Kolaviron pre-treatment suppresses 7, 12 dimethylbenzanthracene-induced alterations in estrogen receptor-α, CYP 1A1, oxidative stress and inflammation in female Wistar rats.

Due to the need to develop locally available, cheaper, and efficacious treatment regimens for breast cancer, the chemopreventive effect of kolaviron (KV), an extract of Garcinia kola seeds was examined. Fifty (50) female Wistar rats (120-180 g) were assigned to five groups (control group, 7, 12 dimethylbenzanthracene [DMBA] groups, tamoxifen group) of 10 rats each. They were pre-treated with KV thrice a week for four weeks except control. Estrogen receptor-α (ER-α) levels were determined in the pre-treated rats before induction of mammary carcinogenesis. After the four weeks pre-treatment period, 80 mg/kg of DMBA was used for induction. A hundred and fifty (150) days after induction, the rats were sacrificed humanely. Significantly higher levels of ER-α, formation of lobular neoplastic cells, epithelial hyperplasia, lymphocyte infiltration, increased cytokines (interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]), CYP1A1 activity and malondialdehyde (MDA) with a corresponding decrease in superoxide dismutase (SOD), catalase and glutathione peroxidase were observed in DMBA-induced rats. Pre-treatment with KV at 200 mg/kg body weight significantly (p < .05) decreased ER-α levels by 19.01% and 37.52%, [IL-6] by 36.37% and 20.55%, TNF-α by 42.2% and 12.33% in serum and mammary tissue respectively. Also, a significant (p < .05) decrease in serum CYP1A1 activity, MDA with concomitant increase in SOD, catalase and glutathione peroxidase activities were observed in serum and mammary tissue respectively. Collectively, the results suggest that KV could be further explored in targeting chemoprevention of DMBA-induced mammary damage. PRACTICAL APPLICATIONS: Garcinia kola is widely cultivated in West and Central Africa with kolaviron (KV) as its major constituents. The seeds which have a bitter astringent taste are widely consumed by people in the region. Locals claim that consumption of the seeds provides relief for the management of several ailments including cancer. However, scientific investigations that provide a basis for these claims are still needed. This study provides evidence that points to the ameliorative potential of KV on breast cancer model. The results will be beneficial to local communities who hitherto had no knowledge on the potential of G. kola in chemoprevention. The results from this study will also attract further research attention from the international scientific community to examine the anti-cancer benefits of G. kola. This will also be beneficial to the global community due to the increasing number of breast cancer cases recorded annually.

Changes in nutrient and antinutrient composition of Vigna racemosa flour in open and controlled fermentation.

This study was conducted to investigate the effect of open and controlled fermentation on the proximate composition, mineral elements, antinutritional factors and flatulence-causing oligosaccharides in Vigna racemosa. The open fermentation was carried out using the microorganisms present in the atmosphere while the controlled fermentation was carried out using Aspergillus niger as a starter. The proximate composition of the Vigna racemosa, some anti-nutrients and the mineral elements were analyzed using standard procedures. The protein content was increased by 12.41 ± 1.73 % during open fermentation while it decreased by 29.42 ± 0.1 % during controlled fermentation. The lipids, carbohydrates, crude fibre and ash content were all reduced in both types of fermentation except the moisture content which increased in controlled fermentation. Apart from calcium, the other elements (Fe, Na, Mg, Zn, and K) suffered reduction in both types of fermentation. The phytate, tannin, alkaloids, hydrogen cyanide, lectins, trypsin inhibitors and oxalate content all had drastic reductions in both types of fermentation. Open and controlled fermentation reduced the levels of both raffinose and stachyose. The percentages of reduction due to controlled fermentation were higher than those of open fermentation in the antinutrients studied. Fermentation is an efficient method for detoxifying the antinutrients in the Vigna racemosa studied in this work.

Hepatotoxic effects of chloroform extract of Artemisia macivera Linn in rats following intraperitoneal administration of different subchronic doses.

