Comprehensive polyphenolic profiling, antioxidant, antimicrobial, and cytotoxicity studies of Rhynchostylis retusa (L.) Blume: a medicinal orchid

Abstract

Rhynchostylis retusa (L.) Blume, commonly known as the Foxtail orchid, has garnered worldwide attention for its diverse medicinal properties. In this study, root extract and its fractions were evaluated for total polyphenols, flavonoids, targeted polyphenols, and antioxidant potential. The antimicrobial activity was assessed against Gram-positive and Gram-negative bacterial strains while cytotoxicity was assessed using the A549 and HCT-116 cell lines. The investigations showed that chloroform and ethyl acetate are the most effective solvents for fractionation of polyphenols from the parent extract. These fractions also exhibited strong antioxidant and cytotoxic potentials. The chloroform fraction showed maximum cell death of 87.35 and 92.36% in A549 and HCT- 116 cell lines respectively. All samples showed growth inhibition against bacterial strains except the n-hexane fraction, whereas the n-butanol fraction showed comparable antimicrobial activity with the tetracycline standard. The possible health benefits and thereby, application of R. retusa were thus revealed in this investigation.

Graphical Abstract

Keywords:

• Rhynchostylis retusa (L.) blume
• orchid
• uplc-pda
• polyphenols
• antioxidant
• antimicrobial
• cytotoxicity

Acknowledgments

The authors would like to acknowledge the AnalytiCSIR and CSIR-Institute of Himalayan Bioresource Technology, Palampur, INDIA for cytotoxicity experiments. The CSIR-IHBT publication number of manuscript is 5594.

Authors’ contributions

Anjna Kumari: Collection, survey, experimentation, data analysis, and manuscript writing; Rishabh Kaundal: Data analysis and manuscript writing; Smita Kapoor: Anticancer activity and data analysis, Subhash Kumar: Antimicrobial activity and data analysis, Dharam Singh: Antimicrobial activity data validation and manuscript editing; Yogesh Kumar Walia: Data validation and manuscript editing; Dr Dinesh Kumar: Conceptualisation, data validation, manuscript editing and supervision.

Disclosure statement

The authors declare that they have no conflict of interest

Additional information

Funding

This work was supported by Department of Science and Technology, Ministry of Science and Technology, India