Procedia Chemistry 14 ( 2015 ) 301 – 307
1876-6196 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
Peer-review under responsibility of the Scientiﬁ c Committee of HK-ICONS 2014
Available online at www.sciencedirect.com
2nd Humboldt Kolleg in conjunction with International Conference on Natural Sciences,
The Potency of Guava Psidium guajava (L.) Leaves as a Functional
Noer Lailya*, Retno Windya Kusumaningtyasa, Iim Sukartia,
Maria Rosari Devi Kartika Rinia
aCenter for Bioindustrial Technology ,The Agency for The Assessment and Application of Technolgy (BPPT),
Komplek Perkantoran Puspiptek Gedung no 611 LAPTIAB 1, Serpong 15314, Indonesia
The potential of natural substances to improve the immune system has long been the subject of investigation. The purpose of
this research was to study Guava (Psidium guajava L.) leaf extract as a functional ingredient for immunostimulant. The study
used water and ethanol as solvents to obtain optimum active compounds of the extracts. The result showed that the higher the
content of phenol total was found in the extract, the higher the stimulation index value was obtained for both solvents. However,
the stimulation index value was not only influenced by antioxidant activity. The reason was that the type of active compound in
Guava leaf extract responsible for immunostimulatory activity was probably not only polyphenolic antioxidant.
© 2015 N. Laily, R.W. Kusumaningtyas, I. Sukarti, M.R.D.K. Rini. Published by Elsevier B.V.
Peer-review under responsibility of the Scientific Committee of HK-ICONS 2014.
Keywords: Antioxidant; functional ingredient; immunostimulant; phenol total; Psidium guajava (L.) extract
*Corresponding author. Tel: +62 21 7560 729; fax: +62 21 756 0694; cell phone: +62 81 2803 0931
E-mail address: email@example.com
GAE Gallic Acid Equivalents, is an expression of total phenol content (mg · g–1)
SI Stimulation Index, is average optical density of treatment (with stimulation) / average
optical density without stimulation (medium only), [%]
RSA Radical Scavenging Activity, [mg BHA equivalent · g–1]
rpm revolutions per minute, 1 hertz is equal to 60 rpm
© 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
Peer-review under responsibility of the Scientiﬁ c Committee of HK-ICONS 2014
302 Noer Laily et al. / Procedia Chemistry 14 ( 2015 ) 301 – 307
Guava (Psidium guajava L.) has been used traditionally in the treatment of various diseases. In Indonesia, Guava
leaf is commonly used to treat diarrhea, gastroenteritis and other digestive complaints, while the Guava fruit has
been used to increase platelets in patients with dengue fever. Many studies have been done to scientifically prove
efficacy in the treatment of guava leaf. Among them were the benefits of guava leaf as a remedy antiarthritison
animal testing using hydro alcoholic extract1.
Another study proved that the flavonoids content in extract of guava leaves acts as an antibacterial activity, while
the antidiarrheal properties of guava leaf extract caused by quercetin content. Quercetin is one of the most abundant
flavonoids found in guava leaf. It is able to relax intestinal smooth muscle and inhibit bowel contractions2. Extract of
Guava leaves showed anti proliferative activity in vitro tests using leukemia cells. Its activity was 4.37 times more
than the activity of vincristine2. Moreover, water extract of guava leaves was described to be effective against a
number of microbial strains and anti-rotavirus activity3. Genotoxic studied of the P.guajava leaf has been done by
Ofodile et al.4. Genotoxicity and mutagenicity testing were an important part of the hazard assessment of chemicals
for regulatory purposes5. The water extract of Guava was effective in inactivating the mutagenicity of direct acting
The ability of guava leaf extract on the treatment of various diseases has been proven scientifically, but the
mechanism hasn’t been fully explained. In general, biological properties of guava have been already associated with
its polyphenolic compounds, such as protocatechuic, ferulic, ascorbic, gallic and caffeic acids and quercetin6.
Polyphenols are secondary metabolites of plants. In the last decade, there has been much interest in the potential
health benefits of dietary plant polyphenol as antioxidant7. The polyphenol compounds in the extract of guava fruits
and leaves can act as an immunostimulant that may lead to an increase in the immune system. Increasing the body's
immune system can keep the body from various infectious diseases. A well-functioning immune system is crucial
for staying healthy. Therefore, the potential of natural substances to strengthen the immune system has long been the
subject of investigation8. There were many synthetic and natural preparations claiming to be immunostimulants.
They seemed to represent useful alternative to vaccination and chemotherapy in the control of disease.
Immunostimulants from natural substances could enhance the specific immune respone9.
The presence of active compounds in food plants or herbs that are beneficial to health can be used as a source of
functional ingredients. Functional ingredient is a bioactive compounds present as natural constituents or as
fortification in food having the potential to provide health benefits beyond the basic nutritional value of the
product10. Some natural substance that can act as an immunostimulant was polysaccharides11, peptides12, oligo-
nucleotide13, and antioxidant14.
