The effects of sub-chronic administration of sub-lethal doses of amitraz/xylene on selected reproductive parameters of male Wistar rats.

This study investigated the effects of sub-chronic administration of sub-lethal doses of amitraz on some testicular parameters of Albino rats. Twenty-four adult male Albino rats (100 ± 10 g) randomly assigned into four groups were used for the study. Groups A, B and C received 10.0, 2.0 and 0.4 mg/kg amitraz in 10 ml/kg water while group D received equivalent volume of water orally and daily for 84 days. Serum testosterone levels (TESL) were assessed on days 0, 28, 56 and 84. Epididymal sperm reserve (ESR), testicular sperm reserve (TSR), testicular weight index (TWI) and testicular histology were evaluated at the end of the experiment. Results revealed dose-dependent reduction (P<0.05) in the mean TESL, ESR and TSR in the amitraz-treated groups as the dose of the amitraz increased. Histological study revealed testicular degeneration characterized by depopulation of seminiferous tubules and depletion of the spermatogenic cells in rats in group A. It was concluded that sub-chronic administration of sub-lethal doses of amitraz could lead to reduced sperm quantity.

The effects of combination of methanolic leaf extract of Azadirachta indica and diminazene diaceturate in the treatment of experimental Trypanosoma brucei brucei infection in rats.

OBJECTIVE: To investigate the effects of combination therapy of methanolic leaf extract of Azadirachta indica (A. indica) and diminazene diaceturate (DDA) in the treatment of experimental Trypanosoma brucei brucei (T. brucei brucei) infection in rats. METHODS: Acute toxicity study of the drug and extract combinations were done. Selection of the best drug and extract combinations was carried out using fifty four rats of both sexes separated into 9 groups. Three dose combinations were derived from selection of the best drug and extract combinations used for the final study viz: 7 mg/kg bw DDA plus 125 mg/kg bw extract (group B), 3.5 mg/kg bw DDA plus 250 mg/kg bw extract (group C), and 1.8 mg/kg bw DDA plus 500 mg/kg bw extract (group D). The final study had in addition to the three groups derived from the dose response study, four other groups viz: uninfected untreated negative control (group F), infected and treated with 3 000 mg/kg bw extract alone (group E), infected and treated with 7 mg/kg bw DDA alone (group A), and infected untreated positive control (group G). The parameters assessed were onset of parasitaemia (OP), level of parasitaemia (LOP), clearance of parasites post treatment (COPPT), relapse infection period (RIP), post infection survival period (PIST). RESULTS: There was no significant difference in OP between the groups (P < 0.05). One day post treatment, the mean LOP of groups A, B, and C were found to be significantly lower than that of group D which in turn was lower than that of group E and G respectively. The mean LOP of group E was significantly lower than group G two days post treatment and this trend continued throughout the experimental period. Mean COPPT of group D was significantly longer than that of groups A, C and B. There was no significant difference in the mean COPPT among groups B, C and A. The mean RIP of group D was significantly shorter than group C, and that of group C was significantly shorter than that of group A. There was no relapse of infection in group B. The PIST of group E did not differ significantly from group G. CONCLUSIONS: This experiment stands to conclude that combination of 125 mg/kg bw extract and 7 mg/kg bw DDA is very effective in the treatment of trypanosomosis, caused by T. brucei. This combination therapy proved to be better than single therapy of DDA.

Investigation of the antitrypanosomal activity of Buchholzia coriacea seed extract against a field strain of Trypanosoma congolense.

The antitrypanosomal activity of the methanol extract of Buchholzia coriacea seed against a field strain of Trypanosoma congolense was investigated using experimentally infected mice of both sexes. Monitoring of parasitaemia was by the rapid matching technique. When parasitaemia was approximately log 7.8 (63 × 10(6) parasites/ml), treatment with graded doses of the extract (250, 500 and 1000 mg/kg) was instituted for 5 consecutive days. Diminazene diaceturate (Dimivet SKM Pharma Pvt. Ltd.) was given at 3.5 mg/kg i.p. to the positive control mice. No significant differences in body weights were observed. The rectal temperatures of infected mice showed fluctuations. The PCV of infected mice were significantly (p < 0.05) lower than those of the uninfected controls. There was no significant difference between the PCV of the extract-treated and untreated animals. Parasitaemia increased steadily in the extract-treated and untreated mice groups till all the animals died. Three days post-treatment with diminazene diaceturate parasitaemia was cleared. Six days later, there was a relapse of infection. By the end of the experiment, a 50 % relapse rate was recorded in the diminazene diaceturate-treated group. The methanol extract of Buchholzia coriacea seeds did not show any antitrypanosomal activity in mice infected with Trypanosoma congolense at the doses tested.

