26-06-2014, 10:09 AM
Psidium guajava: A review of its traditional uses,
phytochemistry and pharmacology
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Abstract
Psidium guajava, is an important food crop and medicinal plant in tropical and subtropical countries is widely used like food and in folk medicine
around of the world. This aims a comprehensive of the chemical constituents, pharmacological, and clinical uses. Different pharmacological
experiments in a number of in vitro and in vivo models have been carried out. Also have been identified the medicinally important phyto-constituents.
A number of metabolites in good yield and some have been shown to possess useful biological activities belonging mainly to phenolic, flavonoid,
carotenoid, terpenoid and triterpene. Extracts and metabolites of this plant, particularly those from leaves and fruits possess useful pharmacological
activities. A survey of the literature shows P. guajava is mainly known for its antispasmodic and antimicrobial properties in the treatment of
diarrhoea and dysentery. Has also been used extensively as a hypoglycaemic agent. Many pharmacological studies have demonstrated the ability of
this plant to exhibit antioxidant, hepatoprotection, anti-allergy, antimicrobial, antigenotoxic, antiplasmodial, cytotoxic, antispasmodic, cardioactive,
anticough, antidiabetic, antiinflamatory and antinociceptive activities, supporting its traditional uses. Suggest a wide range of clinical applications
for the treatment of infantile rotaviral enteritis, diarrhoea and diabetes.
© 2008 Published by Elsevier Ireland Ltd.
Introduction
Psidium guajava, which is considered a native to Mexico
(Rios et al., 1977) extends throughout the South America,
European, Africa and Asia. Based on archaeological evidence.
It has been used widely and known in Peru since pre-Columbian
times. It grows in all the tropical and subtropical areas of the
world, adapts to different climatic conditions but prefers dry
climates (Stone, 1970). The main traditional use known is as
an anti-diarrhoeal. Other reported uses include gastroenteritis,
dysentery, stomach, antibacterial colic pathogenic germs of the
intestine.
Its medicinal usage has been reported in indigenous system
of medicines in America more than elsewhere. Psidium guajava
Linn. (family Myrtaceae), is commonly called guave, goyave or
goyavier in French; guave, Guavenbaum, Guayave in German;
banjiro in Japanese; goiaba, goiabeiro in Portugal; arac¸ ´a-goiaba,
arac¸ ´a-guac¸ ´u, guaiaba in Brazil; guayaba, guayabo in Espa˜nol
and guava in English (Killion, 2000). Psidium guajava is a small
tree which is 10m high with thin, smooth, patchy, peeling bark.
Leaves are opposite, short-petiolate, the blade oval with prominent
pinnate veins, 5–15 cm long. Flowers are somewhat showy,
petals whitish up to 2 cmlong, stamens numerous (Stone, 1970).
Fruit are fleshy yellow globose to ovoid berry about 5 cm in
diameter with an edible pink mesocarp containing numerous
small hard white seeds. There has been a tremendous interest
in this plant as evidenced by the voluminous work. Therefore,
we aimed to compile an up to date and comprehensive review
of Psidium guajava that covers its traditional and folk medicine
uses, phytochemistry and pharmacology.
3.2. Antimicrobial
The inhibitory effects of aqueous and alcoholic extracts of
the Psidium guajava (root as well as leaves) on the growth
of Staphylococcus aureus, Streptococcus mutans, Pseudomonas
aeruginosa, Salmonella enteritidis, Bacillus cereus, Proteus
spp., Shigella spp. and Escherichia coli, causal agent of intestinal
infections in humans were examined using the in vitro agar
well diffusion method (Chah et al., 2006).
Methanolic root extract was further separated by column
chromatograph, yielding four antibacterial compounds. Three
antibacterial substances have been detected in the leaves which
are derivatives of quercetin (Prabu et al., 2006; Arima and
Danno, 2002).
In another study, itwas observed that methanolic extract from
fruit ripe have fungicidal action against Arthrinium sacchari
M001and Chaetomium funicolaM002strains (Sato et al., 2000).
Aqueous and methanolic extracts of the leaves are effective
inhibitors of growth spore formation, and enterotoxin production
of Clostridium perfringens type A. No enterotoxins were
detected when extracts were added to the media at less than the
MIC for growth (Garcia et al., 2002).
Psidium guajava leaf and bark tinctures were subjected to in
vitro sensitivity tests by serial dilution at concentrations ranging
from 5% to 15% against six test dermatophytes, viz., Trichophyton
tonsurans, Trichophyton rubrum, Trichosporon beigelii,
Microsporum fulvum, Microsporum gypseum and Candida albicans.
Bark tincture exhibited higher efficacy in controlling the
mycelial growth of dermatophytes than the leaf tincture.
The bark tincture showed fungicidal activity at different concentrations
but exhibited only fungistatic property in case of
Candida albicans (Dutta and Das, 2000).