The modulation of immune response by using medicinal plant products as a possible therapeutic measure has
become a subject of active scientific investigation. This study aim was to determine the potential of guava leaf as an
immunostimulant. In addition we would also determine a group of active compounds that play a role in immune
2. Material and methods
Dried mashed of guava (P.guajava) leaves, Folin-Ciocalteau’s reagent, and gallic acids (Sigma-Aldrich, St.
Louis, MO, USA) as standard, ethanol absolute, Na2CO3, 1,1-diphenyl-2-picrylhydrazyl (DPPH), Ficol-Hypaque
solution form Sigma, Roswell Park Memorial Institute medium (RPMI)-1640, concovalin A (Con A) (Sigma),
lipopolysaccharides (LPS) (Sigma), penicillin-streptomycin, 3-(4,5-dimethyl thiazole-2-yl)-2,5-diphenyl
tetrazoliumbromide(MTT) (Sigma), tryphan blue, EDTA-Na2H2 · 2H2O, phosphate buffer saline (PBS), Tris-HCl
buffer, 3-tetra-butyl-4-hydroxyanisole (BHA).
Noer Laily et al. / Procedia Chemistry 14 ( 2015 ) 301 – 307 303
2.2. Preparation of the extract
2.2.1 Water extracts
1 g dried mashed of Guava leaves was extracted with 50 mL of boiling water 100 °C for (5, 10, 15 and 20) min.
The obtained Guava leaf extract was filtered using a vacuum pump with filter paper (Whatman No. 1) and
evaporated using rotary evaporator to obtain the final extract volume of 10 mL.
2.2.2 Ethanol extracts
1 g dried mashed of Guava leaf was extracted with 100 mL of 96 % ethanol and shaked at room temperature
with periodical mixing (240 rpm) for (1, 6, 12 and 24) h, and then obtained Guava leaf extract was filtered using a
vacuum pump with filter paper (Whatman No. 1). The residual matter on the filter paper was added with another
ethanol solvent and the extraction was repeated three times. All extracts were collected and mixed into one bigger
glass, and were evaporated under reduce pressure using rotary evaporator at around 50 °C to 55 °C until the solvent
had evaporated (9 mL). The evaporated extract was added with aqueous 96 % ethanol until 10 mL. The supernatant
as the ethanol extract solution was used in this study
2.3. Determination of phenol total content
The phenolic total content was determined by the method of Singleton and Rossi15, by using gallic acids as a
2.3.1 Preparation of reagents.
Gallic acid standard solution (5 mg · mL–1) : 0.25 g of gallic acid was added with 5 mL of 96 % ethanol and
distilled water to a volume of 50 mL.
20 % Na2CO3 solution : 5 g Na2CO3 was added with 20 mL of distilled water, and heated to boiling. Let stand for
24 h, filtered and diluted with distilled water to 25 mL
2.3.2 Preparation of the calibration curve of gallic acid with Folin-Ciocalteu reagent
Stock solution was prepared by dissolving 5 mg of gallic acid in 1 mL of distilled water. (300, 400, 500, 600, and
700) mg · L–1 gallic acids standard solutions were prepared by diluting stock solution step by step with distilled
water (6 mL, 8 mL, 10 mL, 12 mL, 1 mL of stock solution was diluted with distilled water to a volume of 100 mL).
Assay: 0.0395 mL of each standard was added with distilled water up the volume to 0.5 mL and dissolved with
2.5 mL of Folin-Ciocalteu’s reagent (diluted in water 1 : 10) was placed in tubes and, after 8 min, 7.5 mL of sodium
carbonate (20 %) were added. The tubes were kept away from the light and, after two h, the absorbance was read in
a spectrophotometer (Hitachi, Japan) at 765 nm. The total phenolic content was expressed as mg/g gallic acid
2.3.3 Determination of total phenolic content
Determination of total phenol content was done based on the reaction between phenol compounds with
phosphomolybudate-phosphotungstate reagent (Folin-Ciocalteu solution) and will give a yellow color, and the
addition of an alkali will produce a blue color.
A volume of 0.5 mL of the extract and 2.5 mL of Folin-Ciocalteu’s reagent (diluted in water 1 : 10) was placed
in tubes and, after eight min, 7.5 mL of sodium carbonate (20 %) was added. The tubes were kept away from the
light and, after 2 h, the absorbance was read in a spectrophotometer (Hitachi, Japan) at 765 nm. The total phenolic
content was expressed as mg · g–1 of GAE.
