotic-containing products on stool frequency and intestinal transit time (ITT) in constipated adults and to determine the factors that influence the efficacy of these products. Methods We conducted a systematic review of randomized controlled trials that measured weekly stool frequency or ITT in constipated adults receiving probiotic-containing supplements. A random effects meta-analysis was performed; stool frequency was summarized by the mean difference statistic and ITT was summarized by the standardized mean difference (SMD) statistic. Meta-regression and diagnostic model performance testing were used to identify publication bias and sources of heterogeneity. Results A total of 21 studies (23 comparisons) comprising 2656 subjects were included. All studies utilized probiotics containing Lactobacillus or Bifidobacterium species. Probiotic-containing products resulted in a mean increase in weekly stool frequency of 0.83 (95% confidence interval [CI] 0.53-1.14, P<0.001). There was high heterogeneity among the studies (I²=85%, P<0.001) and evidence of significant publication bias (Egger’s P-value <0.01). After adjustment for publication bias, the mean difference in weekly stool frequency was reduced from 0.83 to 0.30. The effects on stool frequency were greater in studies where functional constipation was diagnosed using Rome III (P<0.01), or Rome II or III criteria (P<0.05), compared to non-Rome diagnosis techniques. Probiotic-containing products were also efficacious in reducing ITT (SMD=0.65, 95%CI 0.33-0.97, P<0.001). There was high heterogeneity among studies (I²=66%, P<0.01), but no evidence of publication bias (Egger’s P-value=0.52). A larger total sample size was associated with greater efficacy as regards ITT (P=0.03). The probiotic species, the number of probiotic strains and the daily probiotic dosage had no influence on the outcomes. Conclusion Supplementation with products containing Lactobacillus or Bifidobacterium species increases stool frequency and reduces ITT in constipated adults. However, since significant heterogeneity in outcomes was detected among the studies analyzed, the results should be interpreted with caution.
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Background The gastrointestinal motility is affected by gut microbiota and the relationship between them has become a hot topic. However, mechanisms of microbiota in regulating motility have not been well defined. We thus investigated the effect of microbiota depletion by antibiotics on gastrointestinal motility, colonic serotonin levels, and bile acids metabolism. Methods After 4 weeks with antibiotics treatments, gastrointestinal and colon transit, defecation frequency, water content, and other fecal parameters were measured and analyzed in both wild-type and antibiotics-treated mice, respectively. Contractility of smooth muscle, serotonin levels, and bile acids levels in wild-type and antibiotics-treated mice were also analyzed. Results After antibiotics treatment, the richness and diversity of intestinal microbiota decreased significantly, and the fecal of mice had less output (P < 0.01), more water content (P < 0.01), and longer pellet length (P < 0.01). Antibiotics treatment in mice also resulted in delayed gastrointestinal and colonic motility (P < 0.05), and inhibition of phasic contractions of longitudinal muscle from isolated proximal colon (P < 0.01). In antibiotics-treated mice, serotonin, tryptophan hydroxylase 1, and secondary bile acids levels were decreased. Conclusion Gut microbiota play an important role in the regulation of intestinal bile acids and serotonin metabolism, which could probably contribute to the association between gut microbiota and gastrointestinal motility as intermediates.
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Histomorphology remains a powerful routine evaluating intestinal inflammation in animal models. Emphasizing the focus of a given animal study, histopathology can overstate differences between established models. We aimed to systematize histopathological evaluation of intestinal inflammation in mouse models facilitating interstudy comparisons. Samples of all parts of the intestinal tract from well-established mouse models of intestinal inflammation were evaluated from hematoxylin/eosin-stained sections and specific observations confirmed by subsequent immunohistochemistry. Three main categories sufficiently reflected the severity of histopathology independent of the localization and the overall extent of an inflammation: (i) quality and dimension of inflammatory cell infiltrates, (ii) epithelial changes and (iii) overall mucosal architecture. Scoring schemata were defined along specified criteria for each of the three categories. The direction of the initial hit proved crucial for the comparability of histological changes. Chemical noxes, infection with intestinal parasites or other models where the barrier was disturbed from outside, the luminal side, showed high levels of similarity and distinct differences to changes in the intestinal balance resulting from inside events like altered cytokine responses or disruption of the immune cell homeostasis. With a high degree of generalisation and maximum scores from 4-8 suitable scoring schemata accounted specific histopathological hallmarks. Truly integrating demands and experiences of gastroenterologists, mouse researchers, microbiologists and pathologists we provide an easy-to-use guideline evaluating histomorphology in mouse models of intestinal inflammation. Standard criteria and definitions facilitate classification and rating of new relevant models, allow comparison in animal studies and transfer of functional findings to comparable histopathologies in human disease.
