Hypoglycaemic and Antihyperglycaemic Effect of Syzygium cumini Bark in Streptozotocin-Induced Diabetic Rats

Antihyperglycemic Activity of TLC Isolates from the Leaves of Aloe megalacantha Baker in Streptozotocin-Induced Diabetic Mice

BACKGROUND

Diabetes mellitus (DM) is a group of metabolic disorders that are characterized by hyperglycemia which results from defects in insulin release or its efficient use by the human body. Although significant progress has been made to manage DM and related complications, it remains a major global health problem. To this end, the search for new antidiabetic drugs from traditionally claimed medicinal plants is important. Aloe megalacantha Baker is an endemic plant used traditionally to treat diabetes in Ethiopia. This study aimed to investigate antidiabetic activity of isolates from the leaf of A. megalacantha Baker in streptozotocin-induced diabetic mice.

METHODS

The exudate of A. megalacantha was collected by cutting the leaves and scraping the yellow sap and then dried at room temperature. The dried exudate was subjected to repeated thin layer chromatographic (TLC) separations using a mixture of solvent system to isolate the major compounds identified on the TLC plate. A single dose of streptozotocin (50 mg/kg) was injected intraperitoneally to overnight fasted mice to induce diabetes. Antidiabetic activity of TLC isolates was assessed by in vivo methods including oral glucose tolerance test, antihyperglycemic and hypoglycemic activity tests.

RESULTS

Three major isolates were obtained from the TLC analysis of the exudate of A. megalacantha. Exudate and TLC isolates were found to be non-toxic up to a dose of 2000 mg/kg. The TLC isolates (Ia and Ib) significantly (p<0.05) reduced blood glucose levels and also increased body weight change of the diabetic mice compared with control groups.

CONCLUSION

The present study demonstrated the ability of the exudate of A. megalacantha and its TLC isolates to significantly decrease blood glucose levels and increase body weights in mice, thus strengthening the claim of its traditional use in DM-related disorders.

Medicinal plants used in managing diseases of the respiratory system among the Luo community: an appraisal of Kisumu East Sub-County, Kenya

BACKGROUND

Poor access to healthcare in rural communities causes many people to seek herbalists who use medicinal plants for the treatment of various disease conditions. Most knowledge of traditional herbal medicine makes use of indigenous remedies which are often undocumented and are at risk of being lost. The preservation of this knowledge may facilitate scientific inquiry into promising new therapeutic molecules.

METHODS

Semi-structured questionnaires were used to collect the sociodemographic information of 30 herbalists in Kisumu East Sub County. The local names of medicinal plants used in managing illnesses of the respiratory system, their habit, active parts, indications, methods of preparation, routes of administration, scientific identity, and conservation status were also recorded. Other reported traditional uses, pharmacological activities, and toxicological data were identified via a literature search.

RESULTS

Most herbalists were female (86.7%), aged between 61 and 70 years (43.3%) with no formal education (56.7%), and had 21-30 years of practice (30%). 44 plant species, belonging to 43 genera and 28 families were identified. Leguminosae and Rutaceae plant families were predominant, leaves were frequently used (33%), and trees were the most common habit (44.4%). Most plants were collected in the wild (79.2%), preparation was mainly by decoction (68.8%), and the administration was mainly orally. The main indication was cough and 79.5% of all documented plant species had previously been reported to have a pharmacological activity relevant to the mitigation of respiratory illnesses. Toxicological data was available for 84.1% of the plant species identified.

CONCLUSIONS

The predominant use of roots, root barks, and root tubers by herbalists in Kisumu East Sub County threatens to negatively impact the ecological survival of some plant species. The preservation of herbalists' knowledge of medicinal plants in the study area is a pressing concern considering their advanced age and little formal education. There is a need to conserve some of the medicinal plants documented in this study. The medicinal claims made by herbalists also warrant scientific scrutiny.

Hematologic changes and splenic index on malaria mice models given Syzygium cumini extract as an adjuvant therapy

Aims:

This research aimed to determine the efficacy of Syzygium cumini L. as an adjuvant therapy on blood changes and splenic index of mice model malaria.

Materials and Methods:

Mice were infected intraperitoneally with 0.2 ml red blood cell (RBC) that contains 1×10⁶Plasmodium berghei. 35 mice were divided into seven treatment groups: Group K0: Mice were not infected; K1: Mice were infected; K2: Mice were infected and given chloroquine; P1: Mice were infected and given S. cumini leaf extract; P2: Mice were infected and given chloroquine and also S. cumini leaf extract; P3: Mice was infected and given S. cumini stem bark extract; and P4: Mice were infected and given chloroquine and S. cumini stem bark extract. Treatment was given for 4 days 24 h post -P. berghei infection. 21^st day post-P. berghei infection, blood was taken from the heart for hematological examination, and the spleen was taken to examine the splenic index and also to measure the weight and length of the spleen. Hematological data and splenic index were analyzed by analysis of variance test, and if there is a difference, the test is continued by Duncan’s multiple range test with 5% level.

Results:

The K0 group has normal hemoglobin (HGB), RBC, and hematocrit (HCT) and significantly different (p<0.05) than other groups. HGB, RBC, and HCT of K1 group were under normal range, lowest, and significantly different (p<0.05) than other groups. Mean corpuscular volume and mean corpuscular HGB values of K2 groups showed a decrease. The number of leukocytes, lymphocytes, and monocytes of K1 groups was increasing and significantly different (p<0.05) with K2 and treatment group. The length, width, weight, and splenic index of K1 group were significantly different (p<0.05) with K0 group. K2 and treatment groups showed that the length and width of spleens were significantly different (p<0.05) with K1.

