Asebogenin

Dihydrochalcones from the leaves of Pieris japonica.[Pubmed:15787442]

J Nat Prod. 2005 Mar;68(3):392-6.

Six new dihydrochalcones, 3-hydroxyasebotin (5), Asebogenin 2'-O-beta-D-ribohexo-3-ulopyranoside (6), 2' '-acetylasebotin (7), 3',4,5'-trihydroxy-4'-methoxydihydrochalcone 3',5'-di-O-beta-D-glucopyranoside (8), and pierotins A (9) and B (10), along with four known dihydrochalcones, phloretin (1), phlorizin (2), Asebogenin (3), and asebotin (4), were isolated from the leaves of Pieris japonica. Their structures were elucidated on the basis of spectroscopic analysis including HMQC, HMBC, NOESY, and X-ray crystal diffraction. Compounds 1, 3-5, and 7-10 inhibited the proliferation of murine B cells and compounds 5 and 10 inhibited the proliferation of murine T cells in vitro significantly.

Dihydrochalcones from Piper longicaudatum.[Pubmed:11301876]

Planta Med. 2001 Mar;67(2):186-8.

Bioactivity-guided fractionation of an ethanolic extract of the leaves and twigs of Piper longicaudatum Trelease & Yunker (Piperaceae) resulted in the isolation of one new (1) and three known (2-4) dihydrochalcones. The known compounds are: 2',6'-dihydroxy-4'-methoxydihydrochalcone (2), 2',6',4-trihydroxy-4'-methoxydihydrochalcone (Asebogenin) (3), and 2'-hydroxy-4'-methoxy-2'-[1-hydroxy-1-methylethyl]-2",3"-dihy- drofurano[4",5":5',6"]-3"-[2-hydroxy-5-methoxycarbonylphe- nyl]dihydrochalcone (piperaduncin B) (4). The new compound is 2'-hydroxy-4'-methoxy-2"-[2-hydroxy-5-methoxycarbonyl- phenyl]-furano[4",5":5',6']-dihydrochalcone (longicaudatin) (1). Compounds 1-4 were tested for antibacterial activity against S. aureus and methicillin-resistant S. aureus (MRSA); only compound 3 showed inhibitory activity (IC50 of 10 and 4.5 micrograms/ml, respectively).

Anti-secretory, anti-inflammatory and anti-Helicobacter pylori activities of several fractions isolated from Piper carpunya Ruiz & Pav.[Pubmed:20152892]

J Ethnopharmacol. 2010 Apr 21;128(3):583-9.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Piper carpunya Ruiz & Pav. (syn Piper lenticellosum C.D.C.) (Piperaceae), are widely used in folk medicine in tropical and subtropical countries of South America as an anti-inflammatory, anti-ulcer, anti-diarrheal and anti-parasitical remedy as well as an ailment for skin irritations. AIMS OF THE STUDY: To study the anti-inflammatory, anti-secretory and anti-Helicobacter pylori activities of different fractions isolated from an ethanolic extract of the leaves of Piper carpunya, in order to provide evidence for the use of this plant as an anti-ulcer remedy. Moreover, to isolate the main compounds of the extract and relate their biological activity to the experimental results obtained with the fractions. MATERIALS AND METHODS: Sixteen fractions were obtained from the ethanolic extract (F I-XVI) and 16 pure compounds were isolated and identified from these fractions. We studied the effects of the fractions (0.1-400microg/mL) on the release of myeloperoxidase (MPO) enzyme from rat peritoneal leukocytes, on rabbit gastric microsomal H(+), K(+)-ATPase activity and anti-Helicobacter pylori anti-microbial activity using the microdilution method (MM). The main compounds contained in the fractions were isolated and identified by (1)H- and (13)C NMR spectra analysis and comparison with the literature data. RESULTS: Eight fractions showed inhibition of MPO enzyme (F I-IV, X, XII, XIV and XV). The highest inhibition was observed with F XIV (50microg/mL, 60.9%, p<0.001). F X and XII were the most active ones, inhibiting the gastric H(+), K(+)-ATPase activity with IC(50) values equal to 22.3microg/mL and 28.1microg/mL, respectively. All fractions, except F XV, presented detectable anti-Helicobacter pylori activity, with a diameter of inhibition zones ranging from 11mm up to 50mm. The best anti-Helicobacter pylori activity was obtained with F III and V. Both fractions killed Helicobacter pylori with lowest concentration values, about 6.25mug/mL. Sixteen pure compounds were isolated, five of them are flavonoids that possess strong anti-oxidant and free radical scavenging activity, e.g. vitexin, isovitexin, and rhamnopyranosylvitexin. Terpenoids like sitosterol, stigmasterol and phytol, which have shown gastroprotective activity, and dihydrochalcones, like Asebogenin, with anti-bacterial activity, were also isolated. Furthermore, the rare neolignan 1, that is a DNA polymerase beta lyase inhibitor, and (6S, 9S)-roseoside, that shows strong anti-bacterial activity, were isolated, for the first time, from the genus Piper. CONCLUSIONS: We suggest that the flavonoids isolated from F I and II (vitexin, isovitexin, rhamnopyranosylvitexin and isoembigenin) contribute to the anti-MPO activity, as well as to their anti-Helicobacter pylori activity. These flavonoids may also be responsible for the important inhibition of H(+), K(+)-ATPase activity. Also the phytosterols and phytol obtained from F XIV and XV could be involved in these gastroprotective activities. These results encourage us to continue phytochemical studies on these fractions in order to obtain full scientific validation for this species.

In vitro antiplasmodial activity of Central American medicinal plants.[Pubmed:10540301]

Trop Med Int Health. 1999 Sep;4(9):611-5.

The in vitro antiplasmodial activities of 14 plant species traditionally used in Central America for the treatment of malaria or fever were evaluated. Lipophilic extracts of Piper hispidum, Siparuna andina, S. pauciflora, S. tonduziana, and Xylopia cf. frutescens, proved to be active against both a chloroquine-sensitive and a resistant strain of Plasmodium falciparum. IC50 values ranged between 3.0 microg/ml and 21.9 microg/ml; however, moderate cytotoxicity of active extracts was observed. Bioactivity-guided fractionation of Piper hispidum yielded 2',4, 6'-trihydroxy-4'-methoxydihydrochalcone (Asebogenin) as an active compound.