Elucidation of phenolic profile and bioactive potential of Aeginetia indica L.: A comparative study between newly discovered yellow and native purple flowers

Abstract

Aeginetia indica L. is a wild plant, with scant information on its food and medicinal applications. This research investigated the phenolics, antioxidant properties, in vitro medicinal activities, and genotoxicity of the newly discovered yellow and native purple flowers of A. indica collected from diverse locations in Thailand. Purple A. indica harvested from Ubon Ratchathani Province (PU) exhibited 1.3–1.4-fold higher total phenolic content (TPC) and 1.1–1.4-fold higher total flavonoid content (TFC) than purple A. indica collected from Sakon Nakhon Province (PS) and yellow A. indica collected from Sakon Nakhon Province (YS), with apigenin and naringenin predominantly detected in PU by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). The purple color of PU and PS led to 2.5–2.9-fold higher total anthocyanin content (TAC) than YS. Higher phenolic content in PU led to stronger antioxidant activities by 1.2–1.3- and 1.2–1.8-fold as determined by ferric ion reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays, respectively, while the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was not significantly different from PS. PU and PS exhibited 1.1-fold lower scavenging capacities (50 % of total radicals or SC<inf>50</inf>) than YS, suggesting their higher antioxidant strength. Higher inhibitory activities of most key enzymes relevant to obesity (lipase, 1.6–3.3-fold higher), type II diabetes (α-amylase, 1.3–1.6-fold higher), and Alzheimer's disease (acetylcholinesterase (AChE, 1.6–3.0-fold higher) and butyrylcholinesterase (BChE, 1.1-fold higher)) were also observed in PU. Further investigation of the PU extract with orlistat (a commercially available anti-obesity drug) and donepezil (a commercially available anti-Alzheimer's disease drug) suggested synergistic effects of PU with both drugs. PU did not induce gene mutations as assayed by the bacterial reverse mutation test. The results suggested that PU could be further developed as a future functional food or health ingredient.