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus (Amaryllidaceae).

The anti-snake venom activities of the methanolic extract of the bulb of Crinum jagus plant (Amaryllidaceae) were investigated in vitro and in vivo against the venoms of three notable snake species: Echis ocellatus, Bitis arietans and Naja nigricollis. The extract was prepared by cold marceration in 50% methanol at 37 degrees C with intermittent shaking for 48 h. An yield of 12.8% w/w dry extract was obtained. Oral administration of C. jagus extract (1000 mg/kg) protected 50% of mice, while injection of a 30 min pre-incubated mixture of the same dose of extract and venom gave 100% protection against the lethal effects of E. ocellatus venom (10 mg/kg, i.m.). The intraperitoneal administration of the extract at 250 mg/kg, 30 min before the injection of E. ocellatus venom (10mg/kg, i.m.), significantly (p<0.05) prolonged the death time of poisoned mice. C. jagus extract (500 mg/kg, per os), gave 50% protection against B. arietans venom (9.5mg/kg, i.m.) in mice while the pre-incubation of a mixture of the same dose of venom and extract (500 mg/kg), prior to injection (i.p.) of the mixture, gave only 33.3% protection. The pre-incubation of 500 mg/kg of C. jagus extract with N. nigricollis venom (6 mg/kg) prior to i.p. injection of the mixture protected 50% of the treated mice. There were generally no significant differences in the death times of mice that were given the same dose of the extract orally 30 min before injection of the venoms and those administered with the pre-incubated mixtures of venom and extract. The pre-incubation of the extract and E. ocellatus venom (5mg/kg) for 30 min, before the i.m. injection of the mixture, significantly reduced infiltration of inflammatory cells to the site of injection 4h post treatment. The concentrations of plasma creatine kinase in poisoned mice were significantly (p<0.01 or p<0.05) reduced after the injection (i.p.) of C. jagus extract (1000 mg/kg) pre-incubated with E. ocellatus (5mg/kg) or B. arietans (7 mg/kg) venom, respectively. The bulb extract of C. jagus blocked the haemorrhagic activity of a standard haemorrhagic dose (2.8 mg/ml) of E. ocellatus venom at various concentrations (1.7, 3.3 and 6.7 mg/ml). The methanolic bulb extract of C. jagus was therefore able to significantly protect mice from death, myonecrosis and haemorrhage induced by the lethal effects of venoms of notable snake species in Nigeria.

Investigations of the methanolic leaf extract of Costus afer. Ker for pharmacological activities in vitro and in vivo.

The methanolic leaf extract of Costus afer. Ker (family: Zingiberaceae) was investigated for some pharmacological effects in vivo and in vitro. Brine shrimp lethality test showed that the extract was significantly (p < 0.05) cytotoxic with LC50 of 21.3 ppm. The extract showed moderate local anesthetic property, about twice less than lignocaine of the same concentration, on guinea pig wheal test. The extract contracted the guinea pig ileum in a concentration-dependent manner, but had no effect on pleuripara and nullipara non-gravid uteri at progestogenic and estrogenic phases respectively. The contractile effect on the guinea pig ileum was partially inhibited by atropine but completely reversed by adrenaline. The extract induced expulsion of whole fetuses still enveloped within the placental membrane at the 3rd trimester of pregnancy. The extract exhibited a biphasic antihyperglycemic activity. At 200 mg/kg body wt., p.o., it decreased the blood glucose level by 50% in Streptozotocin-induced hyperglycemia in male rats in 60 minutes post dosing. However, doses above 200 mg/kg body wt., p.o., caused increase in blood glucose level, potentiating the action of STZ. At 10 microg/ml the extract induced about 98% glucose uptake in differentiated 3T3-L1 adipocytes when compared with insulin (340 nm).

The antisnake venom activities of Parkia biglobosa (Mimosaceae) stem bark extract.

