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Abstract

Avocado (Persea americana) oil is rich in nutrient waxes, proteins and minerals, as well as vitamins A, D and E. It is an excellent source of enrichment for dry, damaged or chapped skin. This study aimed to evaluate the wound-healing activity of fruit extract of Persea americana in rats. The effect of topical and oral administration of Persea americana fruit extract (300 mg/kg/day) on excision and dead space wound models was evaluated. The rats used in the excision wound model were divided into four groups of five each and received either topical or oral treatment. The rats used in the dead space wound model were divided into two groups of five each and were treated orally. Healing was assessed by the rate of wound contraction, period of epithelialisation, granulation tissue weight and hydoxyproline content. In the excision wound model, complete healing (full epithelialisation) was observed on average on day 14 in the rats who receive oral or topical treatment. In contrast, the controls took approximately 17 days to heal completely. The extract-treated wounds were found to epithelialise faster than the controls (p < 0.001). Wet and dry granulation tissue weight and the hydroxyproline content of the tissue obtained from extract-treated animals used in the dead space wound model were significantly higher (p < 0.05) compared with the controls. Rate of wound contraction, epithelialisation time together with the hydroxyproline content and histological observations support the use of Persea americana in the management of wound healing.
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JOURNAL OF WOUND CARE VOL 14, NO X, XXXXXXXXX 2005 1
Wound healing activity of Persea
Americana (avocado) fruit: a
preclinical study on rats
B.S. Nayak, MSc, PhD,
FAGE, NRCC-CC, FACB,
job title? Department of
Preclinical Sciences,
Biochemistry Unit,
Faculty of Medical
Sciences, The University
of the West Indies, St.
Augustine, Trinidad;
S.S. Raju, MBBS, MD, job
title? Department of
Pharmacology, School of
Medical Sciences, RAK
Medical and Health
Sciences University, Ras-
al-khaimah, United Arab
Emirates;
A.V. Chalapathi Rao,
MBBS, MD, Department
of Para clinical sciences,
Pathology unit, Faculty of
Medical Sciences, The
University of the West
Indies, St. Augustine,
Trinidad
Email: shiv25@gmail.com
W
ound healing comprises a
complex but well-coordinat-
ed cascade of biochemical
events that follow injury to
the skin and other soft tis-
sues. It is categorised into three phases: inflamma-
tion, proliferation and remodelling. The initial
inflammatory reaction is followed by the prolifera-
tive phase, which is characterised by angiogenesis,
collagen deposition, granulation tissue formation,
epithelialisation and wound contraction.1-4 (Sta-
delmann et al 1998; Iba et al 2004; Quinn
1998; Midwood et al 2004) The extracellular
matrix (okay?) and collagen are remodelled in the
final phase to provide integrity and strength to the
healed tissue (reference?). Factors that impair
wound healing include poor blood supply, lack of
nutrients, systemic disease, infections and the pres-
ence of foreign bodies. The ability to identify and
address these factors will help facilitate healing. Var-
ious nutritional factors and botanical influences,
including carbohydrate, protein, lipid sources (such
as? I assume you mean natural oils, waxes
etc?), vitamins, minerals and other trace elements,
play an important role during the different phases
of wound healing (references?). Adequate dietary
protein is vital for wound healing, and tissue levels
of the amino acids arginine and glutamine may
influence wound repair and immune function.5
(Agrawal et al 2003) Botanical extracts from
sources including Aloe vera, Centella asiatica and the
enzyme bromelain from pineapple have also been
shown to improve healing times and wound out-
comes.6,7 (MacKay and Miller 2003; Douglas et
al 2003 - author, we need the full reference
details for Douglas, seems to be the same as
MacKay and Miller at the moment - thank
you)
Avocado oil (Persea americana) is rich in unsapon-
ifiables (sterolins - please define briefly) com-
prised of biologically active compounds, such as
sterols, tocopherols, squalene and lipidic furans and
also contains vitamins A, C, D and E, proteins, beta-
carotene, lecithin, fatty acids and potassium.8
(Swisher 1988)
The use of avocado oil is considered to be benefi-
cial (by who? how widely accepted is this? or
should we say it has been found to reduce
l Objective: Avocado (Persea americana) oil is rich in nutrient waxes, proteins and minerals, as well as
vitamins A, D and E. It is an excellent source of enrichment for dry, damaged or chapped skin. This study
aimed to evaluate the wound-healing activity of fruit extract of Persea americana in rats.
l Method: The effect of topical and oral administration of Persea americana fruit extract (300mg/kg/day)
on excision and dead space wound models was evaluated. The rats for excision wound model were
divided into two groups, five each for topical and oral treatment. The rats for dead space wound models
were treated orally. Healing was assessed by the rate of wound contraction, period of epithelialisation,
granulation tissue weight and hydoxyproline content.
l Results: Complete healing (full epithelialisation) was observed on average on day 14 in both oral and
topical extract-treated animals. Whereas, controls wound took around 17 days. The extract treated
wounds were found to epithelialise faster as compared with controls (p<0.001). Wet and dry granulation
tissue weight and hydroxyproline contents of the tissue obtained from extract treated animals were
significantly higher (p<0.05) as compared with controls.
l Conclusion: Rate of wound contraction, epithelization time together with the hydroxyproline
content and histological observations support the use of P.americana in the management of wound
healing
l Declaration of interest: None.
Persea americana; hydroxyproline; epithelialisation
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JOURNAL OF WOUND CARE VOL 14, NO X, XXXXXXXXX 20052
age spots etc? but was this in a clinical
study?) in reducing age spots, healing scars and
moisturising the upper layers of the skin.7 (Douglas
et al 2003) A mixture of avocado and soybean
unsaponifiables has also been found to aid wound
healing, possibly by stimulating the deposition and
repair of extracellular matrix components.9,10 (Mar-
garet et al 1982; Boumediene et al 1999)
However, there is no scientifically proven data to
support either the collagen-enhancing or wound-
healing activities of Persea americana. This study
therefore set out to explore the effects of Persea
americana fruit on wound-healing parameters
including collagen synthesis.