The possible hepatotoxic effects of chloroform extract of Artemisia maciverae was evaluated biochemically and histologically using male Swiss albino rats, randomly assigned into four groups of 24 animals each. The groups (control, 50, 100 and 200 mg/kg body weight) were treated for 60 days and then monitored for another 30 days before sacrifice. Alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, bilirubin (total and direct), total protein and albumin were assessed colorimetrically, while tissue specimens were subjected to histological examination following standard hematoxyline-eosin staining techniques. After 1 week of treatment, the extract caused statistically significant elevation in levels of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and bilirubin (total and direct), while there was significant (p < 0.05) decrease in the levels of serum total protein and albumin at the onset of treatment when compared with the control. These abnormalities in the levels of serum biochemical parameters were spontaneously corrected within 2 weeks of treatment. Similarly, histological assessment showed severe hepatic tissue injuries after 1 week, but these organs recovered spontaneously by the second week of treatment. The results indicate that long-term exposure to therapeutic doses of chloroform extract of A maciverae is relatively safe, but high dose exposure may result in hepatocellular injury.

Bioassay-guided fractionation and in vivo antiplasmodial effect of fractions of chloroform extract of Artemisia maciverae Linn.

In the search for new plant-derived anti-malarial compounds, chromatographic fractions of chloroform extract of whole plants of Artemisia maciverae were tested in vivo using chloroquine resistant and chloroquine sensitive Plasmodium berghei NK 65 infected Swiss albino mice. One fraction and a sub-fraction of this were most active at 10/mg and cleared parasitemia in mice within 3 days. The different fractions and sub-fractions were tested with different reagents to determine the broad classes of compounds present. The active fraction tested positive for triterpenes and alkaloids, and the sub-fraction for only triterpenes. These tests suggest that the anti-malarial activities observed with these fractions may be due to these classes of compounds in the chloroform extract of the A. maciverae. Further chemical work is however required to characterize the active constituents.

Antitrypanosomal effects of petroleum ether, chloroform and methanol extracts of Artemisia maciverae Linn.

Petroleum ether, chloroform and methanol extracts of A. maciverae were studied in vitro and in vivo for activity against Trypanosoma brucei brucei in Swiss albino mice. Thereafter, the chloroform extract which showed the highest activity in both in vitro and in vivo assessments was subjected to bioassay-guided fractionation. The crude extracts and the fractions of the chloroform extract of A. maciverae were screened for phytochemicals and secondary metabolites. Combined fractions 54-57 of this extract showed the highest in vitro antitrypanosomal activity, and at 10 mg/kg body weight, this fraction cleared the parasitemia completely from T. brucei brucei infected Swiss albino mice after 7 days of treatment. There was no statistically significant difference in the level of parasitemia when the infected mice treated with this fraction was compared with the standard trypanocidal drug, diminal. The results of the phytochemical analysis showed that the crude extracts contained secondary metabolites like flavonoids, triterpenes, terpenoids, tannins, phlobatannins and alkaloids, while the active fraction contains only triterpenes and alkaloids. It can be inferred that fraction 54-57 contains the active component responsible for the high antitrypanosomal activity of the chloroform extract of A. maciverae.

Quantitative changes in gastric mucosal glycoproteins: effect of cholinergic agonist and vagal nerve stimulation in the rat.

The role of the vagus nerve and cholinergic mechanisms in the control of the rat gastric mucin and protein (PROT) release in vivo was investigated. Under urethane anaesthesia (1.25 g kg(-1)), the rats had their gastric lumen perfused with saline. Mucus secretion was measured as a function of adherent mucus on the mucosa surface and the luminal content of sialic acids (SIA), galactose (GAL), pyruvate and PROT. Electrical stimulation of the vagi significantly increased the levels of mucus (3.23 +/- 025 microg g(-1) tissue, P < 0.05), free sialic acid (FS) (0.18 +/- 0.04 mg mL(-1), P < 0.05) and PROT (0.25 +/- 0.003 mg mL(-1), P < 0.05) when compared with control animals. Bilateral cervical vagotomy had no significant effect on adherent mucus or basal levels of PROT, SIA and GAL (P > 0.05) with respect to the control. In both vagotomized and vagal intact animals, the cholinergic agonist (carbachol, 200 mg kg(-1)) significantly increased PROT, adherent mucus and FS (P < 0.05) and decreased bound sialic acid (P > 0.05). There were no visible haemorrhagic streaks on the gastric mucosa of vagotomized, vagal intact and carbachol-treated animals. The results suggest that vagus nerve does not exert a tonic control on gastric glycoprotein secretion in vivo and that cholinergic effect on the mucus secreting cells may be implemented via the intrinsic nerves of the enteric nervous system.

Effect of dibutyltin(IV) on the ultrastructure of African Trypanosoma spp.

