Simultaneous determination and ADME profiling of betulinic and ursolic acids from Avicennia marina in Wistar rats

Avicennia marina (grey mangrove) (AM) is a significant source of bioactive pentacyclic triterpenoids, specifically Betulinic acid (BA) and Ursolic acid (UA). Owing to their therapeutic potential, the pharmacokinetic (PK) profiles of these bioactives after administration of AM extract can be valuable in deciding their usage in therapeutics. A robust, sensitive RP-HPLC-PDA method was developed and validated according to US-FDA guidelines for the simultaneous quantitation of BA and UA in rat plasma using 18βeta-glycyrrhetinic acid as an internal standard. Following a single oral dose of AM ethyl acetate extract (2000 mg/kg), plasma samples were collected from experimental rats using a sparse sampling strategy and analyzed to determine the PK parameters. The bioanalytical method demonstrated linear response (r 2 = 0.996 and 0.998 for UA and BA), with high recovery (83.89–85.62%) and negligible matrix effects (within ± 3%). Pharmacokinetic analysis revealed a multi-phasic absorption profile with BA exhibiting rapid systemic influx (C max = 25.52 ± 0.215 µg/mL at T max = 0.33 ± 0.001 h) and a prolonged half-life (t 1/2 = 4.39 ± 0.419 h), while UA showed a delayed peak (C max = 29.12 ± 0.498 µg/mL at T max = 2.00 ± 0.001 h) but higher total exposure (AUC 0−∞ = 141.22 ± 1.615 µg/mL*h). The results indicate that the AM extract acts as an effective natural matrix facilitating the systemic absorption of lipophilic BA and UA. This study provides the first quantitative ADME evidence for AM extract, establishing BA and UA as reliable pharmacokinetic markers for its standardization and translation into clinical practices.