Sunil K. Chaudhary

Photoactive furocoumarins in fruits of some umbellifers

Abstract Fruits of Anethum graveolens, Angelica archangelica, Anthriscus cerefolium, Apium graveolens, Carum carvi, Coriandrum sativum, Cuminum cyminum, Daucus carota, Foeniculum vulgare, Heracleum sphondylium, Levisticum officinale, Pastinaca sativa, Petroselinum crispum and Pimpinella anisum were analysed for photoactive furocoumarins using HPLC analysis and photobiological bioassay. These sensitive methods revealed furocoumarins not previously detected.

Furocoumarins in the cultivated carrot, Daucus carota

Abstract A combination of ultrasensitive bioassay and HPLC analysis was employed to analyse the garden carrot for furocoumarins. The earlier reported negative findings were due to the relatively insensitive methods of detection. Low levels of two furocoumarins, 8-MOP and 5-MOP were detected in all parts of fresh carrot plants for the first time. Occasionally one or two other unknown photoactive compounds were also present. Diseased carrot displayed increased levels of 8-MOP and 5-MOP; psoralen was also detected. In this respect carrot is capable of a phytoalexin response similar to celery.

Naturally-occurring crystals of photocarcinogenic furocoumarins on the surface of parsnip roots sold as food

Normal levels of total furocoumarins in fresh parsnip roots are as high as 96 ppm (wet weight). In older ‘spoiled’ and diseased parsnips freely available in grocery stores these values may be increased by 2500%. So high are the amounts in some instances, that mixed crystals of furocoumarins can be detected on the surfaces of the parsnip roots by both conventional low powered microscopy and SEM. The principal crystal form was angelicin but the presence of psoralen, 5-MOP and 8-MOP was confirmed by HPLC, TLC, photobiological assay and analysis of mass spectra.

Coriandrin, a novel highly photoactive compound isolated from Coriandrum sativum

Abstract Extracts of Coriandrum sativum L. were analysed for photoactive constituents using HPLC analysis and photobiological assay. Two new photoactive furoisocoumarins, named coriandrin and dihydrocoriandrin, were isolated, and their structures determined by 1 H and 13 C NMR and X-ray crystallography.

Photodechlorination of polychlorinated biphenyls in the presence of hydroquinone in aqueous alcoholic media

Abstract On exposure to sunlight or photolysis at λ >300nm, the dechlorination of a polychlorinated biphenyl mixture (Aroclor 1254) in the H donor alcohol 2-propanol under neutral conditions is enhanced by the presence of the photosensitizer hydroquinone. Dechlorination is strongly promoted by an increasingly aqueous solvent (1:1 water:alcohol) and by maintaining neutral conditions (pH 7.0 buffer) both in the presence and absence of sensitizer. Atmospheric oxygen (continuous aeration) retards the hydroquinone induced dechlorination less than the direct photolysis process.

Detection of furocoumarins in plants and plant products with an ultrasensitive biological photoassay employing a DNA-repair-deficient bacterium

The application of an ultrasensitive photobiological assay which detects photosensitizing furocoumarins with sensitivities as high as 1 × 10−11 g is discussed in relation to these molecules as phytoalexins. Examples of the utilization of this technique, verified by both HPLC and TLC, are the analyses of healthy and diseased celery and carrots, dry seeds, plant extracts and oils, and whole plants and leaves. The usefulness of this method in following the metabolic detoxification of furocoumarins is also illustrated. The extreme sensitivity of the test has permitted the detection, for the first time, of both 5-methoxypsoralen and 8-methoxypsoralen in fresh carrot roots.

Photodechlorination of methoxychlor induced by hydroquinone: Rearrangement and conjugate formation

Abstract Reductive degradation of the pesticide methoxychlor by photolysis in the presence of hydroquinone in dilute solutions of acetonitrile or 1:1 aqueous t-butanol leads to processes other than simple dechlorination. Direct radical coupling with hydroquinone forms a markedly estrogenic conjugate. A pH dependant molecular rearrangement gives pro-estrogenic 4,4′-dimethoxy-α,α′-dichlorostilbenes, and condensation with hydroquinone yields the chlorine free polycyclic aromatic, 12-hydroxy-3,6-dimethoxybenzo[b]phenanthro[9,10-d]furan.

Novel photoisomerization of 2,3-bis-(p-methoxyphenyl)benzofuran into 2,6-dimethoxy-9-(2-hydroxyphenyl)anthracene

Photolysis of 2,3-bis-(p-methoxyphenyl)benzofuran in benzene under N2 using either a mercury lamp or sunlight yield besides the expected phenanthrene derivative (6), the novel rearrangement anthracene (5).