Method
Fruit paste preparation
The Persea americana fruit (avocado) of 600g in
weight was taken and washed thoroughly with
deionised water, and then ground into a paste
(extract) using an electric blender. Special care was
taken during the procedure, and no water was added
to the extract to avoid contamination. The extract
was stored at a temperature of 4°C. What concen-
tration/amount of avocado was in the final
paste per animal? How was this standard-
ised?
Animals
The ethics committee for animal experimentation
(AHC06/07/1) at the University of the West Indies
approved the study. Healthy, in-house bred, gender-
matched, Sprague Dawley rats weighing 200–250g
were used for the study. They were individually
housed in an animal house and maintained on nor-
mal food and water ad libitum. The rats were anaes-
thetised before and during (to check, is this cor-
rect - both before and during?) infliction of the
experimental wounds. Surgical interventions were
carried out under sterile conditions using ketamine
anaesthesia (120mg/kg body weight). Animals with
signs of infection were excluded from the study and
replaced.
Dose selection
The male rats were treated with increasing doses (1,
2, 4 and 8g/kg body weight) of the extract for 14
days. Doses of up to 4g/kg body weight did not pro-
duce any sign of toxicity, while the animals remained
physically active and consumed food and water in a
regular way. As 1g/kg body weight showed better
healing (do you mean resulted in faster heal-
ing times?), the dose of 300mg/kg body weight
was selected for our experimental study. Author, I
presume the dose response study was sepa-
rate from the main study? this needs to be
made clear. At the moment, this looks like
the same animals were used in both studies,
which would invalidate the study
Wound-healing activity
Excision and dead space wound models were used
to evaluate the wound-healing activity of Persea
americana. Author, you also need to state the
study duration for the two models - thanks
l Excision wound model Excision wounds were
created on the rats, as described by Morton and
Malone.11 The dorsal fur was shaved with an electric
clipper and the anticipated wound area was drawn
on the back of the animals in methylene blue using
a circular stainless steel stencil. A full-thickness
excision wound measuring 250mm2 and 2mm deep
was created along the markings using toothed
forceps, a surgical blade and pointed scissors. The
wounds were kept open. The animals were divided
into four groups of five each. Author, to check
were these 4 groups used in the excision
wound model only, or were groups 1 and 2
used for the excision wound model and
groups 3 and 4 for the dead space wound
model?
l Group 1: the fruit paste (300mg/kg/day) was
applied topically using a sterile stainless steel appli-
cator on a daily basis (how did you ensure the
correct dosage of paste was applied? And
how was this standardised between animals?
How was this kept place? More detail is
required to ensure validity of the study -
thank you ).
l Group 2 (control): 1% carboxymethyl cellulose
dissolved in deionsied water was applied topically
- also on a daily basis? (Author, why add CMC
to the control wounds? CMC on its own has
been demonstrated to affect wound healing.
Therefore, the rationale for this needs
explaining and referencing. Also, as with
the fruit paste, you need to make clear why
the carboxymethyl cellulose was used, and
how it was made up, applied and kept in
place - thank you).
l Group 3: 300mg of fruit paste (do you mean 1g
of fruit paste was dissolved in 100ml of
drinking water?) was dissolved in the animal’s
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JOURNAL OF WOUND CARE VOL 14, NO X, XXXXXXXXX 2005 3
on which the eschar fell off, without leaving any
residual raw wound, was considered the period of
epithelialisation. The rats were euthansised after the
study (A table or diagram summarising the
experimental protocol would be helpful, as
you can see it’s not quite clear which groups
were used for which model. Thank you).
l Dead space wound model Dead space wounds
were inflicted by implanting sterile cotton pellets
(10mg each), one on either side of the groin and
axilla, on the ventral surface of each rat using the
technique of D’Arcy et al., as described by Turner.12
(Again, you need to make clear which groups
were used for this model) This is a well-
established standard method of obtaining collagen
for histology and hydroxyproline determination
(reference?).
Animals in the test group were given the fruit
extract orally (you mean these animals were
all in group 3?). On the 10th post-wounding day,
granulation tissue that had formed on the implant-
ed cotton pellets was carefully removed under
anaesthesia and its wet weight noted. The tissue was
then dried at 60°C for 12 hours and its weight
recorded; 5ml 6N hydrochloric acid was added to
the dried tissue, which was stored at 110°C for 24
hours. The acid hydrolysate (author, please
check this reads correctly - thanks) was neu-
tralised using 10N sodium hydroxide, and the vol-
ume made up to 10ml. This neutralised hydrolysate
was used to determine hydroxyproline,13 (Neuman
and Logan 1950) which is an index of collagen
content. An additional piece of wet granulation tis-
sue was preserved in 10% formalin for histological
studies.
Estimation of hydroxyproline
Dry granulation tissue from both control and treat-
ed group (are these groups 3 and 4?) was used to
estimate the hydroxyproline content. Hydroxypro-
line present in the neutralised acid hydrolysate was
subsequently oxidised by sodium peroxide in the
presence of copper sulphate. Following this, it was
complexed with paradimethylaminobenzaldehyde
to turn it pink, and measured at 540nm by spectro-
photometer.13 (Neuman and Logan 1950)
Histological study
Granulation tissues (from dead space wound model)
were obtained on day 10 from the test and control
group animals (groups 3 and 4?) for the histo-
logical study. For the better appreciation of collagen
deposition Masson’s trichrome stain, which stains
the fibres green, was used. This technique is used for
quantitative determination and to observe cross-
linking of collagen (reference?).
Statistical analysis
The means of wound area measurements between
groups at different time intervals were compared
using a one-way ANOVA, descriptive tests. One-way
ANOVA was used to examine the mean differences
in epithelialisation time, weight of the tissue and
hydroxyproline content between the groups in dead
excision and dead space wound models. Data were
analysed using the SPSS (version 12) and p value
was set <0.05 for all analyses.
