USE OF CITRIC-ACID FOR NEUTRALIZING POLYMERASE-CHAIN-REACTION INHIBITION BY CHLOROGENIC ACID IN POTATO EXTRACTS

Polyphenolics are a widely distributed class of plant constituents imp licated in the inhibition of the polymerase chain reaction (PCR). Sinc e chlorogenic acid forms the bulk of phenolics in the potato tuber, a range of chlorogenic acid concentrations were tested for inhibition of reverse transcription (RT) and PCR steps. The RT step was inhibited a t chlorogenic acid concentrations of 6.0 to 7.5 mu g, while the PCR st ep was inhibited at much lower concentrations of 1.2 to 1.8 mu g. Inco rporation of 1.2% citric acid at the nucleic acid extraction step prev ented darkening of the extract and neutralized the inhibitory effect o f chlorogenic acid. (C) 1998 Elsevier Science B.V. All rights reserved .