Profile of Terpenoid and Flavonoid Compounds by LC-MS/MS and Antioxidant Properties of Tapinanthus ophiodes (Sprague) Danser Flower Extracts

Abstract

The floral phytochemistry of Tapinanthus ophiodes (Sprague) Danser remains poorly documented despite interest in the genus Tapinanthus as a source of plant-derived compounds. This study examined the phytochemical profile and in vitro antioxidant properties of its flowers. Flowers collected in the Central West region of Burkina Faso in May 2023 were freeze-dried and extracted by maceration with acidified methanol. Phenolic compounds, flavonoids and anthocyanins were measured spectrophotometrically. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) was used to assess molecular features and propose compound identities. Free radical-scavenging activity and antioxidant compound content were evaluated using DPPH- and ABTS-based assays. Phenolic, flavonoid and anthocyanin contents were 314.76 ± 1.17 mg GAE/g, 741.25 ± 0.72 mg QE/g and 2.51 ± 0.04 mg CE/g of extract, respectively. LC–MS/MS revealed 17 chromatographic peaks, associated with tentative assignments of 13 flavonoids and three steroidal or terpenoid compounds; one peak remained unassigned. The DPPH IC₅₀ was 34.83 ± 1.8 µg/mL, compared with 21.34 ± 0.14 µg/mL for Trolox. Antioxidant compound contents were 64.76 ± 0.12 mg TE/g using DPPH and 48.76 ± 0.08 mg TE/g using ABTS. These findings document a diverse profile of tentative constituents and measurable in vitro radical-scavenging activity in T. ophiodes flower extract.