title: New free radical scavenging neolignans from fruits of Piper attenuatum.
abstract: OBJECTIVE
  The aim was to study and identify free radicals scavenging and antihyperglycemic principles in fruit of Piper attenuatum.
  
  
  METHODS
  Bioassay guided identification of extracts possessing potent free radical scavenging activity, and isolation of compounds was done. Chloroform extract of P. attenuatum possessing potent radical scavenging activity was also evaluated for antihyperglycemic activity following oral glucose tolerance test in rats.
  
  
  RESULTS
  Nine neolignans namely, denudatin B (1), iso-4', 5'-dimethoxy-3, 4-methylenedioxy-2'-oxo-Δ(3',5',8')-8.1'-lignan (2), lancifolin D (3), denudatin A (4), wallichinin (5), piperenone (6), lancifolin C (7), 2-oxo-piperol B (8), piperkadsin A (9) and a crotepoxide (10) was identified in Chloroform extract of P. attenuatum. Neolignans (1-9) displayed potent 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical and piperkadsin A (9) also displayed 1, 1-diphenyl-2-picrylhydrazyl radical scavenging activity. Analysis of structure-activity relationship revealed that presence of furan ring and methoxy groups is an important criterion to influence 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging potentials. Chloroform extract of P. attenuatum fruit could not display antihyperglycemic activity following oral glucose tolerance test in rats.
  
  
  CONCLUSIONS
  Neolignans present in P. attenuatum fruits are potent free radical scavengers and this is the first report identifying these compounds and activities in this fruit.
authors.affiliation: Division of Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: S Divya
authors.initials: SD
authors.lastname: Reddy
authors.affiliation: Division of Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: Bandi
authors.initials: B
authors.lastname: Siva
authors.affiliation: Division of Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: B
authors.initials: B
authors.lastname: Poornima
authors.affiliation: Division of Medicinal Chemistry and Pharmacology, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: D Anand
authors.initials: DA
authors.lastname: Kumar
authors.affiliation: Division of Medicinal Chemistry and Pharmacology, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Tiwari
authors.affiliation: Center for Chemical Biology, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, Telangana, India.
authors.forename: U
authors.initials: U
authors.lastname: Ramesh
authors.affiliation: Division of Natural Product Chemistry, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: K Suresh
authors.initials: KS
authors.lastname: Babu
keywords: 2, 2-Diphenyl-1-picrylhydrazyl radical; 2, 2’-Azinobis (3-ethyl benzthiazoline-6-sulphonic acid) radical; Piper attenuatum; chloroform extract; glucose tolerance test
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