|Mem Inst Oswaldo Cruz. 2003 Dec;98(8):1115-20. |
|Antibacterial activity of extracts and neolignans from Piper regnellii (Miq.) C. DC. var. pallescens (C. DC.) Yunck.[Pubmed: 15049100]|
|The evaluation of the activity of the aqueous and ethyl acetate extracts of the leaves of Piper regnellii was tested against gram-positive and gram-negative bacteria. |
METHODS AND RESULTS:
The aqueous extract displayed a weak activity against Staphylococcus aureus and Bacillus subtilis with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of 1000 micrograms/ml. The ethyl acetate extract presented a good activity against S. aureus and B. subtilis with MIC and MBC at 15.62 micrograms/ml. In contrast to the relative low MICs for gram-positive bacteria, gram-negative bacteria were not inhibited by the extracts at concentrations < or = 1000 mg/ml. The ethyl acetate extract was fractionated on silica gel into nine fractions. The hexane and chloroform fractions were active against S. aureus (MIC at 3.9 micrograms/ml) and B. subtilis (MIC at 3.9 and 7.8 micrograms/ml, respectively). Using bioactivity-directed fractionation, the hexane fraction was rechromatographed to yield the antimicrobial compounds 1, 2, 5, and 6 identified as eupomatenoid-6, eupomatenoid-5, eupomatenoid-3, and Conocarpan, respectively.
The pure compounds 1 and 2 showed a good activity against S. aureus with MIC of 1.56 micrograms/ml and 3.12 micrograms/ml, respectively. Both compounds presented MIC of 3.12 micrograms/ml against B. subtilis. The pure compound 6 named as Conocarpan was quite active against S. aureus and B. subtilis with MIC of 6.25 micrograms/ml. The antibacterial properties of P. regnellii justify its use in traditional medicine for the treatment of wounds, contaminated through bacteria infections.
|Phytomedicine. 2013 May 15;20(7):600-4. |
|Anti-tuberculosis neolignans from Piper regnellii.[Pubmed: 23474218]|
|The present study determined the anti-Mycobacterium tuberculosis activities of supercritical CO2 extracts, neolignans eupomatenoid-5 (1), Conocarpan (4) and eupomatenoid-3 (7) and their derivatives (2, 3, 5, 6, and 8) from Piper regnellii, as well as their cytotoxicities.
METHODS AND RESULTS:
The supercritical CO2 extract from leaves was purified by chromatographic methods, yielding compounds (1), (4) and (7), which were identified by (1)H NMR and comparison with literature data. Anti-M. tuberculosis activity (H37Rv and clinical isolates) was evaluated using a resazurin microtiter assay plate (REMA) to determine the MIC. The cytotoxicity assay was carried out in macrophages J774G.8 by sulforhodamine B colorimetric assay. The supercritical CO2 extracts from leaves and stems, and compound (4) showed activity against M. tuberculosis (MIC 15.6 μg/ml). Compound (1) showed the best activity (MIC 1.9 μg/ml), with good SI. Compounds (7) and (8) showed low activity against M. tuberculosis H37Rv. The derivative compounds did not show increased anti-M. tuberculosis activity.
This is the first report, to our knowledge, to describe neolignans from P. regnellii with activity against M. tuberculosis, and compound (1) is a potential candidate for future antituberculosis drugs.
|J Nat Med. 2010 Oct;64(4):402-8. |
|Antinociceptive properties of conocarpan and orientin obtained from Piper solmsianum C. DC. var. solmsianum (Piperaceae).[Pubmed: 20473574 ]|
METHODS AND RESULTS:
The antinociceptive properties of some fractions and two pure compounds, Conocarpan and orientin, obtained from P. solmsianum leaves were investigated in several models of pain in mice. The results indicated that this plant exhibits a promising antinociceptive profile, as it produces active principles which are several times more active than some reference drugs used for comparison. The main compound tested, orientin, caused potent and dose-dependent effects against acetic acid-induced writhing and capsaicin- and glutamate-induced nociception, being more effective against the first one, with an ID(50) value of 6.5 mg/kg (14.5 micromol/kg). Orientin was about 20-fold more potent than acetylsalicylic acid and 3.5-fold more active than indomethacin.
The antinociceptive effects of this plant may be attributed, at least partially, to the presence of Conocarpan and, in particular, to the flavonoid orientin.