304 Noer Laily et al. / Procedia Chemistry 14 ( 2015 ) 301 – 307
2.4. Measurement of DPPH radical scavenging activity (RSA)s
2.4.1 Preparation of reagents
0.2 mM DPPH solution: Dissolved 19.7 mg of DPPH in 250 mL of absolute ethanol. Freshly prepare every time
100 mMTris-HCl buffer: Dissolved 12.1 g of Tris in 800 mL of distilled water and adjusted the pH to 7.4 with
HCl, then fill up a volume to 1 000 mL
BHA standards: 5 mM stock solution was prepared by dissolving 90 mg of BHA in 100 mL absolute ethanol.
Standard solutions (50 μM to 500 μM) were prepared by diluting stock solution with ethanol.
The scavenging activity of Guava leaf extracts on the DPPH radical were determined by a spectrophotometer
assay based on procedure described by Yamaghuci16.
The Guava leaf extract solution or BHA (0.2 mL) was mixed with 0.8 mL of 100 mMTris-HCl buffer. Add 0.2
mM DPPH ethanolic solution (1 mL), the mixture was vortex for 1 min and then left to stand at room temperature
for 20 min in the dark, and its absorbance was red at 517 nm. The ability to scavenge the DPPH radical was
calculated as BHA equivalent from the standard correlation obtained from BHA standards. Alternatively, the
activity is revealed as percentage according to the following formula given by Yamaguchi. The content of
antioxidant was expressed as mg BHA equivalent/g.
% RSA which was calculated as a percentage of DPPH discoloration, A is absorbance of control and B is
absorbance of sample.
2.5. Immunostimulatory test
Immunostimulatory activity was tested in vitro using lymphocyte proliferation test by assay17.
2.5.1 Lymphocyte isolation
Human lymphocyte was isolated from peripheral blood by centrifugation based on Ficol-Hypaque differential
density. First centrifugation at 514 g for 10 min was aimed to separate cellular components. Red blood cells which
were heavier would be at the bottom while blood lymphocytes would be concentrated at the top of the solutions.
Buffy coat layer which mainly composed of human lymphocyte would be located in between those layers was taken
carefully and dissolved into 3 mL of RPMI basic media. The next step was separating the lymphocyte suspension in
basic media by following the suspension slowly on top of the Ficol-Hypaque solution to form two layers.
Centrifugation was done at 1 430 g for 30 min to get granulocyte and red blood cells in the bottom while
lymphocyte, monocyte and platelets on the top. The top layer was washed 2 times with basic media and centrifuged
at 228 g for 30 min to get the lymphocyte on the precipitate. Lymphocyte cells were counted by trypan blue method
and dissolved into RPMI media to get 106 cells · mL–1.
2.5.2 Lymphocyte proliferation response analysis with MTT assay
80 μL lymphocyte suspension cells (106 cells · mL–1) grown on RPMI were dispensed into micro wells. Into
each well, 20 μL pomegranate extract with various concentrations were added. Final concentration for each extract
A - B
% RSA = ----------- x 100%
Noer Laily et al. / Procedia Chemistry 14 ( 2015 ) 301 – 307 305
was 0.1 μg . mL–1, 0.25 μg . mL–1, and 0.5 μg . mL–1. As control, RPMI 1 640 media without extract was used.
Incubation was done for 72 h at CO2 incubator. Following incubation, the cells were treated with MTT and were
incubated further for 4 h. Lymphocyte proliferation activity was expressed as % Stimulation Index (% SI).
Measurement was done using ELISA reader.
Where SI is stimulation index, T is optical density of treatment (with stimulation) and C is optical density of control
(without stimulation, medium only), [%]
3. Results and discussion
Extraction is influenced by the type of solvent, temperature and time. Solvents often used for extraction of
phenolic compounds are methanol, ethanol, acetone, water, ethyl acetate, propanol and combinations of these
solvents. However, there is no suitable solvent used for isolation of the whole phenolic components. In this research,
the extraction process had been done by using water and 96 % ethanol. The result of different extraction times and
solvents used on optimization of extraction can be seen in Figure 1 (a) and (b). In water solvent, the highest phenol
total content occurred in the extraction time 20 min. While extraction used ethanol solvent, the highest phenol total
content was achieved at extraction time 6 h. In both conditions, the phenol total content of water and ethanol extract
were not significantly different, 101.93 and 101.20, respectively. However, parameters measured in this study could
not explain why the polyphenolic compounds in the water and ethanol extracts were similar.
The time required to extract the active compounds depend on the amount of active compounds to be extracted
and the solvent used. The more active compounds content, the extraction time required would be longer. The
optimum time required to extract polyphenolic compounds from guava leaves with ethanol was 6 h. In the
subsequent extraction time, the amounts of polyphenolic compounds were relatively stable or decrease. Decreased
levels of phenol content in the extraction of 12 h and 24 h (Fig. 1a), may be caused by the destruction of
polyphenolic compounds due to prolonged contact with solvents.
