SUB-CHRONIC TOXICITY OF METHANOL LEAF EXTRACT OF CRYPTOLEPIS OBLONGIFOLIA (MEISN) SCHLTR ON BIOCHEMICAL PARAMETERS AND MAJOR ORGANS OF WISTAR RATS

Abstract

Medicinal plants are used for primary healthcare needs of many populations across the globe. Efficacy and safety of
these plants must be established in order to maximize their therapeutic benefits and minimize harmful effects from
their long-term intake. Cryptolepis oblongifolia has been used in traditional medicine of African countries including
Nigeria for the treatment of fever, malaria, diarrhoea and stomachache. There is no adequate literature to suggest
previous scientific work on subchronic toxicity profile of the plant on biochemical parameters and internal organs.
This study aims to investigate the toxic effect of methanol leaf extract of Cryptolepis oblongifolia (MLECO) on
liver and kidney function parameters, haematological indices and histology of major organs of Wistar rats after
administration of the extract for 28 days. Fresh leaves of Cryptolepis oblongifolia were collected and extracted with
70% (v/v) methanol. Acute toxicity study and preliminary phytochemical screening were carried out. Twenty-four
(24) Wistar rats of either sex were used for the study. The rats were grouped into four groups of 6 rats each. Rats in
group I received 1 ml/kg of distilled water (Vehicle) and rats in groups II-IV received 375, 750 and 1500 mg/kg
graded doses of the extract. The rats were monitored for signs of toxicity, weight changes, food and water
consumption; and on 29th day the rats in the four groups were humanly euthanized and blood samples were collected
for liver and kidney function tests, heamatological parameters determination and major organs: heart, brain, liver,
kidney, lung and spleen were harvested for histopathological examination. The oral median lethal dose (LD50) of the
extract was > 5000 mg/kg; and preliminary phytochemical screening revealed the presence of alkaloid, phenols,
terpenoids, steroids, flavonoids, saponins, tannins and cardiac glycosides. There was no mortality during the 28-day
repeated oral toxicity study. The extract, at the doses of 375, 750 and 1500 mg/kg, showed no significant effect on
the body weight of the treated rats. The extract showed significant increase in the serum total protein at 375 mg/kg
with no significant effect on other liver function parameters. The extract also showed significant reduction (p < 0.05)
in serum chloride, total white cell counts and bicarbonate at the doses of 375 and 750 mg/kg. The MLECO showed
various degrees of histopathological changes in the heart, brain, kidney, liver, spleen and lungs after 28-day oral
administration of the extract. The MLECO was acutely non-toxic to the rats but has lowered the serum chloride,
bicarbonate and result in leucopenia after 28 days administration. The extract also induced various degrees of
histopathological changes in major organs of the treated rats.