Isopimpinellin

Photochem Photobiol. 1996 Mar;63(3):306-7.

Isopimpinellin is not phototoxic in a chick skin assay.[Pubmed: 8881335]

METHODS AND RESULTS:
Synthetic Isopimpinellin (5,8-dimethoxypsoralen), confirmed to contain as impurities only trace quantities at most of psoralen, bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen), is not phototoxic when tested in a chick skin bioassay system. These findings are at variance with earlier studies showing Isopimpinellin to be phototoxic against chick skin and support the conclusion that Isopimpinellin is photobiologically inactive.
CONCLUSIONS:
As recently proposed by others, the several reports of Isopimpinellin photoactivity are most likely attributable to contamination by small amounts of highly active psoralens such as bergapten or xanthotoxin.

Planta Med. 1987 Jun;53(3):306-7.

Isopimpinellin is not phototoxic to viruses and cells.[Pubmed: 3628561 ]

Isopimpinellin is not phototoxic to viruses and cells.

Acta Crystallographica, 2003, 59(10):o1506–8.

Redetermination and comparative structural study of isopimpinellin: A new inhibitor against the Leishmania APRT enzyme[Reference: WebLink]

The title compound (Isopimpinellin,alternative name 5,8-dimethoxypsoralen), C13H10O5, is a natural product extracted from Adiscanthus fusciflorus (Rutaceae).
METHODS AND RESULTS:
Our biochemical tests show that this compound has inhibitory activity against the enzyme adenine phosphoribosyltransferase (APRT) from Leishmania, a tropical parasite causing endemic disease in poor countries. It crystallizes in the centrosymmetric space group P2(1)/c, with one molecule in the asymmetric unit, and has at least two C-H...O intermolecular interactions, leading to the formation of centrosymmetric dimers.

Carcinogenesis. 2002 Oct;23(10):1667-75.

Oral administration of the citrus coumarin, isopimpinellin, blocks DNA adduct formation and skin tumor initiation by 7,12-dimethylbenz[a]anthracene in SENCAR mice.[Pubmed: 12376476]

The current study was designed to evaluate the effects of oral administration of the citrus coumarin, Isopimpinellin, on skin tumor initiation by topically applied benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA).
METHODS AND RESULTS:
To evaluate the effects of orally administered Isopimpinellin on skin tumor initiation by B[a]P and DMBA, its effects on DNA adduct formation were first evaluated. Female SENCAR mice were pre-treated twice with corn oil, or Isopimpinellin (70 mg/kg body wt per os) at 24 h and 2 h prior to topical treatment with B[a]P or DMBA. Another citrus coumarin, imperatorin, was also included in these experiments for comparison. Orally administered Isopimpinellin and imperatorin significantly inhibited B[a]P-DNA adduct formation by 37 and 26%, respectively. Imperatorin also blocked DMBA-DNA adduct formation by 43%. In a second dose-response study, orally administered Isopimpinellin (35, 70 and 150 mg/kg) blocked DMBA-DNA adduct formation by 23, 56 and 69%, respectively. For the tumor study, mice were pretreated orally with corn oil or Isopimpinellin at 24 and 2 h prior to initiation with DMBA, and 2 weeks later promotion began with 12-O-tetradecanoylphorbol-13-acetate (TPA). Isopimpinellin significantly reduced the mean number of papillomas per mouse by 49, 73 and 78% compared to corn oil controls at 30, 70 and 150 mg/kg body wt, respectively. Orally administered Isopimpinellin also significantly reduced the percentage of mice with papillomas at the highest dose tested (150 mg/kg). The effectiveness of Isopimpinellin given topically over a broad dose range against DMBA tumor initiation was also evaluated for comparison. As part of this study, several parameters of systemic toxicity were evaluated following oral dosing with Isopimpinellin and imperatorin. Mice were treated orally with corn oil, Isopimpinellin or imperatorin (35, 70 and 150 mg/kg body wt per os) once daily for four consecutive days, killed at 24 h after the last dose, and livers, lungs, and kidneys evaluated histologically. In addition, urinary parameters of nephrotoxicity, blood parameters of liver and kidney function, and thrombin clotting time were assayed. No significant changes in blood clotting, or renal or hepatic function were observed. There was, however, a significant increase in liver wt accompanied by cytoplasmic vacuolation of hepatocytes. There were no histopathological changes in lungs or kidneys.
CONCLUSIONS:
Overall, these data indicate that Isopimpinellin (and imperatorin) have chemopreventive effects when administered orally on skin tumor initiation by DMBA.

J Oleo Sci. 2011;60(11):575-8.

Microbial transformation of Isopimpinellin by Glomerella cingulata.[Pubmed: 22027023]

METHODS AND RESULTS:
Microbial transformation studies conducted on Isopimpinellin (1) by the fungus Glomerella cingulata have revealed that 1 was metabolized to give the corresponding reduced acid, 5,8-dimethoxy-6,7-furano-hydrocoumaric acid (2). The structure of metabolite 2 was elucidated by high-resolution mass spectrometry (HR-MS), extensive NMR techniques, including (1)H NMR, (13)C NMR, (1)H-(1)H correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC) and heteonuclear multiple bond coherence (HMBC).
CONCLUSIONS:
The biotransformed product 2 showed weak a in vitro β-secretase (BACE1) inhibitory effect.