Alloxan (250316, Chem Light Laboratories, India), 10% Dextrose (Dana Pharmaceuticals, Nigeria), Glimepiride (Sanofi Aventis, France) and Normal saline (Dana Pharmaceuticals, Nigeria), Glucometer and test strips (Accu-check Active, Roche, Germany).

Male Wistar rats (150-200 g) obtained from the Animal House, Department of Pharmacology and Therapeutics, Ahmadu Bello University Zaria were used for this study. The animals were maintained in a well-ventilated room, fed on standard feed and granted access to water ad libitium.

The whole plant of Chlorophytum alismifolium was collected from Tilden Fulani River in Toro Local Government Area of Bauchi state, Nigeria in June, 2018. It was identified and authenticated by Mallam Musa Muhammed of the Herbarium unit of the Department of Botany, Ahmadu Bello University Zaria, Nigeria. The plant was issued a voucher specimen number (No. 6785) for future reference.

The roots (tubers) were washed and chopped into smaller sizes and then air dried under shade for five weeks. The dried plant was then crushed into fine powder using pestle and mortar. The powdered plant (1 kg) was extracted sequentially with solvents of varying polarities, starting with hexane followed by ethylacetate and then methanol extract was obtained which was then partitioned in butanol to obtain the final fraction. The extract was concentrated to dryness on a water bath set at 45^oC and then stored in a desiccator until further use. The preliminary phytochemical screening of the butanol fraction of C. alismifolium was carried out according to the methods of Evans 16.

GC-MS analysis was performed using an Agilent 7890B GC system, 5977A mass spectrum detector (MSD) (Agilent Technologies, USA). The chromatography was performed on a HP-5 MS capillary column (30m×250μm×0.25μm). The carrier gas used was high purity helium and the con- stant flow rate of the helium was 3.6839 mL/min. Split injection ratio was 5:1. The temperature of the GC started at 50°C for 1 min, raised to 200°C at a rate of 3°C/min and then raised to 300°C at 3°C/min for 15 min and then held at 325°C (1 min). MS program scanned quality range of 30amu - 600amu, ionization voltage of 70eV, ionization current of 150μA (EI). The ion source and the quadrupole temperatures were set at 230°C and 150°C respectively. Compounds in the extract were identified on the basis of standards, isolation and structural determination in National Institute of Standards and Technology (NIST) 14. L database 17.

The median lethal dose (LD50) of the extract was determined using the method described by Lorke 18. The study was carried out in two phases: In the initial phase, three groups of three rats each were orally administered the extract of Chlorophytum alismifolium in widely differing doses of 10, 100 and 1000 mg/kg body weight and observed for signs of toxicity and mortality for 24 hours. In the second phase, three rats were orally administered the butanol fraction at the doses of 1600, 2900 and 5000 mg/kg body weight respectively and then observed for signs of toxicity post-administration and mortality after 24 hours after which the LD50 was estimated.

The method described by Cooperstein and Watkins19 was employed in overnight fasted rats. Forty five (45) Wistar rats were injected with alloxan monohydrate dissolved in sterile 0.9% normal saline and a dose of 120 mg/kg bw i.p was administered. The rats were then kept for the next 24 hours on 10% glucose solution since alloxan is capable of producing initial fatal hypoglycaemia. Three days post-induction with alloxan, the rats were monitored for hyperglycaemia using a glucometer (Accucheck Active, Roche Diagnostics, Germany). Rats with fasting blood glucose levels between 200 and 350 mg/dL were considered hyperglycaemic and selected for the study.

The rats (thirty alloxan-induced and six normal) were randomly divided into six groups; Group 1 served as the negative control and received the vehicle only (normal saline, 1 mL/kg). Group 2 served as the hyperglycaemic control which also received normal saline (1 mL/kg). Groups 3, 4 and 5 received graded doses of the butanol fraction of C. alismifolium at (250, 500 and 1000 mg/kg) respectively. Group 6 served as the positive control and received glimepiride (1 mg/kg b.w.). Blood samples were drawn from the tail vein prior to treatment at (0 h) and then at 1, 2, 3 and 5h after treatment. Fasting blood glucose levels were measured using the glucose-oxidase method.

Data of antihyperglycaemic study were expressed as Mean ± Standard Error of the Mean (S.E.M.) and the differences between means were analyzed by Repeated Measure Analysis of Variance (ANOVA) followed by Bonferroni post hoc test using a computer software application package (SPSS, Version 20). Values of p<0.05 were considered statistically significant.

The percentage yield of the butanol fraction of Chlorophytum alismifolium was calculated to be 2.49 % w/w and the phytochemical screening revealed the presence of alkaloids, saponins, triterpenes, glycosides, cardiac glycosides, tannins and flavonoids (Table 1).

The GC-MS revealed the presence of thirteen compounds covering the total area of 100.2 % (Table 2).

Oral administration of butanol fraction of C. alismifolium (10-5,000 mg/kg) did not produce any visible sign of toxicity or mortality in the animals over a period of 24 hrs. The oral LD₅₀ was estimated to be above 5,000 mg/kg.

A significant (p<0.001) increase in blood glucose levels were observed in the hyperglycaemic control following the administration of alloxan when compared to the normal control. Administration of the butanol fraction at all the doses tested (250, 500 and 1000 mg/kg) reduced the blood glucose levels when compared to the hyperglycaemic control, though the reduction wasn’t statistically significant (p>0.05). The results were also compared over time by comparing 0 hour with the 1^st, 2^nd, 3^rd, and 5^th hours. The extract at 250 mg/kg significantly (p<0.05 and p<0.001) reduced the blood glucose level in the 3^rd, and 5^th hours respectively when compared to 0 hour. At 500 mg/kg, a significant (p<0.01 and p<0.001) reduction in blood glucose levels in the 3rd and 5th hours respectively were also observed when compared to 0 hour. At 1000 mg/kg, the extract significantly (p<0.05, p<0.001 and p<0.001) lowered the blood glucose level in the 2^nd, 3^rd, and 5^th hours respectively when compared to 0 hour. (Figure 1).