Anti-oxidant, anti-diabetic and cytotoxic studies of extracts and bioactive compounds from Citrus sinensis L. osbeck and Artocarpus hirsutus lam.

The present study purports the evaluation of extracts and bioactive constituents, neral from Citrus sinensis and artocarpin from Artocarpus hirsutus for anti-oxidant and anti-diabetic activity in vitro through enzyme inhibition model. Artocarpin and neral were isolated by column chromatography and preparative GC respectively and structure was elucidated by NMR and mass spectrometry. The pet ether, ethanol extracts and isolated compounds were evaluated for anti-oxidant and anti-diabetic activities. Both artocarpin and neral displayed excellent anti-oxidant activity of 89.43% and 81.97% respectively for DPPH and H₂O₂ FRSA activities comparable with that of ascorbic acid, a positive control. Surprisingly, all the samples presented significant anti-diabetic activity where, artocarpin and neral showed marked α-amylase and α-glucosidase inhibition in a mixed inhibition pattern with IC₅₀ of 46.68 & 58.96 and 49.29 & 67.92 mg/ml, respectively. Further, the pet ether and ethanol extracts also showed considerable inhibition of both the enzymes. Artocarpin and neral exhibited substantial increase in the uptake of glucose in HepG2 and L6 myoblasts cells at all tested concentrations in a dose dependent manner compared to the untreated control (negative) but less than the positive control, metformin. The MTT assay on HepG2 cells and L6 myoblasts at 0-200 µg/ml reveals that the both the molecules offered safety profile with only < 20% of cell death. These results suggested that these phytoconstituents and extracts serve as lead molecules for development of viable and suitable formulations and help in the management of diabetes and stress related disorders as well.