Tyrosinase inhibitors from galls of Rhus javanica leaves and their effects on insects.
As a defense mechanism of the leaves of Rhus javanica (Anacardiaceae) against the aphid Melaphis chinensis (Aphididae) attack, tannic acid is rapidly accumulated and forms galls along the midrib of the leaves resulting in a unique natural medicine Gallae Rhois. Tannic acid was found to inhibit the oxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) catalyzed by tyrosinase (EC 1.14.18.1) with an IC50 of 22 microM. The aphid would detoxify the ingested toxic tannic acid to relatively nontoxic gallic acid, whereas the non-adapted pink bollworm Pectinophora gossypiella larvae are sensitive to the ingested tannic acid.
Kubo
Isao
I
Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720-3112, USA. ikubo@uclink4.berkeley.edu
Kinst-Hori
Ikuyo
I
Nihei
Ken-Ichi
K
Soria
Frida
F
Takasaki
Midori
M
Calderón
José S
JS
Céspedes
Carlos L
CL
D000363:Agaricales / Q000201:enzymology; D000818:Animals; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology*; D016166:Free Radical Scavengers; D005707:Gallic Acid / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D007313:Insecta; D007306:Insecticides / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D018515:Plant Leaves / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry; D029045:Rhus / Q000737:chemistry*
D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007306:Insecticides; D005707:Gallic Acid; D014442:Monophenol Monooxygenase