Agriculture Reference
In-Depth Information
yellow, usually 2.5-10 cm long and 2.5-5 cm in diameter, although horticulture varieties with larger
fruits are common. They contain many seeds, and the calyx persists in fruit.
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Habitat and Distribution —
The plant is a native of Central America but is found all over
Africa in semicultivation.
Ethnomedicinal Uses —
The fruits are edible, and the juice is used as a refreshing drink. The
major ethnotherapeutic use of the plant is in malaria; for this purpose, its leaves are used as an
ingredient in the preparation of fever teas. The leaves are also used as part of the potherb in steam
treatment of malaria. A weak infusion of the leaves and tender branches is dispensed for diarrhea
and as a tonic in psychiatry.
Constituents —
The fruits are rich in vitamins (A and C), iron, calcium, and phosphorus.
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The essential oil from the leaves has been shown to contain caryophyllene, nerolidiol, β-bisabolene,
and β-sitosterol and ursolic, oleanolic, crategolic, and guayavolic acids.
494
The plant also contains
leukocyanidins, sterols, and gallic acid in the roots.
494
Pharmacological Studies —
The aqueous alcohol extract has been shown to exhibit sedative
activity. Oral doses of 188.5, 337, and 1131 mg/kg caused a significant dose-dependent decrease of
the motor activity for 90 min after the administration of the extract.
494
In rats, the plant significantly
decreased, in a dose-dependent manner, the intestinal transit time. It also showed
in vitro
antimi-
crobial activity against
Escheria coli, Salmonella typhi, Staphylococcus aureus, Proteus mirabilis,
and
Shigella dysenteria.
890,891
P. guajava
has been evaluated in many laboratory studies to validate its antispasmodic and anti-
microbial properties in the treatment of diarrhea and dysentery. It has also been used extensively as
a hypoglycemic agent. Literature is available on the ability of guava to exhibit antioxidant, hepato-
protective, antiallergic, antimicrobial, antigenotoxic, antiplasmodial, cytotoxic, antispasmodic, car-
dioactive, anticough, antidiabetic, anti-inflamatory, and antinociceptive activities, which provided
scientific rationale for its traditional uses.
Apart from its antihyperglycemic properties, guava may be beneficial for preventing cardiovas-
cular complications associated with diabetes. It has been established that nonenzymatic glycosyl-
ation (glycation) between reducing sugar and protein results in the formation of advanced glycation
end products (AGEs), which are believed to play an important role in diabetes-associated cardiovas-
cular complications. Thus, agents that inhibit the formation of AGEs are believed to have therapeu-
tic potential against diabetic complications. The antiglycative potential of the ethyl acetate fraction
of
Psidium guajava
has been evaluated by administering the extract to STZ-induced diabetic rats.
Daily administration of the extract for a period of 1 month significantly decreased the blood glu-
cose, glycated hemoglobin, and fructosamine levels in a dose-dependent manner. Evaluation of the
toxicity markers like SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic
pyruvic transaminase) revealed the nontoxic nature of the extract. The presence of the cardiac
isoform of liver alpha 2 macroglobulin, which is a major protein associated with earlier stages of
cardiac hypertrophy, was also evaluated. SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel
electrophoresis) analysis showed that the level of this protein decreased significantly in extract-
treated groups compared to a diabetic control.
892
A wide range of clinical applications has been suggested for the treatment of oxidative stress,
infantile rotaviral enteritis, diarrhea, and diabetes.
893
The dried leaves and extracts of the fruits have
been formulated as dietary supplements.
PUNICA GRANATUM
Botanical Name —
Punica granatum
L.
Synonym —
P. nana
L.
