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Antibacterial Effects of Aloe Vera Extracts on some Human and Animal Bacterial Pathogens

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Darioush Gharibi at Shahid Chamran University of Ahvaz
Darioush Gharibi
Mohammad Khosravi at Shahid Chamran University of Ahvaz
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Zohreh Hosseini
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Introduction: Aloe Vera compounds have inhibitory activity on fungi, bacteria, and viruses. This study examines the antibacterial activity of A. Vera purified extracts including gel, boiled skin, boiled gel, and distilled extract against pathogenic bacteria, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Klebsiella pneumonia and Pseudomonas aeruginosa were elucidated. Method: The bacterial strains were collected from veterinary hospital. Freshly collected A. vera leaves were used for the juice extraction of gel, skin and distilled extracts. Antibacterial effects of various A. Vera extracts were evaluated using broth microdilution method. The crude polysaccharides of boiled skin extract were purified by phenol method; and fractionated by anion exchange chromatography. For each bacterium, minimum inhibitory concentration of various A. Vera extracts was determined. The protein expression changes of treated bacteria were detected by SDS-PAGE electrophoresis. Results: The distillate extract exhibited more antibacterial effects than other extracts. Out of seven-carbohydrate fractions of the skin extract, the fractions 6 and 7 had antibacterial effects on S. aureus and MRSA at 0.089 and 0.134 mg/ml, respectively; also fraction 5 showed antibacterial effects on MRSA at 0.113 mg/ml concentration. The protein profiles of these strains before and after treatment with A. Vera showed significant differences at 175, 60, 200 and 70 kDa protein bands of S. aureus, MRSA, P. aeruginosa and K. pneumonia, respectively. Conclusion: This finding showed that the distillate extract despite the minimal amount of carbohydrate and protein was more efficient against both Gram-positive and Gram negative bacteria.
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J Med Microbiol Infec Dis, 2015, 3 (1-2): 6-10
http://jommid.pasteur.ac.ir
Original Article
Antibacterial Effects of
Aloe Vera
Extracts on some Human and Animal
Bacterial Pathogens
Darioush Gharibi, *Mohammad Khosravi, Zohreh Hosseini, Fatemeh Boroun, Seyedeh Kolsum Barzegar,
Ali Forughi Far
Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Received Mar 15, 2016; accepted Sep 13, 2016
INTRODUCTION
Antibiotics are the first choice for treating bacterial
infection. Long time exposure to antibiotics lead to the
development of antibiotic resistance; therfore this need
alternative approach for treatments of infectious disease.
These require other agents with greater antibacterial effect
and lower toxicity. However, despite a push for
development of new antibiotics, the rate of approved agents
has declined. Many plants contain numerous antibacterial
constituents that can be used for the treatment of infectious
diseases, especially in the cases of multiple bacterial
infections. The effects of herbal medicine are relied on their
chemical components. About 80% of world population use
herbs to treat disease [1]. Biological or pharmacological test
on plants has led to the discovery of a significant number of
new natural or semi-synthetic antibiotics [2, 3].
Aloe Vera is a juicy plant species originated in northern
Africa; it has frequently been cited as being used in herbal
medicine since the beginning of the first century AD [4]. It
contains several ingredients such as vitamins, sugars,
minerals and enzymes, anthraquinones, phenolic
compounds, prostaglandins, saponins, glycoproteins,
acemannan, sterols, salicylates, magnesium lactate, amino
acids and superoxide dismutases with antioxidant activity
[5, 6]. These compounds have inhibitory action on fungi,
bacteria, and viruses; in addition A. Vera has been used for
medicinal purposes and as an element in many beauty
products [7]. A. Vera gel consists of 99.3% water; the
remaining 0.7% is made up of solids with glucose and
mannose constituting for a large part. The amino acids and
sugars together with enzymes give the special properties as
a skin care product [8, 9]. The A. Vera gel is extensively
used in treatments of gastrointestinal disorders for example
peptic ulcer [10].
Staphylococcus aureus, Klebsiella pneumonia, and
Pseudomonas aeruginosa are the most important pathogens
in human nosocomial infection. S. aureus colonizes in the
nasal cavity, nasopharynx, skin and mucous membranes of
human and animals [11, 12] and causes a variety of
significant economic disease in human and animals [13].
The rate of methicillin-resistant S. aureus (MRSA)
continues to raise in nosocomial infections surveillance
system hospitals [14]. MRSA infections of S. aureus and
coagulase-negative staphylococci are serious concerns of
the human population [15].
Introduction: Aloe Vera compounds have inhibitory activity on fungi, bacteria, and viruses. This study examines the
antibacterial activity of A. Vera purified extracts including gel, boiled skin, boiled gel, and distilled extract against pathogenic
bacteria, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Klebsiella pneumonia and Pseudomonas aeruginosa were
elucidated. Method: The bacterial strains were collected from veterinary hospital. Freshly collected A. vera leaves were used for
the juice extraction of gel, skin and distilled extracts. Antibacterial effects of various A. Vera extracts were evaluated using
broth microdilution method. The crude polysaccharides of boiled skin extract were purified by phenol method; and
fractionated by anion exchange chromatography. For each bacterium, minimum inhibitory concentration of various A. Vera
extracts was determined. The protein expression changes of treated bacteria were detected by SDS-PAGE electrophoresis.
Results: The distillate extract exhibited more antibacterial effects than other extracts. Out of seven-carbohydrate fractions of
the skin extract, the fractions 6 and 7 had antibacterial effects on S. aureus and MRSA at 0.089 and 0.134 mg/ml, respectively;
also fraction 5 showed antibacterial effects on MRSA at 0.113 mg/ml concentration. The protein profiles of these strains
before and after treatment with A. Vera showed significant differences at 175, 60, 200 and 70 kDa protein bands of S. aureus,
MRSA, P. aeruginosa and K. pneumonia, respectively. Conclusion: This finding showed that the distillate extract despite the
minimal amount of carbohydrate and protein was more efficient against both Gram-positive and Gram negative bacteria. J Med
Microbiol Infec Dis, 2015, 3 (1-2): 6-10.
