In Vitro and In Vivo Neutralizing Activity of Uvaria chamae Leaves Fractions on the Venom of Naja nigricollis in Albino Rat and Bovine Blood.

BACKGROUND: Snakebite envenomation is a global priority ranked top among other neglected tropical diseases. There is a folkloric claim that Uvaria chamae is beneficial for the management of snakebite and wounds in African ethnobotanical surveys. Besides, there are many registered patents asserting the health benefits of U. chamae. OBJECTIVE: This study aimed to investigate U. chamae's potentials and identify candidates for the development of tools for the treatment and management of N. nigricollis envenomation. METHODS: Freshly collected U. chamae leaves were air-dried, powdered, and extracted in methanol. The median lethal dose of the extract was determined and further fractionated with n-hexane, n-butanol and ethyl acetate. Each fraction was tested for neutralizing effect against venom-induced haemolytic, fibrinolytic, hemorrhagic, and cytotoxic activities. RESULTS: U. chamae fractions significantly (p<0.05) neutralized the haemolytic activity of N. nigricollis venom in n-butanol; 31.40%, n-hexane; 33%, aqueous residue; 39.60% and ethyl acetate; 40.70% at the concentration of 100mg/ml of each fraction against 10mg/ml of the snake venom when compared to the positive control. The fibrinolytic activity of N. nigricollis venom was significantly (p<0.05) neutralized in n-hexane at 73.88%, n-butanol; 72.22% and aqueous residue; 72.22% by the fractions of U. chamae. In addition, haemorrhagic activity of N. nigricollis venom was significantly (p<0.05) neutralized by U. chamae fractions at the concentrations of 100mg/ml, 200mg/ml and 400mg/ml except for n-butanol and aqueous residues at 400 mg/ml. CONCLUSION: U. chamae leaves fractions possess a high level of protection against N. nigricollis venoms-induced lethality and thus validate the pharmacological rationale for its usage in the management of N. nigricollis envenomation.

Anti-proliferative study and isolation of Ochnaflavone from the ethyl acetate-soluble fraction of Ochna kibbiensis Hutch & Dalziel.

Anti-proliferative activity of the ethyl acetate fractions of Ochna schweinfurthiana F. Hoffm. and Ochna kibbiensis Hutch. and Dalziel methanol leaf extracts were investigated against glioblastoma multiforme (GBM U-1242 MG) cell line. O. kibbiensis significantly (p < 0.001) and dose dependently (IC50 = 25.74 µg/mL) reduced cell count. At 125 µg/mL, O. kibbiensis extract reduced cell count by about 92% compared to the untreated control. On the other hand, at 125 µg/mL, O. schweinfurthiana extract reduced cell count only by 20%, indicating a much weaker activity (IC50 = 823.51 µg/mL). Following from the result obtained, ethyl acetate fraction of O. kibbiensis was subjected to chromatographic purification. This led to the isolation of ochnaflavone; the structure of the isolated compound was identified by analysis of its nuclear magnetic resonance (NMR) spectral data and comparison with data in the literature. Although the isolated ochnaflavone could not be tested for anti-proliferative activity due to insufficient quantity, the obtained results indicate the presence of bioactive anti-GBM principles in O. kibbiensis.

Neurobehavioural evaluation of Lophira alata (Ochnaceae) stem bark extract in mice.

BACKGROUND: Stem bark and leaves of Lophira alata (Family: Ochnaceae) have been used traditionally for their anti-psychotic, anti-convulsant and anxiolytic properties. Since no existing data was found on the neurobehavioural properties, this study was carried out to evaluate some neurobehavioural properties of the aqueous extract of the stem bark of L. alata in animal models. METHODS: The oral mean lethal dose (LD50) of the extract was estimated, and preliminary phytochemical screening was conducted. Lophira alata extract (200, 400 and 800 mg/kg, p.o.) was investigated for antidepressant effect using the forced swim and tail suspension tests, and the anxiolytic potential was assessed using the stair case and hole board tests. Pentylenetetrazole-induced convulsion test was used to investigate the anticonvulsant potential of the extract. RESULTS: The LD50 was estimated to be >5000 mg/kg. Oral administration of L. alata extract produced a significant (p<0.05) non-dose-dependent decrease in the period of immobility in both the forced swim and tail suspension tests. While a significant decrease (p<0.05) in episodes of grooming was recorded in the staircase test, the number of head dips was not significantly reduced (p>0.05) in the hole board test. In the pentylenetetrazole-induced convulsion, a non-dose-dependent increase in onset of tonic-clonic seizures and protection from death was recorded. CONCLUSIONS: The results obtained suggest that the aqueous stem bark extract of L. alata possesses neurobehavioural properties which may account for its use in ethnomedicine.