Results
In the excision wound model the topically treated
animal wounds were found to fully have epithelial-
ised faster (13.8 ± 0.48 days) than the controls (17 ±
0.00 days). This difference was statistically signifi-
cant (p<0.001).
Animals given the oral extract also achieved full
epithelialisation significantly faster (13.0 ± 0.54
days) than the controls, who received plain drink-
ing water (16.6 ± 1.1 days). Again, this was sta-
tistically significant correct? (p<0.001).
In the dead space wound model, the tissue
obtained from the extract-treated animals (which
group?) showed significantly increased levels of
hydroxyproline content (68.0 ± 12.1mg/g tissue)
compared with the controls (30.0 ± 16.2mg/g tis-
sue). The wet (120.0 ± 25.84mg/100g rat) and dry
(28.40 ± 6.20mg/100g rat) weight of the granulation
tissue of animals treated with the fruit extract was
higher when compared with wet (57.6 ± 9.70mg/100g
rat) and dry (11.80 ± 0.9 mg/100g rat) weights of
tissue from animals received placebo control (what
placebo? you state plain drinking water).
This was statistically significant in both cases
(p<0.001).
The histological study of the granulation tissue
obtained on 10th day from the experimental ani-
mals (which group?) showed increased well-
organised collagen and more fibroblasts (Fig 1) when
compared with a section of granulation tissue from
the controls which showed inflammatory cells,
scanty collagen fibres and fibroblasts (Fig 2).
Discussion
These results show that avocado extract significant-
ly increased the rate of wound contraction/epitheli-
alisation, and the weight of the granulation tissue.
The latter is predominantly composed of fibroblasts,
collagen, oedema and new small blood vessels. The
increased rate of wound contraction is indicative of
increased collagen synthesis. The heavier weight of
the dry granulation tissue from excision wounds of
the extract-treated animals suggests it had a higher
collagen content. It is possible that the proinflam-
matory activity of the constituents of avocado fruit
could attract macrophages to the wound site. Mac-
rophages stimulate the chemotaxis and prolifera-
13 Neuman, R.E., Logan, M.
A. The determination of
hydroxyproline. J Biol
Chem 1950; 184: 1,
299-306.
14 Lu, Q.Y., Arteaga, J.R.,
Zhang, Q. et al. Inhibition of
prostate cancer cell growth
by an avocado extract: role
of lipid-soluble bioactive
substances. J Nutr Biochem
2005; 16: 1, 23-30.
15 Pacetti, D., Boselli, E.,
Lucci, P., Frega, N.G.
Simultaneous analysis of
glycolipids and phospholids
molecular species in
avocado (Persea Americana
Mill) fruit. J Chromatogr A
2007; 1150: 1-2, 241-251.
16 Pereira, L.M., Hatanaka,
E., Martins, E.F. et al. Effect
of oleic and linoleic acids
on the inflammatory phase
of wound healing in rats.
Cell Biochem Funct 2007;
26: 2, 197-204.
17 Balkan, M., Beyzadeoglu,
M., Oysul, K. et al. Retinoic
acid and intestinal wound
healing in intra-operatively
irradiated rat. Acta Chir
Belg 2006; 106: 1, 73-76.
18 Tom, W.L., Peng, D.H.,
Allaei, A. et al. The effect of
short-contact topical
tretinoin therapy for foot
ulcers in patients with
diabetes. Arch Dermatol
2005; 141: 11, 1373-1377.
19 Muehlberger, T., Moresi,
J.M., Schwarze, H. et al. The
effect of topical tretinoin
on tissue strength and skin
components in a murine
incisional wound model. J
Am Acad Dermatol 2005;
52: 4, 583-588.
20 Lateef, H., Abatan, O.I.,
Aslam, M.N. et al. Topical
pretreatment of diabetic
rats with all-trans retinoic
acid improves healing of
subsequently induced
abrasion wounds. Diabetes
2005; 54: 3, 855-861.
21 Musalmah, M., Nizrana,
M.Y., Fairuz, A.H. et al.
Comparative effects of
palm vitamin E and alpha-
tocopherol on healing and
wound tissue antioxidant
enzyme levels in diabetic
rats. Lipids 2005; 40: 6, 575-
580.
22 Alleva, R., Nasole, E., Di
Donato, F. et al. alpha-Lipoic
acid supplementation
inhibits oxidative damage,
accelerating chronic wound
healing in patients
undergoing hyperbaric
oxygen therapy. Biochem
Biophys Res Commun
2005; 333: 2, 404-410.
23 Stipcevic, T., Piljac, A.,
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JOURNAL OF WOUND CARE VOL 14, NO X, XXXXXXXXX 20054
tion of fibroblasts, and attract endothelial cells to
the wound and stimulate their proliferation to pro-
mote angiogenesis (reference?).
Avocado fruit is a rich source of monounsaturated
fatty acids and contains the highest content of
lutein (70% of the measured carotenoids) of com-
monly eaten fruits, as well as significant amounts of
related carotenoids and (should we mention
vitamin A as well?) vitamin E,14 (Lu et al 2005)
various phospholipids and glycolipids.15 (Pacetti
et al 2007) Because the avocado also contains a
significant amount of monounsaturated fat, these
bioactive carotenoids are likely to be better absorbed
into the bloodstream.15 (Lu et al 2005) Vitamin A
is required for epithelial formation, cellular differ-
entiation and immune function, and vitamin E is
the major lipid-soluble antioxidant in the skin.
Monounsaturated fatty acids,16 (Pereira et al
2007) topical and systemic carotenoids17-20 (Bal-
kan et al 2006; Tom et al 2005; Muehlberget
et al 2005; Lateef et al 2005) and vitamin E21
(Musalmah et al 2005) promote wound healing.
