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Biomedical effects of Laurus nobilis L. leaf extract on vital organs in streptozotocin-induced diabetic rats: Experimental research

  • Biochemistry


Diabetes mellitus (DM) has been treated with herbs for centuries and many herbs reported to exert antidiabetic activity. Laurus nobilis is an aromatic herb belonging to the Lauraceae family, commonly known as bay. This study aimed to investigate the activity of Laurus nobilis leave extracts on histopathological and biochemical changes in β-cells of streptozotocin (STZ)-induced diabetic rats. Thirty healthy adult male albino rats were included in the study and divided equally into 5 groups for 4 weeks, control group (C), diabetic group (D), diabetic Laurus nobilis extract group (DLN), Laurus nobilis extract group (LN) and diabetic acarbose (DA) group. The results revealed that the administration of LN to diabetic rats significantly decreased (p < 0.05) blood glucose within 4 weeks of treatment. Additionally, LN also showed protection of liver and kidney functions. The glucose concentration decreased significantly in both diabetic rats treated with L. nobilis and acarbose (p < 0.05), the levels of aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and alanine aminotransferase (ALT) enzyme were insignificantly decreased in both diabetic rats treated with L. nobilis and acarbose (p ˃ 0.05). Outcomes of this study said that leave extracts of L. nobilis has valuable effect on blood glucose level and ameliorative effect on regeneration of pancreatic islets, it also restored the altered liver enzymes, urea, creatine kinase, total protein levels, calcium and ferritin to near normal.
Annals of Medicine and Surgery 61 (2021) 188–197
Available online 21 November 2020
2049-0801/© 2020 The Authors. Published by Elsevier Ltd on behalf of IJS Publishing Group Ltd. This is an open access article under the CC BY license
Biomedical effects of Laurus nobilis L. leaf extract on vital organs in
streptozotocin-induced diabetic rats: Experimental research
Rebin Rafaat Mohammed
, Abdullah Khalid Omer
, Zabit Yener
, Ahmet Uyar
Avin Kawa Ahmed
Sulaimani Veterinary Directorate, Chamchamal Veterinary Hospital, Sulaimani, Iraq
Department of Food Hygiene and Quality Control, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran
Department of Pathology, Faculty of Veterinary Medicine, Van Yuzuncu Yil University, Van, Turkey
Department of Pathology, Faculty of Veterinary Medicine, Hatay Mustafa Kemal University, Hatay, Turkey
Diabetes mellitus
Laurus nobilis
Blood glucose
Diabetes mellitus (DM) has been treated with herbs for centuries and many herbs reported to exert antidiabetic
activity. Laurus nobilis is an aromatic herb belonging to the Lauraceae family, commonly known as bay. This study
aimed to investigate the activity of Laurus nobilis leave extracts on histopathological and biochemical changes in
β-cells of streptozotocin (STZ)-induced diabetic rats. Thirty healthy adult male albino rats were included in the
study and divided equally into 5 groups for 4 weeks as follow; control group (C), diabetic group (D), diabetic
Laurus nobilis extract group (DLN), Laurus nobilis extract group (LN) and diabetic acarbose (DA) group. Histo-
pathologically, D group rats exhibited various degenerative and necrotic changes in their liver, pancreas and
kidney, whereas the DLN rats had nearly normal histology. Insulin immunostaining in the pancreatic beta cells
was decreased in the D group compared to the C group, whereas the DLN group was similar to the C group. The
glucose concentration decreased signicantly in both diabetic rats treated with L. nobilis and acarbose (p <0.05).
Additionally, the levels of aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT) and alanine
aminotransferase (ALT) enzyme were signicantly decreased in both diabetic rats treated with L. nobilis and
acarbose, compared to the D group (p ˃ 0.05). Outcomes of this study said that leave extracts of L. nobilis has
valuable effect on blood glucose level and ameliorative effect on regeneration of pancreatic islets, it also restored
the altered liver enzymes, urea, creatine kinase, total protein levels, calcium and ferritin to near normal.
1. Introduction
Diabetes mellitus (DM) is a chronic endocrine disorder of multiple
etiologies distinguished by hyperglycemia resulting from defects in in-
sulin secretion, insulin action, or both [1]. The clinical diagnosis of
diabetes is often indicated by the presence of symptoms such as polyuria,
polydipsia, unexplained weight loss, and is conrmed by documented
hyperglycemia [2,3]. Diabetes complications can be classied as
microvascular complications such as nervous system damage (neurop-
athy), renal system damage (nephropathy) and eye damage (retinop-
athy), and macrovascular complications for example cardiovascular
disease, stroke, and peripheral vascular disease [46].
Natural supplements are widely used around the world to treat
diabetes, but medical research does not support their effectiveness. DM
has been treated with herbs for centuries and there are many herbs that
have been reported to exert antidiabetic activity [79]. Traditional
plants have been used as a cure for diabetes for a long time before the
introduction of modern medicine. Historically, traditional herbal treat-
ments have been shown to possess successful pharmacological activity,
such as in the case with metformin, isolated from Galega ofcinalis
The dried leaves of Laurus nobilis are used as a spice or avoring
agent in the culinary and food industries [13]. The essential oil (EO)
prepared from the leaves has been reported to have antibacterial, anti-
oxidant and anti-inammatory activities [14,15]. Further leaves of
Laurus nobilis have been also used to treat rheumatism, neuralgia, and
scabies [16,17].
The main volatile compounds in laurel herb extract are usually 1,8-
cineole, methyl eugenol,
-terpinyl acetate.
-pinene, β-pinene, sabi-
nene, and linalool. Generally, leaves and berries are widely utilized,
* Corresponding author.
E-mail address: (R.R. Mohammed).
Contents lists available at ScienceDirect
Annals of Medicine and Surgery
journal homepage:
Received 6 October 2020; Received in revised form 18 November 2020; Accepted 18 November 2020
Annals of Medicine and Surgery 61 (2021) 188–197
oxygenated monoterpene 1,8-cineole is one of the major constituents of
leaves and berry fruits essential oil obtained from Laurus nobilis [18].
The leaves contains about 1.3% essential oils. The EOs obtained of berry
fruit depending on provenance and storage conditions. The oil extracted
from berries contain fatty acids, which include lauric (54%) linoleic
(17%) oleic (15%) and palmitic (5%) and volatile compounds such as
β-ocimene (22%), 1,8-cineole (9.5%), bicyclogermacrene (4.5%) and
β-elemene (2%) [19,20]. The bioactive components in bay leaves have
been shown to have effects on insulin sensitivity, glucose uptake, anti-
oxidant status, inammatory response, and glucose emptying.
Laurus nobilis is an aromatic herb belonging to the Lauraceae family
known as bay, daphne, bay laurel, true bay, or sweet bay. It is an
evergreen tree or shrub, is a native plant from the Southern Mediterra-
nean region, found in warm climate regions with high rainfall, especially
distribution in Turkey, Greece, Spain, Portugal, Italy, France, Morocco
and Mexico [21,22]. In Turkey, Laurus nobilis grows in the Marmara,
Aegean and Mediterranean regions [23,24]. Its one of the oldest known
spices, widely used as a condiment and spice. With relevant medicinal
properties due to its important chemical composition and its potential
therapeutic effects [14]. A et al. [25] reported that aqueous extracts
of Laurus nobilis seeds were effective in reducing ethanol-induced gastric
ulcer in rats.
Traditionally bay leave extract have been used orally to treat the
symptoms of gastrointestinal problems, such as epigastric bloating,
impaired digestion, eructation, and atulence [25]. As a traditional
medicine, the decoction or tea of bay leaves is often used as therapy,
intestinal and gastric antispasmodic, against diarrhea, for rheumatic
pains, also diseases of the respiratory tract, as a cough, asthma, and
cardiac diseases [26].
