ArticlePDF Available

Effect of Aloe Vera and Wax Gourd Extracts in Reducing Burning Sensation of Capsicum Gel

Authors:
  • College​ of​ Herbal​ Pharmacy

Abstract and Figures

The aim of this research was to develop a capsicum analgesic gel with a reduced burning sensation. The study started by determining a suitable vehicle with optimal proportions. The soothing substances, aqueous extracts of aloe vera and wax gourd, were used with a formulary concentration of 0.0125% capsaicin. A clinical trial was conducted with 30 healthy volunteers to test the product’s efficacy. It was observed that after applying the capsicum analgesic gel the burning sensation started with itching, then flushing followed by burning. The maximum burning sensation was experienced at 30 min., after which time it gradually declined and finally dissipated at 480 min. The burning sensation when using capsicum gel with aloe vera and wax gourd was reduced by 21.49% and 36.25%, respectively. The concentration of soothing vehicle was correlated with the burning sensation while the burning sensation was related to the skin erythema with a correlation coefficient (R2) of 0.9584.
Content may be subject to copyright.
Original Article 107
J Health Res 2010, 24(3): 107-111
EFFECT OF ALOE VERA AND WAX GOURD EXTRACTS IN
REDUCING BURNING SENSATION OF CAPSICUM GEL
Weerasak Samee1,*, Kwanchanok Rinako Nakakita1, Anusorn Panyawachira1
and Narisa Kamkaen2
1Faculty of Pharmacy, Srinakharinwirot University, Nakhon-Nayok province, 26120
2Suan Dusit Poll, Suan Dusit Rajabhat University, Dusit, Bangkok, 10300
ABSTRACT: The aim of this research was to develop a capsicum analgesic gel with a reduced
burning sensation. The study started by determining a suitable vehicle with optimal
proportions. The soothing substances, aqueous extracts of aloe vera and wax gourd, were used
with a formulary concentration of 0.0125% capsaicin. A clinical trial was conducted with 30
healthy volunteers to test the product’s efficacy. It was observed that after applying the
capsicum analgesic gel the burning sensation started with itching, then flushing followed by
burning. The maximum burning sensation was experienced at 30 min., after which time it
gradually declined and finally dissipated at 480 min. The burning sensation when using
capsicum gel with aloe vera and wax gourd was reduced by 21.49% and 36.25%, respectively.
The concentration of soothing vehicle was correlated with the burning sensation while the
burning sensation was related to the skin erythema with a correlation coefficient (R2) of 0.9584.
Keywords: capsicum gel, burning, aloe vera, wax gourd
INTRODUCTION: Capsicum is an annual crop
which is found all over tropical countries such as
Africa, Mexico, India and Asia. In Thailand, it is
commonly found in home vegetable gardens. The
pungent substances called “capsaicinoids” consist
of capsaicin, dihydrocapsaicin, nordihydro-
capsaicin, homocapsaicin and homodihydro-
capsaicin1,2). Capsaicin (C18H27NO3) is a phenolic
amide whose chemical name is 8-methyl-N-
vanillyl-6- nonenamide or (E)-8-Methyl-N-vanillyl-
6-nonenamide. The colorless crystal has a
molecular weight of 305.46 and a melting point of
65oC, and a boiling point of 210-220 o
C3). It is
insoluble in cold water, but soluble in ethanol,
ether and acetone. Capsaicinoids are located in
the inner wall of the fruit and the septum of the
placenta. The maximum amount of 89% capsaicin
is found at the dissepiments4).Capsaicin is an
analgesic due to selective action on the small
diameter afferent nerve fibers, or C fibers of
nocicepters which are believed to mediate muscle
pain. It is believed that substance P is released
and it is this which causes the burning sensation.
After repeatedly applying capsaicin, substance P
is depleted and then the pain is relieved5-7).
Capsicum products such as creams and gels
contain 0.0125-0.075% capsaicin. They are used
to relieve pain from osteoarthritis, rheumatiod
arthritis, and neuropathic pain. However, these
products may cause irritation and burning skin
even though they are potent pain relievers8).