Keywords: Aloe Vera, Extracts, Antibacterial.
*Correspondence: Mohammad Khosravi
Department of Pathobiology, Faculty of Veterinary
Medicine, Shahid Chamran University of Ahvaz, Golestan
Blvd, Ahvaz, Iran, 6135714333.
Email: dr.khosravim@gmail.com
Tel: +98 (937) 6211901 Fax: +98 (61) 33360807
Downloaded from jommid.pasteur.ac.ir at 1:26 IRST on Thursday February 9th 2017
Antibacterial analysis of A. Vera extracts
J Med Microbiol Infec Dis 7 2015 Vol. 3 No. 1-2
K. pneumonia is an opportunistic pathogen and is
known to cause different infections including urinary tract
diseases to pneumonia in human and animals [16]. In recent
years, K. pneumonia has emerged as an important pathogen
in nosocomial infections [17]. P. aeruginosa is an
opportunistic pathogen that causes infection in animals and
human in some condition such as trauma, debilitation and
change of normal flora. It expressed the efflux systems
which plays a major role in antibiotic resistance [18, 19].
The above mentioned bacterial strains can develop
resistance to antibiotics; for this reason, the present study
was designed to evaluate the antibacterial activity of
various A. Vera extracts on these bacteria. The gel, boiled
skin, boiled gel and distilled extract of A. Vera were
purified, and their antibacterial effects against S. aureus, K.
pneumonia, and P. aeruginosa were elucidated. Also, the
protein profiles of these bacteria were analyzed before and
after the treatments to identify the most potent antibacterial
extract of A. Vera. Because the skin of A. Vera often
discarded as waste in food processing industry [20]; this
research also aimed to analyze the antibacterial properties
of polysaccharide fractions of A. Vera skin extract.
MATERIAL AND METHODS
The A. Vera leaves were collected from different areas
of Khuzestan Province. The bacterial strains of S. aureus, P.
aeruginosa, and K. pneumonia were isolated from animals
referred to the veterinary hospital of Shahid Chamran
University of Ahvaz, and the MRSA was a standard strain
(PTCC:33591). Blood agar and Mueller Hinton Broth were
used for propagation and maintenance of bacterial cultures.
Broth cultures were incubated under aerobic conditions at
37°C.
Preparation of A. Vera extracts. Freshly collected A.
vera leaves (250 gr) were washed and cut in half. Half of
inner tissue was squeezed, and the extract was separated
(gel extract); the remaining part was cut in small pieces in
100 mL PBS (phosphate-buffered saline: 0.06 mM sodium
phosphate buffer containing 0.15 M NaCl, pH 7.4) and
boiled at 50°C for 20 min (boiled gel). The outer parts of
leaves (150 gr), homogenized with 100 ml PBS in a blender
and boiled at 50°C for 20 min (boiled skin). All extracts
were filtered on a Whatman no. 2 paper to remove the
insoluble materials and then centrifuged at 6000 rpm for 30
min. The precipitate was discarded and the clear yellow
supernatant stored at 4°C to be used. In order to prepare
distillate extract, the whole leaves were ground with double
distilled water and used for distillation by utilization of
common distillation apparatuses. These extraction
procedures were repeated three times and the recovered
extracts were pooled.
Antibacterial and SDS-PAGE analysis. Antibacterial
effects of the various A. Vera extracts were evaluated using
a broth microdilution method in 96-well microplates. For
each bacterium, minimum inhibitory concentration (MIC)
of various A. Vera extracts was determined. The bacterial
strains were cultured on blood agar and incubated overnight
at 37°C. One colony was selected from the pure culture of
each strain and inoculated at 37°C in Mueller-Hinton Broth
and checked until the yield the bacterial suspension reached
to 0.5 McFarland standard turbidity. A serial of two-fold
dilution (1/2, 1/4, 1/8, 1/32, 1/64 and 1/128) of A. Vera
extracts was prepared in Mueller-Hinton Broth; the equal
volume of each prepared bacteria was added to the wells
and incubated at 37°C for 24 h. The lowest concentration of
each extract which inhibited visible bacterial growth was
taken as the MIC of extract [21]. Also, the bacteria were
treated with ½ and ¼ dilution of A. Vera distilled extract
and their total protein profiles before and after the treatment
were detected by SDS-PAGE electrophoresis. We used
12% separating gel and 4% stacking gel, and
electrophoresis was performed in running buffer (25 mM
Tris base pH 6.8, 192 mM glycine, 1% SDS) at 100 V for
90 min. The polyacrylamide gels were stained for 30 min
with Coomassie staining solution followed by destaining
with 7% acetic acid solution overnight.
Purification and fractionation of the crude
polysaccharides of boiled skin extract. The skin extracts
polysaccharides were purified by phenol methods; briefly,
the same volume of 90% phenol was added to the extracts
and shaked at 68°C for 15 min. The suspensions were
cooled and centrifuged at 8500 g for 15 min. The
supernatants were transferred to other tubes and phenol
phases were re-extracted. Carbohydrates were precipitated
by addition of sodium acetate at 0.5 M final concentration,
and ten volumes of 95% ethanol to the supernatants and
samples were stored at -20°C overnight. Tubes were then
centrifuged at 2000×g, 4°C for 10 min and the pellets were
suspended in distilled water. Extensive dialysis against
double distilled water was performed at 4°C [22].
The crude polysaccharides were fractionated by anion
exchange chromatography on a DEAE-C (Sigma, Cat No:
D6418) column. In brief, 50 mg of skin polysaccharide was
filtered through a 0.45-μm Millipore filter (MilliporeCo.,
Billerica, MA, USA), and applied onto the column of
DEAE-cellulose, previously equilibrated with 10mM Tris–
HCl buffer (pH 8.5). After removing the unabsorbed
carbohydrates, the carbohydrate fractions were eluted with
0.1 to 2 M NaCl gradually [23]. The total carbohydrate
content was determined by the phenol-H2SO4 method
using glucose as the standard [24]. The different fractions
were concentrated and dialyzed in distilled water. The
antimicrobial effects of A. Vera boiled skin carbohydrate
fractions were evaluated using broth microdilution method
in 96-well microplates [21].