Bay leaves have also shown that display insulin-enhancing activity in
vitro [27], however these enhance glucose metabolism and the overall
condition of individuals with diabetes not only by hypoglycemic effects
but also by improving lipid metabolism, antioxidant status, and capillary
function [28]. Bay leaves reduced serum glucose, total cholesterol, LDL
cholesterol and triglycerides, and increased HDL-cholesterol levels in
people with type 2 diabetes [27]. This study aimed to evaluate the ef-
fects of Laurus nobilis leave extracts on biochemical and histopatholog-
ical changes of pancreas, liver and kidney on diabetic rats.
2. Materials and methods
2.1. Materials
2.1.1. Animals
All experimental protocols were approved by the Experimental An-
imal Center of Yuzuncu Yil University, Van, Turkey. In the present study,
thirty male Wistar rats, weighting about 160200 g with averagely 7
weeks old were randomly divided into ve groups based on treatment
each group containing 6 animals. All animals were housed under safe
laboratory conditions in a temperature-controlled room (2224
C) and
kept on a 12 h light/dark cycle. Blood glucose and body weight were
monitored before treatment once a week throughout 4 weeks of exper-
imental period.
2.1.2. Equipments
All measurements were performed by using Automatic tissue pro-
cessor (LEICA TP 1020 Semi-enclosed Benchtop), Centrifuge (Hettich
TD4, Shanghai, China), Nikon digital camera (DXM-1200F), Glucometer
(Accu-Chek, Taiwan), Tissue imbedded parafn (LEICA Eg115H
Shanghai, China).
2.2. Methods
2.2.1. Preparation of plant material and diet
The bay leave purchased from traditional herbal markets, a specimen
was deposited at the herbarium of the Hatay. The laurus nobilis leaves
were ground to powder by electric grinder and extracted with ethanol,
and the extraction oils were stored at room temperature in dark place.
200 mg kg
of bay oils was administered daily orally using intragastric
tube at the time of work [29].
2.2.2. Diabetes model with streptozotocin (STZ)
Diabetes mellitus was induced by single intraperitoneal (IP) injection
of freshly prepared STZ (Sigma-aldrich, Saint Louis, MO) at dose of 70
mg kg
b.w. dissolved in 0.01 M citrate buffer, pH 4.5 [30]. After 72 h
of STZ injection, and overnight fast, blood was taken from tail artery of
the rats. Accu-Chek monitoring used to rapidly changing blood glucose
level, when rats with blood glucose higher than 250 mg dl
selected for the diabetic groups and involved to the examination. Strict
monitoring of all diabetic group rats was done for blood glucose after
2448 h of STZ administration.
Injection of STZ and attack on pancreas cause hypersecretion of in-
sulin and this lead to intensive hypoglycemia and this may cause death
to many animals, to avoid this, drinking water containing 10% dextrose
were given to rats directly after I.P of STZ. In addition for taken care
about rats, blood glucose was measured at 3rd, 15th and 28th days of
throughout experimental model in blood taken from tail artery.
2.2.3. Experimental protocols
Experimental animals were randomly divided into 5 groups; each
group was included 6 animals. The examination period was continuous
for four weeks as below:
1. Control group (C): did not receive any other kind of co-
supplementation. Rats were given a standard diet.
2. Diabetes group (D): in this group diabetes was induced by adminis-
tered 70 ml/kg single dose of STZ IP injection [30], and given
standard diet.
3. Diabetes treated with Laurus nobilis leave extract group (DLN) given
200 mg kg
of bay extract that administered every day orally using
intragastric tube for 28 days during the examination [29].
4. Laurus nobilis extract group (LN): 200 mg kg
of bay leave was
administered every day orally using intragastric tube [29].
5. Diabetes with drug (Acarbose) group (DA): The rats of this group
were treated with 150 mg kg
dose of Acarbose tablet (Glucobay),
(Bayer Türk Kimya San) each day orally using intragastric tube [31].
2.2.4. Blood sample collection and biochemical analysis
At the end of the treatment period, all rats were fasted for 18 h,
weighed and then anaesthetized via IP injection of ketamine hydro-
chloride (50 mg kg
b.w.) and xylazine (8 mg kg
b.w.). Blood
samples were collected from the heart puncture of rats and transferred to
suitable tubes for biochemical analysis using Merck commercial diag-
nostic kits (Darmstadt, Germany) on a blood chemistry analyzer (BTS-
350, BioSystems S.A. Barcelona, Spain).
2.2.5. Histopathological studies
Histopathological investigation were performed at last day of the
experiment. Pancreas, liver and kidneys were removed and kept in 10%
formaldehyde and embedded in parafn. Blocks of the preserved tissues
were sectioned (35
m) on a microtome (Leica RM 2135: Leica Bio-
systems Nussloch GmbH, Nussloch, Germany) and mounted on glass
slides. Hematoxylin and eosin (H&E) staining was done and histopath-
ological examination was done in accordance with the method adopted
by Nagy and Ewais [32].
2.2.6. Immunohistochemical investigation
Insulin expressions were stained using the streptavidin-peroxidase
method (ABC), with the streptavidin / biotin immunoperoxidase kit
(Histostain-Plus Bulk Kit; Zymed, South San Francisco, CA, USA) in
accordance with the staining procedures of the manufacturer com-
panies. After the sections taken in 45 micron thick by microtome had
R.R. Mohammed et al.
Annals of Medicine and Surgery 61 (2021) 188–197
been placed on adhesive slides, they were passed through xylene and
alcohol series. In order to remove the endogenous peroxidase activity,
the sections were kept in 3% Hydrogen peroxide (H
) for 20 minutes
after being washed with PBS (phosphate buffer solution). After placing
the antigen in the retrieval solution (citrate buffer), it was heated twice
in the microwave oven for 20 minutes. Then it was taken out of the oven
and it was left to cool until it reached room temperature. After being
washed again with PBS, the sections were blocked by protein blocking
(non-immune serum) for 20 minutes. Insulin antibody (Catalog no: ab-
181547; Abcam, Toronto, Canada, diluted 1:1.000) were dropped into
each tissue and left overnight at +4C. Sections were washed again with
PBS and incubated for 20 minutes at room temperature with bio-
tinylated secondary antibody. The sections washed again with PBS were
left in streptavidin-peroxidase for 20 minutes and then washed in the
same way as PBS. After washing, 3,3-Diaminobenzidine (DAB) was
dropped and left for 12 minutes. Then all sections were kept in Mayers
hematoxylin (Bio-Optika, 05-06002E) for 12 minutes and washed in
tap water. Sections were passed through of 70%, 80%, 90%, 96%
alcohol for 3 minutes, respectively, and 100% alcohol for 10 minutes
and of the xylol series for 5 minutes were closed using entellan. Negative
controls reacted with PBS were used instead of primary antibodies to
conrm staining. Sections were examined and photographed under a
light microscope. The immunoreactivity staining intensities of the
testicular samples obtained from the groups with primary antibodies
were scored as mild (+), moderate (++) and strong (+++).
2.2.7. Statistical analysis
Statistical analyses were performed by using ‘IBM SPSS Alan C.
Elliott software. ANOVA test was applied to analysis the signicant
differences in all groups. (Kruskal-Wallis) huc Dunns test was done to
compare among groups, differences were considered signicant when
the p <0.05.
3. Results
3.1. Effect on body weight
The diabetic rats exhibited profound body weight loss as compared
to normal rats. The initial, half-way and nal body weights of the rats
are shown in (Table 1).
The nal body weights in diabetic group (D), diabetes Laurus nobilis
group (DLN), and diabetic Acarbose group (DA) were signicantly
decreased when they compared with measuring at 14 days and also
higher decreased compared with baseline weight at the beginning of the
study. In contrast, body weights in control group (C) were signicantly
higher in comparison to other groups during experimental period while
laurus nobilis group (LN) was not signicantly changed in body weight.
