Ismaila Alhaji Umar

Evaluation of extraction protocols for anti-diabetic phytochemical substances from medicinal plants

AIM To examine the efficacy of three extraction techniques: Soxhlet-extraction (SE), cold-maceration (CM) and microwave-assisted-extraction (MAE) using 80% methanol as solvent. METHODS The study was performed on each of 50 g of Vernonia amygdalina (VA) and Occimum gratissimum (OG) leaves respectively. The percentage yield, duration of extraction, volume of solvent used, qualitative and quantitative phytoconstituents present was compared. The biological activities (hypoglycemic effect) were investigated using albino wistar rat model of diabetes mellitus (n = 36) with a combined dose (1:1) of the two plants leaf extracts (250 mg/kg b.w.) from the three methods. The extracts were administered orally, once daily for 21 d. RESULTS In this report, the percentage VA extract yield from MAE was highest (20.9% ± 1.05%) within 39 min using 250 mL of solvent, when compared to the CM (14.35% ± 0.28%) within 4320 min using 900 mL of solvent and SE (15.75% ± 0.71%) within 265 min using 500 mL of solvent. The percentage differences in OG extract yield between: MAE vs SE was 41.05%; MAE vs CM was 46.81% and SE vs CM was 9.77%. The qualitative chemical analysis of the two plants showed no difference in the various phytoconstituents tested, but differs quantitatively in the amount of the individual phytoconstituents, as MAE had significantly high yield (P > 0.05) on phenolics, saponins and tannins. SE technique gave significantly high yield (P > 0.05) on alkaloid, while CM gave significant high yield on flavonoids. The extracts from CM exhibited a significantly (P > 0.05) better hypoglycemic activity within the first 14-d of treatment (43.3% ± 3.62%) when compared to MAE (36.5% ± 0.08%) and SE methods (33.3% ± 1.60%). However, the percentage hypoglycemic activity, 21 d post-treatment with 250 mg/kg b.w. extract from MAE was 72.6% ± 1.03% and it was more comparable to 10 mg/kg b.w. glibenclamide treated group (75.0% ± 0.73%), unlike the SE (69.5% ± 0.71%) and CM (69.1% ± 1.03%). CONCLUSION CM technique produces extract with better hypoglycemic activity, whereas; MAE is a better option for high yield of phytoconstituents using less solvent within a short time.

Appropriate Insulin Level in Selecting Fortified Diet-Fed, Streptozotocin-Treated Rat Model of Type 2 Diabetes for Anti-Diabetic Studies

Background Pathophysiological investigation of disease in a suitable animal model is a classical approach towards development of a credible therapeutic strategy. This study examined appropriate insulin level in selecting animal model for type 2 diabetes (T2D) studies. Method Albino Wistar rats (150-200g) were divided into two groups fed with commercially available normal-diet-feed (NDF) and water or fortified diet feed (FDF) (10g NDF per gram of margarine) with 20% fructose solution as drinking water. After 6 weeks of dietary regimen both groups were divided into 5 sub-groups and injected intraperitoneally with a graded dose of streptozotocin (STZ) (0, 25, 35, 45 & 55mg/kg bw.). Result The result showed that the FDF-fed rats increased significantly in body weight, basal serum insulin, total cholesterol, triglycerides and blood glucose levels as compared to NDF-fed rats. Ten days post STZ induction, the groups treated with STZ (45 & 55 mg/kg) developed frank hyperglycaemia with < 46.8% serum insulin, a severe deficiency typical of diabetes type 1. The NDF25 and NDF35 groups with 75.7% and 64.4% serum insulin respectively presented relative normoglycemia, whereas the FDF35 (85.8% serum insulin) were notably hyperglycaemia (>300 mg/dL) throughout the 6weeks post diabetes confirmation. These FDF35 rats were sensitive to glibenclamide, metformin and pioglitazone in lowering hyperglycaemia, hypertriglyceridemia and hypercholesterolemia Conclusion The hyperglycaemia stability of the FDF35 rats (85.5% insulin) together with their sensitivity to 3 different hypoglycaemic drugs strongly suggests their suitability as a non-genetic model of T2D. Hence the study shows that circulating serum insulin ≥ 85.8% with overt hyperglycaemia may be utilized as the benchmark in selecting rat models for T2D studies.

