Evaluation of Antidiabetic Activity of the Leaf Latex of Aloe pulcherrima Gilbert and Sebsebe (Aloaceae)

Validation of Antidiabetic and Antihyperlipidemic Effects of 80% Methanolic Extract of the Lonchocarpus laxiflorus Leaves in Streptozotocin-Induced Diabetic Swiss Albino Mice

Introduction

Diabetes mellitus (DM) is a chronic endocrine disorder that requires long-term treatment. In Ethiopian traditional medicine practice, plants have been provided with a vital role in fighting human and animal diseases since ancient times. The aqueous extract of Lonchocarpus laxiflorus (L. laxiflorus) leaves has been consumed for treating diabetes mellitus without confirming its safety and efficacy scientifically. This experiment aimed to evaluate the safety and antidiabetic efficacy of the leaf extract of L. laxiflorus in mice models.

Methods

The crude extraction was conducted using a cold maceration technique and 80% methanol solvent. Normoglycemic, oral glucose-loaded, and streptozotocin-induced (STZ) diabetic models were employed. Male Swiss albino mice were randomly grouped into five categories( with six mice per group during normoglycemic, oral glucose-loadingtest as a negative control, positive control, and three treatment groups. In STZ-induced diabetic models, the groups include normal and diabetic negative control, diabetic positive control, and three diabetic treatment groups. The negative control groups received vehicles, the positive control received 5 mg/kg glibenclamide, and the treatment groups received the crude extract at 100, 200, and 400 mg/kg doses, respectively.

Results

Up to 2000 mg/kg crude extract, neither signs of toxicity nor death were observed. In normoglycemic mice, there was a significant blood glucose reduction at 200 and 400 mg/kg doses starting from the 2^nd h post-administration. The oral glucose load showed a significant antihyperglycemic effect at 200 and 400 mg/kg of the crude extract and glibenclamide. In STZ-induced diabetic models, the 200, 400 mg/kg crude extract, and glibenclamide showed a significant antidiabetic activity and enhancement of a good serum lipid profile.

Conclusion

This study confirmed that the leaf of L. laxiflorus was safe and possesses antidiabetic and antidyslipidemic activities.

Aloe arborescens: In Vitro Screening of Genotoxicity, Effective Inhibition of Enzyme Characteristics for Disease Etiology, and Microbiological Activity

The present study assessed the genotoxicity, the possibility of inhibiting selected enzymes, and the microbial activity of lyophilisate from 3-year-old A. arborescens leaves obtained from controlled crops. The lyophilisate from 3-year-old A. arborescens leaves was standardized for aloin A and aloenin A content. Moreover, concentrations of polyphenolic compounds and phenolic acids were determined. The first stage of the research was to determine genotoxicity using the comet test, which confirmed the safety of A. arborescens. Assays of enzymatic inhibition were performed for hyaluronidase (IC50 = 713.24 ± 41.79 µg/mL), α-glucosidase (IC50 = 598.35 ± 12.58 µg/mL), acetylcholinesterase and butyrylcholinesterase (1.16 vs. 0.34 µM of eserine/g d.m., respectively). The next stage of the research was to determine the ability of the healing properties using the scratch test, which showed a positive response using the extract. Microbial activity was evaluated and obtained against Gram-negative and Gram-positive bacteria and yeasts. We concluded that A. arborescens leaf gel meets the important conditions for plant raw materials to obtain semi-solid forms of herbal medicinal products.

In vivo hypoglycemic, antihyperglycemic and antidyslipidemic effects of the solvent fractions of Hagenia abyssinica leaves in mice

Background

Hagenia abyssinica leaves have been used traditionally for the management of different diseases including diabetes mellitus (DM) although the antidiabetic effect of different solvent fractions of hydromethanol H. abyssinica leaf extract has not been scientifically studied. Thus, this study was conducted to investigate the in vivo hypoglycemic, antihyperglycemic and antidyslipidemic effects of the solvent fractions of Hagenia abyssinica leaf extract.

Methods

The antidiabetic effect of the solvent fractions was evaluated in normal, oral glucose loaded and streptozotocin-induced diabetic mice. Hypoglycemic, antihyperglycemic, antidyslipidemic activities and effect on body weight change were evaluated after administration of three different doses of the solvent fractions (100, 200, and 400 mg/kg). One-way ANOVA followed by Tukey's post hoc test was used for data analysis, and p<0.05 was considered as statistically significant.