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Objective: the objectives of this study are to isolate and characterize oligosaccharide composition in the flesh and peel of red pitaya, white pitaya and papaya using high performance liquid chromatography analysis (HPLC). Methods: the oligosaccharide composition in both flesh and peel of red pitaya, white pitaya and papaya was determined and quantified by comparing peak areas of sugar samples to those of the standard solutions (Sigma Aldrich, USA). Results: the results of the present study revealed both flesh and peel of red pitaya were significantly higher in dry matter as compared with white pitaya and papaya. The high total soluble solid content of the red pitaya flesh was reflected in the amount of glucose, sucrose and fructose which were significant higher than the amount in white pitaya and papaya flesh. The composition of raffinose and stachyose in red pitaya flesh was found to be significantly higher than white pitaya flesh and papaya flesh. This study clearly showed that red pitaya flesh has a significantly higher composition of maltotriose, maltotetriose and maltopentaose contents as compared to white pitaya flesh and papaya flesh. Therefore, comparatively the composition of maltotriose, maltotetriose and maltopentaose in the fruit's flesh is significantly higher in value than the peel of the fruit. The flesh of red pitaya was found to have reasonably high proportions of prebiotic oligosaccharides as compared to white pitaya and papaya. Conclusion: the red pitaya fruit may represent a rich source of prebiotic oligosaccharides. It should be regarded as a valuable new source of prebiotic oligosaccharides with the potential of being an economic value-added ingredient to be used as a substrate for the development of functional foods to assist in the prevention of chronic diseases.
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The loop diuretic furosemide has an action to inhibit Na(+) -K(+) -2Cl(-) co-transporter at the thick ascending limb of Henle's loop resulting in diuresis. Furosemide also has the non-diuretic effects by binding to GABA-A receptor which may involve the gastrointestinal tract. The aim of this study was to investigate the effects of furosemide on smooth muscle contractions in mice ileum and proximal colon. Each intestinal segment suspended in an organ bath was connected to a force transducer. Signal output of mechanical activity was amplified and recorded for analysis using PowerLab(®) System. After equilibration, the intestine was directly exposed to furosemide, GABA, GABA-A receptor agonist (muscimol), or muscarinic receptor antagonist (atropine). Furosemide (50, 100, and 500 μM) acutely reduced the amplitude of ileal and colonic contraction. In the ileum, 1 mM GABA and 10-60 μM muscimol significantly increased the amplitude, whereas in the colon, 50-100 mM GABA and 60 μM muscimol decreased the contractions. The contractions were also significantly suppressed by atropine. To investigate the mechanisms underlying the inhibiting effect of furosemide, furosemide was added to the organ bath prior to the addition of muscimol or atropine. A comparison of furosemide combined with muscimol or atropine group and furosemide group showed no significant difference of the ileal contraction, but the amplitude of colonic contraction significantly decreased when compared to adding furosemide alone. These results suggest that furosemide can reduce the ileal and proximal colonic contraction mediated by blocking and supporting of GABA-A receptor, respectively, resulting in decreased acetylcholine release. This article is protected by copyright. All rights reserved.