Snake bites in rural Nigeria are commonly treated with plant extracts. We have studied the ability of one such traditionally used plant (Parkia biglobosa; [Jacq.] Benth., Mimosaceae) to reduce the effects of two snake venoms (Naja nigricollis, and Echis ocellatus) in several experimental models. A water-methanol extract of P. biglobosa stem bark significantly (p<0.001) protected the chick biventer cervicis (cbc) muscle preparation from N. nigricollis venom-induced inhibition of neurally evoked twitches when it was added to the bath 3-5 min before or after the venom. The extract also reduced the loss of responses to acetylcholine (Ach), carbachol and KCl, which are normally blocked by N. nigricollis venom, and significantly reduced the contractures of the preparation induced by venom. P. biglobosa extract (75, 150 and 300 microg/ml) significantly (p<0.05) protected C2C12 murine muscle cells in culture against the cytotoxic effects of N. nigricollis and E. ocellatus venoms. The extract protected egg embryos exposed to lethal concentrations of E. ocellatus venom for more than 12 h and completely blocked the haemorrhagic activity of the venom at concentrations of 5 and 10 microg/1.5 microl. P. biglobosa extract (400 mg/kg) did not protect mice injected i.p. with 5 and 2.5 mg/kg of E. ocellatus and N. nigricollis venoms, respectively. It, however, protected 40% of the mice from death caused by E. ocellatus venom after the extract and venom were pre-incubated for 30 min before injecting the mixture.

A preliminary evaluation of antifertility activity of a triterpenoid glycoside (DSS) from Dalbergia saxatilis in female Wistar rats.

Antifertility activity of a triterpenoid glycoside, DSS, isolated from the root of Dalbergia saxatilis was investigated in female Wistar rats of breeding age. When administered by gastric intubation at a dose rate of 200 mg kg(-1)body weight at the premating period, conception was inhibited in 71.4% of the treated animals. Fertility Index (FI) for this group was 107.82 compared with 373.5 value for control rats that received 30% aqueous Tween 20 vehicle. DSS, did not significantly alter the fertility of rats at the first and second trimesters of pregnancy but did cause a significant decrease (P<0.05) in the mean Day 20 foetal crown-rump length when administered at the premating period and at the third trimester of pregnancy; with a concurrent decline in the mean maternal body weights. The potential use of DSS as a chemosterilant in fertility control are discussed.

The antiinflammatory activity of Icacina trichantha tuber.

Five fractions (hexane, chloroform, ethylacetate, methanol and water) of Icacina trichantha tuber were obtained by gradient solvent extraction and tested for their ability to inhibit the Croton oil-induced ear edema in mice. The most active fraction was the chloroform one which significantly inhibited ear edema in a dose-dependent manner, showing an ID50 (dose giving 50% edema inhibition) of 107 micrograms/cm2. The ID50 of the reference drug indomethacin was 93 micrograms/cm2. The chloroform fraction significantly reduced also the carrageenin-induced paw edema in rats, after oral adiminstration: 50, 100 or 200 mg/kg of the fraction reduced the global edematous response by 15, 20 or 34%, whereas 10 mg/kg of indomethacin induced 40% inhibition.

The antiinflammatory activity of extracts from the root of Combretum dolichopetalum.

The methanol and chloroform extracts of the root of Combretum dolichopetalum were obtained and gave yields of 6.48% w/w and 0.38% w/w respectively. The methanol extract significantly inhibited carageenin-induced mouse paw edema in a dose-dependent manner after an oral treatment. The maximum effect was achieved at a dose of 600 mg/kg and the result was comparable to that of indomethacin (10 mg/kg). The antiinflammatory activity of the chloroform extract against croton-oil induced mouse ear edema was significant (p < 0.001) and increased with the dose. The maximum effect (93%) was achieved with 1.0 mg of the extract per ear.

Search for the centrally active component of Icacina trichantha tuber.

The chloroform extract of Icacina trichantha tuber was obtained after defatting with petroleum ether by overnight maceration. The extract gave a yield of 0.67% w/w after drying in a hot air oven at 40 °C. The dried residue was extracted with 50% methanol and gave a yield of 4.8% w/w. An extract of the freshly dried tuber with 50% methanol gave a yield of 4.98% w/w. The chloroform extract potentiated pentobarbitone induced sleeping time in mice dose-dependently. It also induced significant analgesia and muscle relaxant effects in mice. Mice poisoned with a convulsive dose (100 mg/kg) of pentylenetetrazole were significantly (60%) protected by the chloroform extract. Proportionate doses of the extracts based on their percentage yields were comparatively tested for analgesia in mice and the results obtained showed that the chloroform fraction alone exhibited almost the entire CNS activity.

