Quantitative Phytochemical Analysis Reveals Significant Antibiofilm Activity in Pleione maculata, an Endangered Medicinal Orchid

Abstract

Pleione maculata has no scientific reports on quantitative phytochemical and antibiofilm activity till date. The objective of the study was to quantify and determine medicinally important bioactivity in P. maculata and analyse its anti-biofilm activity against clinical isolates Staphyloccocus aureus, Klebsiella pneumoniae and Proteus mirabilis. P. maculata exhibited the highest Total Antioxidant Capacity (TAC) about 193.98±0.1 mg, highest Total Phenolic Content (TPC) at 552±0.0 mg and Total Flavonoid Content (TFC) were observed highest at 879.5±0.2 mg. The acetone and ethyl acetate extracts of P. maculata pseudobulb showed distinct and significant zone of inhibition (ZOI) against drug-resistant S.aureus about 16±0.00 mm (MIC 0.875 mg/mL), ZOI of acetonitrile pseudobulb extract against P. mirabilis was 15.33±0.4 mm (MIC 1 mg/mL), ZOI of acetonitrile extracts of leaves and stem, ethyl acetate extract of pseudobulb was 12±0.0 mm, 12±01.4 mm, 12±2.8 mm against K. pneumoniae (MIC 1.8 mg/mL, 0.68 mg/mL and 3 mg/mL). Acetonitrile extract of pseudobulbs exhibited the highest Minimum Biofilm Inhibition concentration (MBIC) at 0.25 mg/mL against S. aureus, water root extract inhibited attachment of K. pneumoniae with lowest MBIC value 0.093 mg/mL, water and acetone extract of leaves inhibited cell attachment of P. mirabilis at lowest MBIC 0.117 and 0.171 mg/mL. The UV-VIS absorption band of P. maculata extracts ranges from 204-665 nm indicating the presence of phenolic and flavonoid compounds. The study indicates the potentiality of P. maculata as a rich source of medicinal active compounds as an antibiofilm agent against antibiotic-resistant clinical isolates.