Article
Dragon fruit is becoming more popular due to their nutritional benefits. It has been reported as a potential source of natural prebiotic since it contains oligosaccharides. This research aimed to optimize conditions for extraction and purification of oligosaccharides from dragon fruit's flesh. The extraction was performed using pectinase at various concentrations while the purification was carried out using yeast (Saccharomyces cerevisiae) fermentation. The optimal concentration of pectinase was 124 units/g solid since the oligosaccharides yield was not significantly (p > 0.05) different compare to pectinase at concentration of 177 units/g solid. The optimal extraction conditions of dragon fruit's flesh were using pectinase of 124 units/g solid at 40°C for 45 min. The yields of oligosaccharides, sucrose, glucose and fructose and were 34.52, 2.12, 49.20 and 14.17% on dry basis, respectively. The optimum conditions for purification of the extract with Saccharomyces cerevisiae obtained by using 2.5% (v/v) inoculum. Addition of urea at concentration of 0.1% (w/v) in the dragon fruit's extract showed the highest on removal of sugars during fermentation by yeast. The yeast fermentation at 30°C for 96 h could completely remove glucose, fructose and sucrose moreover it did not affect the oligosaccharides content.
Article
Background Colonic microbiota digest resistant starches producing short chain fatty acids (SCFAs). The main SCFAs produced are acetate, propionate, and butyrate. Both excitatory and inhibitory effects of SCFAs on motility have been reported. We hypothesized that the effect of SCFAs on colonic motility varies with chain length and aimed to determine the effects of SCFAs on propagating and non-propagating contractions of guinea pig proximal and distal colon.Methods In isolated proximal colonic segments, Krebs solution alone or containing 10–100 mM acetate, propionate, or butyrate was injected into the lumen, motility was videorecorded over 10 min, and spatiotemporal maps created. In distal colon, the lumen was perfused with the same solutions of SCFAs at 0.1 mL/min, the movement of artificial fecal pellets videorecorded, and velocity of propulsion calculated.Key ResultsIn proximal colon, butyrate increased the frequency of full-length propagations, decreased short propagations, and had a biphasic effect on non-propagating contractions. Propionate blocked full and short propagations and had a biphasic effect on non-propagating contractions. Acetate decreased short and total propagations. In distal colon, butyrate increased and propionate decreased velocity of propulsion.Conclusions & InferencesThe data suggest that luminal SCFAs have differing effects on proximal and distal colonic motility depending on chain length. Thus, the net effect of SCFAs on colonic motility would depend on the balance of SCFAs produced by microbial digestion of resistant starches.
Article
We investigated the role of GABA on intestinal motility using as model the murine distal colon. Effects induced by GABA receptor recruitment were examined in whole colonic segments and isolated circular muscle preparations to analyze their influence on peristaltic reflex and on spontaneous and neurally-evoked contractions. Using a modified Trendelenburg set-up, rhythmic peristaltic contractions were evoked by gradual distension of the colonic segments. Spontaneous and neurally-evoked mechanical activity of circular muscle strips were recorded in vitro as changes in isometric tension. GABA, at low concentrations (10-50µM), potentiated peristaltic activity and the neural cholinergic contractions, whilst it, at higher concentrations (500µM - 1mM), had inhibitory effects. GABA excitatory effects were mimicked by muscimol, GABAA-receptor agonist, and prevented by bicuculline, GABAA-receptor antagonist, which per se reduced peristaltic activity and the cholinergic contractile responses. Inhibitory effects were mimicked by baclofen, GABAB-receptor agonist, and antagonized by phaclofen, GABAB-receptor antagonist and by hexamethonium, neural nicotinic receptor. Guanethidine was ineffective on GABA effects. Non-cholinergic responses were not affected by GABA agents. All drugs failed to affect the response to carbachol. Lastly, GABAC receptor agonist/antagonist had any effect on colonic motility. In conclusion, GABA in mouse distal colon is a modulator of peristaltic activity via the regulation of acetylcholine release from cholinergic neurons through interaction with GABAA or GABAB receptors. GABAA receptors are recruited at low GABA concentrations, increasing acetylcholine release and propulsive activity. At high GABA concentrations the activation of GABAB receptors overrides GABAA receptor effects, decreasing acetylcholine release and peristaltic activity.