In our laboratory, an analgesic gel containing
capsicum extract with soothing vehicles was
formulated. In order to assure the efficacy of this
product, the reduction in the burning sensation
was evaluated in this study.
MATERIALS AND METHODS:
Materials
Fresh plant materials (Capsicum Yod Son,
Aloe Vera, and Wax Gourd) were purchased from
a local market, Pathumthani Province. Chemicals
purchased from PC drug center, Thailand were
carbopol 934, carbopol 940, polysorbate 20
(tween20), methyl paraben, propyl paraben,
propylene glycol, and ethyl alcohol. Chemicals
imported from BASF, Germany were neutrol TE®
(N,N,N’,N’-Tetrakis (2-hydroxypropyl) ethylenediamine
and uvinul MS 40® 3-(4-methylbenzylidene)-
camphor. EDTA sodium was purchased from
Carlo ERBA, France. Solvents purchased from
To whom correspondence should be addressed.
E-mail: weerasak@swu.ac.th,
Tel. +66 3739 5094 ext. 1626, Fax. +66 3739 5096
Capsaicin
108 Original Article
J Health Res 2010, 24(3): 107-111
Merck, Germany were acetonitrile and acetic acid.
Acetone was purchased from LAB-SCAN,
Thailand. The other instruments were a blender
(Otto® PRO) and Cutometer MPA580 (CK
electronics).
Chromatographic system
HPLC-UV (Thermo Separation Product®)
consisted of Spectra system sn4000, Spectra
system p1500, Spectra system uv1000, and
Spectra system as3000. HPLC column (Phenomenex®
)
containing C18 with particle size 5 micron and
diameter 4.6×250 mm. Mobile phase was acetonitrile
: water : acetic acid (60 : 40 : 1). Flow rate was 1
ml/min. Injection volume was 20 µl. UV detector
was set at wavelength 280 nm.
Preparation of capsicum extract
Capsicum materials were collected and dried
at 50°C for 4 hr. The dry plants were then blended
using the electric blender and passed through a
no.60 sieve. 50 grams of dry capsicum powder
was extracted with ethanol with the proportions of
1:5 using the sonicator for 30 min. The crude
extract was then filtered under vacuum and
passed through a no.1 paper filter and washed
with 50 ml ethanol 3 times. The ethanol extract
was concentrated using the rotary evaporator. The
capsaicin in the capsicum extract was then
analyzed using the HPLC technique.
Preparation of aloe vera extract
Two year-old aloe vera plants were selected
and the leaves were minced. The leaves were
peeled and washed with water. The leaves were
cut and blended into small pieces. The pieces
were heated in water at 70-80 °C for 30 min. The
water extracts were then filtered through cotton
cloth and kept in a tightly sealed container in the
refrigerator at 4-8 °C.
Preparation of wax gourd extract
Three month-old wax gourd fruit were
selected. The outer peels and inner seeds were
separated and thrown away. The fruits were cut
and blended into small pieces. The pieces were
heated in water at 70-80 °C for 30 min. The water
extracts were then filtered through cotton cloth
and kept in a tightly sealed container in the
refrigerator at 4-8 °C.
Preparation of capsicum gel
Eleven formulations of capsicum gel containing
0.0125% capsaicin were prepared using water,
aloe vera extract and wax goard extract at 0%,
10%, 25%, 50%, 75% and 100% as the soothing
vehicle as shown in Table 1. First the capsicum
extract was dissolved in ethanol. Then, Carbopol
940 was ground in the mortar and dispersed with
uvinul MS 40®, EDTA was added to the soothing
vehicle and then mixed. Next, TWEEN®, Paraben
conc., and Neutral TE® were dissolved in water
and mixed. Finally all the ingredients were mixed
together in the mortar to form a smooth gel.
Finally, the capsicum extract was added to gel to
make the capsicum gel.
The evaluation of burning sensation level
The burning sensation level was measured
after applying the capsicum products in order to
compare them with the commercial product. The
study was approved by the Institutional Ethics
Committee at Faculty of Pharmacy, Srinakharinwirot
University on January 2008. A clinical trial was
conducted on 30 healthy volunteers, aged 20-23
yr. The subjects were instructed to apply 200 mg
of each of the test products to the lower arm to an
area of 5×10 cm. The burning sensation was
recorded after applying the test product at 5, 15,
30, 120, 240, 360 and 480 min on a work sheet to
record the burning sensation as shown in Table 2.