Ethanolic extract from the shell of ripe fruit presenting activity
on Streptococcus mutans and Escherichia coli (Neira and
Ramirez, 2005). Results supported the utilization of Psidium
guajava in traditional medicine for intestinal diseases produced
by microorganisms.
3.3. Acne lesions
Acne vulgaris is a chronic inflammatory disease involving
colonization of Propionibacterium acnes, plus activation of neutrophils
and lymphocytes. Circumstantial evidence suggests that
antigen-independent and -dependent immune responses against
Propionibacterium acnes are involved in the pathogenesis of
inflammatory acne. Epidermal keratinocytes are also suggested
to be involved in initiation and progression of cutaneous inflammation.
Psidium guajava leaf extracts have potent antimicrobial
activities against Propionibacterium acnes and may be beneficial
in treating acne especially when they are known to have
anti-inflammatory activities (Qadan et al., 2005).
3.4. Effect on dental plaque
The adhesion of early settlers of dental plaque to the tooth
surface has a role in the initiation of the development of dental
plaque. The hydrophobic surface properties of the bacteria
cell wall are indirectly responsible for the adhesion of the bacteria
cell to the acquired pellicle on the tooth surfaces. Tooth
brushing is considered a superior technique for reducing plaque
accumulation. Chemical agents may be used to reduce plaque
accumulation on tooth surfaces. The treatment of the early
plaque settlers with 1 mg/ml aqueous extract leaf of Psidium
guajava reduced the cell-surface hydrophobicity of Staphylococcus
sanguinis, Staphylococcus mitis and Actinomyces sp. by
54.1%, 49.9% and 40.6%, respectively (Razak et al., 2006).
These results provide some scientific rationale for its use in
the treatment of dental diseases and suggested that guava leaf
extracts may inhibit the caries-inducing properties of Streptococcus
and thus may be beneficial for the dental care.
Infectious gastroenteritis
In the Laboratory of Medicinal Plants Research Unit of Neurological
Diseases, Mexico, a randomized double-blind trial
examined the efficacy of a standardized aqueous leaf extract
Psidium guajava ([QG-5] estimated at quercetin-equivalent
1mg per 500 mg capsule) versus placebo in 100 patients
with infectious gastroenteritis. The experimental group (n = 50)
received 1 capsule of QG-5 orally every 8 h for 3 days, while the
control group (n = 50) received the same regimen with matching
placebo capsules. Conventional oral rehydration therapy
was initiated in both groups. Outcome measures included number
of daily stools, consistency, presence of mucus, degree of
abdominal pain, number of spasms in 24 h, fever, and number of
vomiting episodes. Results indicated a significant difference in
outcome measures favouring the experimental group, mostly due
to an antispasmolytic effect, which helped reduce the number of
episodes of abdominal pain. No adverse effects were reported
for patients treated with QG-5 (Lozoya et al., 2002). Besides
constipation, no serious adverse reactions have been reported in
patients taking QG-5. Guava is commercially available in capsules,
liquids, powders, and tablets in a standardized form for
gastroenteritis.
In Cuba, a longitudinal randomized double blind study was
carried out among 100 adult patients with acute diarrhoea. The
effect of an oral treatment with 10 ml tincture from Psidium
guajava dissolved in water, every 8 h, on the treatment of diarrhoea
was determined. The results revealed that this 20% leaf
tincture significantly reduced the time to ceasing diarrhoea and
no adverse reactions were detected (Echemendia and Moron,
2004). Guava offers an effective and safe alternative treatment
for patient with diarrhoea disease.
Conclusion
The pharmacological studies conducted on Psidium guajava
indicate the immense potential of this plant in the treatment
of conditions such as diarrhoeal, gastroenteritis and
rotavirus enteritis, wounds, acne, dental plaque, malaria, allergies,
coughs, diabetes, cardiovascular disorder, degenerative
muscular diseases, inflammatory ailments including rheumatism
and menstrual pain, liver diseases, cancer, etc. Not surprisingly,
guava also exhibits antioxidant and anti-inflammatory effects as
oxidative injury underlies many of these diseases. However, the
diverse pharmacological activities of guava extracts and isolated
phytochemicals have only been assayed in in vitro tests using
laboratory animals, and the results obtained may not necessarily
be portable to the situation in humans. While there are gaps in
the studies conducted so far, which need to be bridged in order to
exploit the full medicinal potential of guava, it is still very clear
that this is a plant with tremendous widespread use now and also
with extraordinary potential for the future.Onthe basis of the low
toxicity of guava extracts and derived phytochemicals and their
use as nutraceutical (fruit) and medicinal (leaves, bark, seeds,
roots) agents, backed by proven activity of both the traditional
formulations (infusions, decoctions, tinctures) and their derived
phytochemicals (phenolics, flavonoids, carotenoids, triterpenes,
essential oil constituents and others), further research, clinical
trials and product development can only cement Psidium guajava
as a very important part of our biodiversity to respect and
sustainably use for generations to come.