In vitro assessment of antidiabetic properties of herbs and spices extract in adipocytes

Abstract

The prevalence and suffering of diabetes and obesity has been increasing among the various communities of the world including Malaysia. The cost of treatment is also rising. Therefore, it is important to explore non pharmacological regime that are noninvasive and with less health risks and cost burden to the patients, healthcare professionals and nations. Medicinal plants have been used for the treatment and prevention of diabetes since ancient time. Therefore, nine common traditional antidiabetic herbs namely Andrographis paniculata (Hempedu bumi), Lagerstroemia speciosa (Banaba/bungur), Orthosiphon stamineus (Cat whisker), Peronema canescens (Sungkai), Momordica charantia (Bitter gourd/bitter melon), Tinospora crispa (Patawali), Pithecellobium jiringa (Jering) and spices namely Syzygium polyanthum (Bay leaf) and Cinnamomum zeylanicum (Cinnamon), were screened for their antidiabetic properties in in vitro model. Water extracts of these herbs and spices were prepared and evaluated for their effects on cell proliferation, adipogenesis, adipolysis, glucose uptake and glucose oxidase assay in 3T3-L1 preadipocytes. The study was then continued with quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) for selected herbs and spices extracts for the genes; adipogenesis-regulator (Ppar? mRNA), insulin-sensitive glucose transporter 4 (Glut4 mRNA) and gene associated with obesity and insulin resistance (Adiponectin mRNA). The results of aforementioned extracts promoted cell proliferation at a concentration of 0.25mg/ml which showed a maximum viability after 48 hours of treatment. Insulin and A. paniculata extract significantly (p<0.05) induced adipocyte differentiation, inhibited lipolysis and stimulated glucose uptake/oxidase in adipocytes. This activity was accompanied by significant (p<0.05) up-regulation of Ppar?, Glut4 and Adiponectin transcriptional levels. This finding reveals that A. paniculata extract have similar effect to that of insulin activity. Whilst the study on C. zeylanicum and O. stamineus extracts have similar activity for adipogenesis significantly (P<0.01), stimulated glucose uptake and reduced adipolysis activity. Thus, it is suggested that these extracts might have insulin-mimicking effects which could be potentially used as preventive agents for diabetes. In contrast to insulin, water extracts of L. speciosa did not induced adipocyte differentiation, significantly (P<0.01) decreased Ppar? mRNA, exhibited adipolysis activity and stimulated glucose uptake/oxidase due to significant (P<0.05) up-regulation of Glut4 transcriptional levels in adipocytes. This combination suggested that L. speciosa extract may be useful for the treatment of hyperglycemia and obesity in type 2 diabetes. It is well known fact that an appropriate balance between the adipogenesis, adipolysis and glucose uptake/oxidase in diabetes is of primary importance. The present study provides some important clues both on the biochemical and transcriptional aspects of the effect induced by the herbs and spices screened. The present study suggests that these herbs and spices possess antidiabetic properties as well as can be used for the associated metabolic dysfunctions.