Evaluation of anti-diabetic, anti-oxidant and anti-bacterial activities of essential oil collected from wildly growing Calotropis gigantea (Linn.) Aiton f. and its therapeutic applications: insights from chemical profiling, in-vitro and in-silico studies

Abstract

Calotropis gigantea, often known as giant milkweed, the plant is widely known for producing herbal essential oils that are used as traditional and complementary medicine to cure various ailments. The aim of the present study was evaluation of anti-diabetic, anti-oxidant and anti-bacterial activities of essential oil collected from wildly growing Calotropis gigantea and its its therapeutic applications via chemical profiling, in-vitro and in-silico studies. After Calotropis gigantea (CEO) essential oil was extracted by hydro-distillation, its phytochemical, antioxidant, antibacterial, and anti-diabetic properties were assessed. Fingerprint analysis and GC-FID were used to create a chemical profile. Various tests for antioxidants, such as DPPH, nitric oxide radical, and iron chelating activity, were conducted. The disk diffusion approach was used for antibacterial efficacy against Gram-negative (G-) bacteria. The test of α-amylase inhibition was utilized to investigate anti-diabetic efficacy. In-silico analysis was also conducted to find out interaction of some components to α-amylase enzyme. Chemical profiling indicated the presence of phytol (24%), stearic acid (10%), and cyclohexyl ketone (6%), as predominant components. There was notable antioxidant activity ranged from 82 to 97% for various assays. IC50 values for various assays were iron chelating activity: 18.610, DPPH scavenging activity: 28.246, nitric oxide radical scavenging activity: 58.113. CEO showed a zone of inhibition value of 0.5 cm and significant antibacterial activity against Gram-negative (G-) bacteria. CEO blocked α-amylase in dose-dependent way. At a higher amount of 250 µl, CEO inhibition was 63% and mode of inhibition un-competitive. In-silico analysis validated the blocking of α-amylase and interaction of phytocomponents to α-amylase enzyme which were further validated by UV and fluorescent quenching techniques. It was determined that CEO may be extensively used in many different industries, including as food, herbal medicine, cosmetics.