RESULTS
Protein and carbohydrate analysis. The highest value
of carbohydrate and protein were observed in boiled skin
and boiled gel extracts, respectively (as shown in Table 1).
The minimal amount for these was seen in distillate extract.
The antimicrobial effects of A. Vera extracts. The
MICs of the A. Vera extracts against S. aureus, MRSA, P.
aeruginosa and K. pneumonia were determined (Table 2).
Out of these four extracts, distilled extracts exhibit the most
potent antibacterial effects. There was no difference in the
vulnerability of gram-positive and gram-negative bacteria
toward distillate extracts.
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Gharibi et al.
J Med Microbiol Infec Dis 8 2015 Vol. 3 No. 1-2
Table 1. The protein and carbohydrate contents (mg/mL) of various A. Vera extracts.
Gel
Boiled gel
Boiled skin
Distilled
5.71
3.35
2.25
0.06
11
19
47
0.7
Table 2. The antimicrobial effects of A. Vera extracts. The MICs were observed at ¼ dilutions.
Gel
Boiled gel
Boiled skin
Distilled
-
-
+
+
+
+
+
+
-
-
-
+
-
-
-
+
SDS-PAGE analysis. SDS-PAGE analysis of whole-
cell protein extracts from the four bacteria produced
patterns containing discrete bands with molecular weights
ranging from >5 to <200 kDa. The protein profiles of these
strains before and after treatment with A. Vera were
compared. Significant differences were seen at 175, 60, 200
and 70 kDa protein bands of S. aureus, MRSA, P.
aeruginosa and K. pneumonia, respectively (Figure 1).
Purification and Fractionation of crude
polysaccharides. The phenol method showed to be more
useful for carbohydrate purification of A. Vera skin extract.
Seven carbohydrate fractions were purified by DE-C
column (Table 3). The fractions eluted with 0.1 M NaCl
have the highest carbohydrate concentration and the one
eluted with >2 M NaCl have negligible carbohydrate
concentration. Out of seven-carbohydrate fractions of skin
extract, fractions 6 and 7 had antibacterial effects on S.
aureus and MRSA at 0.089 and 0.134 mg/ml, respectively.
Moreover, fraction 5 showed bacteriostatic effects on
MRSA at 0.113 mg/ml concentration (Table 4)
Fig. 1 SDS-PAGE analysis of whole-cell protein of bacterial strains: A) S. aureus, B) MRSA, C) K. pneumonia, D) P. aeruginosa. Lanes 1-
3: The first lane of each group was the untreated bacteria, and lanes 2 and 3, treated with ½ and ¼ dilution of A. Vera distilled extract,
respectively.
Table 3. The carbohydrate concentration of seven isolated fractions (1-7) of boiled skin extract.
Fraction
1
2
3
4
5
6
7
Carbohydrate
(mg/mL)
0.16
5.8
0.88
0.2
0.452
0.356
0.536
Table 4. The antimicrobial effects of A. Vera skin boiled carbohydrate fractions.
Fraction
1
2
3
4
5
6
7
S. aureus
-
-
-
-
-
+
+
MRSA
-
-
-
-
+
+
+
Fractions 6 and 7 fractions have the bacteriostatic effects on S. aureus and MRSA, fraction 5 also has the bacteriostatic effects on MRSA. The MICs were
observed at ¼ dilutions.
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Antibacterial analysis of A. Vera extracts
J Med Microbiol Infec Dis 9 2015 Vol. 3 No. 1-2
DISCUSSION
Previously, various preparations of A. Vera including
confection, lotion, and juice, have been used as traditional
medicine in several communities for curing various
diseases [25]. In present study, only A. Vera distilled
extract was effective against P. aeruginosa. However, by
using the A. Vera gel extracts, Agarry et al. [9] and
Azghani et al. [26] reported a reduction in P. aeruginosa
infection and inhibition of attaching it to human lung
epithelial cells. This disagreement may be due to the
difference in the source of A. Vera and extracts preparation
process, various bacterial isolates or the test conditions. In
agreement with the current study, Kaithwas et al. [27]
showed that the A. Vera gel is rich in variety metabolites,
such as, anthraquinone, polysaccharides, glycoproteins,
glycosides, gamma-linolenic acid and prostaglandins which
are effective against gram-positive bacteria in particular
against S. aureus. Also, previously, antibacterial activity of
A. Vera essential oil against S. aureus and P. aeruginosa
was reported [28]. In addition, the antibacterial component
of A. Vera extract was reported to be effective against S.
aureus, Streptococcus pyogenes, Escherichia coli, K.
pneumoniae, Salmonella typhi, P. aeruginosa, Helicobacter
pylori and Propionibacterium acne [29-31].
In the current research, out of the four A. Vera
extracts, the distillate extract, despite containing the lowest
amount of carbohydrate compared to other extracts,
exhibited the most antibacterial effects against four
bacterial strains which included both gram positive and
gram negative bacteria. This could be due to the activation
of some antibacterial elements after distillation.
The gel and boiled skin extracts were only effective
against S. aureus; such a weak antibacterial effect for
aqueous extract was reported by others [32, 33]. Various
antibacterial effects by different extraction methods were
reported by others; in agreement with the results of the
current study, Nejatzadeh-Barandozi [20] suggested the
skin extracts as a source of antibacterial agents against S.
aureus and MRSA. The alcoholic extracts was reported as a
stronger antibacterial and antifungal agent than aqueous
extract [34] and the methanolic A. Vera gel extract had
more antibacterial activity against gram-positive bacteria
compared to gram-negative bacteria [35]. This may be due
to the difference in cell walls of gram positive and negative
bacteria. Also, whole leaf component of A. Vera, mainly
anthraquinones and saponins had antibacterial activities [29,
36].