Diabetes seemed to be more effective in decreasing body weight
(Table 1).
3.2. Effect on serum glucose
The serum glucose concentration (mg dl
) in the Group C was
signicantly (p <0.05) lower, whereas Group D showed signicantly (p
<0.05) higher concentration as compared to other groups throughout
the experiment (Table 2). On the other hand, L. nobilis-fed group rats
showed relative to control (C) rats during the rst, second and fourth
week, respectively.
The two diabetic treated Groups (DLN and DA) showed signicant (p
<0.05) decrease in glucose concentration on last week and as compared
to Group C; the decrease was the highest in Groups C and LN. All Higher
blood glucose concentrations were observed in group D, DLN and DA
group after 72 h of STZ injection, and gradually decreased on day 14th
and 28th also signicant difference between group D and treated dia-
betes groups (DLN, DA). Laurus nobilis inhibited the development of
diabetes induced by STZ treatment (Table 2).
3.3. Histopathological ndings
3.3.1. Liver
The normal histological view of the liver was observed in the Control
and LN groups (Fig. 1-A and D). Degeneration and necrosis in the he-
patocytes were detected in Diabetes group. Additionally, disrupted he-
patic cords and sinusoidal architecture were detected. Varying in size
vacuoles were determined in the cytoplasm of degenerated hepatocytes
(Fig. 1-B). These ndings were found to be signicantly reduced in the
liver of rats in DLN group such as degeneration and necrosis (Fig. 1-C).
Similar histological appearance to the Control group were found in DA
group except for slight hydropic degeneration and dilation of sinusoids
(Fig. 1-E).
3.3.2. Pancreas
Histological views in cells of Langerhans islet in a Control and LN
groups were normal (Fig. 2-A and D). The diabetic rats had degenerative
and necrotic changes in the cells of Langerhans islet. As a result, atro-
phied islets which is cells with degenerative and picnotic nucleus had
deteriorated and shrunken architecture (Fig. 2-B). Partially, Langerhans
islet were preserved in rats in DLN group (Fig. 2-C). A signicant re-
covery in DA group was observed in the islets (Fig. 2-E).
3.3.3. Kidney
Kidney had normal histological view in both Control and LN groups
(Fig. 3-A and D). Severe balloon degeneration and necrosis of tubular
epithelium, vascular congestion, degeneration and necrosis of podocytes
of glomeruli of kidney of diabetic rats. Inammatory cells were focally
detected in the periglomerular areas. It were adhesion Bowman capsule
in some Glomeruli (Fig. 3-B). Slight degeneration and necrosis were
determined in some parts of the tubular epithelial cells and dilation of
some lymphatic in the kidney of rats in DLN group. Additionally, seldom
adhesions in bowman capsule of some glomeruli were observed (Fig. 3-
C). DA group were similar to DLN group (Fig. 3-E).
3.4. Immunohistochemical evaluation
The insulin secreting β-cells represented the major cell population of
Table 1
Results of body weight (g) in different groups (mean ±Standard deviation).
G 1st day 15th day 28th day
C 195.33 ±15.31
233.66 ±17.90
268.00 ±13.91
D 204.33 ±19.28
195.83 ±33.18
189.66 ±24.76
DLN 217.33 ±19.00
211.66 ±10.38
214.33 ±10.46
LN 212.33 ±13.10
229.83 ±17.26
262.16 ±21.16
DA 215.66 ±18.85
213.83 ±24.11
211.16 ±34.56
*G; groups were C (control group), D (diabetic group), DLN (diabetic with Laurus
nobilis trated group), DA (diabetic with drug treated group), LN (Laurus nobilis
fed group).
Data are means ±S.D.
Signicantly different from Control group in initial.
Table 2
Results of blood glucose (mg dl
) in different groups (mean ±Standard
G 1st day 15th day 28th day
C 128.16 ±10.87
157.50 ±30.73
138.33 ±24.23
D 600.00 ±0.00
592.50 ±18.37
457.66 ±170.57
DLN 563.16 ±53.21
479.16 ±164.36
287.33 ±109.83
LN 120.00 ±4.97
127.33 ±20.61
140.00 ±7.29
DA 521.66 ±14.26
587.33 ±18.61
316.16 ±70.00
*G; groups were C (control group), D (diabetic group), DLN (diabetic with Laurus
nobilis trated group), DA (diabetic with drug treated group), LN (Laurus nobilis
fed group).
Data are means ±S.D.
Signicantly different from Control group.
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Annals of Medicine and Surgery 61 (2021) 188–197
the islets, occupying mainly the central zone in the Langerhans islets.
Positive insulin expression was seen in the form of dark brown granules
present in the cytoplasm of β-cells. Strong insulin immunoreaction were
found in the Langerhans islets of Control and LN groups (Fig. 4-A and D).
Immunoreactivity in the Diabetes group had dramatically reduced ac-
cording to the control group and only a few β-cells displayed minimal
insulin immunoreaction (Fig. 4-B). In diabetic rats treated L. nobilis
extracts was increased in the number and percentage area of reactive
β-cells an apparent observed, as compared with the diabetic group.
Moderate insulin immunoreaction in the DLN group were detected
compared to diabetic rats. (Fig. 4-C). DA group showed signicantly
recovery compared to Diabetes group (Fig. 4-E).
Fig. 1. Hematoxylin and eosin-stained sections of liver. A) Control group: Normal histological appearance. B) Diabetic group: Disseminated vacuolization (arrows) in
the hepatocytes and dilation of sinusoids (stars). C) Diabetic +L. nobilis treated group: Slight hydropic degeneration in the some hepatocytes (arrows) and dilation of
sinusoids (star). D) L. nobilis-fed group: Almost normal histological appearance of the liver. E) Diabetic +drug- treated group: rat administered with acarbose
showing slight hydropic degeneration (arrows) and dilation of sinusoids. Bar =100
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Annals of Medicine and Surgery 61 (2021) 188–197
Fig. 2. Hematoxylin and eosin-stained sections of pancreas. A) Control group: Normal histological appearance of islets of Langerhans. B) Diabetic group: Note that
islets of Langerhans is atrophic, and there are hydropic degeneration and necrosis (arrows) of some cells of islets of Langerhans. C) Diabetic +L. nobilis treated group:
Almost normal histological appearance of islets of Langerhans. D) L. nobilis group: Normal histological appearance of pancreas. E) Diabetic +Acarbose treated group:
Showing slight hydropic degeneration and a few necrotic cells of islets of Langerhans. Bar =20
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Annals of Medicine and Surgery 61 (2021) 188–197
Fig. 3. Hematoxylin and eosin-stained sections of kidney. A) Control group: Normal histological appearance. B) Diabetic group: Showing adhesions (arrows) be-
tween the glomerulus and Bowman capsule, and severe degeneration (stars) of tubular epithelium. C) Diabetic +L. nobilis treated group: Almost normal histological
appearance of tubular epithelium and glomerulus. D) L. nobilis group: Normal histological appearance of tubular epithelium and glomerulus. E) Diabetic +Acarbose
treated group: showing degenerative and necrotic changes (arrows) in some tubular epithelium. Bar =20
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Annals of Medicine and Surgery 61 (2021) 188–197
3.5. Biochemical results
The glucose concentration decreased signicantly in both diabetic
rats treated with L. nobilis and acarbose (p <0.05) (Table 3). The levels
of alanine aminotransferase (ALT) enzyme were signicantly (p <0.05)
decreased in L. nobilis diabetic treated rats compared to diabetic group
rats. Also ALT level was signicantly (p <0.05) lower in acarbose dia-
betic treated group as compared to that of diabetes group (Table 3).
