In vitro Antioxidant and Antidiabetic Activities of Wild and Micropropagated Plants Aqueous Extracts of Caralluma bicolor – An Endangered Medicinal Plant

Abstract

Purpose: Caralluma bicolor is a succulent perennial herb growing wild in dry hill regions. It belongs to the family Asclepiadaceae. This species is endemic to the eastern slopes of the Western Ghats of the Coimbatore District, Tamil Nadu. The present study was carried out to assessment of its in vitro antioxidant and antidiabetic activities. Methods: In vitro antioxidant and antidiabetic activities in wild C. bicolor (WCB) and micropropagated C. bicolor (MCB) aqueous extracts studied through 1, 1-diphenyl-2-picrylhydrazil (DPPH), 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS+), reducing power assay, hydroxyl radical scavenging activity, nitric oxide scavenging activity, and inhibition of α-amylase and α-glucosidase enzyme assays. Results: The highest antioxidant activities were observed in C. bicolor against in all five assays, namely, DPPH (IC50 = WCB 54.65 μg/mL, MCB 52.76 μg/mL), ABTS+ (IC50 = WCB 71.04 μg/mL, MCB 69.10 μg/mL), reducing power assay (IC50 = WCB 62.25 μg/mL, MCB 53.90 μg/mL), hydroxyl radical scavenging assay (IC50 = WCB 60.93 μg/mL, 61.15 μg/mL), and nitric oxide scavenging assay (IC50 = WCB 70.20 μg/mL, MCB 74.75 μg/mL). Furthermore, in antidiabetic activity, the highest inhibition was observed in α-amylase and α-glucosidase enzyme activities and the IC50 values of WCB and MCB were 58.93, 60.55, 64.70, and 70.08 μg/mL, respectively. Conclusion: This study suggests that the aqueous extract of C. bicolor has great antioxidant and antidiabetic activities. The results revealed that the plant has rich in bioactive compounds, which serve as a novel therapeutic applications for drug discovery.