Cock et al. [37] investigated the antimicrobial effects of
different methanolic fractions of A. Vera inner tissues and
showed that five fractions had antimicrobial activities,
which first fraction had the highest antibacterial effects;
however, in the current study, the three last fractions of the
aqueous skin extracts showed antibacterial effects.
In overall, the extraction methods may influence on
antibacterial effects of A. Vera extracts. The most
antibacterial active components of A. Vera are volatile or
saturated compounds which are mainly obtained in distillate
extracts of A. Vera. It is noteworthy to suggest the distillate
extract as antibacterial agents against the tested bacteria.
Although, the most affected protein bands were recognized
at SDS-PAGE analysis; this needs an additional research to
realize the exact mechanism of antibacterial effects of A.
Vera extracts.
ACKNOWLEDGEMENT
This study was financially supported by Shahid
Chamran University, Ahvaz, Iran grant.
CONFLICT OF INTEREST
The authors declare that there are no conflicts of interest
associated with this manuscript.
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... The current study showed agreement with previous studies where it was also found that AV extract possessed broad-spectrum antimicrobial activity due to its inhibitory and bactericidal effect against mastitis-causing organisms including S. aureus, S. agalactiae, E. coli, P. aeroginosae, P. vulgaris, E. faecalis, S. epidermididis, and Bacillus subtilis [17][18][19]. The present result is in accordance with previous findings in which crude extract of AV showed antibacterial potential against Gram-positive and Gram-negative bacterial organisms such as S. aureus, S. agalactiae (Fig. 2) [10,20]. ...
... The current study showed agreement with previous studies where it was also found that AV extract possessed broad-spectrum antimicrobial activity due to its inhibitory and bactericidal effect against mastitis-causing organisms including S. aureus, S. agalactiae, E. coli, P. aeroginosae, P. vulgaris, E. faecalis, S. epidermididis, and Bacillus subtilis [17][18][19]. The present result is in accordance with previous findings in which crude extract of AV showed antibacterial potential against Gram-positive and Gramnegative bacterial organisms such as S. aureus, S. agalactiae (Fig. 2) [10,20]. ...
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  • Jun 2022
The extensive use of antibiotics has developed antibacterial resistance and also may cause toxic effects (hepatotoxicity, nephrotoxicity) on vital organs. To overcome this problem, Scientists gain attention towards medicinal plants. Pure Aloe vera (AV) is a common alternative antimicrobial medicine, hence, the current study was conducted to explore its antibacterial potential and compared it with a commonly used antibiotic amoxicillin. During this study, clinically positive mastitis milk samples (n=50) were collected from buffaloes, after microbial culture analysis. Various concentrations (C1=40, C2=20, C3=10, C4=5, C5=2.5, C6=1.25, C7= 0.62, C8=0.31, C9=0.15, C10=0.07 and C11=0.03µl) of pure AV and amoxicillin (μg/μl) were used to evaluate antibacterial activity through minimum inhibitory concentration (MIC) against Gram-positive organisms including Staphylococcus aureus and Streptococcus agalactiae. The MIC was evaluated based on turbidity and transparency of the medium. Prevalence of S. aureus was recorded at 25 (50 %) whereas, 15 (30 %) positive samples for S. agalactiae and 10 (20 %) positive samples were found in mixed bacterial colonies from milk samples. The mean values of MIC at 10 μl of pure AV showed 50% sensitivity against S. aureus whereas, at 5 μl of pure AV showed 52.5 % sensitivity against S. agalactiae. While amoxicillin inhibited the growth of S. aureus and S. agalactiae at 2.5 μg/μl and 1.25 μg/μl concentrations showed 52.5 %, and 55 % sensitivity respectively. A significant (P ˂ 0.05) difference was noticed between both tested groups. It has been concluded that pure AV possessed antibacterial potential and can be used as a safe and economic alternative against infections caused by S. aureus and S. agalactiae.
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... Aloe vera root and leaf ethanol extracts exhibited good antibacterial activity with a zone of inhibition of > 13 mm at a concentration of 30 mg [83]. Arbab et al [84] also concluded that ethanol extracts are more efficacious than conventional extracts. Antifungal activity was noted against Fusarium and Aspergillus [83]. ...
Current scenario of traditional medicines in management of diabetic foot ulcers: A review
Article
Full-text available
  • Jan 2023
Diabetic foot infections and diabetic foot ulcers (DFU) cause significant suffering and are often recurring. DFU have three important pathogenic factors, namely, microangiopathy causing local tissue anoxia, neuropathy making the foot prone to injuries from trivial trauma, and local tissue hyperglycaemia favouring infection and delaying the wound healing. DFU have been the leading cause for non-traumatic amputations of part or whole of the limb. Western medicines focus mainly on euglycaemia, antimicrobials, debridement and wound cover with grafts, and off-loading techniques. Advances in euglycaemic control, foot care and footwear, systemic antimicrobial therapy, and overall health care access and delivery, have resulted in an overall decrease in amputations. However, the process of wound care after adequate debridement remains a major cost burden globally, especially in developing nations. This process revolves around two basic concerns regarding control/eradication of local infection and promotion of faster healing in a chronic DFU without recurrence. Wound modulation with various dressings and techniques are often a costly affair. Some aspects of the topical therapy with modern/Western medicines are frequently not addressed. Cost of and compliance to these therapies are important as both the wounds and their treatment are “chronic.” Naturally occurring agents/medications from traditional medicine systems have been used frequently in different cultures and nations, though without adequate clinical base/relevance. Traditional Chinese medicine involves restoring yin-yang balance, regulating the ‘chi’, and promoting local blood circulation. Traditional medicines from India have been emphasizing on ‘naturally’ available products to control wound infection and promote all the aspects of wound healing. There is one more group of chemicals which are not pharmaceutical agents but can create acidic milieu in the wound to satisfy the above-mentioned basic concerns. Various natural and plant derived products (e.g., honey, aloe vera, oils, and calendula) and maggots are also used for wound healing purposes. We believe that patients with a chronic wound are so tired physically, emotionally, and financially that they usually accept native traditional medicine which has the same cultural base, belief, and faith. Many of these products have never been tested in accordance to “evidence-based medicine.” There are usually case reports and experience-based reports about these products. Recently, there have been some trials (in vitro and in vivo) to verify the claims of usage of traditional medicines in management of DFU. Such studies show that these natural products enhance the healing process by controlling infection, stimulating granulation tissue, antimicrobial action, promoting fibroblastic activity and collagen deposition, etc. In this review, we attempt to study and analyse the available literature on results of topical traditional medicines, which are usually advocated in the management of DFU. An integrated and ‘holistic’ approach of both modern and traditional medicine may be more acceptable to the patient, cost effective, and easy to administer and monitor. This may also nevertheless lead to further improvement in quality of life and decrease in the rates of amputations for DFU.