Effects of aqueous extracts of Acacia albida stem bark on Wistar albino rats infected with Trypanosoma evansi.

The effect of aqueous extract of Acacia albida stem bark was investigated in Wistar albino rats infected with Trypanosoma evansi. The extract showed highest reduction in parasitemia at the dose of 600 mg/kg body weight (bw). A dose of 300 mg/kg bw improved packed cell volume the most by 14.35%. The group treated with 150 and 600 mg/kg bw of the extract showed significant decrease (P < 0.05) in alanine transaminase and aspartate transaminase levels which were lower than those of the group treated with diminazene aceturate. The group treated with 150 mg/kg bw of the extract showed the least urea, albumin and protein level and lowest relative organ weight. There was a significant difference (P < 0.05) in the levels of catalase and Thiobarbituric acid reactive substances in liver and kidney of the animals in the infected-untreated group and the extracts-treated groups. The results of this study show that the extracts of A. albida have antitrypanosomal activity against T. evansi infection.

Trypanosuppresive effects of ellagic acid and amelioration of the trypanosome-associated pathological features coupled with inhibitory effects on trypanosomal sialidase in vitro and in silico

BACKGROUND The search for novel antitrypanosomal agents had previously led to the isolation of ellagic acid as a bioactive antitrypanosomal compound using in vitro studies. However, it is not known whether this compound will elicit antitrypanosomal activity in in vivo condition which is usually the next step in the drug discovery process. PURPOSE Herein, we investigated the in vivo activity of ellagic acid against bloodstream form of Trypanosoma congolense and its ameliorative effects on trypanosome-induced anemia and organ damage as well as inhibitory effects on trypanosomal sialidase. METHODS Rats were infected with T. congolense and were treated with 100 and 200mg/kg body weight (BW) of ellagic acid for fourteen days. The levels of parasitemia, packed cell volume and biochemical parameters were measured. Subsequently, T. congolense sialidase was partially purified on DEAE cellulose column and the mode of inhibition of ellagic acid on the T. congolense sialidase determined. Molecular docking study was also conducted to determine the mode of interaction of the ellagic acid to the catalytic domain of T. rangeli sialidase. RESULTS At a dose of 100 and 200mg/kg (BW), ellagic acid demonstrated significant (P < 0.05) trypanosuppressive effect for most of the 24 days experimental period. Further, the ellagic acid significantly (P < 0.05) ameliorated the trypanosome-induced anemia, hepatic and renal damages as well as hepatomegaly, splenomegaly and renal hypertrophy. The trypanosome-associated free serum sialic acid upsurge alongside the accompanied membrane bound sialic acid reduction were also significantly (P < 0.05) prevented by the ellagic acid treatment. The T. congolense sialidase was purified to a fold of 6.6 with a yield of 83.8%. The enzyme had a KM and Vmax of 70.12mg/ml and 0.04µmol/min respectively, and was inhibited in a non-competitive pattern by ellagic acid with an inhibition binding constant of 1986.75μM. However, in molecular docking study, ellagic acid formed hydrogen bonding interaction with major residues R39, R318, and W124 at the active site of T. rangeli sialidase with a predicted binding free energy of -25.584kcal/mol. CONCLUSION We concluded that ellagic acid possesses trypanosuppressive effects and could ameliorate the trypanosome-induced pathological alterations.