Derivatives of phospholipids and glycolipids also
have wound-healing properties.22-25 (Alleva et al
2005; Stipcevic et al 2006; Xu et al 2007; Linet
al 2006)
We hypothesise that carotenoids and, to a certain
extent, monounsaturated fatty acids might have
accelerated (okay?) the epithelialisation rate in the
excision wound model. Phospholipids are essential
co-factors in the blood coagulation cascade and
platelet activation, and it is possible that the phos-
pholipids of avocado fruit might have facilitated the
initial phase of cutaneous repair by initiating hae-
mostasis and the development of (okay?) a provi-
sional matrix for cell migration.
One known, (2R)-(12Z,15Z)-2-hydroxy-4-oxohe-
neicosa-12,15-dien-1-yl acetate (please double
check this is written correctly - thanks), and
two novel compounds, persenone A and B, isolated
from avocado fruit have been identified as inhibi-
tors of superoxide (O2-) and nitric oxide (NO) gen-
eration in cell culture systems.26 (Kim et al 2000)
Avocado has good hypochlorous acid, but not
hydrogen peroxide, scavenging ability.27 (Murcia
et al 2001) While there has been controversy over
the role of free radicals in wound healing,28
(Juranek and Bezek 2005) the efficacy of honey
is well correlated with its antioxidant properties.29
(Henriques et al 2006)
Avocados also have 60% more potassium than
bananas and are rich in vitamins B and K.14 (Lu et
al 2005) Vitamin B promotes wound healing.30
(Neiva et al 2005) However, the role of potassium
and vitamins K and D on wound healing is not
known (according to our reviewer, this is not
true. There is evidence that vitamin D is
involved in regulation of SAMs (fibronec-
tin).
Author, you need to fully acknowledge the
study limitations
Conclusion
Avocado fruit promotes wound healing and the
constituents present in the avocado fruit extract
may be responsible for promoting the collagen for-
mation at the proliferative stage of wound healing.
Its wound healing promoting activity could be due
to its antioxidant, antimicrobial, vitamins or some
unknown activities. However, it needs to be studied
further to isolate the active ingredients that pro-
mote wound healing, before considering it for clini-
cal use.
Fig 1: Experimental group granulation tissue with
more collagen (Masson’s trichrome stain) a =
inflammatory cells, b= fibroblast, c= collagen fibres
Fig 2. Control group granulation tissue with less
collagen (Masson’s trichrome stain) a = inflammatory
cells, b= fibroblast, c= collagen fibres
Piljac, G. Enhanced healing
of full-thickness burn
wounds using di-
rhamnolipid. Burns 2006;
32: 1, 24-34.
24 Xu, K.P., Yin, J., Yu, F.S.
Lysophosphatidic acid
promoting corneal
epithelial wound healing by
transactivation of
epidermal growth factor
receptor. Invest
Ophthalmol Vis Sci 2007;
48: 2, 636-643.
25 Lin, C.I., Chen, C.N.,
Chen, J.H., Lee, H.
Lysophospholipids increase
IL-8 and MCP-1
expressions in human
umbilical cord vein
endothelial cells through an
IL-1-dependent mechanism.
J Cell Biochem 2006; 99: 4,
1216-1232.
26 Kim, O.K., Murakami, A.,
Nakamura, Y. et al. Novel
nitric oxide and superoxide
generation inhibitors,
persenone A and B, from
avocado fruit. J Agric Food
Chem 2000; 48: 5, 1557-
1563.
27 Murcia, M.A., Jiménez,
A.M., Martínez-Tomé, M.
Evaluation of the
antioxidant properties of
Mediterranean and tropical
fruits compared with
common food additives. J
Food Prot 2001; 64: 12,
2037-2046.
28 Juránek, I., Bezek, S.
Controversy of free radical
hypothesis: reactive oxygen
species: cause or
consequence of tissue
injury? Gen Physiol Biophys
2005; 24: 3, 263-278.
29 Henriques, A., Jackson,
S., Cooper, R., Burton, N.
Free radical production and
quenching in honeys with
wound healing potential. J
Antimicrob Chemother
2006; 58: 4, 773-777.
30 Neiva, R.F., Al-Shammari,
K., Nociti, F.H. Jr et al.
Effects of vitamin-B
complex supplementation
on periodontal wound
healing. J Periodontol 2005;
76: 7, 1084-1091.
... Persea americana, commonly known as avocado fruit, has recently achieved significant popularity and is often marketed as a "superfood" because of its unique nutritional composition, phytochemical content, and health benefits (Segovia et al., 2018) [15] . Apart from its use as food, the avocado is traditionally used for several medicinal purposes including hypotensive, hypoglycemic, anti-viral and antidiarrheal and cardiovascular diseases (Cortés-Rojo et al., 2019; Nayak et al., 2013) [3,12] . Avocado is the most nutritive among fruits and is regarded as the most important contribution of the New World to human diet. ...
... Persea americana, commonly known as avocado fruit, has recently achieved significant popularity and is often marketed as a "superfood" because of its unique nutritional composition, phytochemical content, and health benefits (Segovia et al., 2018) [15] . Apart from its use as food, the avocado is traditionally used for several medicinal purposes including hypotensive, hypoglycemic, anti-viral and antidiarrheal and cardiovascular diseases (Cortés-Rojo et al., 2019; Nayak et al., 2013) [3,12] . Avocado is the most nutritive among fruits and is regarded as the most important contribution of the New World to human diet. ...
... International Journal of Research and Analytical Reviews (IJRAR) 442 et al., 2010 55 it was found that honey treated wounds healed quicker while avocado (P. Americana) was noticed to heal wound completely at a longer duration of 14-17days, the wet and dry granulation tissue weight and the hydroxyproline content of the tissue obtained from extract-treated animals used in the dead space wound model were significantly higher when compared with those of the controls 56 . From the study, aloe vera gel, avocado leaves and honey can be used for treatment of wounds. ...