The burning sensation was rated on a 9-point
severity scale (0 – 9). The degree of burning
sensation for each formulation was compared
with the commercial product.
The evaluation of erythema after applying
capsicum gel
The erythema value was measured by
Cutometer® in 30 healthy volunteers. The changes
in the erythema value were determined in terms of
the difference between before and after applying
the capsicum gel. The maximum burning
sensation was at 30 min and then it declined to
nil 480 min after applying the product. The
difference of the erythema value from the base
line was then analyzed for four test products;
capsicum gel with three different vehicles; water,
aloe vera extract and wax gourd extract and these
Original Article 109
J Health Res 2010, 24(3): 107-111
figures were compared with the commercial
product.
RESULTS:
Physicochemical properties of capsicum gel
containing the soothing vehicles
The capsicum gel containing water as a
vehicle was dark orange in color, had a very
strong odor, a high viscosity and pH > 7. The
capsicum gel containing 100% aloe vera extract
as a vehicle was orange in color, had a strong
odor, medium viscosity and pH < 7. The capsicum
gel containing 100% wax gourd extract as a
vehicle was pale orange in color, had a less strong
odor, lower viscosity and pH < 7. The results
showed that among the three soothing vehicles,
the capsicum gel containing 100% aloe vera had
the best physicochemical properties as shown in
Table 3.
The effect of the different of vehicles on
reducing burning sensation of capsicum gel
The burning sensation experienced by healthy
subjects after applying the four test products was
similar. The level of the burning sensation showed
a typical bell shaped curve. The observed bell
shaped curve was located in the time range (0-
480 min). The peak of the bell shape curve was at
30 min, then the burning sensation gradually
reduced at 120, 240 and 360 min and then
reached a minimum at 480 min as shown in
Figure 1. The maximum burning sensation was
experienced with the capsicum gel in the
commercial product, followed by the formulation
with water vehicle, aloe vera extract and the wax
gourd extract. The reductions in the burning
sensation with aloe vera and wax gourd were
21.49% and 36.25% respectively.
The effect of the different concentration of
vehicles on reducing the burning sensation of
capsicum gel
The different concentrations of vehicles on
reducing the burning sensation of capsicum gel
were observed in the concentration range of 0-
100. The results in Table 4 showed that the ability
to reduce the burning sensation was correlated
with the concentration of the vehicle, especially for
the wax gourd extract. The reduction in burning
sensation achieved with the 75% and 100% aloe
vera extracts were similar. The burning sensation
level showed a typical bell shaped curve which
gave the highest figures at 30 min, and decreased
gradually at 120, 240 and 360 min reaching a
minimum at 480 min as shown in Figure 2.
The evaluation of erythema value
The erythema value measures the redness of
the skin when stimulated or irritated. In this
experiment, the erythema value was measured
Table 1 The Composition of preliminary batch of
capsicum gel
Ingredients M.F.
Capsaicin 0.0125%
Carbopol 940 1%
Neutral TE® 1.5%
Polysorbate 20 (Tween 20®) 0.2%
Uinul MS 40
®
0.01%
Paraben conc. 1%
EDTA 0.02%
Ethanol 38%
Vehicle q.s. to 100%
Table 2 The work sheet for recording the burning
sensation
Time
(min) Rating scale of burning sensation
0 1 2 3 4 5 6 7 8 9
5
15
30
60
120
240
360
480
No symptoms; 0 = none
Mild symptoms; 1= itch, 2 = red, 3 = hot
Moderate symptoms; 4 = less burning, 5 = burning, 6 =
more burning
Severe symptoms; 7 = a lot of burning 8 = burning,
but tolerable 9 = burning, not tolerable
Table 3 Physicochemical properties of capsicum gel
containing three soothing vehicles
Vehicle pH Color Odor Viscosity
Water 7.38
Dark
orange Very
strong High
Aloe vera
extract 100%
6.52 Orange Strong Medium
Wax gourd
extract 100%
6.53 Pale
orange
Less
strong Less
110 Original Article
J Health Res 2010, 24(3): 107-111
with a Cutometer® and studied for the relationship
with the burning sensation after applying four
capsicum gel products to 30 healthy products.