Fig. 4. Immunohistochemical staining of islets of Langerhans of pancreas by streptavidin-peroxidase (ABC) method. A) Control group: Strong insulin immunore-
activity in β cells, which occupy most of the islet. B) Diabetic group: Weak insulin immunoreactivity in a few β cells (arrows). C) Diabetic +L. nobilis treated group:
Moderate insulin immunoreactivity in β cells. D) L. nobilis group: Strong insülin immunoreactivity in β cells. E) Diabetic +Acarbose treated group: Moderate insulin
immunoreactivity in β cells. Bar =20
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The mean values of aspartate aminotransferase (AST) activities were
signicantly decreased in both diabetic rats treated with L. nobilis and
acarbose (p <0.05), the level of AST was lower in L. nobilis treated rats
as comparison other rat groups (Table 3). As shown in (Table 3), the
mean values of Gamma-glutamyltransferase (GGT) activities were
signicantly decreased in all groups when compared with diabetes
group (p <0.05). However, the differences within other groups were not
signicant (p ˃ 0.05).
A statistically non-signicant decrease (p >0.05) found in alkaline
phosphatase (ALP) level L. nobilis diabetes treatment group in compar-
ison with diabetes groups. In addition, statistically signicant decrease
(p <0.05) can be seen in both diabetes drug treatment acarbose and
undiabetes treatment of L. nobilis extracts as compared with diabetes
group (Table 3).
The mean values of Urea level were signicantly decreased in DLN
extracts group as compared with diabetic groups (p <0.05). Diabetic
treated group of rats showed a signicant high level of calcium as
compared to other group of rats (p <0.05). The L. nobilis-fed group was
no signicant when compared with control group (Table 3). No signif-
icant difference in magnesium level was observed in treated rats group
with the diabetic group (p >0.05), (Table 3). In the phosphor (p) level
did not show any signicant difference in L. nobilis extract compared to
both diabetic and control group of rats (p >0.05) (Table 3).
Statistically non-signicant and slight reduction found in the total
protein (TP) levels as compared with diabetic group. L. nobilis leave
extract and control group are relative and signicant when compared
with diabetic group (p >0.05), (Table 3).
A insignicantly (p >0.05) increased can be seen in the Albumin
(ALB) level in the L. nobilis leave extract group in comparison with
diabetic group (Table 3). The level of creatinine kinase (CK) was
decreased signicantly (p <0.05) in the diabetic L. nobilis group in
comparison with the diabetic group (Table 3). Iron (Fe) levels in the
diabetic rats were treated with L. nobilis signicantly increased when
compared to diabetic group rats, there was no signicant difference in
the treated diabetes groups with control group in the levels of Fe (p >
0.05), (Table 3).
4. Discussion and conclusion
Conventional therapies for DM have many side effects and high rate
of secondary failure. On the other hand herbal extracts are expected to
have similar efcacy with fewer side effects than conventional drugs
[33]. Nowadays, more than 1200 plant species are used to treat symp-
toms of DM, the hypoglycemic property of almost 50% of these tradi-
tionally consumed medicines has been experimentally tested [34].
In our study detected weight loss in all STZ-induced rats group when
comparisons with control group, and exhibited hyperglycaemia in STZ-
induced rats with decrease in serum glucose levels in the treated diabetic
groups. L. nobilis leaves extracts (LNLE) inhibit the development of
diabetes induced by STZ and decrease serum glucose levels. LNLE
treatment did not induce a signicant change in the body weight of the
diabetic rats, however, LNLE had a signicant decrease in the blood
glucose levels for 28 days of the diabetic ratstreatment group.
In this study, we observed histopathological and biochemical
changes in STZ-induced rats and these changes were reduced with LNLE
treatment. The promising mechanism by which LNLE mediated its
antidiabetic effect could be by potentiation of pancreatic secretion of
insulin from existing β-cells of islets, as was evident by the signicant
decrease in the level of glucose in the extract treated animals.
The hypoglycemic activity of LNLE was compared with acarbose, a
standard hypoglycemic drug, since the results of the present study, it
may be suggested that the mechanism of action of L. nobilis may be
similar to acarbose action. In this essay indicated that the pathological
effects in rats liver and pancreas tissues induced by STZ were reversible
and normalized by received extracts bay leaves for 4 weeks of experi-
ment, this could be attributed to its antidiabetic effects. Several studies
have reported that the hepatocytes of STZ-induced diabetic rats showed
cytoplasmic alterations, sinusoidal dilation and congestion, periportal
inammation, showed kupffer cells activation, cytoplasmic vacuoliza-
tion of hepatocytes and necrosis [35].
The hepatocyte nuclei were generally enlarged and sometimes
showed irregular contours and intranuclear inclusions [36]. In pancre-
atic sections of untreated diabetic rats disclosed that the islets were
comparatively small and shrunken and severe degenerative changes in
the pancreatic islets, mainly at the center of the islets and karyolysis of
the nuclei was visible [37]. The L. nobilis treated diabetic rats were
reversed and the normalization of pancreatic architecture revealed
vacuolations of β-cells was observed.
In addition regarding the immunohistochemistry, different sizes of
islets of pancreas were observed with increasing immunoreaction to
insulin antibody in β-cells treated with L. nobilis leaves extracts com-
parison to diabetic group, langerhans with increasing insulin immuno-
reactivity in cytoplasm of its β-cells, in the number and percentage area
of reactive β-cells, areas of dark brown staining (strong positive) for
insulin antibody were seen in islet β-cells cytoplasm from diabetic
treated by L. nobilis.
In STZ-induced diabetic rats the liver was necrotized. An increase in
the activities of ALT, AST and GGT in plasma might be mainly an indi-
cation of the hepatotoxic effect of STZ [38]. ALT, AST and GGT were
signicantly decreased in diabetic bay leaves treatment, and related to
normal control group. In contrast diabetic group signicantly higher
level of enzymatic liver function test observed [39]. Al Chalabi et al.
Table 3
Changes in the serum of Glucose(mg dL
), ALT(U l
), AST(U l
), GGT(U l
), ALP(U l
), Urea(mg dL
), Calcium(mg dL
), Magnesium(mg dL
Phosphor(mg dL
), Total protein(g dL
), Albumin(mg dL
), Creatinine(mg
), and Iron(
mol L
) levels in different groups under study (mean ±
standard error).
ALT 49.16 ±
251.83 ±
51.83 ±
34.16 ±
77.66 ±
AST 136.50 ±
547.33 ±
98.50 ±
110.33 ±
216.33 ±
GGT 0.51 ±
9.16 ±2.08
2.18 ±1.16
0.16 ±
1.08 ±
ALP 203.16 ±
678.50 ±
654.33 ±
281.16 ±
366.50 ±
Urea 31.61 ±
53.76 ±
19.90 ±
15.05 ±
30.56 ±
Ca 11.10 ±
10.21 ±
12.58 ±
11.35 ±
10.98 ±
Mg 3.52 ±
3.50 ±0.18
3.13 ±
2.64 ±
3.51 ±0.22
P 9.03 ±
9.10 ±0.45
7.39 ±1.59
4.49 ±
9.75 ±1.02
TP 6.64 ±
6.23 ±
5.90 ±0.13
5.87 ±
6.57 ±0.21
ALB 3.65 ±
3.17 ±
3.56 ±0.10
3.35 ±
3.58 ±0.09
CK 725.6 ±
664.1 ±
282.1 ±
331.6 ±
809.6 ±
Fe 32.08 ±
17.20 ±
32.20 ±
35.15 ±
40.30 ±
*BC; biochemical tests were ALT (alanine aminotransferase), AST (aspartate
aminotransferase), GGT (gamma-glutamyltransferase), ALP (alkaline phospha-
tase), Ca (calcium), Mg (magnesium), P (phosphor), TP (total protein), ALB
(albumin), CK (creatinine kinase), Fe (iron).