Article
Full-text available
Wound infections are common in developing countries and can lead to wound sepsis and bacterial infection. The aim of the study was to evaluate the antibacterial activities of traditional wound healing agents on wound isolates. A total of 5 typed strains comprising of Providencia vermicola strain 6G (KC775772), Proteus terrae strain TYFW6 (MZ960174), Proteus vulgaris strain LC-693 (CP063314), Klebsiella aerogenes strain CX-70 (MH368390) and Pseudomonas aeruginosa strain PHB3 (JQ327806) were obtained from Prof. Tasie, F.0 of the Department of Applied Microbiology of Enugu State University of Science and Technology, Agbani. Traditional wound healing agents comprising of 10 Aloe barbadensis miller (Aloe vera) leaves, 20mls of honey, and Persea americana (avocado) leaves were obtained from local vendors at Ogbete main market, Enugu. The avocado leaves were macerated and extracted using ethyl-acetate and methanol solvents; the Aloe vera leaves were lyophilized and extracted using ethyl-acetate and methanol solvents while honey was checked for physiochemical parameters and further extracted using ethyl acetate and methanol solvents. Preliminary qualitative and quantitative phytochemical analysis were done using standard methods to reveal the presence of concentrations of basic phytocomponents. The ethyl-acetate and methanol extracts of the avocado and Aloe vera gel were reconstituted using 4ml of Dimethyl Sulfoxide (DMSO) (w/v) to concentrations of (mg/ml) 500, 250, 125, 62.5, 31.25, 15.625 while 20mls of honey extracts, each was reconstituted using 4ml of hot water to concentrations(ml) (v/v) of 500, 250, 125, 62.5, 31.25, 15.625mg/ml. The isolates were screened for sensitivity to the extracts using agar well diffusion method. Minimum inhibitory concentration was determined by agar well diffusion method. Antibiotics susceptibility pattern of isolates was analyzed by Kirby-Bauer disc diffusion method. The phytochemical analysis of ethyl-acetate and methanol extracts of honey, Aloe vera gel and avocado leaves showed presence of phytochemicals (phenol, terpernoids, alkaloids, flavonoids, saponins, steroids, glycosides and tannins). Quantitative analysis of the extracts showed varied concentration of the phytocomponents. At 500mg/ml the methanol extracts of honey, aloe vera gel and avocado leaves showed higher zones of inhibition on all the isolates. Methanol extracts of honey showed the highest zone of inhibition at 26mm on Proteus vulagris; 28mm on Providencia vermicola, Proteus terrae, Klebsiella aerogenes and Pseudomonas aeruginosa © 2024 IJRAR June 2024, Volume 11, Issue 2 www.ijrar.org (E-ISSN 2348-1269, P-ISSN 2349-5138) IJRAR24B4553 International Journal of Research and Analytical Reviews (IJRAR) 429 respectively. Methanol extracts of avocado leaves, honey and aloe vera gel compared well with the control antibiotic (Ciprofloxacin). Minimum inhibitory concentration of ethyl-acetate extracts and methanol extracts of avocado leaves, honey and aloe vera gel were 15.625mg/ml on all isolates. Most of the isolates were sensitive to the antibiotics tested while all isolates showed 100% resistance to septrin and Providencia vermicola, Proteus vulgaris and Pseudomonas aeruginosa showed 100% resistance to augmentin. From the study, at P >0.05, Methanol extract of honey showed the highest efficacy in inhibition of wound isolates while ethyl-acetate extract of avocado leaves showed the least efficacy. Honey, Aloe vera gel and Avocado leaves are easily accessible, potent, economical and safe to man, therefore, it is recommended as a topical agent for the inhibiting isolates from wounds in developing countries.
... Higher phenolic content facilitates better bioactivity, meaning that methanolic extract (APEM) would possess better antioxidant activities" [41]. "Phenolic compounds are important plant constituents with redox properties responsible for antioxidant activity" [42]. ...
... [18] In the excision wound model the rate of wound closure (epithelialization) by creating a circular wound on the rats' backs is evaluated. [19] The animals undergo anesthesia before and during the procedure. Excision wounds are induced following the method outlined by Morton and Malone. ...
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Wound healing is a complex process crucial for maintaining tissue integrity. While human trials offer the ultimate testing ground for wound treatments, ethical and practical limitations necessitate pre-clinical models. This review explores the strengths and limitations of various animal models used in wound healing research. The article highlights the contributions of rodents and pigs in elucidating fundamental wound management principles. However, it emphasizes the lack of a perfect model due to inter-species anatomical and physiological variations. Additionally, factors like age, sex, and wound location can influence results. The review then categorizes wound healing models into in vitro (cultured cells), ex vivo (tissues), and in vivo (whole animals) approaches. Each category encompasses various sub-models suitable for studying specific aspects of wound healing. Strengths of pre-clinical models include efficient data generation, controlled environments, and the ability to test therapies in disease states like diabetes. However, limitations include discrepancies in healing mechanisms between species and the difficulty of replicating complex chronic wounds. The review concludes by discussing how incorporating patientderived cells and advanced technologies like induced pluripotent stem cells (iPSCs) and microengineering hold promise for developing more accurate pre-clinical models. This can ultimately expedite drug development and improve wound management in humans.
... This suggests that avocado oil could be a promising choice for the treatment of skin wounds. The findings of the current investigation indicate that the topical application of avocado oil, either in its natural form or as part of pharmaceutical preparations, can enhance the production of collagen, decrease the presence of inflammatory cells, expedite the blood clotting process, hasten the regeneration of epithelial tissue in wound healing, and accelerate the overall skin wound healing process, thereby reducing the duration required for wound healing (Nayak, Raju and Rao, 2008;Ranade and Thiagarajan, 2015;Mawazi et al., 2022). ...