Results

The crude hydromethanol extract of H. abyssinica leaves did not show any sign of toxicity at the dose of 2000 mg/kg in mice. In normoglycemic mice, both aqueous and ethyl acetate fractions of H. abyssinica leaves showed significant (P<0.05) hypoglycemic activity. In oral glucose loaded mice, the two doses of the aqueous fraction, 200 mg/kg (p<0.05) and 400 mg/kg (p<0.001), showed a significant antihyperglycemic effect at 60 and 120 minute post-oral glucose loading while the ethyl acetate fraction showed significant antihyperglycemic effect at 60 (P<0.05 for 200 mg/kg and P<0.001 for 400 mg/kg) and 120 min (P<0.01 for 400 mg/kg) post-oral glucose loading. In single dose-treated diabetic mice, all doses of the solvent fractions caused a significant (P<0.05) reduction in blood glucose level except 100 mg/kg of the aqueous and chloroform fractions. Additionally, repeated daily treatment with the aqueous fraction significantly reduced hyperglycemia, body weight loss, and improved dyslipidemia of diabetic mice.

Conclusion

This study has revealed that the solvent fractions of H. abyssinica leaves possess in vivo blood-glucose-lowering activities on normal, oral glucose loaded, and streptozotocin-induced diabetic mice. Additionally, the aqueous fraction prevented diabetic body weight loss and dyslipidemia in mice after repeated daily dose administration.

Medicinal Plant Extracts Evaluated In Vitro and In Vivo for Antidiabetic Activities in Ethiopia: Bases for Future Clinical Trials and Related Investigations

Background

Diabetes mellitus (DM) is a metabolic disorder characterized by a persistent rise in the blood glucose level resulting from defects in cellular insulin function, secretion, or both, which affects millions of people every year. Several drawbacks have been stated with the use of marketed antidiabetic medicines such as drug resistance, adverse effects, toxicities, and even costs. Due to these several limitations, searching for novel antidiabetic medicines from medicinal plants (MPs) is becoming an active area of research. Therefore, MPs are exemplary sources of medicines with many accessible agents being obtained from them because numerous active constituents are isolated from them for direct use as pharmacological medicines or act as lead compounds. This paper was aimed to synthesize a concluding remark using in vitro and in vivo evaluations of extracts and fractions for antidiabetic potentials in Ethiopia, which can be used to direct future clinical trials and related investigations.

Method

So as to get data on the different investigations, publications related to experimental evaluations on animal diabetic models in Ethiopia were searched from databases, such as Google Scholar, Web of Science, Medline, PubMed, and Scopus using English key terms.

Results

In this paper, about 37 research findings based on data from various areas of Ethiopia published until the end of November 2020 were included. A total of 37 MP species extracts and fractions belonging to 19 families have been revealed in vitro or in vivo for potential antidiabetic activities. Crude extracts were carried out mostly by hydromethanolic whereas fractions were done mostly by chloroform. Leaves were the most commonly experimentally investigated plant part. Among the MP species experimentally studied, the most frequently used to treat DM in Ethiopia were Thymus schimperi Ronniger (Lamiaceae), Moringa stenopetala (Baker f.; Moringaceae), Ajuga remota Benth (Lamiaceae), and Datura stramonium Linn. (Solanaceae).

Conclusion

This paper gives aggregate evidences on the potential antidiabetic activities of MPs in Ethiopia. Antidiabetic MPs used in Ethiopia represent crucial input for the future development of novel antidiabetic drugs. To this end, more pharmacological and toxicological investigations need to be considered to prove the safety of constituents obtained from these MPs. Finally, we recommend upcoming research to ensure future success in the clinical study and development of novel medicines for DM treatment from these frequently evaluated MPs.

Efficacy, safety and phytochemistry of medicinal plants used for the management of diabetes mellitus in Ethiopia: a systematic review

Background

Despite tremendous developments in synthetic medicine, medicinal plants are still commonly used for the management of diabetes mellitus. This study synthesized scientific evidence on commonly used medicinal plants for the management of diabetes mellitus (DM) in Ethiopia.

Methods

Databases (PubMed, Cochrane, CINAHL and Google Scholar) have been thoroughly sought and evidence was synthesized.

Results

Thirty studies conducted anti-diabetic activities studies on 19 medicinal plants in Ethiopia. Most of the studies were in vivo studies (25). Others include; clinical study (1), in vitro studies (2), and both in vivo and in vitro study (2). Trigonella foenum-graecum L., clinical study, showed an improved lipid profile in type II diabetic patients. Comparable blood sugar level (BSL) lowering effect to glibenclimide was observed with Persea Americana and Moringa stenopetala. Noteworthy in vitro half maximal inhibitory concentration (IC 50) of Aloe megalacantha B and Aloe monticola R were observed. Animal model studies demonstrated the relative safety of the plants extract and phytochemistry studies showed various components.

Conclusion

Medicinal plants used for management of diabetes mellitus in Ethiopia are worthy for further study for pharmacologically active ingredients and clinical evaluation.