Premium
Derivatives of Pheophorbide‐ a and Pheophorbide‐ b from Photocytotoxic Piper penangense Extract
Author(s) -
Adzhar Kamarulzaman Fadzly,
Shaari Khozirah,
Siong Hock Ho Anthony,
Haji Lajis Nordin,
Hwang Teo Soo,
Boon Lee Hong
Publication year - 2011
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.201000341
Subject(s) - pheophorbide a , chemistry , piper , stereochemistry , photodynamic therapy , organic chemistry , botany , biology
In our screening program for new photosensitizers from Malaysian biodiversity for photodynamic therapy (PDT) of cancer, MeOH extracts of ten terrestrial plants from Cameron Highlands in Pahang, Peninsular Malaysia, were tested. In a short‐term 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2 H ‐tetrazolium bromide (MTT) assay, 20 μg/ml each of these extracts were incubated in a pro‐myelocytic leukemia cell‐line, HL60, with or without irradiation with 9.6 J/cm 2 of a broad spectrum light. Three samples, Labisia longistyla, Dichroa febrifuga , and Piper penangense , were photocytotoxic by having at least twofold lower cell viability when irradiated compared to the unirradiated assay. The extract of the leaves of Piper penangense , a shrub belonging to the family Piperaceae and widely distributed in the tropical and subtropical regions in the world, was subsequently subjected to bioassay‐guided fractionation using standard chromatography methods. Eight derivatives of pheophorbide‐ a and ‐ b were identified from the fractions that exhibited strong photocytotoxicity. By spectroscopic analysis, these compounds were identified as pheophorbide‐ a methyl ester ( 1 ), ( R , S )‐13 2 ‐hydroxypheophorbide‐ a methyl ester ( 2 and 3 ), pheophorbide‐ b methyl ester ( 4 ), 13 2 ‐hydroxypheophorbide‐ b methyl ester ( 5 ), 15 2 ‐hydroxylactone pheophorbide‐ a methyl ester ( 6 ), 15 2 ‐methoxylactone pheophorbide‐ a methyl ester ( 7 ), 15 2 ‐methoxylactone pheophorbide‐ b methyl ester ( 8 ).