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Skin aging is a multifaceted biological process that is impacted by both internal (genetics, hormones, cellular metabolism, and metabolic processes) and external (long-term exposure to UV light, pollution, ionizing radiation, chemicals, and toxins) aspects. Monounsaturated fatty acids, especially oleic acid, found in avocado oil are beneficial for wound healing, moisturizing, and anti-aging. Finding avocado oil's role as an active ingredient in cosmeceuticals was the aim of this investigation. The study's article review technique entails a thorough search of the Pubmed, Google Scholar, Proquest, Springer Link, and Science Direct databases for articles published between 2018 and 2024. The sample utilized in this study consisted of research publications that satisfied the inclusion criteria, resulting in a total of 12 articles. The result of this study showed that avocado oil is mostly formulated in emulgel and cream preparation. Avocado oil can be used as sunscreen due to the presence of the unsaturated fatty acid such as oleic acid and linoleic acid. All of the topical application of avocado oil showed the potential of this oil as antioxidant, anti-aging and sunscreen. Avocado oil is potential as cosmeceutical at the concentration of 3% to 20%.
... The aqueous leaf extract has also been demonstrated to possess analgesic and anti-inflammatory activities (Adeyemi et al., 2002). Other medicinal properties of Persea americana are wound healing (Nayak et al., 2008) and hepatoprotection (Kawagishi et al., 2001). ...
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Aim: To investigate anti-hyperlipidemic activity of methanol leaf extract of Persea americana (MEPA) in cholesterol-induced hyperlipidemic rats. Methodology: The animals were randomly divided into five groups of 5 rats each. Group1 served as the normal control (NC) and received distilled water. Group 2, the cholesterol-induced hyperlipidemic control (CHOL) was given cholesterol diet (20% groundnut oil, 1% cholesterol and 0.5% cholic acid mixed with rat pellet) orally. Groups 3 and 4 received oral administration of cholesterol diet and MEPA at a dose of 20 and 40 mg/kg body weight respectively, while group 5 was treated orally with cholesterol diet and cholestyramine (0.26g/kg body weight). Cholesterol diet, MEPA and cholestyramine were administered daily for a period of eight weeks. Results: The changes observed in the plasma levels of total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL) of hyperlipidemic control rats were reversed by MEPA in a dose-dependent manner. At 20 mg/kg body weight, MEPA significantly (p<0.05) reduced TC, TG and LDL plasma levels by 54.2%, 46.2% and 65.6% respectively, and increased HDL plasma level by 60.0%. At a higher dose of 40 mg/kg, MEPA reduced TC, TG and LDL levels by 60.4%, 69.2% and 87.5% respectively while HDL was increased by 80.0%. There was a significant increase of change in body weight of hyperlipidemic rats compared to the change in normal control. MEPA caused a reduction of change in body weight to nearly that of the normal control. MEPA also dose-dependently caused significant reduction (p<0.05) of plasma lipid peroxidation in the rats. The anti-hyperlipidemic effect of MEPA was comparable to that of the standard drug, cholestyramine. Conclusion: The results of this study showed that Persea americana could be a source 236 of good alternative remedy for hyperlipidemia. Further studies are needed to fully understand the mechanism of action of the plant.
... It was comparable to earlier findings, which showed that topical application of avocado and jojoba oil to rats increased collagen production and reduced the number of inflammatory cells during wound healing. [40][41][42] Inflammation can also contribute to the production and degeneration of skin cells. Therefore burns, which are prone to severe inflammation, should be treated with anti-inflammatory and antioxidant drugs to reduce the risk of delayed healing. ...
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Objective To investigate the Pinus halepensis extracts and determine its healing and antibacterial effects, and to evaluate the treatment of skin burns. Methods Aqueous and ethanolic extracts and topical based on Aleppo pine plant extracts were prepared. Thirty male and female Wistar rats were used to study the cutaneous toxicity of extracts from the bark of P. halepensis. The extracts’ healing potential for burn wounds were also assessed by evaluating the clinical and macroscopic aspects of the wounds. The antibacterial activity of crude extracts of P. halepensis as well as its wound healing abilities was verified in this investigation. Results In animals with acute dermal toxicity, there were no signs of treatment-related toxicity or death. The extracts of these plants could be transformed into phytomedicines for the treatment of infected wounds. The results demonstrated that formulated ointments are successful in treating second-degree burns in rats and may be suitable for the short-term therapeutic treatment of second-degree burns. Conclusion This study successfully answered our problem, regarding the efficacy of our extract for treating second-degree burns in rats. Further studies are needed to confirm these results by identifying the molecules responsible for these activities and examining their mechanism of action.
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Background Wounds have become a major health challenge worldwide, presenting marked humanistic and economic burdens such as disabilities and death. Annually, approximately 14 million people suffer from wounds worldwide and 80 % of these occur in developing countries like Uganda. In Uganda, besides many cases of daily wound occurrences, approximately 10 % of surgical procedures become septic wounds and consequently lead to increased morbidity and mortality. Accordingly, several ethnomedicinal studies have identified plants used for wound treatment in different parts of Uganda and the wound healing activities of some plants have been reported. However, at present, these information remain largely separated without an all-inclusive repository containing ethnomedicinal and pharmacological information of the plants used for wound healing in Uganda, thus retarding appropriate evaluation. Therefore, this review focused on extensively exploring the plants used for treating cutaneous wounds in Uganda, along with associated ethnomedicinal information and their globally reported pharmacological potential. Methods Electronic data bases including Google Scholar, PubMed, and Science Direct were searched using key terms for required information contained in English peer reviewed articles, books, and dissertations. Additionally, correlations between selected parameters were determined with coefficient of determination (r²). Results The literature survey revealed that 165 species belonging to 62 families are traditionally used to treat wounds in Uganda. Most of the species belonged to families of Asteraceae (14 %), Fabaceae (10 %), and Euphorbiaceae (7 %). The commonest plant parts used for wound treatment include leaf (48 %), root (22 %), stembark (11 %), and stem (7 %), which are prepared majorly by poultice (34 %), decoction (13 %), as well as powdering (25 %). Fifty-four (33 %) of the plant species have been investigated for their wound healing activities whereas, one hundred eleven (67 %) have not been scientifically investigated for their wound healing effects. Pearson correlation coefficient between the number of wound healing plant families per part used and percent of each plant part used was 0.97, and between the number of wound healing plant families per method of preparation and percent of each method of preparation was 0.95, showing in both strong positively marked relationships. Conclusion The preliminarily investigated plants with positive wound healing properties require further evaluation to possible final phases, with comprehensive identification of constituent bioactive agents. Additionally, the wound healing potential of the scientifically uninvestigated plants with claimed healing effects needs examination. Subsequently, information regarding efficacy, safety, bioactive principles, and mechanism of action could prove valuable in future development of wound healing therapies.
