Phytochemical composition and in vitro pharmacological investigations of Neurada procumbens L. (Neuradaceae): A multidirectional approach for industrial products

The plants of genus Neurada have been utilized for medicinal purposes. This study probed into the biological propensities and endeavored to achieve the detailed phytochemical profile, via ultra-high performance liquid chromatography -UHPLC-MS analysis and high performance liquid chromatography photodiode array -HPLC-PDA of different polarity extracts (methanol, n-hexane, chloroform, and n-butanol) of Neurada procumbens L. The biological features were studied by determining the antioxidant potential via 2,2-Diphenyl-1-picrylhydrazyl -DPPH, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid -ABTS, ferric reducing antioxidant power -FRAP, cupric reducing antioxidant power -CUPRAC, phoshomolybdenum and metal chelation assays and clinically significant major enzymes (cholinesterases, α-amylase, α-glucosidase and tyrosinase inhibition). Moreover, the correlation among the biological activities and total bioactive contents of the extracts were studied via multivariate statistical analysis. The methanol and n-butanol extracts revealed the presence of total phenolic and flavonoid contents in highest concentrations which tend to correlate with their maximum anti-oxidant capacities for radical scavenging and reducing power assays. The n-hexane extract was most active in the phosphomolybdenum assays whereas the chloroform extracts showed the highest metal chelation potential. The UHPLC-MS phytochemical profiling of the methanolic extract (both positive and negative ionization mode) revealed the existence of eighteen phytochemicals representing four different classes (phenolics, flavonoids, sesquiterpenoids, and alkaloids). The n-butanol extract inhibited acetylcholinesterase (4.10 mg galantamine equivalent -GALAE/g) and tyrosinase (127.65 mg kojic acid equivalent -KAE/g) significantly as compared to the control. The n-hexane extract exhibited highest inhibition against butyrylcholinesterase (1.93 mg GALAE/g) and α-glucosidase (59.0 mmol acarbose equivalent -ACAE/g), while chloroform extract exhibited prominent inhibitory action inimical to α-amylase (0.65 mmol ACAE/g). Overall, it was observed that FRAP and tyrosinase activities were the most contributive biological activities for the formation of first component with p values of 0.018 and 0.023, respectively, whereas, for the formation of second component, glucosidase activity was the most contributive assay with p value of 0.002. It can be concluded that the manifestation of dynamic phytochemicals with multi-pharmacological potential marks N. procumbens as a prospective origin of health-promoting molecules warrants further exploration as a unique therapeutic medicinal plant.