Antioxidant, anti-TB activities, phenolic and amide contents of standardised extracts of Piper sarmentosum Roxb

Abstract

Ethanol and aqueous extracts of the different parts of Piper sarmentosum were analysed by HPLC for marker compounds to standardise these extracts. The standardised extracts were investigated for antioxidant activity (β-carotene linoleate model and DPPH model), anti-TB activity (microplate tetrazolium assay), and estimation of total phenolic and amide contents. The extracts of the different parts exhibited different antioxidant activity, phenolic and amide contents (p < 0.01). The ethanol extracts exhibited better antioxidant activity as compared to the aqueous extracts. The leaf ethanol extract was further investigated for dose response relationship and its EC₅₀ was found to be 38 µg mL⁻¹. All the extracts have exhibited anti-TB activity with MIC/MBC 12.5 µg mL⁻¹. The leaf methanol extract was fractionated and the ethyl acetate fraction exhibited anti-TB activity with MIC/MBC 3.12 µg mL⁻¹ while MIC/MBC of isoniazid (INH) was found to be 0.5 µg mL⁻¹. A positive correlation was found between antioxidant activity and total polyphenols, flavonoids and amides, in the β-carotene linoleate model (p = 0.05) and in the DPPH model (p = 0.01). The analytical method was found to have linearity >0.9922, coefficient of variance <5% and accuracy 95.5 ± 5 to 96.9 ± 5. This plant possesses promising antioxidant as well as anti-TB properties.

Keywords:

• Piper sarmentosum
• antioxidant
• anti-TB
• standardisation
• total phenolic

Acknowledgements

The authors wish to thank the Government of Malaysia for providing scholarship under Commonwealth Fellowship and Scholarship Plan, the School of Pharmaceutical Sciences, Universiti Sains Malaysia, for providing laboratory facilities, and the University of the Punjab, Pakistan for granting study leave.