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... This antibacterial activity of A. vera purified extracts including gel, boiled skin, boiled gel, and distilled extract against pathogenic bacteria, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Klebsiella pneumonia and Pseudomonas aeruginosa were elucidated. The A. vera distillate extract despite the minimal amount of carbohydrate and protein was more efficient against both Gram-positive and Gram negative bacteria [26]. ...
Aloe a Gel in a Cell
Article
Full-text available
  • May 2018
Aloe a miracle plant obtained from many species namely aloe vera, aloe barbadensis, aloe perryi, aloe ferox and various other species. Aloe vera the Indian species cultivated in India and other species are cultivated in Africa. Aloe is a cactuslike plant that grows in hot, dry climates. Aloe plant can withstand drought conditions and can grow without rainfall. Aloe produces two substances, gel and latex. Aloe gel is a clear, jelly-like substance found in the inner part of the aloe plant leaf. Aloe latex comes from the plant's skin and is yellow in color. Some aloe products are made from the whole crushed leaf, so they contain both gel and latex. Aloe vera plant has enormous activities in treatment of various skin diseases such as acne, burns, psoriasis, etc. and used in herbal cosmetics. Aloe gel is used in many cosmetic preparations as face wash and herbal creams etc. since the potency, efficacy, safety is more toxicity and side effects are comparatively less. Aloe is used in gum diseases in, dental problems and dental plaque etc. Aloe gel has anti-diabetic activity, used in treatment of glaucoma, and can treat vision problems. It is also used in hepatitis, osteoarthritis, varicose veins, weight loss etc. aloe has tremendous other activities. This review includes various uses, medicinal properties, pharmacological actions, various extracts of these Aloe species are traditionally used and their application used to cure, arthritis, inflammation, immunity, diabetes, hyperlipidemic, antioxidant, atherosclerosis, coronary heart diseases, laxative, antibacterial, antifungal, antiviral, wound healing and antitumor effect. Since aloe has been reviewed in many journal and articles, this review is compiled from recent article of aloes. Hence aloe is an invaluable gift of nature and a miracle plant. Aloe is a medicinal plant from the past, present and future and the invaluable activities present in this plant leads us to promising activities for the research and development for finding new entities.
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... Because drugs can have a toxic effect on humans, there is a growing interest in alternative, natural antimicrobial agents that would inhibit the growth and reproduction of opportunistic bacteria. Plants and natural preparations that have potential to inhibit the growth of microorganisms and ensure lower toxicity than drugs are nowadays very interesting [6]. Among these plants are also Aloe arborescens and Aloe barbadensis. ...
Enzymatic and Antimicrobial Activity of Biologically Active Samples from Aloe arborescens and Aloe barbadensis
Article
Full-text available
  • Aug 2021
Recently, the use of Aloe species has become very widespread. These are extensively used as a nutraceutical in a variety of health care products and food supplements. In addition, the occurrence of the quickly adaptable microorganisms, particularly bacteria, which can develop resistance to antibiotics, is a major problem for public health, and therefore, it is necessary to search for new antimicrobials. In our study, the content of total phenols, proanthocyanidins, and proteins in fresh and lyophilized samples of A. arborescens and A. barbadensis and their ethanol extracts was investigated. Furthermore, enzymatic and antioxidant activity of samples were studied. Since antimicrobial activity of fresh samples was determined in our latest research, a more detailed study of antimicrobial effectiveness of A. arborescens and A. barbadensis (lyophilized, extracts) was performed. Ethanol extracts in particular contain higher concentrations of bioactive substances and show the topmost antioxidant activity. The novelty of the study refers to the observation of industrially important enzyme activities such as α-amylase, cellulase, lipase, peroxidase, protease, and transglutaminase in the samples as well as the microbial growth inhibition rates determination (MGIR) at different concentrations of added aloe samples. All samples inhibited the growth of all tested microbial cells. MIC90 for A. arborescens and A. barbadensis were also determined in case of B. cereus, P. aeruginosa, P. fluorescens, and S. aureus. The results of our study tend to give credence to the popular use of both aloes in medicine and in the cosmetic, food, and pharmaceutical industries.
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... The active components of Aloe vera include vitamins (A, C, E and B12), enzymes (Bradykinase which helps to reduce excessive inflammation), minerals, sugars, anthraquinones (aloin and emodin) (Fig. 3), lignin, saponins, phenolic compounds, hormones (auxins and gibberellins that help in wound healing), salicylic acid (anti-inflammatory and antibacterial properties) and amino acids [19]. [20][21][22]. Bashir et al. [23] evaluated the antibacterial activity of leaf extracts and gel of A. vera against Gram-positive (S. aureus, Staphylococcus epidermidis and Streptococcus pyogenes) and Gram-negative (P. aeruginosa) bacteria isolated from human skin wounds, burns, and acne and compared it with standard antibiotics (methicillin, bacitracin, vancomycin, novobiocin and erythromycin). ...
