Fungal Infection Enhances Anthocyanin Production in Blue Flowers of Clitoria ternatea

Abstract

Penicillium citrinum Aims: A white fungus which commonly infects blue petals of Clitoria ternatea L. (CT) was identified and total anthocyanin content and antioxidant activity of CT extracts from infected and uninfected CT were compared. Study Design:  Experimental research. Place and Duration of Study: Samples of infected and non-infected CT were collected from Muang, Khon Kaen and chemical analysis was undertaken at Khon Kaen University between July and December 2012. Fungus was identified at Department of Microbiology in April 2013. Methodology: Samples of dried CT, with and without white fungus infection, were collected. The CT-infected fungus was isolated for microscopic characterization and DNA isolated for amplifying of its ITS rDNA, and analyzing their sequences with neighbor joining phylogenetic tree. Total anthocyanin content by pH differential method and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay were used to compare infected and non-infected CT extracts in comparison to trolox.  Both extracts were analyzed by HPLC in comparison to cyanidin. Results: Morphology and DNA of the infected fungus was characterized and confirmed to be Penicillium citrinum KKU-Rx1. In comparison to aqueous extracts of non-infected CT, infected CT gave about 1.5 times higher total anthocyanin content (P=.002) and cyanidin (P = .009). Trolox equivalent antioxidant capacity of infected-CT extracts was 1, while that of non-infected CT extracts was 0.7 (P<.001). Conclusion: Penicillium citrinum was identified from white fungus infection on deep blue flowers of Clitoria ternatea and shown to enhance the anthocyanin content and antioxidant activity of the CT extracts.