Deny et al.6 found that the phenolic total content of ethanol extract from Guava pomace was (3.40 ± 0.09) mg
GAE · g –1. In this study, the extraction time used was 30 min by ethanol solvent. While other researchers used 75 %
acetone as a solvent for 24 h extraction time at room temperature produced phenolic content of Guava extract was
44.05 mg GAE · g–1 18. Such difference between the values of phenol total obtained showed that the values of phenol
total produced depend on the type of solvent, extraction time and part of the plant used. In this study we used Guava
SI = ---------- ×100 %
Fig.1. (a) average of phenol total content in ethanol extract at different time extractions;
(b) average of phenol total content in water extract at different time extractions.
306 Noer Laily et al. / Procedia Chemistry 14 ( 2015 ) 301 – 307
leaf, while other studies used waste Guava6 and Guava fruit18. Guava fruit had high levels of polyphenolic
compounds such as myricetin and apigenin, ellagic acid, and anthocyanins16. While Guava leaf contained
polyphenolic compounds such as isoflavonoids, gallic acid, catechin, epicathechin, rutin, naringenin, kaempferol19.
The measurement result of antioxidant content in ethanol and water extracts showed difference. Antioxidant
content of ethanol extract was higher than water extract (Table 1). Water is a common solvent used in the extraction
process, but ethanol has a greater polarity than water, so it can dissolve more polar compounds contained in the
sample than water solvent. Kim et al.20 mentioned that the extraction efficiency of the bio-active ingredients was
correlated with the solvent polarity.
Table 1. Comparison of stimulation index, antioxidant and phenol total contents in water and ethanol extracts
Phenol total content (mg GAE · g–1)
Antioxidant content (mg BHA eqv · g–1)
Stimulation Index (%)
The level of antioxidant in the leaf extract was higher than that in fruit extract (1.426 mg · g–1 and 0.722 mg · g–1
in white and pink pulp18. While the level of antioxidant in the steam bark extract was 1.12 mg · g–1 21. Barbalhoet
et al.19 have reported the presence of higher amounts of phenolic compounds with antioxidant activity in the leaf of
white (P.guajava var. pyrifera L.) and red guava (P.guajava var. pomifera L.) when compared with other vegetable
There were no linier correlation between radical scavenging activity and phenolic content (Table 1). This result
was in contrast to Asha et al.22 which had found that phenolic compounds mainly responsible factor for the high
antioxidant activity in Guava, a strong positive correlation was found between antioxidant activity and phenolic
compounds. Asha et al.22 used Guava fruit, while in this study we used Guava leaf. Joseph and Priya2 mentioned that
there were differences in the active compounds in the Guava leaf and fruit.
Many researchers have been demonstrating the presence of a wide variety of bioactive compounds in the leaf of
P.guajava that are capable of showing beneficial effects on human health. Extract of Guava leaves has analgesic,
anti-inflammatory, antimicrobial, hepato protective and antioxidant activities. These effects are probably due to the
presence of polyphenolic compounds19.
The potential extract of Guava leaves as an immunostimulatory agent had been measured in this study. The
immunostimulatory activity was expressed as % Stimulation Index (% SI). The result of immunostimulatory activity
of the water and ethanol extract showed on Table 1. There were no differences in percent of stimulation index of the
water and ethanol extract. These values had correlation to the phenol content in these extracts, but not with the
antioxidant content. Immunostimulatory activity of the extract was influenced by the type of active compounds. The
active compounds in guava leaf extract that contributes to the immunostimulatory activity were probably not only
Guava leaf had high contents of polyphenolic compounds and antioxidant, and high activity of immunostimulant
(Table 1). Compared with LPS as a comparison sample, the percent of stimulation index of water and ethanol
extracts were 12.7 times and 12.5 times, respectively. While for Con A as a comparison sample, the percent of
stimulation index of water and ethanol extracts were 5.4 times and 5.3 times, respectively. These indicated that
guava leaf was excellent source of active compounds for immunostimulatory functional ingredient additives.
Guava leaf has great potential to be developed as functional ingredients. Firstly, they are widely available, with a
guaranteed supply. Secondly, guava leaf naturally occurring compounds, and their extraction is relatively cost
effective. Lastly, they contained high level of antioxidant, phenolic compound and biological activities as
Based on the measurements results of phenol total content, antioxidant and immunostimulant activity, the active
compounds of the guava leaf expected to have immunostimulatory activity were probably not only polyphenolic
Noer Laily et al. / Procedia Chemistry 14 ( 2015 ) 301 – 307 307
antioxidant compounds. Further research is needed to determine the active compounds that act as
immunostimulatory agents from extract of guava leaves.
This work is supported through PPKP program, funded by the Ministry of Research and Technology, Indonesia
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