The anthelmintic effects of the leaf extract of Ocimum gratissimum (L.).

The leaf extract (F005) of Ocimum gratissimum was isolated by a bioassay-guided chromatographic separation technique using the brine shrimp lethality test assay. The effects of various concentrations (0.5, 1.0, 2.0, 4.0, and 8.0 mg/ml) of F005 were tested in vitro on infective larvae (L(3)) of Haemonchus contortus and Heligmosomoides polygyrus. Cockerels experimentally infected with Ascaridia galli infective eggs were also treated with various doses (500, 1000, and 1500 mg/kg) of F005 in vivo. F005 produced 15% and 16.6% paralysis of H. contortus and H. polygyrus larvae, respectively, at 8 mg/ml. It induced significant anthelmintic effect in chicks infected with A. galli in a dose-dependent manner with 1,500 mg/kg producing the highest effect (55.8%).

The effects of hyperosmolar agents lithium chloride and sucrose on the brain concentration of diminazene aceturate in rats.

The concentrations of diminazene aceturate in the brain of Trypanosoma brucei brucei infected and uninfected rats treated with diminazene aceturate (3.1 mg/kg, im) and either LiCl (2.5, 5.0 and 10 micrograms/kg) or sucrose (0.25, 0.5 and 1.0 g/kg) were determined. When diminazene aceturate was administered at a standard dose of 3.1 mg/kg (im), the addition of LiCl (10 micrograms/kg, im) increased significantly (P < 0.05) the concentration of the drug in the brains of both trypanosome infected and normal infected rats. The addition of sucrose (1.0 g/kg, im) instead of LiCl failed to give any significant increase in diminazene aceturate levels in the brain. The diminazene aceturate levels were significantly (P < 0.05) higher in the organs (brain, kidney, liver and spleen) of trypanosome infected compared to uninfected rats. The concentration of diminazene aceturate in the organs increased significantly (P < 0.05) with increasing concentrations of LiCl.

The chemotherapeutic efficacy of diminazene aceturate and lithium chloride against relapse infection of Trypanosoma brucei brucei in rats.

The chemotherapeutic efficacy of diminazene aceturate (Berenil) and lithium chloride (LiCl) in relapse infection of trypanosomiasis was investigated in rats experimentally infected with Trypanosoma brucei brucei. The study showed that the combination of diminazene aceturate at (7 mg/kg) and LiCl (10 micrograms/kg) appeared more effective therapeutically than diminazene aceturate, or diminazene aceturate and LiCl and dexamethasone group, as more of the rats in the diminazene aceturate and LiCl treated-group remained aparasitaemic for longer days (60 days). Relapse parasitaemia occurred on days 10 and 12 in diminazene aceturate (7 mg/kg); diminazene aceturate (7 mg/kg) and LiCl (10 micrograms/kg) plus dexamethasone (1 mg/kg) treated group respectively, while relapse parasitaemia did not occur in the diminazene aceturate and LiCl treated group until day 20. Histopathological examination of the brain did not show any signs of inflammatory reaction in the diminazene aceturate and LiCl and dexamethasone treated group. However lesions associated with meningoencephalitis, such as cellular infiltration of mononuclear cells, perivascular cuffings and perivascular congestion and oedema were observed in the diminazene aceturate; diminazene aceturate and LiCl treated groups.

Effects of Morinda lucida leaf extract on Trypanosoma brucei brucei infection in mice.

The dried leaves of Morinda lucida were extracted with 50% methanol and the extract was recovered in a 9.7% w/w yield. Acute toxicity tests were performed in mice and the intraperitoneal LD50 of the extract was 2000 mg/kg. The extract induced purgation in mice from the first hour after oral administration and reached its peak between the third and fourth hour. The purgation was not dose-dependent. M. lucida leaf extract i.p. significantly suppressed the level of parasitemia after Trypanosoma brucei infection in mice. Suppression of existing parasitemia appeared dose-dependent with 1000 mg/kg i.p. producing the maximum effect. The best trypanocidal activity was obtained when treatment with M. lucida extract commenced simultaneously with trypanosome inoculation.