Perspective on the application of medicinal plants and natural products in wound healing: A mechanistic review
Article
Wound is defined as any injury to the body such as damage to the epidermis of the skin and disturbance to its normal anatomy and function. Since ancient times, the importance of wound healing has been recognized, and many efforts have been made to develop novel wound dressings made of the best material for rapid and effective wound healing. Medicinal plants play a great role in the wound healing process. In recent decades, many studies have focused on the development of novel wound dressings that incorporate medicinal plant extracts or their purified active compounds, which are potential alternatives to conventional wound dressings. Several studies have also investigated the mechanism of action of various herbal medicines in wound healing process. This paper attempts to highlight and review the mechanistic perspective of wound healing mediated by plant-based natural products. The findings showed that herbal medicines act through multiple mechanisms and are involved in various stages of wound healing. Some herbal medicines increase the expression of vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) which play important role in stimulation of re-epithelialization, angiogenesis, formation of granulation tissue, and collagen fiber deposition. Some other wound dressing containing herbal medicines act as inhibitor of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) protein expression thereby inducing antioxidant and anti-inflammatory properties in various phases of the wound healing process. Besides the growing public interest in traditional and alternative medicine, the use of herbal medicine and natural products for wound healing has many advantages over conventional medicines, including greater effectiveness due to diverse mechanisms of action, antibacterial activity, and safety in long-term wound dressing usage.
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Expression, purification, and study on the efficiency of a new potent recombinant scFv antibody against the SARS-CoV-2 spike RBD in E. coli BL21
Article
Many efforts have been made around the world to combat SARS-CoV-2. Among these are recombinant antibodies considered to be suitable as an alternative for some diagnostics/therapeutics. Based on their importance, this study aimed to investigate the expression, purification, and efficiency of a new potent recombinant scFv in the E. coli BL21 (DE3) system. The expression studies were performed after confirming the scFv cloning into the pET28a vector using specific PCRs. After comprehensive expression studies, a suitable strategy was adopted to extract and purify periplasmic proteins using Ni²⁺-NTA resin. Besides the purified scFv, the crude bacterial lysate was also used to develop a sandwich ELISA (S-ELISA) for the detection of SARS-CoV-2. The use of PCR, E. coli expression system, western blotting (WB), and S-ELISA confirmed the functionality of this potent scFv. Moreover, the crude bacterial lysate also showed good potential for detecting SARS-CoV-2. This could be decreasing the costs and ease its utilization for large-scale applications. The production of high-quality recombinant proteins is essential for humankind. Moreover, with attention to the more aggressive nature of SARS-CoV-2 than other coronaviruses, the development of an effective detection method is urgent. Based on our knowledge, this study is one of the limited investigations in two fields: (1) The production of anti-SARS-CoV-2 scFv using E. coli [as a cheap heterologous host] in relatively high amounts and with good stability, and (2) Designing a sensitive S-ELISA for its detection. It may also be utilized as potent therapeutics after further investigations.
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Effects of Aloe vera utilization on physochemical and microbiological properties of Turkish dry fermented sausage
Article
Full-text available
  • Jul 2021
The study aimed to determine the minimum inhibitory concentration of Aloe vera extracts obtained by different extraction methods on eight strains from five different pathogens (Pseudomonas fluorescens, Listeria monocytogenes, Salmonella spp., Escherichia coli and Staphylococcus aureus) in the first phase and utilize Aloe vera extract in sausage processing in the second phase. Sausages were evaluated for thiobarbituric acid reactive substances (TBARS), physicochemical and microbiological properties. The first phase results indicated that the highest inhibition was determined in Listeria monocyctogenes 472 regardless of tested Aloe vera extract doses and extraction methods (Tukey HSD, P < 0.05). The highest Listeria monocyctogenes 472 levels reached was 0.38 log10 cfu/g. The second phase results revealed that Aloe vera containing treatments of sausage had lower pH than others after storage (ANOVA, P < 0.05). Dry matter, protein, fat and ash contents of sausage dough increased in all treatments after fermentation (ANOVA, P < 0.05). After 30 d storage, 48 and 45% TBARS reductions were obtained in sausages with only nitrite and those with only Aloe vera extract compared to control respectively. The lowest TBARS (68% reduction) were obtained in Aloe vera extract and nitrite incorporated sausages (Tukey HSD, P < 0.05). Result showed that the use of Aloe vera extract and nitrite combination in sausage formulation is a useful approach to control lipid oxidation in the product. Supplementary information: The online version contains supplementary material available at 10.1007/s13197-021-05183-5.
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Phytochemical Mediated Synthesis of Praseodymium Doped Beta-eucryptite Nanophosphor for Ultraviolet Stimulated Fluorescence Based Unclonable Security Applications
Article
Herein, we reported the preparation of orange-red emitting Pr³⁺ (1-11 mol %) doped beta-eucryptite (LiAlSiO4) nanophosphors via a simple low-temperature solution combustion method. The prepared beta-eucryptite revealed hexagonal crystal structure. The Pr³⁺ doped beta-eucryptite displays broad emission peak at 608 nm along with a weak intensive peak at 632 nm ascribed to ¹D2 → ³H4 and ³P0 → ³F2 transitions, respectively. Furthermore, color coordinates of Pr³⁺ doped beta-eucryptite nanophosphors are well located in orange-red region. In the dispersion of ac conductivity over the frequency band comprises with two significant frequency nonresponsive and responsive conductive bands. The luminescent unclonable security ink is prepared using Pr³⁺ doped beta-eucryptite nanophosphors to encode security labels and are completely invisible under normal white light, while it exhibits clear orange-red emission upon ultraviolet 365 nm light. The overall aforementioned results clearly validated that the Pr³⁺ doped beta-eucryptite nanophosphors is establish to be a suitable component for multifunctional applications.