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Topical zinc is widely used in wound treatment although the beneficial effect of zinc has only been documented in zinc-deficient patients who were given zinc orally. The main purpose of this study was to investigate the effect of topically applied zinc on leg ulcer healing and examine its effect on some mechanisms in wound healing using standardized animal models. Additionally, absorption of zinc into wounds and intact skin treated topically with zinc was studied. In a double-blind trial involving 37 leg ulcer patients with low serum zinc levels, topical zinc oxide promoted cleansing and re-epithelialization. Infections and deteriorations of ulcers were less common in zinc oxide treated patients. Re-epithelialization, an important mechanism in the closure of leg ulcers, was enhanced with zinc oxide applied topically on partial-thickness wounds in pigs with normal zinc status. Zinc sulfate at three different concentrations did not, however, result in this beneficial effect on the resurfacing of wounds. The inflammatory reaction was diminished in zinc treated wounds except when a high zinc sulfate concentration was applied. Bacterial growth and concomitant diseases such as diabetes can complicate wound healing. In normal rats, bacterial growth in full-thickness wounds was reduced with topical zinc oxide but not in hyperglycemic diabetic rats. The anti-bacterial mechanism of zinc oxide seemed to be more indirect and to be mediated via local defense systems rather than being directly toxic to the bacteria. Healing of 21-day-old skin incisions was impaired in zinc deficiency, as measured by a significantly decreased wound breaking strength in zinc-deficient rats compared with that of pair-fed controls. The decreased breaking strength did not seem to be due to differences in collagen concentration of the wounds. Zinc oxide was slowly but continuously solubilized when applied on open wounds in rats. On the other hand, with zinc sulfate, the zinc concentrations, either locally or systemically, did not maintain a constant level for the 48-hour post-operative treatment period as they did with zinc oxide. Zinc absorption in and through normal human forearm skin was demonstrated after treatment with a zinc oxide medicated occlusive dressing by increased zinc levels in epidermis, interstitial fluid and dermis compared with the non-zinc control dressing. In conclusion, topical zinc may stimulate leg ulcer healing by enhancing re-epithelialization, decreasing inflammation and bacterial growth. When zinc is applied on wounds it not only corrects a local zinc deficit but also acts pharmacologically.(ABSTRACT TRUNCATED AT 400 WORDS)
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Several Mediterranean and tropical fruits have been analyzed in order to assess their antioxidant activity compared with that of common food additives (butylated hydroxyanisole [BHA], butylated hydroxytoluene [BHT] and propyl gallate). Among Mediterranean fruits, red grape and plum were more effective (P < 0.05) scavengers of peroxyl radicals than BHA, BHT, and propyl gallate. Of the tropical fruits, banana was the most effective scavenger of peroxyl radicals. Mediterranean and tropical fruits showed very good scavenger activity against hydroxy radicals (OH*), protecting deoxyribose better than BHA and BHT. The HOCI scavenging ability of Mediterranean fruits tested was, in decreasing order, lemon > plum > apricot > white grape > melon > red grape > mandarin > watermelon > peach > medlar > apple > orange > cherry > strawberry. However, the four varieties of pear were poor scavengers (P < 0.05). Among tropical fruits, the order of efficiency as HOCI scavengers was passion fruit > lime > passiflora > kumquat > avocado > pineapple > physalis > papaya fruit > carambola > mango > banana. All Mediterranean fruits showed an effect on hydrogen peroxide except peach. Tropical fruits also had a strong effect on hydrogen peroxide except avocado, which had no effect. The effect of Mediterranean and tropical fruits on the protection factor of refined olive oil, analyzed by the Rancimat method and compared with common food additives, was clear. Watermelon conferred a significantly (P < 0.05) greater protection than the other Mediterranean fruits. Among tropical fruits, physalis had the most stabilizing effect.
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Biochemical and mechanical experiments were conducted to determine the effect of dietary thiamine on collagen maturation during wound repair. The breaking strength of excised wounds, the isometric shrink tension of skin, and the lysyl oxidase activity of normal and repairing skin were determined. Rats were divided into three dietary groups and fed either a thiamine-deficient diet (-B1), a thiamine-deficient diet supplemented with 1 mg thiamine-HCl (+B1) or a thiamine-deficient diet supplemented with 3 mg thiamine-HCl (+3B1). When -B1 rats were demonstrated to be deficient in urinary thiamine, all animals were wounded. Ten days after wounding the animals were killed and the tissues harvested. Significant differences were observed in lysyl oxidase activity between -B1 and +B1 in both wounded and unwounded tissue, and in isometric shrink tension between -B1, +B1, and breaking strength between all three dietary treatment groups. The changes observed in this study demonstrate a definite involvement of thiamine in wound repair and scar development.
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In the last few decades, a great deal of progress has been made in understanding the cellular and biochemical interplay that comprises the normal wound healing response. This response is a complex process involving intricate interactions among a variety of different cell types, structural proteins, growth factors, and proteinases. The normal wound repair process consists of three phases--inflammation, proliferation, and remodeling--that occur in a predictable sequence and comprise a series of cellular and biochemical events. A review of the biochemical and physiologic processes that regulate wound healing and the cascade of cellular events that gives rise to the healing process is presented here.
