Comparison of different parts of Plumbago zeylanica L. through UPLC-MS/MS metabolite profiling and evaluation of their antioxidant and antifungal potential

The metabolites were extracted from the leaves (BHY), roots (BHG), and stems (BHJ) of Plumbago zeylanica L. (P.zeylanica) using 70 % ethanol. Subsequently, the metabolite profiles, antifungal, and antioxidant activities of the extracts were evaluated. The highest contents of total phenols (91.63±1.08 mg GAE/g DW) and total flavonoids (146.5±5.48 mg RE/g DW) were found in BHJ. All extracts of P.zeylanica effectively neutralized DPPH (83.47 %-93.44 % in 5 mg/mL) and ABTS radicals (99.42 %-102.1 % at 5 mg/mL), demonstrating potent antioxidant properties, particularly in BHG. The DPPH activity of P.zeylanica extracts (3.0 mg/mL) showed higher radical scavenging activity when compared with the positive control, ascorbic acid. The extracts of P.zeylanica displayed significant antifungal effects against all tested microorganisms (B.cinerea, F.moniliforme, B.dothidea, P.expansum, and G.candidum), with inhibition rates ranging from 37.96 % to 99.65 % and MIC values between 0.063 and 1.00 mg/mL. The most susceptible strain was G.candidum (average inhibition rate: 95.47 %). BHG demonstrated the highest effectiveness in inhibiting the growth of P.expansum, G.candidum, and F.moniliforme, while BHJ showed the strongest activity against B.cinerea and B.dothidea. 2116 metabolites were identified by UPLC-MS/MS, of which 2026 were common to the three extracts. Notably, BHG was found to be a rich source of alkaloids and quinones (including the pharmacologically active compound plumbagin), with superior antioxidant and antifungal capacities. Most of the metabolites were isolated and identified for the first time in P.zeylanica, including Hydroxyplumbagic acid, 3′-O-Beta-D-xylopyranosyl plumbagic acid, Loliolide, Atractylolide III, Cinchonain Ib, and Cinchonain Ic. Correlation analysis identified 115 potential metabolic biomarkers, primarily consisting of phenolic acids, flavonoids, and alkaloids, which likely explain some of the potent observed bioactivity. As regards the results mentioned above, all parts of the P.zeylanica could be utilized as a promising source of bioactive compounds for potential applications in the food, cosmetic, and pharmaceutical industries due to its notable antioxidant and antifungal properties.