Quantification of Phenolic Compounds, Evaluation of Antioxidant and Antimycobacterial Activities of Extracts of Clerodendrum splendens, Sansevieria trifasciata and Sacoglottis gabonensis

An In vitro study was conducted to investigate the extracts of three plants: Clerodendrum splendens, Sansevieria trifasciata and Sacoglottis gabonensis, which are traditionally utilized in Côte d’Ivoire for the treatment of Buruli ulcer. The objectives of this study were to quantify phenolic compounds, assess antioxidant activity against the DPPH● radical and evaluate the effects of aqueous and hydroethanolic extracts from the leaves, roots and barks on a strain of Mycobacterium ulcerans. Quantitative analysis revealed significant concentrations of total polyphenols, flavonoids, condensed and hydrolyzable tannins. The highest total phenolic content was found in the decoction and hydroethanolic macerate of Sacoglottis gabonensis (DSG: 367.15±4.88; MhSG: 317.51 ​​± 3.87 mgEAG/g). Total flavonoids were more abundant in hydroethanolic and aqueous macerates of Clerodendrum splendens (MhCS: 73.64±3.01; MCS: 44.31±0.50 mgEQ/g), as well as in decoctions of both Sacoglottis gabonensis and Clerodendrum splendens (DSG: 46.17±1.13 and DCS: 41.40±0.90 mgEQ/g). Condensed tannins were primarily found in the decoction and hydroethanolic macerate of Sacoglottis gabonensis (DSG: 30.29 ± 1.00 and MhSG: 21.36 ± 0.68 mgEC/g) and in the macerate of Clerodendrum splendens (MCS: 23.12±0.34 mgEC/g). Hydrolyzable tannins were more concentrated in the hydroethanolic and aqueous macerates and decoction of Clerodendrum splendens (MhCS: 2.01±0.13; MCS: 1.5±0.03 and DCS: 1.68±0.14%). The antioxidant activity, assessed against the stable DPPH, showed that the extracts of Sacoglottis gabonensis (CR50: decoction 0.0085; aqueous radical and hydroethanolic macerates: 0.0209 and 0.0062) and Clerodendrum splendens (CR50: decoction 0.005) exhibited activities comparable to that of vitamin C (CR50: 0.002), which served as a reference. All extracts demonstrated significant activity against the Mycobacterium ulcerans strain CD1539 at concentrations ranging from 0.1 mg/mL to 0.5 mg/mL, with enhanced activity noted for the plant decoctions.