*G; groups were C (control group), D (diabetic group), DLN (diabetic with Laurus
nobilis trated group), DA (diabetic with drug treated group), LN (Laurus nobilis
fed group).
*a - c Means with the same column are not signicantly different P ˃ 0.05. *
Means with different column are statistically signicant P ˂ 0.05.
R.R. Mohammed et al.
Annals of Medicine and Surgery 61 (2021) 188–197
[40] reported that the bay leave extract resulted in a decrease in fasting
blood glucose and a higher level of fasting insulin, also LDL, ALT, and
AST were also decreased, whereas HDL and body weight increased in
groups of diabetic rats relative to control not treated groups. In another
study recommended that the L. nobilis tea consumption in healthy vol-
unteers can improve blood lipid prole (HDL level increased and a small
decrease in levels of LDL and triglycerides) and this implies a possible
positive impact on the risk reduction of coronary heart disease [41].
Similar results were reported by Casamassima et al. [42] and investi-
gated a substantial reduction in blood lipid prole, glycemic prole and
liver enzymes, with decreased levels of LDL, ALT and AST, and increased
HDL, has resulted from dietary incorporation of dried bay leaves meal.
Treatment of the diabetic rats with LNLE reduced the activity of
these enzymes in plasma compared to the diabetic untreated group and
consequently alleviated liver damage caused by STZ-induced diabetes
and indicated the hepato protective role in preventing diabetic com-
plications. The diabetic rats treated with bay leave extract displayed a
statistically signicant reduction in the urea and creatinine levels with
respect to diabetic rats. In this sense, kidney failure is manifested by
increasing urea and creatinine but a decrease indicates clinical
improvement [43].
Theres still clearly a signicant dispute about the use of natural or
cultivated plants, which has both positive and negative aspects in bio-
physical terms, as well as in terms of economics. L. nobilis is a signicant
socioeconomic evergreen tree belonging to the Lauraceae family.
L. nobilis are used as antihyperglycaemic herbs, used to treat bacterial
and fungal contaminations, to treat eructation, atulence and gastro-
intestinal problems. It also exhibits anti-inammatory, anticonvulsive,
antiepileptic and antioxidant properties [44,45].
In conclusion, from this study, based on the experimental ndings, it
was suggested that administration of L. nobilis leave extracts, at a safe
dose level, signicantly suppressed STZ-induced diabetic rats. We
believe that further preclinical research into the utility of L. nobilis
treatment may indicate its suitability as a potential treatment in diabetic
patients, our results expressed that leave extracts of L. nobilis has valu-
able effect on blood glucose level and ameliorative effect on regenera-
tion of pancreatic islets. It also restored the altered liver enzymes (ALT,
AST, and GGT), urea, creatine kinase, total protein levels calcium and Fe
to near normal. It may be used as a therapeutic agent in the management
of diabetes mellitus.
Author contributions
All authors contribute to this research study.
Rebin R. Mohammed, Abdullah K. Omer, Avin K, Ahmed: Data
collection and analysis, original draft preparation, Zabit Yener, Ahmet
Uyar: Study design, conceptualization and writing, review and editing.
5. Provenance and peer review
Not commissioned, externally peer reviewed.
The authors wish to acknowledge Van Yuzȕncu Yıl University for the
support (Grant number 2015-SBE-YL309).
Ethical approval
All experimental protocols were approved by the Experimental An-
imal Center of Van Yȕzȕncȕ Yıl University, Turkey.
All experimental protocols were approved by the Experimental An-
imal Center of Van Yȕzȕncȕ Yıl University, Turkey.
Rebin R.Mohammed (on behalf of all authors).
Declaration of competing interest
There is no conict of interest.
The authors wish to acknowledge Van Yȕzȕncȕ Yıl University for the
support (Grant number 2015-SBE-YL309).
Appendix A. Supplementary data
Supplementary data to this article can be found online at https://doi.
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R.R. Mohammed et al.
... Antimicrobial, antioxidant, antiproliferative, antiprotozoal, and cytotoxicity activity studies were conducted on the laurel leaves in vitro conditions (Julianti et al. 2012;Abu-Dahab et al. 2014;Kıvrak et al. 2017;Rizwana et al. 2019;Dobroslavic et al. 2021;Batiha et al. 2020). The antidiabetic, antidiarrheal, gastroprotective, hepatoprotective, neuroprotective, and wound healing effects of the leaves have been demonstrated by in vivo studies (Nayak et al. 2006;Ham et al. 2011;Speroni et al. 2011;Qnais et al. 2012;Ravindran et al. 2013;Mohammed et al. 2021). ...
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Laurus nobilis L. is an aromatic shrub or tree, Mediterranean element. The leaves are employed as a spice and for medicinal purposes. It is known by various names in Turkey, such as “defne, har and tehnel.” In this study, 15 different laurel leaf samples were purchased from 6 different cities in Turkey, diagnosed, and evaluated in terms of quality. The conditions of use and sale of these samples were evaluated. The essential oils obtained from the leaf samples were analyzed, and their physical properties such as density, refractive index, and optical rotation were determined. In the chemical composition of the oils, 1,8-cineole (41.2–64.4%), sabinene (1.5–15.9%), and α-terpinyl acetate (1.5–15%) have been found to be the major components. However, in one station, the presence of 1,8-cineole was not be determined. Laurel leaf drugs offered for sale in some provinces of Turkey were purchased from the market and their morphological characteristics and essential oil profiles were examined and evaluated in terms of public health. It was determined that these samples should be standardized and quality-controlled before being released to the market.
... It was evident from the results that at the week 0, the FBG levels of the diabetic animals (DC, DCDL, DCDH and DMF) was significantly (p < 0.05) elevated compared to the non-diabetic animals (NC and NCDH), thereby confirming successful induction of T2D. The hyperglycemia could be attributed to the insulin resistance, induced by fructose feeding (Derouiche et al., 2020) and the degenerative effect of STZ to the Langerhans islet β-cells (Mohammed et al., 2021). Interestingly, the reduction of FBG recorded in the DCDL (32.4 %) and DCDH (61.5 %) were significantly (p < 0.05) higher compared to DC group and comparable to 54.6 % reduction in the DMF group ( Figure 1). ...
... Salim et al. (2021) stated that rabbits had an increase in body weight gain and a decrease in FCR with 0, 1, 2, ve 4 g/kg adding of dried laurel leaves to their diet. The supplementation of bay laurel has been shown to increase the body weights of quails (0%, 1%, 2%, 3% laurel leaf), rats (200 mg/kg LLP), and catfish (0%, 0.5%, 1%, 1.5% laurel leaf extract) (Turan et al., 2016;Alrubaee, 2018;Mohammed et al., 2021) In terms of carcass characteristics, it was found that the influence of LLP did not cause a meaningful difference. It may be argued that enhancing the growth of beneficial bacteria in the digestive tract, such as eugenol and Lactobacillus found in the bay laurel leaves, suppresses the development of unde- sired microbes, and improves the health and performance of the animals. ...
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... LLE, because of its wide presence of bioactive molecules, is an excellent source of antioxidant potential for pharmaceutical and cosmetic applications [41]. Our investigation on the antioxidant activity of LLE was consistent with many studies using UMH LLE [36,40,48], but there were no reported studies about MH LLE. The efficacy of conventional heat-reflux extraction (CRE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE) was studied to evaluate the antioxidant activity of LLE, and the highest antioxidant capacity was obtained via CRE [41]. ...
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... Some experiences realized in vivo reported also the possible ameliorative effect of bay leaves extracts on diabetic people; for example, the study conducted by Mohammed et al. (2021) on streptozotocin-induced diabetic rats showed that leaves extract of L. nobilis, 200 mg/kg of bay extract administered every day orally using the intragastric tube for 28 days, decreases significantly the blood glucose level and improves the regeneration of the pancreatic islets. Al Chalabi et al. (2020) reported that the polyphenols contained in the alcoholic extract of L. nobilis decrease significantly the fasting blood glucose level and improve insulin secretion in alloxan-induced diabetic rats. ...