The maximum erythema value was reached at 30
min while the minimum value occurred at 480
min. The average erythema value (Δ erythema
value) was the value subtracted from the base line
as shown in Table 5. The results showed that the
burning sensation was similar among the four
products and it was extinguished at 480 min.
The average erythema values of healthy
volunteers after 30 min applying four products
were different. Capsicum gel containing wax
gourd extract as the vehicle gave the lowest
average erythema value of 80.91 ± 12.98. The
average burning sensation level was correlated
with the average difference of erythema value 30
min after applying the capsicum gel with a
correlation coefficient (R2) of 0.9584 as shown in
Figure 3. The degree of redness of the skin was
obviously related to the burning sensation level.
DISCUSSION AND CONCLUSION: The formulation
of capsicum gel containing soothing vehicles was
studied in order to reduce the burning sensation
of capsaicin. The physicochemical properties of
capsicum gel were enhanced in terms of pH, color,
order and viscosity. The burning sensation level
showed a typical bell shaped curve that was
located in the time range (0- 480 min). The peak
burning sensation was experienced at 30 min,
then it gradually declined at 120, 240 and 360
min and was extinguished at 480 min. The
maximum burning sensation at 30 min was
similar for two test products; the commercial
product and the formulated product containing
the water vehicle. The reductions in the burning
sensation achieved with capsicum gel with aloe
vera and wax gourd were 21.49% and 36.25%,
respectively. The higher soothing vehicle concentrations
were correlated with a lower burning sensation
level. In addition, the burning sensation was
related to the erythema value with a correlation
coefficient (R2) of 0.9584. The best formulation in
this study was the analgesic gel containing
0.0125% capsaicin with 100% wax gourd extract
which gave the lowest erythema value and the
lowest burning sensation level.
-1
0
1
2
3
4
5
6
7
0 100 200 300 400 500
Time
(
minute
)
Burning sensati on leve
l
Water
Come rcial produc t
Aloe vera
Wax go urd
Figure 1 The burning sensation level experienced by
subjects after applying capsicum gel with the different
vehicles; water (), aloe vera extract (Δ) and wax gourd
extract (O) compared with the commercial product ()
-1
0
1
2
3
4
5
6
7
0 100 20 0 3 00 400 5 00
Burning sensation leve
l
Aloe vera 0%
Aloe vera 10%
Aloe vera 25%
Aloe vera 50%
Aloe vera 75%
Aloe vera 100%
-1
0
1
2
3
4
5
6
0 100 200 300 400 5 00
Time
(
minute
)
Burning sensation leve
l
Wax go urd 0%
Wax gourd 10%
Wax gourd 25%
Wax gourd 50%
Wax gourd 75%
Wax gourd 100%
Figure 2 The burning sensation level experienced by
subjects after applying capsicum gel containing different
concentrations of aloe vera and wax gourd extract
y = 0.0332x + 0.6955
R2 = 0.9584
3
3.5
4
4.5
5
5.5
6
70 80 90 100 110 120 130 140 150
Average difference of erythema value
Average burning sensation level
Figure 3: The linear regression between the average
burning sensation level and the average difference of
erythema value 30 min after applying the capsicum gel
Original Article 111
J Health Res 2010, 24(3): 107-111
ACKNOWLEDGEMENTS: The research was
enabled by a research grant from Srinakharinwirot
University (Research code 058/2552). The Faculty
of Pharmacy is acknowledged for providing
research resources and facilities.
REFERENCES:
1. Schweiggert U, Carle R and Schieber A.
2006. Characterization of major and minor
capsaicinoids and related compounds in chili
pods (Capsicum frutescens L.) by high-
performance liquid chromatography/atmospheric
pressure chemical ionization mass spectrometry.
Anal Chim Acta 557(1-2): 236-44.
2. Constant HL, Cordel GA, West DP, Johnson
JH. 1995. Separation and quantification of
capsaicinoids using complexation chromato-
graphy. J Nat Prod 58(12): 1925-8.