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Production of cheap hand sanitizer with herbal ingredients
Article
Full-text available
  • Feb 2021
Novel Corona Virus has spread to 188 countries around the world which made the people infected, facing moderate respiratory illness. Currently one of the major strategies to deal with COVID-19 and reduce community transmission of infections is the frequent use of hand sanitizers. However, a large section of common mass is unable to buy them due to higher price. Therefore, an approach has been presented here to produce cheaper sanitizers with easily available herbal ingredients like Aloe Vera gel, boiled water, surgical spirit, Glycerine etc. The estimated making cost of 100 ml of sanitizer was 16 rupees. The mass production of this sanitizer can be very effective for large scale use of sanitizers by common people.
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ETHNO-MEDICINAL POTENTIALS AND PHYTOCHEMICAL PROPERTIES OF Aloe vera: A REVIEW
Article
Full-text available
  • Jul 2019
Aloe vera is a perennial ethno-medicinal potential plant with a xerophytic characteristic, but not a cactus. It has a famous history owing to its phytopharmaceutical properties and this had made it useful in the pharmaceutical, cosmetic and food industries. Studies had shown the positive effects of its extract against bacteria, fungi, virus and parasitic organisms. The phytochemical properties of A. vera have been exploited for various economic and commercial purposes. This review contributes literature on the bioactive potential composition, processing and the pharmaceutical potential uses, an adverse side-effect that might spring up in case of overdosage and important safety precautions are summarized. More scientific innovations and developments in the aspect of analytical chemistry are on the way to provide a more acceptable, purified chemical characterization of A. vera using sophisticated laboratory equipment and machines.
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Comparative antimicrobial activities of Aloe vera gel and leaf
Article
Full-text available
The comparative antimicrobial activities of the gel and leaf of Aloe vera were tested against Staphylococcus aureus, Pseudomonas aeruginosa, Trichophyton mentagraphytes, T. schoeleinii, Microsporium canis and Candida albicans. Ethanol was used for the extraction of the leaf after obtaining the gel from it. Antimicrobial effect was measured by the appearance of zones of inhibition. Antimicrobial susceptibility test showed that both the gel and the leaf inhibited the growth of S. aureus (18.0 and 4.0 mm, respectively). Only the gel inhibited the growth of T. mentagrophytes (20.0 mm), while the leaf possesses inhibitory effects on both P. aeruginosa and C. albicans. The results of this study tend to give credence to the popular use of both Aloe vera gel and leaf.
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Negatively charged polysaccharide derivable from aloe vera
Patent
Full-text available
  • Jan 2014
A new composition of matter is provided comprising negatively charged polysaccharides which can be derived from Aloe vera and a process to prepare that composition of matter by sub fractionation of an extract of Aloe vera, passing the formed subfraction over a positively charged column and eluting the same with a salt solution. Optionally the Aloe vera is pre purified over a Sephadex G-25 column. This composition of matter and also the extract comprising the same which is formed after pre purification or ultra filtration of an Aloe vera extract is useful as a food supplement or in dietary foods, for use in personal care and in cosmetics, especially to prevent an infection with the bacteria Helicobacter pylori, Pseudomonas aeruginosa, Streptococcus mutans or Streptococcus sanguis.
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Extraction, Purification and Characterization of Lipopolysaccharide from Escherichia coli and Salmonella typhi
Article
Full-text available
  • Mar 2011
Lipopolysaccharide (LPS) is an important structural component of the outer cell membrane complex of gram negative microorganisms. Its causative role in gram negative bacteria-induced diseases and broad applications in different kinds of cell stimulation experiments provided a conceptual basis for studies directed at the isolation, purification, and detailed chemical characterization of LPS. The main problem with LPS purification protocols is the contamination of the end product with nucleic acids and proteins in variable proportions which could potentially interfere with downstream applications. In this study, a simple procedure for purification of LPS from Escherichia coli (E.coli) and Salmonella typhi (S.typhi) with high purity and very low contaminating nucleic acids and proteins based on the hot phenol-water extraction protocol has been introduced. The purity of extracted LPS was evaluated by silver and coomassie blue staining of SDS-PAGE gels and HPLC analysis. Limulus Amebocyte Lysate (LAL) coagulation activity and rabbit pyrogen assay were exploited to monitor the functionality of purified LPS. The results showed that DNase and RNase treatment of the sample is essential after the sonication step to eliminate nucleic acid contamination in the LPS fraction. Silver staining demonstrated ladder pattern which is characteristic of LPS. No contaminating protein was found as assessed by coomassie blue staining. HPLC fractionation revealed high degree of purity comparable with commercial LPS. Parenteral administration of purified LPS resulted in substantial increase of rabbits' body temperature (mean: 1.45°C). LAL coagulation assay confirmed the functional activity of the purified LPS. In conclusion, the protocol presented here could be employed for isolation of LPS with high purity and functional activity.
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FT-IR study of the polysaccharides isolated from the skin juice, gel juice, and flower of Aloe vera tissues affected by fertilizer treatment
Article
Full-text available
  • Oct 2012
Background This experiment was conducted to evaluate the effect of different amounts of fertilizers on the polysaccharides of Aloe vera plant. There were four different treatments, viz. T1 = 150% N, T2 = 150% P, T3 = 150% K, and T4 = 150% NPK (50% N + 50% P + 50% K) soil. Crude water-soluble polysaccharides were isolated from the gel juice, skin juice, and flowers of A. vera planted in these soils. Results Result indicates that skin juice contained 2.4 times the level of polysaccharides in gel juice from one plant, suggesting the potential industrial application of A. vera skin rather than discarding it. After anion-exchange chromatography, neutral polysaccharides accounted for 58.1% and 78.5% of the total recovered neutral and acidic polysaccharide preparations from the gel juice and skin juice, respectively, whereas the crude flower polysaccharides were largely composed of weakly acidic polysaccharides (84.2%). Sugar analysis of the polysaccharides after gel permeation chromatography revealed that glucose and galactose were the most abundant monosaccharide in the neutral polysaccharides from the gel juice and skin juice, respectively. The acidic polysaccharides from the two juices consisted of glucuronic acid, galactose, glucose, mannose, and xylose with variable proportions. Conclusions Except glucuronic acid (15.4%) in flower acidic polysaccharide, the flower neutral and acidic polysaccharides contained galactose, glucose, and mannose as the main sugar components. Glucuronic acid was the major uronic acid in all acidic polysaccharides from different tissues.
