Green synthesis of carbon dots (CDs) using aerial parts of Ipomoea obscura and evaluation of in vitro biological activities

Ipomoea obscura also called as Obscure morning glory is a versatile perennial herb with medicinal properties. Carbon dots (CDs) are prepared from the aerial parts (Leaf, Stem and Flower) of such plant via hydrothermal method. The as-synthesized CDs optical, structural and surface chemical characteristics were analysed by using UV-Vis, PL, PLQY, FTIR, XRD and Raman. Their morphology, elemental composition, particle size and hydrodynamic size distribution were further examined through SEM-EDAX, HRSTEM and DLS analyses. The CDs exhibited ultrasmall particle sizes (3–4 nm), partially graphitized carbon domains and abundant oxygen-containing surface functionalities. Comparative biological evaluation demonstrated that Flower CDs exhibited the highest α-amylase (76.6%) and α-glucosidase (66.5%) inhibition, whereas Stem CDs showed superior antioxidant activity with DPPH radical scavenging (83.9%) and ferric reducing antioxidant power (FRAP) (96.2%) at 40 μg mL −1 . Leaf and Stem CDs exhibited comparatively higher antimicrobial activity against Aspergillus niger and Candida albicans , while Flower CDs demonstrated enhanced anti-inflammatory activity in protein denaturation, heat-induced RBC haemolysis and proteinase inhibition assays. The synthesized CDs also exhibited concentration-dependent cytotoxicity toward SH-SY5Y neuroblastoma cells. Overall, I. obscura -derived CDs exhibit promising in vitro biological activity, highlighting their potential as green, bioactive carbon nanomaterials. However, further mechanistic, in vivo and safety studies are needed to validate their biomedical applications.