Author(s)

Mussie Sium^1*, Patrick Kareru², Beatrice Kiage-Mokua³, Kaushal Sood⁴, John Langley⁵, Julie Herniman⁵

¹Department of Chemistry, College of Science, Eritrea Institute of Technology, Asmara, Eritrea.
²Department of Chemistry, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
³Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya.
⁴Centre for Studies in Biotechnology, Dibrugarh University, Dibrugarh, India.
⁵Department of Chemistry, University of Southampton, Southampton, UK.

This paper reports the in vitro anti-diabetic profile of certain medicinal plants traditionally used in Eritrea for the management of type 2 diabetes. The crude methanolic extracts and fractions of Meriandra dianthera, Aloe camperi, a Polyherb and their fractions were investigated. The in vitro screening of the crude extracts has generally elicited a dose dependent α-glucosidase and α-amylase inhibition activities. M. dianthera displayed the highest α-glucosidase inhibitory activity (IC₅₀: 0.074 ± 0.032 mg/mL) at the highest concentration tested (0.800 mg/mL) relative to A. camperi, the Polyherb and Acarbose (IC₅₀: 0.37 ± 0.052, 0.56 ± 0.024 and 0.55 ± 0.029 respectively). The α-glucosidase inhibition activities of A. camperi and M. dianthera, except for the Polyherb and Acarbose, were significantly different (P < 0.05) at various ranges of concentrations (0.025 - 0.800 mg/mL). The percentage α-amylase inhibitions of M. dianthera, A. camperi, the Polyherb and Acarbose, at the highest concentrations (0.800 mg/mL), were 78.3%, 15.9%, 16.4%, and 82.9% respectively. A. camperi and the Polyherb displayed lower α-amylase inhibitory activities (IC₅₀: 1.72 ± 0.06 and 2.57 ± 0.07 mg/mL respectively) compared to Acarbose and M. dianthera (IC₅₀: 0.31 ± 0.01 and 0.43 ± 0.02 mg/mL respectively). For the α-amylase inhibition activity, even at lower concentrations (0.025 mg/mL), there were statistically significant differences (P < 0.01) among the values generated for all the extracts. The in vitro anti-diabetic screening of the fractions, at 0.800 mg/ml, displayed characteristic enzyme inhibition activities. Generally, the non-polar fractions showed higher enzyme inhibitory activities compared to the polar fractions. The most bioactive non-polar fractions, thus, were subjected to GC-MS analysis and presented various essential oils, fatty acid methyl esters (FAMEs) and benzoic acid derivatives in those plants.

Anti-Diabetic, α-Glucosidase, α-Amylase, GC-MS, Essential Oils, Fatty Acid Methyl Esters

Sium, M. , Kareru, P. , Kiage-Mokua, B. , Sood, K. , Langley, J. and Herniman, J. (2017) In Vitro Anti-Diabetic Activities and Phytochemical Analysis of Bioactive Fractions Present in Meriandra dianthera, Aloe camperi and a Polyherb. American Journal of Plant Sciences, 8, 533-548. doi: 10.4236/ajps.2017.83037.