Effects of chronic oral administration in mice of the gut-stimulating crystals of Croton penduliflorus seed oil.

Crystals from Croton penduliflorus seeds (CPC) were administered at weekly intervals in two doses (7 mg/kg and 21 mg/kg) by gastric intubation to mice over 12 weeks. CPC induced purgation in the treated mice, with the higher dose having a more profound effect. Mice treated with CPC developed skin lesions with swollen scrotums. There were significant changes in the PCV, Hb and plasma proteins of treated mice. Gangrene of the tail with subsequent sloughing was observed, particularly in the low dose group. Mice in the low dose group also experienced retarded growth. A significant clinical finding in the treated mice was abortion during late pregnancy and 100% fetal mortality. It was concluded that, apart from its purgative effect, CPC can cause toxic effects in chronic administration. Use in pregnant women should be discouraged.

Screening of Icacina trichantha extracts for pharmacological activity.

Some preliminary studies were conducted on the biological activities of Icacina trichantha in mice. In vitro tests performed with the 70% ethanol, petroleum ether and aqueous extracts of tubers, roots, stems and leaves did not show contraction of isolated guinea pig ileum up to a bath concentration of 40.5 mg/ml. Graded oral doses (100, 200, 400 and 800 mg/kg) of the aqueous extract of tubers produced wet faeces in mice with the number of wet faeces increasing with increasing dose up to 400 mg/kg. A time-course study of the purgative effect showed the maximum purgative response to be 7-8 h after oral dosing. The aqueous extract of tubers significantly potentiated pentobarbital-induced loss of righting reflex at a dose of 80 mg/kg i.p. but this dose did not protect mice from strychnine or leptazole convulsions and death.

Effects of the gut-stimulating principle in Croton penduliflorus seed oil on the central nervous system.

The gut-stimulating principle in Croton penduliflorus seed oil isolated as white crystals (CP crystals) significantly reduced pentobarbitone-induced sleeping time in mice at doses of 3 and 6 mg/kg intraperitoneally. Indomethacin (4 mg/kg) and atropine (0.044 mg/kg) significantly reversed the action of CP crystals on pentobarbitone sleeping time with indomethacin having a profound reversal effect. CP crystals significantly reduced the mean onset of convulsions and the mean death time in mice treated with a surely convulsive dose of strychnine. CP crystals significantly reduced the intensity of morphine and pethidine analgesia and prolonged the duration of pethidine analgesia. Most actions of CP crystals suggest that it stimulates the CNS and reduces the intensity of opioids (except codeine) while prolonging their duration of analgesic action.

The toxic effects of a chronic administration of the gut-stimulating principle in Croton penduliflorus hutch. seeds in mice.

Albino mice (8-10 wks) weighing between 14 and 25 g were divided into 2 groups and dosed orally once per week with 2 doses (7 mg/kg and 21 mg/kg) of the gut-stimulating principle in Croton penduliflorus seeds (CP crystals) for 12 weeks. Some mice (3-4) from each group were killed at 10 days intervals for the first 6 wks of the experiment and at 20 days intervals for the last 6 weeks. Gross and histopathological changes in the brain, heart, liver, kidney, adrenal, spleen, testis, lung and various segments of the gastrointestinal tract including the stomach, duodenum, ileum and colon were observed. The relative weights of the visceral organs were also recorded. Significant weight change in the spleen was evident. The congestion of the lung was the most common gross pathological observation made. Other observations were splenomegaly, enlarged heart, swollen uterine horns, etc. Histopathological changes observed included haemorrhages in the lungs, myocardium, liver, kidney, testis, brain etc. Goblet cell hyperplasia with mucin present in the lumen were observed in the jejunum, ileum and colon. In conclusion, CP crystals produced severe lesions in the visceral organs and the brain after chronic oral administration at low and high dosage levels which should indicate caution in administering the extract to humans.

The extraction, isolation and identification of the purgative component of Croton penduliflorus seed oil.

The purgative principles in Croton penduliflorus seed oil were isolated as white crystals by a bioassay-guided chromatographic separation process. The crystals were recovered in 7% w/w yield and identified (IR, 1H-NMR, GC-MS) as a mixture of palmitic, stearic and arachidic acids in approximately equimolar concentration.