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Evaluation of the antibacterial and anticancer activities of some South African medicinal plants
Article
Full-text available
Several herbs are traditionally used in the treatment of a variety of ailments particularly in the rural areas of South Africa where herbal medicine is mainly the source of health care system. Many of these herbs have not been assessed for safety or toxicity to tissue or organs of the mammalian recipients. This study evaluated the cytotoxicity of some medicinal plants used, inter alia, in the treatment of diarrhoea, and stomach disorders. Six selected medicinal plants were assessed for their antibacterial activities against ampicillin-resistant and kanamycin-resistant strains of Escherichia coli by the broth micro-dilution methods. The cytotoxicities of methanol extracts and fractions of the six selected plants were determined using a modified tetrazolium-based colorimetric assay (3-(4, 5-dimethylthiazol)-2, 5-diphenyl tetrazolium bromide (MTT) assay). The average minimum inhibitory concentration (MIC) values of the plants extracts ranged from 0.027 mg/mℓ to 2.5 mg/mℓ after 24 h of incubation. Eucomis autumnalis and Cyathula uncinulata had the most significant biological activity with the least MIC values. The in vitro cytotoxicity assay on human hepatocarcinoma cell line (Huh-7) revealed that the methanol extract of E. autumnalis had the strongest cytotoxicity with IC(50) of 7.8 μg/mℓ. Ethyl acetate and butanol fractions of C. uncinulata, Hypoxis latifolia, E. autumnalis and Lantana camara had lower cytotoxic effects on the cancer cell lines tested with IC(50) values ranging from 24.8 to 44.1 μg/mℓ; while all the fractions of Aloe arborescens and A. striatula had insignificant or no cytotoxic effects after 72 h of treatment. Our results indicate that the methanol fraction of E. autumnalis had a profound cytotoxic effect even though it possessed very significant antibacterial activity. This puts a query on its safety and hence a call for caution in its usage, thus a product being natural is not tantamount to being entirely safe. However, the antibacterial activities and non-cytotoxic effects of A. arborescens and A. striatula validates their continuous usage in ethnomedicine.
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Antimicrobial Activity of Aloe barbadensis Miller Leaf Gel Components
Article
Full-text available
  • Jan 2007
Methanolic extracts of Aloe barbadensis Miller inner leaf gel were fractionated by RP-HPLC and the resultant fractions were tested for inhibitory activity against a panel of bacteria and fungi. Five fractions were identified as having antimicrobial activity. Fraction 1 had the broadest antibacterial activity, being capable of inhibiting growth of both Gram-positive and Gram-negative bacteria as well as inhibiting growth of a nystatin resistant strain of the fungus Aspergillus niger. Fraction 1 had similar UV spectral properties as aloe emodin and was chromatographically identical to the pure compound. The other fractions tested were much more selective in their antimicrobial activities, being only capable of inhibiting the growth of specific Gram-negative rod bacteria. Two of these antimicrobial fractions were identified by ESI mass spectroscopy as being isomers of 8-C-β-D-[2-0-(E)-coumaroyl] glucopyranosyl -2-[2-hydroxy]-propyl-7-methoxy-5-methylchromone. Yes Yes
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Nasal carriage of Staphylococcus aureus: epidemiology, underlying mechanisms, and associated risks.
Article
  • Jul 1997
Staphylococcus aureus has long been recognized as an important pathogen in human disease. Due to an increasing number of infections caused by methicillin-resistant S. aureus (MRSA) strains, therapy has become problematic. Therefore, prevention of staphylococcal infections has become more important. Carriage of S. aureus appears to play a key role in the epidemiology and pathogenesis of infection. The ecological niches of S. aureus are the anterior nares. In healthy subjects, over time, three patterns of carriage can be distinguished: about 20% of people are persistent carriers, 60% are intermittent carriers, and approximately 20% almost never carry S. aureus. The molecular basis of the carrier state remains to be elucidated. In patients who repeatedly puncture the skin (e.g., hemodialysis or continuous ambulatory peritoneal dialysis [CAPD] patients and intravenous drug addicts) and patients with human immunodeficiency virus (HIV) infection, increased carriage rates are found. Carriage has been identified as an important risk factor for infection in patients undergoing surgery, those on hemodialysis or CAPD, those with HIV infection and AIDS, those with intravascular devices, and those colonized with MRSA. Elimination of carriage has been found to reduce the infection rates in surgical patients and those on hemodialysis and CAPD. Elimination of carriage appears to be an attractive preventive strategy in patients at risk. Further studies are needed to optimize this strategy and to define the groups at risk.
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Antimicrobial Activity of Some Important Medicinal Plant Against Plant and Human Pathogens
Article
  • Nov 2007
The methanol leaf extracts of Acacia nilotica, Sida cordifolia, Tinospora cordifolia, Withania somnifer and Ziziphus mauritiana showed significant antibacterial activity against Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens, Staphylococcus aureus and Xanthomonas axonopodis pv. malvacearum and antifungal activity against Aspergillus flavus, Dreschlera turcica and Fusarium verticillioides when compare to root/ bark extracts. A. nilotica and S. cordifolia leaf extract showed highest antibacterial activity against B. subtilis. and Z. mauritiana leaf extract showed significant activity against X. a. pv. malvacearum. Root and leaf extract of S. cordifolia recorded significant activity against all the test bacteria. A. nilotica bark and leaf extract showed significant antifungal activity against A. flavus , Ziziphus mauritiana and Tinospora cordifolia recorded significant antifungal activity against D. turcica The methanol extract of Sida cordifolia exhibited significant antifungal activity against F. verticillioides.
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