In-Vitro Antidiabetic Effect of Ziziphus mucronata Leave Extracts

Background: Diabetes is a metabolic disorder characterized by hyperglycemia due to the body’s inability to produce insulin or inaction of the produced insulin or a combination of both. One antidiabetic therapeutic approach is to reduce gastrointestinal glucose production and absorption through the inhibition of carbohydrate digesting enzymes such as alpha-amylase as well as through the inhibition of hemoglobin glycosylation. Objective: This study sets out to evaluate the in vitro antidiabetic activity of Ziziphus mucronata extracts for their effect on alpha-amylase and glycosylation of hemoglobin. Methods: Successive gradient maceration of Z. mucronata leaves were carried out using Hexane, Acetone, Methanol and separately with water to obtain four (4) extracts labelled HE, AE, ME, and WE respectively. These were subjected to in vitro studies for their inhibitory effect on alpha-amylase and hemoglobin glycosylation, Standard laboratory methods were used to screen for phytochemicals of the most potent extract. Results: The result showed that AE, ME and WE extract exhibited a dose-dependent increase in percentage inhibition of both alpha-amylase and hemoglobin glycosylation. However, on a stricking note, the AE showed a more potent data result with percentage (%) potency of 71.02 at 1mg/ml, the lowest glucose concentration (of 25mg/ml) at 0.242nm as well as the highest hemoglobin glycosylation inhibitory mean concentration of 3.663nm after 72 hours. The AE of Z. mucronata (the most potent) revealed the presence of alkaloids, anthraquinone, glycosides, flavonoids, phenols, saponin, tanins and terpenoids. Conclusion: Thus, the Acetone extract is more likely to give a lead antidiabetic drug molecule of drug when further explored; which somewhat justify the folkloric claims of Z. mucronata leave as an antidiabetic. Keywords: Heamoglabin glycosylation, Alpha-amylase enzymes, Inhibition, Glucose.

Interaction of Ziziphus mucronata subsp. mucronata Methanol Extract and First-Line Antibiotics is Synergistic In Vitro through Production of Reactive Oxygen Species

With the increased incidence of antibacterial resistance in microorganisms, combining natural products from plants with antibiotics may be considered interesting alternatives for synergy to attain multitarget effects. In this study, the antioxidant activity of the methanol extract of Ziziphus mucronata and its interactions with antibiotics against bacteria of clinical importance were investigated. While its phytochemicals and antioxidant activities were determined by free radical scavenging assays, the antibacterial activities of the extract and its interactions with the antibiotics were determined by macrobroth dilution and the checkerboard methods. From the results, total phenolic content was 29.67 ± 1.90 mg GAE/100 g, total flavonoid content was 8.72 ± 0.08 mg QE/100 g, and total proanthocyanidin content was 1.94 ± 0.00 mg CE/100 g of dry plant material. The inhibition concentration 50% (IC50) of DPPH, BHT, and ascorbic acid was equal to 0.04 ± 0.02 mg/ml, respectively. Those of the ABTS, BHT, and ascorbic acid were equal to 0.02 ± 0.02, 0.04 ± 0.03, and 0.04 ± 0.02 mg/ml, respectively. The checkerboard assay showed that combining the extract with different antibiotics resulted in synergistic (38.75%), indifferent (30%), additive (28.75%), and antagonistic (2.5%) interactions. The interactions between the extract and antibiotics resulting in enhanced antibacterial activities could have resulted from the antioxidant activities of the extract mopping up the ROS generated by the antibiotics or the ability of both extract and antibiotics simultaneously producing reactive oxygen species with deleterious effects resulting in synergistic antibacterial effects.

Anticholinesterase and Antioxidant Potential of Hydromethanolic Extract of Ziziphus mucronata (Rhamnaceae) Leaves on Scopolamine-Induced Memory and Cognitive Dysfunctions in Mice

Ziziphus mucronata Willd, also known as “buffalo thorn,” belongs to the family Rhamnaceae. Its bark and leaves are used in folk medicine for the treatment of various deficiencies related to nociception, inflammation, mood, and depression. Still, there is a lack of scientific data regarding its potential effect on learning and memory process. The present study was designed to investigate the neuroprotective potential of Ziziphus mucronata (ZM) on learning and memory impairment in a scopolamine-induced model of dementia in mice. The phytochemical analysis revealed five cyclopeptide alkaloids (sanjoinines) in the extract from Ziziphus Mucronata leaves using LC-HRMS, and the structural characterization of these compounds was determined via MS/MS. Alzheimer-type amnesia was induced by an intraperitoneal injection of scopolamine (1 mg/kg) to mice for 7 consecutive days. ZM (150 mg/kg, 300 mg/kg, and 600 mg/kg) and piracetam (150 mg/kg) were orally administrated to mice daily for a period of 14 days. Memory-related behavioural parameters were evaluated using the radial arm maze task for 7 days, Y-maze, and novel object recognition task. At the end of protocol schedule, animals were sacrificed, and the levels of acetylcholinesterase, malondialdehyde, catalase, and superoxide dismutase were determined in brain homogenates. Histological studies of the hippocampus were subsequently performed. The long-term scopolamine-injected group decreased the spontaneous alternation (Y-maze), the discrimination index, and the time taken to explore the new object (novel object recognition task). These effects were significantly reversed by ZM at all the doses tested. In the radial arm maze task, ZM (300 and 600 mg/kg) significantly decreased the working and reference memory errors when compared with the demented group. Scopolamine-mediated changes in AChE activity were also attenuated by ZM in mice. In addition, extract-treated groups showed a significant increase in the level of CAT and SOD activity and decreased levels of MDA in the mice brains, as compared with the control group. The present study suggests that ZM could have an important role in neuroprotection on this scopolamine-induced model of Alzheimer-type dementia.