Citation
Yahaya, Nurshieren
(2020)
Evaluation of in vitro antidiabetic mechanisms of methanolic extracts from four Ficus deltoidea jack varieties.
Doctoral thesis, Universiti Putra Malaysia.
Abstract
Diabetes Mellitus has been a global metabolic disorder and affected people of various ages.
In this research, four varieties of methanolic Ficus deltoidea extracts containing natural
products that possess anti-diabetic properties has been studied. The study was carried out
because antidiabetic synthetic drugs have been reported to have negative side effects on
diabetes patients. Therefore, the study was done to elucidate insulin-secreting activity
towards the beta pancreatic cell, to elucidate glucose uptake activity in insulin targeted
cells, to determine the potential of insulin-sensitizing activity in adipocytes cells and to
determine the potential of antiglycation activities of four methanolic Ficus deltoidea
varieties. The viability study which manifests viability assay has shown that methanolic
Ficus deltoidea variety deltoidea, angustifolia and motleyana does not toxic towards the
treated cells with the highest viability were portrayed by the highest viability can be seen
when treated with 500 μg/ml of methanolic extract Ficus deltoidea variety angustifolia
with 151.42 ± 0.08 percent (p<0.001) on beta pancreatic cell, 1000 μg/ml of methanolic
extract Ficus deltoidea variety angustifolia with 122.66 ± 1.92 percent (p<0.01) on L6
muscle cell and the highest viability can be seen at 100 μg/ml when treated with methanolic
Ficus deltoidea variety motleyana at 110.58 ± 3.45 percent on 3T3F442A adipocytes cell
but not significant. Besides, insulin secretion study conducted with insulin secretion assay
showed methanolic extracts of Ficus deltoidea varieties can stimulate insulin release from
pancreatic cells through the KATP independent pathway. The highest insulin secretion was
shown by methanolic extract Ficus deltoidea variety deltoidea with 6.24 fold (p<0.001).
In addition, the extracts able to stimulate glucose uptake in basal and insulin-mediated
state where the highest uptake can be seen in insulin-mediated state of L6 muscle cell
treated with methanolic extract Ficus deltoidea variety motleyana with 3.65 fold (p<0.001)
when compared to control and 2.90 fold (p<0.001) when compared to insulin 100 nM.
Apart from that the highest uptake can be seen in insulin-mediated state of 3T3F442A
adipocyte cell treated with methanolic extract Ficus deltoidea variety motleyana with 1.39
fold (p<0.001) when compared to control and 1.27 fold (p<0.001) when compared to
insulin 100 nM. All of the extracts follow the phosphatidylinositol-3-kinase-independent pathway except for Ficus deltoidea variety motleyana where when treated to 3T3F442A
cell, the extract does not follow both of phosphatidylinositol-3-kinase-dependent and
independent pathway. While in gene expression study through using Quantigene assay kit,
showed methanolic Ficus deltoidea variety bilobata as the highest expression for
phosphatidylinositol-3-kinase-dependent pathway with 1.24 fold in 6 hours while Ficus
deltoidea variety motleyana showed the highest expression for phosphatidylinositol-3-
kinase-independent pathway with 1.21 fold in 6 hours. All four varieties at a concentration
of 100 μM in insulin-mediated state shown a significant glucose uptake activity in insulin
resistance cell with the best secretion of leptin and inhibition of tumor necrosis factor-α
was significantly recorded by methanolic extract Ficus deltoidea variety angustifolia with
2.56 fold (p<0.001) and 0.73 fold (p<0.001). Last but not least, the highest antiglycation
activity was exhibited by methanolic Ficus deltoidea variety bilobata with 78.92 percent
of advanced glycation endproducts inhibition formation along with the highest detection
of fructosamine inhibition with 86.40 percent reduction. While Ficus deltoidea variety
deltoidea showed significant results with protein thiol preservation of 6.14 fold (p<0.001)
and protein carbonyl reduction with 1.76 fold (p<0.001). Total phenolic content assay
showed that methanolic Ficus deltoidea variety bilobata to have highest phenolic content
of 299.78 ± 2.88 mg GAE/ g of extract (p<0.001). The varieties also showed significant
antioxidant activities. In conclusion, methanolic Ficus deltoidea extract showed that most
extract follow independently of ATP-sensitive potassium channel in insulin secretion
activity. Apart from that, the extracts follow glucose uptake phosphatidylinositol-3-kinase
independent pathway, able to sensitize insulin and inhibit advanced glycation formation.
Therefore, it is suggested that methanolic Ficus deltoidea extracts can be a promising
candidate to be used as phytopharmaceutical agents to manage diabetes mellitus.
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