Conclusion:

The combination of chloroquine with leaf and chloroquine with stem bark extract of S. cumini as adjuvant therapy may increase the amount of erythrocyte; decrease the number of leukocytes, lymphocytes, and monocytes; and decrease the length, width, and splenic index on malaria mice models.

Bioassay-guided fractionation and identification of α-amylase inhibitors from Syzygium cumini leaves

CONTEXT

Pancreatic α-amylase and α-glucosidase inhibitors serve as important strategies in the management of blood glucose. Even though Syzygium cumini (L.) Skeels (Myrtaceae) (SC) is used extensively to treat diabetes; scientific evidence on antidiabetic effects of SC leaves is scarce.

OBJECTIVE

SC leaf extract was investigated for α-amylase inhibitory effect and continued with isolation and identification of α-amylase inhibitors.

MATERIALS AND METHODS

Bioassay-guided fractionation was conducted using in vitro α-amylase inhibitory assay (with 20-1000 μg/mL test material) to isolate the inhibitory compounds from ethyl acetate extract of SC leaves. Structures of the isolated inhibitory compounds were elucidated using 1H NMR and 13C NMR spectroscopic analysis and direct TLC and HPLC comparison with authentic samples. Study period was from October 2013 to October 2015.

RESULTS

An active fraction obtained with chromatographic separation of the extract inhibited porcine pancreatic α-amylase with an IC50 of 39.9 μg/mL. Furthermore, it showed a strong inhibition on α-glucosidase with an IC50 of 28.2 μg/mL. The active fraction was determined to be a 3:1 mixture of ursolic acid and oleanolic acid. Pure ursolic acid and oleanolic acid showed IC50 values of 6.7 and 57.4 μg/mL, respectively, against α-amylase and 3.1 and 44.1 μg/mL respectively, against α-glucosidase.

DISCUSSION AND CONCLUSIONS

The present study revealed strong α-amylase and α-glucosidase inhibitory effects of ursolic acid and oleanolic acid isolated from SC leaves for the first time validating the use of SC leaves in antidiabetic therapy.

Aldose reductase and protein tyrosine phosphatase 1B inhibitory active compounds from Syzygium cumini seeds

CONTEXT

Syzygium cumini (L.) Skeels (Myrtaceae), commonly known as jamun, is an Indian plant, traditionally well known for its medicinal properties including antidiabetic activity.

OBJECTIVE

To isolate the antidiabetic compounds from Syzygium cumini seeds and evaluate their activity using aldose reductase (AR) and protein-tyrosine phosphatase 1B (PTP1B) inhibition assays.

MATERIALS AND METHODS

The dried seeds were extracted with methanol and partitioned with ethyl acetate, butanol, and water. The extracts were screened for antidiabetic activity at a concentration of 100 µg/mL using in vitro AR and PTP 1B inhibition assays.

RESULTS AND DISCUSSION

The highly enriched fractions obtained from broad ethyl acetate fraction yielded maslinic acid (1), 5-(hydroxymethyl) furfural (2), gallic acid (3), valoneic acid dilactone (4), rubuphenol (5), and ellagic acid (6). Structures were elucidated by (1)H-NMR and (13)C-NMR. The initial ethyl acetate fraction showed AR inhibitory activity with the IC50 value of 2.50 μg/mL and PTP1B enzyme inhibition with the IC50 value of 26.36 μg/mL. Compounds 3, 4, 5, and 6 were found to inhibit AR with IC50 values of 0.77, 0.075, 0.165, and 0.12 μg/mL while the compounds 4, 5, and 6 inhibited PTP1B with IC50 values of 9.37, 28.14, and 25.96 μg/mL, respectively.

CONCLUSION

The results of this study demonstrate that the isolated constituents show promising in vitro antidiabetic activity and, therefore, can be candidates for in vivo biological screening using relevant models to ascertain their antidiabetic activity.

Evaluation of antihyperglycemic activity of Cocos nucifera Linn. on streptozotocin induced type 2 diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Cocos nucifera Linn. (Arecaceae) is commonly known as coconut. Traditionally the juice of the young spadix when fresh is used in diarrhea and diabetes. The objective of the present study was to investigate the effect of antidiabetic activity and effect on lipid profile as well as cardioprotective effect of hydro-methanol extract of Cocos nucifera (HECN) on streptozotocin (STZ)-induced diabetic rats.

MATERIALS AND METHODS

After 72 h of STZ (50 mg/kg, b.w. i.p.) administration, animals showing plasma sugar level more than 250 mg/dl were considered as diabetic rat. Fasting blood glucose (FBG) levels were measured on 0th (after 72 h of STZ), 5th, 10th, and 15th day. On the 15th day all the animals were sacrificed and the serum biochemical parameters and antioxidant enzyme status were measured.

RESULTS

HECN treated animals showed a significant reduction in FBG level as compared with diabetic control group. Serum enzyme level (SGOT, SGPT, SALP), lipid peroxidation and antioxidant enzyme level such as CAT, GSH, SOD and cholesterol and triglycerides in the HECN treated groups were restored towards normal level as compared to diabetic control groups and the values were comparable with the standard groups (glibenclamide).

CONCLUSION

Improvement in the FBG and the restoration of all other biomarker as well as enzymes indicates that HECN has very good antidiabetic activity with very low side effects and provides a scientific rationale for the use as an antidiabetic agent.