Abstract

IN VITRO ANTIOXIDANT AND ANTIDIABETIC ASSESSMENT OF EXTRACTS FROM THE BARK OF MICHELIA CHAMPACA, A MEDICINAL PLANT IN BANGLADESH

Ruksana Yesmin, Plabon Kumar Das, Hazrat Belal, Suraiya Aktar, Mst. Ayesha Siddika, Saharia Yeasmin Asha, Sayeda Nusrat Jahan, Sha Md. Shahan Shahriar, Md. Abdur Rakib, Farhadul Islam and Jahan Ara Khanam*

Abstract

Michelia champaca (MC), family Magnoliaceae, is a medicinally important plant. Different parts of this plant are used in various ailments in folk medicine. The present study was conducted to demonstrate antioxidant potentiality of Michelia champaca bark in two different solvents and evaluate their in vitro antidiabetic activity along with screening for their phytochemical composition. The dried coarse powder of Michelia champaca bark was exhaustively extracted with ethanol (MCBEE) and water (MCBWE). The antioxidant activity of resulted extracts was determined by several assays: total antioxidant capacity assay, DPPH, ABTS, lipid peroxidation, Nitric oxide and Superoxide scavenging assays. Quantitative analysis of phytochemicals such as total phenolics, flavonoids, flavonols and proanthocyanidins contents were also measured. In vitro anti-diabetic activity was determined in terms of DNSA and starch iodine colorimetric assay. All the extractives showed strong antioxidant activities related to the standard. The total antioxidant capacity of extracts in most of the cases was in the following order: MCBEE>MCBWE. In free radical scavenging assay, the percent scavenging value of the extracts were concentration dependent manner and ethanol extract showed the most potent inhibitory activity, which was significantly different (p< 0.05) from water extract. At the highest concentration, 51.59 and 41.94% of α-Amylase inhibition were observed in DNSA method by MCBEE and MCBWE respectively, where standard Acarbose exhibited 65.84% inhibition. Total phenolics content and total flavonoids content were strongly correlated (p< 0.01) with antioxidant activity. The present study suggests that methanol extract of Michelia champaca bark possess significant in-vitro antioxidant and anti-diabetic activity. Bark of M. champaca may therefore be a good source for natural antioxidants and a possible pharmaceutical supplement.

Keywords: Phytochemicals, Antioxidants, Antidiabetic, Mycchelia champaca, Bark.