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Objective: Avocado and soya unsaponifiables (ASU) have been reported to exert beneficial effects in the treatment of periodontal and osteoarticular diseases. They are supposed to stimulate deposition and repair of extracellular matrix components, but the mechanisms underlying their action are not well understood. In view of the repair potential of osteoarthritic (OA) cartilage and the role that the transforming growth factor beta (TGFbeta) system could play in that process, we carried out in vitro studies to determine the mechanism of action of ASU on articular chondrocytes that may account for the beneficial effects on cartilage metabolism. Methods: Cultured bovine articular chondrocytes were treated with various concentrations of ASU, and the expression of both TGFbeta isoforms, 1 and 2, and their receptors (TGFbetaRI and TGFbetaRII) was determined by Northern blot and reverse transcriptase-polymerase chain reaction. Cell transfection with TGFbeta1 promoter constructs was also used to delineate the cis-acting sequences mediating ASU responsiveness in chondrocytes. The level of plasminogen activator inhibitor 1 (PAI-1) was also evaluated by Northern blotting and protein radiolabeling. Results: The data indicated that ASU stimulate the expression of TGFbeta1, TGFbeta2, and PAI-1 by articular chondrocytes. In contrast, the levels of TGFbetaRI and TGFbetaRII were not significantly affected by the compound. Treatment of bovine articular chondrocytes transiently transfected with TGFbeta1 promoter constructs suggested that the effect on TGFbeta1 expression is mediated by the region located between -732 and -1132 bp. Conclusion: The results indicate that the ASU-induced stimulation of matrix synthesis previously reported in cultured articular chondrocytes could be explained by the ability to enhance TGFbeta expression in these cells. Further, ASU increase the production of PAI-1, an effect that could help in blocking the plasmin cascade that leads to metalloprotease activation. These data suggest that the compound has properties that might promote TGFbeta-induced matrix repair mechanisms in articular cartilage.
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One known, (2R)-(12Z,15Z)-2-hydroxy-4-oxoheneicosa-12,15-dien+ ++-1-yl acetate (1), and two novel compounds, persenone A (2) and B (3), have been isolated from avocado fruit (Persea americana P. Mill), as inhibitors of superoxide (O(2)(-)) and nitric oxide (NO) generation in cell culture systems. They showed marked inhibitory activities toward NO generation induced by lipopolysaccharide in combination with interferon-gamma in mouse macrophage RAW 264.7 cells. Their inhibitory potencies of NO generation (1, IC(50) = 3.6; 2, IC(50) = 1.2; and 3, IC(50) = 3.5 microM) were comparable to or higher than that of a natural NO generation inhibitor, docosahexaenoic acid (DHA; IC(50) = 4.3 microM). Furthermore, compounds 1-3 and DHA markedly suppressed tumor promoter 12-O-tetradecanoylphorbol-13-acetate-induced O(2)(-) generation in differentiated human promyelocytic HL-60 cells (1, IC(50) = 33.7; 2, IC(50) = 1.4; 3, IC(50) = 1.8; and DHA, IC(50) = 10.3 microM). It is notable that they were found to be suppressors of both NO- and O(2)(-)-generating biochemical pathways but not to be radical scavengers. The results indicate that these compounds are unique antioxidants, preferentially suppressing radical generation, and thus may be promising as effective chemopreventive agent candidates in inflammation-associated carcinogenesis.
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Non-healing wounds are a common cause of morbidity worldwide. The wounds are the result of inadequate repair in an optimum period and are due to the presence of predisposing factors. The abnormalities of certain biochemical factors are important in impeding wound healing. One hundred patients with non-healing wounds of more than six weeks duration were studied for nutritional and vitamin status and their correlation with healing time. The healing time was significantly prolonged in patients with serum protein concentrations below 6 gram/dl, but the healing time was not correlated with the concentrations of vitamin C or vitamin E. Anemia also did not alter the healing time. Adequate protein intake is the most important prerequisite for good wound healing.
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Repair of tissue after injury depends on the synthesis of a fibrous extracellular matrix to replace lost or damaged tissue. Newly deposited extracellular matrix is then re-modeled over time to emulate normal tissue. The extracellular matrix directs repair by regulating the behavior of the wide variety of cell types that are mobilized to the damaged area in order to rebuild the tissue. Acute inflammation, re-epithelialization, and contraction all depend on cell-extracellular matrix interactions and contribute to minimize infection and promote rapid wound closure. Matricellular proteins are up-regulated during wound healing where they modulate interactions between cells and the extracellular matrix to exert control over events that are essential for efficient tissue repair. Here, we discuss how the extracellular matrix changes during the stages of tissue repair, how matricellular proteins affect cell-extracellular matrix interactions, and how these proteins might be exploited for use therapeutically.
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We examined possible roles of mast cells in cutaneous wound healing using mast cell deficient (W/Wv) mice and their normal littermates (+/+). A round full-thickness wound was made on the back skin of these mice. The wounds closed completely within 20 days, and there was no difference in wound contraction between +/+ and W/Wv mice during the wound healing. While either chymase or tryptase activities were hardly detectable in W/Wv mice, chymase activities decreased at the impaired sites and recovered to the control level within 20 days in +/+ mice. Tryptase activities were higher than the control level on day 15 and day 20 in +/+ mice. Histological observations on day 15 and day 20 in +/+ mice revealed that mast cells were abundant at the wound edges but absent at the center. The latent and the active forms of MMP-2 and MMP-9 increased on day 10 and day 15 but recovered nearly to control levels on day 20 in both mice groups. The hydroxyproline contents in W/Wv mice were significantly higher than those in +/+ mice on day 15 and day 20. Furthermore, histological observations revealed that the collagen aggregation at the wound edges was tighter and less interwoven in W/Wv mice compared with +/+ mice. These results suggest that mast cells accumulated at the wound edge may participate in tissue remodeling in the late phase of wound healing.