Potential role of Indian long pepper (Piper longum L.) volatiles against free radicals and multidrug resistant isolates

In the present study, the extracted volatiles from dried leaf and fruit of Piper longum were analysed by gas chromatography-mass spectrometry (GC-MS) and each detected 53 constituents having 92.41% and 96.31% of the total volatiles respectively. E-nerolidol (19.56%), β-pinene (17.07%) and α-pinene (6.8%) were main constituents in leaf volatiles whereas the fruit volatiles dominated by germacrene-D (23.38%), 8-heptadecene (8.95%) and β-caryophyllene (8.20%). Antioxidant potential of the volatiles were assessed by DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assays. The fruit volatiles revealed higher radical scavenging activities as compared to leaf. The samples were also evaluated against multidrug resistant (MDR) isolates including one non MDR fungal strain. The fruit volatiles showed a very strong activity against Acinetobacter baumannii than others whereas leaf volatiles possessed strong activity against Klebsiella pneumoniae as compared to other strains. Thus, the dried fruits can be exploited for drug development towards therapeutic purpose.