High resolution UPLC-PDA-QTOF-ESI-MS/MS analysis of the flavonoid-rich fraction of Lasianthera africana leaves, and in vivo evaluation of its renal and cardiac function effects

Lasianthera africana P. Beauv. (Icacinaceae) is a traditional Nigerian medicinal plant used for treatment of ulcers, diarrhea, parasitic infections and diabetes. This study was aimed at characterizing the bioactive principles extractable from the flavonoid-rich fraction of L. africana leaves (LAFRF), and to evaluate its effects on renal and cardiac functions. Isolation, and purification of the LAFRF was achieved using standard methods. The in vitro antioxidant activity was evaluated on DPPH∗ and ferric reducing antioxidant potential (FRAP). The total flavonoids (281.05 ± 7.44 mg QE/g), were identified, structurally characterized and quantified using high resolution ultra-performance liquid chromatography, in tandem with quadrupole-time-of-flight electrospray ionization mass spectrometer (UPLC-PDA-QTOF-ESI-MS/MS). Fifty Wistar rats of both sexes (110-130 g), were distributed into 10 groups (n = 5). Groups 1 and 2 served as the normal and CCl₄ controls respectively. Groups 3A-6B constituted the preventive and curative studies. The effects of the LAFRF at 3, 10, and 30 mg/kg body weight on urea and creatinine concentrations, lactate dehydrogenase (LDH), and creatine kinase (CK) activities of CCl₄-intoxicated rats were assessed. The LAFRF displayed remarkable in vitro antioxidant property by scavenging the DPPH∗, with an IC₅₀ of 5.40 ± 0.00 μg/ml which is more potent than the scavenging activity of the ascorbic acid (IC₅₀ of 7.18 ± 0.00 μg/ml), and also effectively reduced Fe³⁺ to Fe²⁺ when compared to gallic acid. The UPLC-PDA-QTOF-ESI-MS/MS fingerprint of the LAFRF indicated presence of quercetin (758983.6 mg/kg), rutin (17540.4 mg/kg), luteolin (126524.3 mg/kg), isorhamnetin (197949.0 mg/kg), and other non-phenolic compounds. The LAFRF significantly (p < 0.05) improved renal function, and normalized cardiac enzyme activities in vivo. The ability of the LAFRF to scavenge the DPPH and Fe³⁺ radicals, improve renal and cardiac functions following CCl₄ intoxication shows its potential in the development of alternative therapy for combating oxidative stress-related complications.

Keywords: Antioxidants; Biological sciences; Carbon tetrachloride; Cardiac enzymes; Ethnopharmacology; Flavonoid-rich fraction; Isolation and characterization; Lasianthera africana P. Beauv.; Natural product; Oxidative stress; Pharmaceutical science; Polyphenolic phytochemicals; Reactive oxygen species; Renal function; Toxicology; UPLC-PDA-QTOF-ESI-MS/MS.