Antibacterial, In Vitro Analgesic, and Antioxidant Activities of Crude Extract of Habenaria plantaginea Lindl

Abstract

The rising problem of antibiotic resistance and oxidative stress–related disorders has increased the need for natural sources of therapeutic agents. Habenaria plantaginea Lindl., a medicinally important orchid, is known to contain bioactive phytochemicals with potential pharmacological effects. This study evaluated the antibacterial, in-vitro COX-2 inhibitory, and antioxidant activities of the crude root extract of H. plantaginea. Antibacterial activity was assessed against five clinically significant bacterial strains (Escherichia coli, Klebsiella pneumoniae, Staphylococcus epidermidis, Staphylococcus aureus, and Bacillus subtilis) using the disc diffusion method, with streptomycin as a standard. The crude extract exhibited broad-spectrum antibacterial activity, showing the highest inhibition against B. subtilis (26.89 ± 1.00 mm) and E. coli (24.50 ± 1.29 mm). In the COX-2 inhibitory assay, the extract demonstrated moderate, concentration-dependent inhibition with a maximum of 42.36 ± 1.18% at 250 µg/mL (IC₅₀ = 190.2 ± 2.5 µg/mL), whereas the standard drug celecoxib achieved 94.21 ± 1.10% inhibition. Similarly, the extract showed moderate antioxidant activity in the H₂O₂ scavenging assay, with a maximum inhibition of 46.38 ± 1.30% at 250 µg/mL (IC₅₀ = 205.4 ± 3.1 µg/mL), compared to 91.45 ± 1.12% for ascorbic acid. These results suggest that the crude extract of H. plantaginea possesses significant antibacterial, anti-inflammatory, and antioxidant potential, supporting its traditional use and highlighting its promise as a source of bioactive compounds for pharmaceutical applications.