HPLC-BASED IDENTIFICATION AND QUANTIFICATION OF QUERCETIN IN ABELMOSCHUS ESCULENTUS FRUIT EXTRACT AND EVALUATION OF ITS ANTIMICROBIAL ACTIVITY

Abstract

Background: Abelmoschus esculentus (okra) contains bioactive phytochemicals, particularly flavonoids and phenolic compounds, which are responsible for its therapeutic activity. Objectives: To identify and quantify quercetin (principle flavonoid) in the aqueous fruit extract of A. esculentus via high-performance liquid chromatography (HPLC) method and to assess its antimicrobial activity. Materials and Methods: Fresh okra fruits were shade dried, pulverized, and extracted with distilled water. The extract was initially subjected to qualitative phytochemical screening to confirm flavonoid presence. Quercetin was quantitatively determined using reverse-phase HPLC on a C18 column with an isocratic mobile phase (acetonitrile and 0.05% orthophosphoric acid 50:50, v/v). Chromatographic separation was performed with a mobile phase flow rate of 0.7 mL/min and UV detection at 280 nm. Antimicrobial efficacy was assessed against specific organisms using the agar well diffusion assay. Results: The developed HPLC method exhibited excellent linearity within the concentration range of 10–50 µg/mL (R² = 0.999). A characteristic quercetin peak was detected at ≈ 3.88 min retention time, and the extract contained 15.40% (w/w) quercetin. The extract exhibited antibacterial activity, with the greatest inhibition against S. aureus (22 mm), while antifungal activity was observed against A. niger (11 mm) and F. oxysporum (9 mm). Conclusion: The HPLC method provided a reliable approach for the identification and quantification of quercetin in A. esculentus fruit extract. The measurable quercetin content together with the demonstrated antimicrobial activity highlights the potential of the extract for pharmaceutical applications.