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... Along with anise, a recent study [40] showed that the leaf extract of another typical Mediterranean plant, Laurel nobilis, significantly decreased blood glucose levels and restored altered liver enzymes, urea, creatine kinase, total protein levels, calcium, and ferritin in six streptozotocin (STZ)-induced DM rats after a daily consumption period of 28 days when compared to the same number of untreated diabetic rats. Alam Khan et al. [41] have also proved that the encapsulation of 1, 2, or 3 g of ground bay leaves significantly reduces serum glucose, total cholesterol, Low-Density Lipoprotein (LDL) cholesterol, and triglycerides, and increases the High-Density Lipoprotein (HDL) cholesterol levels after 30 days in patients with type 2 DM with respect to a placebo group (a total of 40 individuals with more than 40 years were included and continued their normal diets and diabetic medications, except for insulin therapy, throughout the study). ...
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Essential oils (EOs) are mixtures of volatile compounds belonging to several chemical classes derived from aromatic plants using different distillation techniques. Recent studies suggest that the consumption of Mediterranean plants, such as anise and laurel, contributes to improving the lipid and glycemic profile of patients with diabetes mellitus (DM). Hence, the aim of the present study was to investigate the potential anti-inflammatory effect of anise and laurel EOs (AEO and LEO) on endothelial cells isolated from the umbilical cord vein of females with gestational diabetes mellitus (GDM-HUVEC), which is a suitable in vitro model to reproduce the pro-inflammatory phenotype of a diabetic endothelium. For this purpose, the Gas Chromatographic/Mass Spectrometric (GC-MS) chemical profiles of AEO and LEO were first analyzed. Thus, GDM-HUVEC and related controls (C-HUVEC) were pre-treated for 24 h with AEO and LEO at 0.025% v/v, a concentration chosen among others (cell viability by MTT assay), and then stimulated with TNF-α (1 ng/mL). From the GC-MS analysis, trans-anethole (88.5%) and 1,8-cineole (53.9%) resulted as the major components of AEO and LEO, respectively. The results in C- and GDM-HUVEC showed that the treatment with both EOs significantly reduced: (i) the adhesion of the U937 monocyte to HUVEC; (ii) vascular adhesion molecule-1 (VCAM-1) protein and gene expression; (iii) Nuclear Factor-kappa B (NF-κB) p65 nuclear translocation. Taken together, these data suggest the anti-inflammatory efficacy of AEO and LEO in our in vitro model and lay the groundwork for further preclinical and clinical studies to study their potential use as supplements to mitigate vascular endothelial dysfunction associated with DM.
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The purpose of this study was to collect data for future clinical investigations and research on the safe and efficient use of various herbal medicines to treat hyperglycemia. One of the primary contributing reasons to the onset and progression of diabetic nephropathy is hyperglycemia, and many modern treatments are made from plants since they frequently have fewer side effects than the conventional medications that are now available. The medicinal plants include Sesbania sesban, Elaeis guineensis, Tecoma stans, Aloe barbadensis miller, Zingiber officinale Roscoe, Olea europaea, Anogeissus acuminata, Juglans regia L., Fragaria ananassa, Ginkgo biloba, Laurus nobilis L., Dryopteris dilatata, Moringa oleifera, Punica granatum L., Lycium chinense, Rumex nervous alkaloids and flavonoids are the primary phytoconstituents that aid in the therapy or cure of diabetic nephropathy. The therapeutic effects of medicinal plant leaf extract may be due to the wide range of bioactive compounds present, including various phytoconstituents such as alkaloids and flavonoids, glycosides, steroids, terpenoids, and phenolics. Alkaloids and flavonoids are the primary phytoconstituents that aid in the therapy or cure of diabetic nephropathy.
It has been proposed that Niemann-Pick C1 like-1 (NPC1L1) is an intermediate membrane protein that facilitates cholesterol absorption at enterocytes, yet it is still being unknown mechanism. The study aimed to evaluate the pharmacokinetics of anti-cholesterol in traditional spices and investigate the interactions between anti-cholesterol compounds and NPC1L1. This research analyzed binding pocket, Admet, drug-likeness, the interactions, and binding affinities by DoGSiteScorer and Depth, AdmetSAR tools, and MOE.2009 software, respectively. The interactions and binding affinities were determined by molecular docking between NPC1L1 and 18 ligands derived from spices such as Cinnamon, Bay leaf, coriander, Garlic, Red Onion, Tumeric, Indosenian Chilli Pepper. Inhibitors were docked with NPC1L1 (PDB ID: 3QNT), and a comparison was made between the results of Ezetimibe, a prescribed NPC1L1 inhibitor. The Lipinski Rule of Five aids in identifying drug-like compounds and those that are not. As an octanol–water partition coefficient log P not greater than 5, all ligand including Ezetimibe has a higher affinity for the aqueous phase. 11 out of 18 inhibitors were well absorbed and distributed by forecasting oral bioavailability. Quercetin, Curcumin, and 6-Gingerol from onion, turmeric, and ginger are the potential to inhibit cholesterol absorption in the small intestine. These three highest binding energy ligands (-14.0320 to -12.3998 kcal/mol) had high binding affinities as Ezetimibe (-15.5075 kcal/mol). High binding affinities of Ezetimibe and these ligands interact at almost in the exact locations of the N-terminal domain. Through Ser_102 of N-terminal domain NPC1L1 binding with the ligands, we suggest that traditional spices of three ligands could interfere with cholesterol absorption at the early stages. © Manuscript received 29 Apr. 2022; revised 9 Jan. 2023; accepted 1 Mar. 2023. Date of publication 30 Apr. 2023. IJASEIT is licensed under a Creative Commons Attribution-Share Alike 4.0 International License.
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Submission 10/11/2022, Publication date 31/01/2023, 1 RESUME Les maladies non transmissibles constituent un véritable problème de santé publique dans de nombreux pays du monde. Au Cameroun, de nombreuses études ethnobotaniques ont mis en évidence l'utilisation des plantes dans le traitement de diverses maladies dont le diabète et l'hypertension artérielle. Cette étude a pour but de recenser les connaissances locales sur les plantes médicinales, et de valoriser les connaissances liées à leur utilisation. Un inventaire des plantes médicinales antidiabétiques et antihypertensives vendues dans cinq marchés de Yaoundé a été réalisé entre avril et juin 2022, en utilisant la technique des entretiens semi-structurés ouverts. 57 vendeurs et 478 patients ont été interviewés, dont (34 femmes et 23 en tant que vendeurs) ; et (258 femmes et 220 hommes en tant que patient). Un total de 65 espèces appartenant à 63 genres et 36 familles a été enregistré. Les Fabaceae et les Apocynaceae étaient les familles les plus représentées. Parmi celles-ci, 20 sont utilisées pour traiter le diabète ainsi que l'hypertension artérielle, 24 sont antidiabétiques et 15 sont antihypertenseurs. Les plantes les plus citées étaient Guibourtia tessmannii, Annickia chlorantha, Annona muricata, Morinda lucida, Alstonia bonei, Rauvolfia vomitoria, Picralima nitida, Mangifera indica, Alafia multiflora, Aloe vera, Entandrophragma cylindricum, Erythrophleum ivorense, Pteleopsis hylodendron et Persea americana. En outre, les résultats de l'étude ont montré que les écorces et les feuilles sont les organes les plus utilisés. Les organes recommandés ont été utilisés pour formuler 57 recettes, dont les plus dominantes sont plurispécifiques, composées de 2 à 9 plantes, et ont été préparées principalement par décoction et administrées par voie orale. Le facteur de consensus des informateurs (FCI) pour l'utilisation de ces plantes était élevé pour le traitement des maladies non transmissibles étudiées (hypertension, FCI = 0,8 ; diabète, FCI = 0,77). Les espèces Annickia chlorantha, Morinda lucida, Alstonia boonei, Rauvolfia vomitoria, Picralima nitida ont les meilleures fréquences de citation (5,91 à 11,29) pour le diabète. Alors que pour l'hypertension artérielle, des fréquences de citation élevées ont été enregistrées pour Persea americana (8,78), Guibourtia tessmannii (9,45), Cymbopogon citratus (10,81), Annona muricata (25) et Viscum alba (31,57). L'observation sur le terrain des lieux de récolte des organes des plantes à des fins médicinales montre que, les plantes très sollicitées deviennent rares dans le site de collecte. Cette recherche constitue une source de données pouvant servir de base à la découverte de nouvelles molécules à potentiel antidiabétique et antihypertenseur et au développement de médicaments traditionnels améliorés et abordables.