3. Capsaicin-USP Monograph. Available from:
http://www. Pharmacopoeia.com.cn/v29240/usp
29nf24s0_m 12365.html [Accessed Dec 10, 2008].
4. Sosanuy S. Capsicums and the advantages
of capsaicin. Available from: http://yalor.yru.ac.
th/~dolah/notes/4902-1-48G13/SEMREP/Sb_
404652078.doc [Accessed Jun 30, 2008].
5. Lynn B. 1990. Capsaicin: actions on
nociceptive C-fibres and therapeutic potential.
Pain 41(1): 61-9.
6. Purkiss J, Welch M, Doward S, Foster K.
2000. Capsaicin-stimulated release of substance
P from cultured dorsal root ganglion neurons:
Involvement of two distinct mechanisms.
Biochem Pharmacol 59: 1403–6.
7. Erin N, Zık B, Sarıgül M, Tütüncü S. 2009.
The effects of chronic low-dose capsaicin
treatment on substance P levels. Regul Pept 153:
83–7.
8. Keawnopparat N. 2000. Department of
Pharmaceutical Technology, Faculty of Pharmacy,
Prince Songkla University, Capsicums and
capsicum extracts in medicinal used. Available
from: http://herbal.pharmacy.psu.ac.th/Article
/03-45/Capsicum.htm [Accessed Jun 30, 2008].
Table 4 The average burning sensation in healthy volunteers (n=30) after applying the capsicum gel
formulations containing different vehicles: water, aloe vera extract and wax gourd extract
Vehicle Burning sensation level ± SD (n=30)
5 min 15 min 30 min 60 min 120 min 240 min 360 min 480 min
Wate
r
2.65±0.75 4.54±0.84 5.49±0.92 5.04±0.89 2.98±0.65 1.80±0.73 0.31±0.59 0.17±0.38
Aloe vera 10
%
2.50±0.96 4.39±0.91 5.28±0.82 4.73±0.73 2.96±0.88 1.73±0.45 0.31±0.66 0.17±0.47
Aloe vera 25
%
2.25±0.77 3.78±0.87 4.88±0.65 4.33±0.97 2.77±0.72 1.66±0.53 0.30±0.53 0.16±0.35
Aloe vera 50
%
1.59±0.85 3.13±0.68 4.47±0.71 4.06±0.89 2.58±0.63 1.41±0.60 0.31±0.46 0.17±0.31
Aloe vera 75
%
1.20±0.55 2.80±0.74 4.30±0.89 3.75±0.56 2.43±0.54 1.35±0.32 0.31±0.52 0.15±0.40
Aloe vera 100
%
1.12±0.60 2.75±0.58 4.31±0.95 3.76±0.71 2.43±0.33 1.34±0.47 0.29±0.55 0.16±0.33
Wax gourd 10
%
2.43±0.66 4.05±0.64 4.98±0.79 4.59±0.88 2.81±0.70 1.75±0.56 0.30±0.45 0.17±0.27
Wax gourd 25
%
2.20±0.56 3.62±0.76 4.29±0.83 4.07±0.72 2.53±0.56 1.54±0.60 0.29±0.77 0.16±0.19
Wax gourd 50
%
1.98±0.43 3.24±0.69 4.06±0.57 3.78±0.77 2.28±0.44 1.24±0.43 0.30±0.52 0.17±0.36
Wax gourd 75
%
1.50±0.54 2.86±0.55 3.75±0.64 3.26±0.61 2.15±0.51 1.01±0.37 0.28±0.49 0.16±0.27
Wax gourd 100
%
1.33±0.35 2.67±0.83 3.50±0.45 3.05±0.66 1.95±0.55 0.87±0.53 0.25±0.33 0.15±0.38
Table 5: The average erythema value of healthy volunteers after applying four products at 30 and 480 min
compared with the base line
Test samples
Δ Erythema value ± SD (n = 30)
30 min 480 min
Capsicum gel (commercial product) 145.96 ± 17.62 10.51 ± 8.43
Capsicum gel using water as the vehicle 139.72 ± 20.13 12.98 ± 9.17
Capsicum gel using aloe vera extract as the vehicle 117.64 ± 15.27 13.92 ± 7.82
Capsicum gel using wax gourd extract as the vehicle 80.91 ± 12.98 11.79 ± 9.96
ResearchGate has not been able to resolve any citations for this publication.