Diorganotins (R2SnX2) are compounds with a wide variety of biological properties. In an attempt to follow the morphological events and to characterize the toxic effects of diorganotins on in vitro cultured African Trypanosoma spp., the ultrastructural alterations induced on the parasites by dibutyltins (Bu2SnX2) were followed. The data obtained indicate that these compounds induced irreparable damage to the in vitro cultured bloodstream forms of the parasites. Transmission and scanning electron microscopy allowed observations on the perturbation of the kinetoplast, extensive cytoplasmic swellings, disconfiguration around the flagellar pocket and membrane disintegration. Fluorescence microscopy with 4,6-diamidine-2-phenylindole stain was also used to visualize the survival or degeneration of kDNA. Understanding the collateral cellular toxic effect of these compounds on the parasites may shed light on the possible mechanism by which they kill trypanosomes. Agarose gel electrophoresis resolution of isolated kDNAs revealed no fragmentation by these compounds following in vitro incubation at 37 degrees C. However, fragmentation was observed from the gel electrophoresis of kDNA isolated from in vitro cultured Bu2SnX2-exposed parasites. Transmission electron microscopy of the kDNAs revealed the same pattern as observed with gel electrophoresis. These results provide evidence for the possible involvement of the Bu2Sn moiety in the in vivo-induced fragmentation of trypanosomal kDNA and consequent trypanolysis. This observation also underlies the relevance of organometallics in the therapy of African trypanosomiasis.

In vitro trypanocidal activity of dibutyltin dichloride and its fatty acid derivatives.

Searching for new compounds against pathogenic trypanosomes has been substantially accelerated by the development of in vitro screening assays. In an attempt to explore the chemotherapeutic potential of organotin compounds and to broaden the search for newer trypanocides, fatty acid derivatives of dibutyltin dichloride were synthesized and their in vitro trypanocidal profiles studied on Trypanosoma brucei brucei, Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense. A 24-h time course experiment was conducted with various concentrations of the compounds using a 24-well microtiter plate technique. The compounds tested were trypanocidal in a dose-dependent fashion: inhibiting survival and growth, resulting in irreversible morphological deformation and the eventual death of the parasites. The minimum inhibitory concentrations of the tested diorganotins are at low micromolar ranges: from 0.15-0.75 microM for T. b. brucei, T. b. gambiense and T. b. rhodesiense. These observations suggest that organotin has chemotherapeutic potential.

Indigenous knowledge system for treatment of trypanosomiasis in Kaduna state of Nigeria.

A survey was carried out in Kaduna State of Nigeria to establish the indigenous knowledge system for treating trypanosomiasis in domestic animals. Questionnaire and interviews were, respectively, administered to, or conducted with about 200 livestock farmers and traders spread around the state. Data obtained revealed the use of several plants either alone or in combination, for the treatment and management of trypasonomiasis. The most common plants encountered were Adansonia digitata, Terminalia avicennoides, Khaya senegalensis, Cissus populnea, Tamarindus indica, Lawsonia inermis, Boswellia dalzielli, Pseudocedrela kotschi, Syzyium quinensis, Sterculia setigera, Afzelia africana, Prosopis africana, Lancea kerstingii. The method of preparation and mode of administration of some of these plants in the treatment of trypanosomiasis are reviewed and discussed.

Phospholipase A2 from Trypanosoma brucei gambiense and Trypanosoma brucei brucei: inhibition by organotins.

Activity and kinetics of phospholipase A2 (PLA2) from Trypanosoma brucei gambiense (Wellcome strain) and Trypanosoma brucei brucei (GUTat 3.1) were examined using two different fluorescent substrates. The activity in the supernatants of sonicated parasites was Ca2+-independent, strongly stimulated by Triton X-100 with optimum activity at 37 degrees C and pH 6.5-8.5. To encourage a possible interaction between the parasite enzyme and organotin compounds, fatty acid derivatives of dibutyltin dichloride were synthesized and evaluated as potential inhibitors of PLA2. The enzyme from the two-trypanosome species differ with respect to kinetic parameters and are noncompetitively inhibited by the organotin compounds. The Michaelis constant (KM) for PLA2 from T. b. brucei is 63.87 and 30.90 microM while for T. b. gambiense it is 119.64 and 32.91 microM for the substrates 1,2-bis-(1-pyrenebutanoyl)-sn-glycero-3-phosphocholine (PBGPC) and 2-(12-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)dodecanoyl-1-hexadecanoyl-sn-glycero-3-phosphocholine (NBDC12-HPC), respectively.

