Chemical profiling of citrus fruit-peel and stem extracts by modified UHPLC-TOF-MS and their antiplasmodial, antioxidant and antimicrobial activities

Abstract

Citrus jambhiri (Lush) and paradisi (Macf.) have wide usage as food spices. Therefore, the presence of profiled phytochemicals, the antioxidant, antimicrobial and anti-plasmodial activities of the stem and fruit-peel extracts were studied. The citrus stem and fruit-peel extracts were analyzed using ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-qTOF/MS) and anti-plasmodial activities against chloroquine-sensitive (CQS) strain of Plasmodium falciparum, antimicrobial against Gram-positive and Gram-negative bacterial strains as well as antioxidant potentials were determined in triplicate. Metabolite fingerprinting of C. jambhiri stem and C. paradisi fruit-peel extracts revealed rutamarin and spicatin respectively. The stem and fruit-peel of C. jambhiri showed moderate antimalarial activity. C. paradisi stem revealed a weak activity; however, C. paradisi fruit-peel showed no antimalarial activity (IC₅₀ >100 μg/mL). C. paradisi and C. jambhiri extracts exhibited lower inhibition concentration (IC₅₀: 3.0–7.0 µgmL⁻¹), than ascorbic acid (IC₅₀: 9.0 µgmL⁻¹). C. paradisi stem DCM/methanol extract showed a reducing value of EC₅₀: 8.00 µgmL⁻¹ whereas reference compound used, (ascorbic acid) had EC₅₀: 11.00 µgmL⁻¹. Furthermore, C. jambhiri stem extract showed the best antimicrobial activity against the clinical isolates with high inhibition zones ≥ 15 mm. There is a paucity of information on the identification and importance of rutamarin and spicatin from Citrus extracts as a functional food ingredient with a promising compound implicated in the development of antimalarial drugs. Overall result however showed that the two citrus plants contain antioxidant constituents whereas C. jambhiri could be important source of antimicrobial agents. The study profiled two new compounds from the citrus extract and showed the potentials of the plant as source of antimalaria drug.