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Bay leaf, also known as laurel leaf, is produced by the sweet bay tree (Laurus nobilis), an evergreen member of the Lauraceae family that is indigenous to areas bordering the Mediterranean. Bay leaves have been shown to increase insulin activity. It is used to treat or prevent the onset of type 2 diabetes. The term "bay leaf" describes a variety of aromatic plant leaves that are used in cooking. Its chemical composition of it mainly consists of tanning agents, 2-phenyl-4H-chromen-4-one, Flavones with additional hydroxyl groups such as quercetin, kaempferol, and myricetin, organic compounds containing nitrogen and often with pharmacological effects, such as caffeine, morphine, and nicotine, 2-methoxy-4-(prop-2-en-1-yl)phenol, 3,7-dimethyl-1,6-octadien-3-ol, 1-allyl-4-methoxybenzene and water-soluble pigments responsible for the red, purple, and blue colors in fruits, vegetables, and flowers, such as cyanidin, delphinidin, and pelargonidin. Bay leaves have numerous biological properties that make them useful for various purposes. They have wound-healing abilities, act as antioxidants, and have antibacterial, antiviral, and immunostimulant properties. Additionally, they possess anticholinergic, antifungal, and insect-repellent properties, making them versatile for different applications. They also have anticonvulsant and antimutagenic effects and can act as analgesics and anti-inflammatory agents. The bay leaf found in India, also referred to as malabathrum, tej patta, Malabar leaf, Indian bark, or Indian cassia, shares a similar appearance with the bay laurel leaf. However, it differs significantly in terms of its flavor and aroma. This abstract presents information on the botanical and chemical characteristics of Laurus nobilis (Bay Laurel), along with their traditional and modern medicinal uses. Indian bay leaves are found in the Himalayas and are a common ingredient in Indian cuisine. In addition to being used as a spice, they contain various nutrients, such as iron, manganese, and vitamins. The essential oil extracted from the bay leaves, specifically myrcene, is used in perfumery and as a pest deterrent. For centuries, Bay Laurel has been employed in traditional medicine to provide relief for a range of health conditions, including respiratory disorders, gastrointestinal discomfort, and gynecological issues, among others. Furthermore, bay leaves contain minerals like calcium, iron, and zinc, and they exhibit powerful antioxidant properties. The chemical constituents of both species include a range of essential oils, flavonoids, terpenes, and esters, which contribute to their medicinal properties. This information may be useful for researchers and practitioners interested in exploring the potential health benefits of these plant species. The objective of this research was to examine the pharmacological properties of Laurus nobilis, which is popularly known as bay leaf. The findings demonstrated that bay leaf's methanolic extracts had a more significant impact on preventing the growth of different strains of bacteria and fungi. Additionally, bay leaf's essential oils displayed effective antibacterial activity against Staphylococcus intermedius, Bacillus subtilis, and Staphylococcus aureus. Moreover, the researchers also evaluated the antioxidant and anticancer activity of bay leaf. Bay leaf also exhibited antioxidant properties, and its extracts had a moderate to strong DPPH radical scavenging effect. In addition, the fresh essential oil of bay leaf showed more growth inhibitory effects against five different human cancer cell lines compared to stored essential oil. The results indicate that bay leaf possesses promising qualities as a natural agent for antimicrobial, antioxidant, and anticancer purposes.
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Diabetes mellitus is a global metabolic epidemic affecting essential biochemical activities in almost every age group. Indian literatures like Ayurveda have already mentioned herbal remediation for a number of human ailments. Among Indian traditional medicinal plants several potential anti-diabetic plants and herbs are being used as part of our diet since prehistoric time. India has a long list of native medicinal plants with confirmed blood sugar lowering property. Some of these have proved remarkable for cure of diabetes and its complications. The current paper is aimed at providing a review on clinical and experimental studies carried out on the most effective and commonly used hypoglycemic plants and herbs species from traditional Indian flora. This write-up includes hypoglycemic and anti-hyperglycemic activities of plants, active hypoglycemic compounds and constituents along with their available toxicity status.
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Objectives: To identify the prevalence of micro- and macro-vascular complications and their associated factors for type 2 diabetes mellitus in Bangladesh. Methods: This retrospective and cross-sectional study was conducted in six diabetes hospitals, covered urban and rural population. From April to September in 2017, a total of 1253 type 2 diabetes patients aged ≥18 years were recruited. Participants answered a pre-tested electronic questionnaire, and their medical records were reviewed for documented diabetes complications. Results: Mean age was 55.1 (±12.6) years. Among macrovascular complications, the prevalence of coronary artery disease was found to be 30.5%, 10.1% for stroke and 12.0% for diabetic foot. Among microvascular complications, nephropathy was prevalent among 34.2%, retinopathy among 25.1% and neuropathy among 5.8% of patients. Risk factors found to be associated with one or more of the complications were female gender, higher age, lower education level, an urban area of residence, higher household income, smoking, physical inactivity, hypertension, poor glycaemic control, poor adherence to treatment, longer duration of diabetes, and insulin use. Conclusion: Diabetes complications are highly prevalent among type 2 diabetes population in Bangladesh. Prevention strategies should focus on increasing physical activity, weight loss, smoking cessation, and more strict control of hypertension and glycaemic level.
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Diabetes mellitus is a notorious endocrine disorder with a high global prevalence. Currently available drugs to manage such noncommunicable disease and related complications are associated with various adverse effects and discomforts. It has been argued that the use of herbs and spices can inhibit key carbohydrate and lipid digestive enzymes (amylase, glucosidase, and lipase), thereby regulating blood glucose levels and postprandial peaks in diabetics. Indeed, before the expansion of conventional medicine, dietary measures and food plants were the mainstay therapies to manage panoply of diseases, including diabetes. Nonetheless, there is still a dearth of comprehensive compilation of the potential of traditionally used herbs and spices to inhibit key digestive enzymes. This study aimed to bring to the limelight of the scientific community a comprehensive updated systematic review of the potential of traditionally used herbs, spices, and food plants which have been used traditionally against diabetes. Using the PRISMA methodology, a comprehensive and structured literature search was conducted in key databases (Pubmed, ScienceDirect, and Google Scholar). Published literature was scrutinised using specific keywords and only those published from 2008 to 2017 were included in this review. A total of 94 plants were identified as having digestive enzyme inhibitory properties; five of them against all three enzymes, 41 for both amylase and glucosidase, and one against both amylase and lipase. Different families of plants, plant parts, and type of extracts have been found to exhibit different strengths of enzyme inhibitory activities. Several research gaps have been identified that warrants due attention in future studies. It is anticipated that this study will open new avenues for research and advocates the need to probe traditional and indigenous herbs and food plants in the management of diabetes.