Trypanocidal activity of organotin chlorides on Trypanosoma brucei-infected mice.

The organotin compounds dibutyltin (DBTC) and diphenyltin dichlorides (DPTC) were tested for trypanocidal activity on a Trypanosoma brucei-infected mice model. At a dose of 10 mg DBTC and 15 mg DPTC/kg/day for five consecutive days, they cleared the parasites from the peripheral blood of the infected mice. Subinoculation of some healthy mice with the homogenates of liver, spleen, kidney, cerebrospinal fluid and blood from the mice considered cured, showed a few cases of relapse. The LD50 of DBTC and DPTC are 90 mg/kg and 75 mg/kg respectively.

Antihypertensive effect of roselle (Hibiscus sabdariffa) calyx infusion in spontaneously hypertensive rats and a comparison of its toxicity with that in Wistar rats.

The LD(50) of roselle calyx extract and its effect on blood pressure were determined. The LD(50) was found to be above 5000 mg kg(-1). Roselle calyx infusion was found to lower significantly (p<0.05) both systolic and diastolic pressure in spontaneously hypertensive and normotensive Wistar-Kyoto rats at tested doses of 500 and 1000 mg kg(-1) body weight. The reduction in blood pressure in both groups was positively correlated with weight. Continuous consumption of the infusion at 1000 mg kg(-1) was discovered to lead to sudden death in spontaneously hypertensive rats but not in Wistar-Kyoto rats. Water intake was not significantly different (p>0.05) in the control groups of the two strains of rats used, neither was there a significant difference in their urine output. The water intake in the treated spontaneously hypertensive and normotensive rats was not different from the corresponding control groups. However the urine output of the treated spontaneously hypertensive rats was significantly higher. A significant decrease in serum creatinine, cholesterol, and glucose in the treated rats compared with the control as well as a significant increase in serum uric acid was observed. The serum proteins (albumin and total protein) in the treated rats when compared with the control groups was not changed significantly.

Normal plasma lactose concentrations and kinetics of intravenously infused lactose in cattle.

Plasma lactose concentration and its kinetics were determined in apparently normal cattle, as a prelude to investigating its chemotherapeutic significance in bovine trypanosomiasis. It is hoped that intravenously administered lactose may be able to reduce the rate of sequestration of desialylated erythrocytes during Trypanosoma vivax infection of cattle; thus decreasing the rate of development of trypanosomal anaemia in infected animals. A range of 0.061 to 0.55 mM with a mean of 0.208 +/- 0.128 mM standard deviation (SD), observed in adult cattle was significantly lower (P<0.001) than corresponding values in recently weaned calves; 0.429 to 1.496 mM (0.972 +/- 0.318 mM). Semi-logarithmic plots from calves given a single dose (0.5 g lactose per kg bodyweight as a solution in normal saline, infused at the rate of 18 ml min(-1)) showed a biexponential pattern of regression lines. Decrease in plasma concentrations was biphasic and lactose was rapidly distributed into the extravascular space after administration. The biological half-life (t1/2) of the infused lactose ranged from 4.10 to 6.00 hours (5.01 +/- 0.81 hours); its mean elimination rate constant was 0.14 +/- 0.02 hour(-1), mean apparent volume of distribution was 168.09 +/- 56.65 ml kg(-1) while its mean total clearance was 23.54 +/- 8.31 ml kg(-1) hour(-1). A single dose rapidly reached a peak and gradually fell below the pre-infusion level while repeated doses did not cause accumulation of the lactose in the plasma as each infusion fell back to normal relatively rapidly.

Effects of acute bovine trypanosomosis (Trypanosoma vivax) on plasma kinetics of intravenously administered lactose.

Four calves infected with Trypanosoma vivax and four uninfected control calves were each injected intravenously with repeated doses of 0.5 g lactose kg-1 body weight, thrice daily at intervals of 4 h. Plasma samples were collected at specified time intervals and analysed for lactose. Pharmacokinetic parameters were calculated from the data. T. vivax infection delayed excretion of lactose from the body, thus leading to significantly (P < 0.001) increased biological half life (t1/2) and a significantly (P < 0.001) reduced elimination rate constant for lactose in the body. The apparent volume of distribution and total clearance of lactose were not affected by the infection. T. vivax infection also appeared to cause accumulation of lactose in the plasma after repeated intravenous administration.