Stigmasterol retards the proliferation and pathological features of Trypanosoma congolense infection in rats and inhibits trypanosomal sialidase in vitro and in silico

Stigmasterol has been reported to possess antitrypanosomal activity using in vitro model but information on the in vivo antitrypanosomal effects which is necessary in drug development process has not been evaluated. Hence, the present study investigates the in vivo effects of stigmasterol against T. congolense in addition to its inhibitory effects of trypanosomal sialidase. Stigmasterol, at 100mg/kg BW, did not significantly (p>0.05) reduce the progression of T. congolense infection in animals but a 200mg/kg BW stigmasterol treatment significantly (p<0.05) reduced the parasitemia, although, it did not completely eliminate the parasite from the bloodstream of infected animals. However, the stigmasterol treatments significantly (p<0.05) ameliorated the T. congolense induced anemia as well as hepatic and renal damages. Furthermore, the T. congolense-associated increase in free serum sialic acid with a corresponding decrease in membrane bound sialic acid were prevented, though insignificantly (p>0.05), by the 200mg/kg BW treatment. Subsequently, in vitro enzyme kinetic studies revealed that stigmasterol is an uncompetitive inhibitor of a partially purified bloodstream T. congolense sialidase with an inhibition binding constant of 356.59μM. Using molecular docking studies, stigmasterol formed a single hydrogen bonding interaction with a major residue (D63) at the catalytic domain of T. rangeli sialidase with a predicted binding free energy of -24.012kcal/mol. We concluded that stigmasterol could retard the proliferation and the major pathological features of T. congolense infection whilst the anemia amelioration was mediated via inhibition of sialidase.

Socio-economic status of patients with type 2 diabetes and hypertension attending the Ahmadu Bello University Teaching Hospital, Zaria, North-West Nigeria.

Hypertension (HTN) and Type 2 diabetes (T2D) are lifestyle interrelated diseases of global significance. Interestingly, the prevalence of these diseases in Africa and indeed Nigeria seems to be on the increase. This study, therefore, investigated the socioeconomic status (based on income, education and occupational activity) of 400 subjects (52% female and 48% male) aged 20 years and above who were sampled randomly among the newly diagnosed HTN and/or T2D cases at the Ahmadu Bello University Teaching Hospital, Zaria, North-West Nigeria. A semi-structured questionnaire was used to collect information from the subjects. From the result obtained, most of the respondents who live in towns or city suffer from either HTN or T2D while more town dwellers (28%) suffer from a combination of both diseases. It was also discovered that most respondents who suffer from HTN and from a combination of HTN and T2D belong to the old generation (60-79 years). There is higher prevalence rate of diabetes among the respondents who had no formal education or attended only basic Arabic schools. Most respondents who earn good income (₦50,000-₦100,000 and above ₦100,000) suffer HTN, T2D and a combination of both diseases. Those engaged in heavy occupational activities had the lowest prevalence of the disease compared with those of light or moderate occupational activities. These data will be found useful in planning intervention healthcare preventive programs especially on public enlightenment workshops and seminars to educate the populace on the importance of lifestyle modification, healthy diet and regular exercises.

In vitro antitrypanosomal and antioxidant activities of methanol extracts of selected Nigerian plants

ABSTRACT The methanol extracts of Acacia albida (stem bark), Pericopsis laxiflora (leaves and stem bark), Artemisia absinthium (leaf), Gongronema latifolium (leaf), and Leptadenia hastata (leaf) were tested in vitro for antitrypanosomal and antioxidant properties. Stem bark extract of P. laxiflora was the most effective against the motility of the protozoans. Preliminary phytochemical analyses indicated the presence of cardiac glycosides and saponins in all extracts and the absence of anthraquinones. All extracts had terpenes except that from P. laxiflora stem bark; all extracts had flavonoids except those from A. albida and P. laxiflora stem barks. The methanol leaf extracts of A. absinthium and G. latifolium had the greatest flavonoids while the stem bark extract of P. laxiflora had the highest total phenol. The extracts demonstrated concentration-dependent antioxidant activity. P. laxiflora stem bark had the highest scavenging activity against 2,2-diphenyl-1-picrylhydrazyl radical. A. albida, P. laxiflora, and A. absinthium had the greatest scavenging power against H2O2 with EC50 of 0.92, 1.2, and 1.10 mg mL−1, respectively.