Introduction: Laurus nobilis is known in the field of herbal medicine and in vitro studies that it has beneficial effects such as antibacterial, antifungal, antidiabetes, and anti-inflammatory properties. Objective: We investigated whether L. nobilis tea consumption affects the plasma levels of lipid biomarkers in healthy volunteers. Methods: Thirty healthy Tunisian volunteers aged between 20 and 57 years old consumed L. nobilis infusion, prepared from 5 g of dried L. nobilis leaves in 100 ml boiled water, once a day during 10 days. Plasma concentrations of serum low-density lipoprotein (LDL) cholesterol, triglycerides and HDL (high-density lipoprotein) cholesterol were measured by Beckman Coulter D × 600 analyzer before L. nobilis consumption and at the end of the experiment. Results: L. nobilis tea consumption significantly increased the concentration of HDL cholesterol ([HDL cholesterol] D0 = 1.34 ± 0.25 pg/mL, D11=1.42 ± 0.29, p = 0.01). However, a slight decrease that was statistically non-significant in LDL cholesterol and triglycerides levels was observed (p < 0.05). Conclusions: These findings highlight the improving blood lipidic profiles, which means a possible positive effect on reducing the risk of cardiovascular disease of L. nobilis tea consumption in healthy volunteers. However, more powerful studies with an extended treatment period are required.
Ethnopharmacological relevance: Type 2 diabetes mellitus (T2DM) regarded as a "hot" disease in traditional Chinese medicine (TCM). Accordingly, TCM uses a cold drug or formula such as the Chinese herbal formulae "Yitangkang" (YTK) as a treatment. YTK exhibited a good clinical antidiabetic effect in several experiments. The correlation between the properties of a TCM drug or formula and its ability to regulate the substance metabolism, the energy metabolism and the endocrine system has been proven. Aim of the study: The present study aiming to evaluate the mechanism of antidiabetic action of YTK from the above perspective. Materials and methods: Three groups of streptozotocin (STZ)-diabetic rats have been treated with YTK at oral doses of 56 g/kg/d, 28 g/kg/d and 14 g/kg/d for 28 days using metformin as a reference drug. After treatment, several indices correlated with energy metabolism (superoxide dismutase, glutathione peroxidase, lactic dehydrogenase, adenotriphos, creatine phosphate kinase, AMPK, Na+-K+-ATPase and Respiratory Chain Complex I, II, III, IV), substance metabolism (hepatic glycogen, acetyl-coenzyme A, pyruvic acid, adipose triglyceride lipase, triglycerides, high-density lipoproteins, low-density lipoproteins, malonyldialdehyde), endocrine system (triiodothyronine, thyroxine, 17-hydroxycorticosteroid) and cyclic nucleotide system (cyclic adenosine monophosphate, cyclic guanosine monophosphate) have been determined. The specialty and tendency of YTK's effects were analyzed to elucidate its property and mechanism of action according to the theory of TCM. Results: Our findings showed that the formulae YTK could effectively regulate the levels of blood glucose, HbA1c, glucagon-like peptide-1, and significantly down-regulate the substance metabolism, energy metabolism and endocrine system indices of the diabetic rats. Conclusion: These results were consistent with the TCM description of YTK as a "cold" treatment. It could provide an effective way to interpret the scientific connotation and comprehensive system of the Chinese herbal formulae.
The delayed diagnosis and the inadequate treatment of diabetes increase the risk of chronic complications. The study of regulatory molecules such as miRNAs can provide expression profiles of diabetes and diabetes complications. We evaluated the mononuclear cell miRNA profiles of 63 Type 1 and Type 2 diabetes patients presenting or not microvascular complications, and 40 healthy controls, using massive parallel sequencing. Gene targets, enriched pathways, dendograms and miRNA-mRNA networks were performed for the differentially expressed miRNAs. Six more relevant miRNAs were validated by RT-qPCR and data mining analysis. MiRNAs associated with specific complications included: i) neuropathy (miR-873-5p, miR-125a-5p, miR-145-3p and miR-99b-5p); ii) nephropathy (miR-1249-3p, miR-193a-5p, miR-409-5p, miR-1271-5p, miR-501-3p, miR-148b-3p and miR-9-5p); and iii) retinopathy (miR-143-3p, miR-1271-5p, miR-409-5p and miR-199a-5p). These miRNAs mainly targeted gene families and specific genes associated with advanced glycation end products and their receptors.
This research explored the essential oil (EO) of Laurus nobilis. Various parameters were recorded, including the amount of yield, chemical composition and antioxidant activity. The EO was obtained by hydro-distillation (HD), hydro-steam distillation (HSD), microwave-assisted hydrodistillation (MAHD), and ohmic-assisted hydrodistillation (OAHD). The micromorphology of the plant leaves were studied under the different extraction methods. The yields of EOs obtained by the mentioned extraction methods were 1.40, 0.74, 1.00 and 0.83 (% w/w), respectively. The main chemical components in EOs obtained by these methods were eucalyptol (34.4–50.0%), α-terpinenyl acetate (14.9–18.8%), terpinene-4-ol (4.7–6.0%) and sabinene (4.9–5.9%). Two of the extraction methods, i.e. OAHD and MAHD, yielded EOs that contained higher proportions of eucalyptol. SEM images of the leaves were taken after extraction. It was observed that the MAHD method had the most destructive effect on secretory cells, while the HSD method failed to damage numerous cells in the leaves. Generally, the results suggest that MAHD and OAHD can be recognized as clean and faster methods because of their shorter processing time and less energy requirements. The HD and HSD methods extracted EOs with more sesquiterpenes, while the MAHD and OAHD methods yielded higher amounts of oxygenated monoterpenes in the EO.
Background: Liver diseases and diabetes are serious health disorders associated with oxidative stress and ageing. Some plant polyphenols can lower the risk of these diseases. Purpose: We investigated the phytochemical profiling of a root extract from Ximenia americana var. caffra using HPLC-PDA-ESI-MS/MS. The antioxidant activities in vitro were investigated. The hepatoprotective activities were studied in rat models with d-galactosamine (d-GaIN)-induced hepatotoxicity and the antidiabetic activities in STZ-diabetic rats were also investigated. Materials and methods: HPLC-PDA-ESI-MS/MS was used to identify plant phenolics. The antioxidant activities in vitro were determined using DPPH and FRAP assays. The in vivo hepatoprotective activities were determined for d-GaIN-induced hepatotoxicity in rats. We determined the liver markers alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT), liver peroxidation product malondialdehyde (MDA), glutathione content (GSH), albumin and total bilirubin concentration. The histopathological changes in rat liver were also studied. The antidiabetic activities were also investigated in STZ-diabetic rats and serum glucose, serum insulin hormone, and lipid peroxides were determined. Results: The root extract is rich in tannins with 20 compounds including a series of stereoisomers of (epi)catechin, (epi)catechin-(epi)catechin, (epi)catechin-(epi)catechin-(epi)catechin, and their galloyl esters. Promising antioxidant potential was observed in vitro in DPPH assay with EC50 of 6.5 µg extract / 26 µg raw material and in FRAP assay with 19.54 mM FeSO4 compared with ascorbic acid (EC50 of 2.92 µg/ml) and quercetin (FeSO4 24.04 mM/mg), respectively. Significant reduction of serologic enzymatic markers and hepatic oxidative stress markers such as ALT, AST, MDA, GGT, and total bilirubin, as well as elevation of GSH and albumin were observed in rats with d-galactosamine-induced liver damage treated with the extract. These findings agree with a histopathological examination suggesting a hepatoprotective potential for the root extract. The root extract can mediate an antidiabetic effect by reducing elevated blood glucose and serum lipid peroxides levels and by increasing insulin in STZ-diabetic rats by -107, -31.1, +11.3%, respectively. Conclusions: The results of this study suggest that the tannin-rich extract from Ximenia americana var. caffra could be an interesting candidate for the treatment of several health disorders associated with oxidative stress such as hepatocellular injury and diabetes.