Article
A reliable and reproducible method to separate and quantitate capsaicin and its analogues using argentation hplc, which permits the base-line separation of norcapsaicin, zucapsaicin (civamide), capsaicin, nordihydrocapsaicin, nonivamide, homocapsaicin, dihydrocapsaicin, and homodihydrocapsaicin-I, is described.
Article
Capsaicinoids were extracted from fresh chili pods (Capsicum frutescens L.) and characterized by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry. Among the 23 compounds detected, 3 major and 12 minor capsaicinoids belonging to the ‘capsaicin’, ‘dihydrocapsaicin’ and ‘N-vanillyl-n-acylamide group’, respectively, were characterized by their specific fragmentation pattern in collision-induced dissociation experiments. Additionally, with the exception of ω-hydroxycapsaicin, several closely related compounds were tentatively identified as alkyl dehydrogenated and -hydroxylated derivatives, respectively, for the first time in Capsicum fruits.
Article
Capsaicin, the pungent component of “hot” chilli peppers, selectively activates a distinct population of primary sensory neurons responsive to noxious stimuli. Many of these fibres express neuropeptides including the tachykinin, substance P. Using cultured dorsal root ganglion neurons, we found that capsaicin (10 μM) stimulated a 2-fold increase in release of substance P in the absence of extracellular Ca2+. Elevated potassium (75 mM) was unable to induce release under these conditions. The introduction of Ca2+ enhanced capsaicin-induced release and brought about a robust response to potassium. Preincubation of cells with botulinum neurotoxin A (100 nM) completely blocked potassium-induced release but the capsaicin response, in the absence of Ca2+, was unaffected. However, toxin treatment dramatically reduced capsaicin-stimulated release in the presence of Ca2+. It is concluded that capsaicin induces release of substance P from dorsal root ganglion neurons via two mechanisms, one requiring extracellular Ca2+ and the intact synaptosomal-associated protein 25 kDa (SNAP-25), and the other independent of extracellular Ca2+ and not involving SNAP-25.
Article
Capsaicin, the pungent ingredient of red pepper, is consumed in varying amounts by many ethnic groups. It serves both therapeutically and as a specific tool to investigate sensory neurons. Although effects of high capsaicin doses are well-established, systemic effects of chronic low-dose capsaicin exposure are unknown. Sprague-Dawley rats (21-day old) were injected with capsaicin (0.5 mg/kg, ip) for 6 and 19 days. Changes in Substance P (SP) levels of lung and skin were measured. Two-step sequential acetic acid extraction was used to estimate neuronal and non-neuronal SP. Six-day, but not 19-day capsaicin treatment decreased SP levels in first as well as second extractions of both tissues. Because the cumulative dose used here was much lower than the neurotoxic doses of capsaicin, initial decrease of SP levels must be due to continuous release of SP from nerve endings as well as non-neuronal tissues. The fact that SP levels returned to control values at the end of 19-day treatment demonstrates that reactive increases in SP synthesis occurred. These findings suggest that systemic exposure to low-dose capsaicin enhances sensory nerve function and also increases SP in non-neuronal tissues. In addition, significantly decreased SP levels of both tissues were observed in 40-day, compared to 27-day old rats.
Article
Recent work on the excitatory action of capsaicin on somatic and visceral afferent neurones shows that depolarization is selective for C-fibre polymodal nociceptor afferents and involves opening a non-selective cation channel. Exposure to significantly suprathreshold amounts of capsaicin causes permanent degeneration of C-fibre afferents in adult rats. Functional changes in rats (hypalgesia, diminished neurogenic inflammation) are likely to be a direct consequence of the loss of C-fibre nociceptors, and so are the reductions in neuropeptide levels that follow adult capsaicin treatment. Clinical trials of topical capsaicin treatment for post-herpetic neuralgia have yielded promising results. The selective nature of the action of capsaicin in reducing just C-nociceptor activity may make it particularly useful for treating pain states triggered by C-fibre input.