title: Root cultures of Hypericum perforatum subsp. angustifolium elicited with chitosan and production of xanthone-rich extracts with antifungal activity.
abstract: Hypericum perforatum is a well-known medicinal plant which contains a wide variety of metabolites, including xanthones, which have a wide range of biological properties, including antifungal activity. In the present study, we evaluated the capability of roots regenerated from calli of H. perforatum subsp. angustifolium to produce xanthones. Root biomass was positively correlated with the indole-3-butyric acid concentration, whereas a concentration of 1 mg l(-1) was the most suitable for the development of roots. High auxin concentrations also inhibited xanthone accumulation. Xanthones were produced in large amounts, with a very stable trend throughout the culture period. When the roots were treated with chitosan, the xanthone content dramatically increased, peaking after 7 days. Chitosan also induced a release of these metabolites into the culture. The maximum accumulation (14.26 ± 0.62 mg g(-1) dry weight [DW]) and release (2.64 ± 0.13 mg g(-1) DW) of xanthones were recorded 7 days after treatment. The most represented xanthones were isolated, purified, and spectroscopically characterized. Antifungal activity of the total root extracts was tested against a broad panel of human fungal pathogen strains (30 Candida species, 12 Cryptococcus neoformans, and 16 dermatophytes); this activity significantly increased when using chitosan. Extracts obtained after 7 days of chitosan treatment showed high antifungal activity (mean minimum inhibitory concentration of 83.4, 39.1, and 114 μg ml(-1) against Candida spp., C. neoformans, and dermatophytes, respectively). Our results suggest that root cultures can be considered as a potential tool for large-scale production of extracts with stable quantities of xanthones.
authors.affiliation: Department of Environmental Biology, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
authors.forename: Noemi
authors.initials: N
authors.lastname: Tocci
authors.forename: Giovanna
authors.initials: G
authors.lastname: Simonetti
authors.forename: Felicia Diodata
authors.initials: FD
authors.lastname: D'Auria
authors.forename: Simona
authors.initials: S
authors.lastname: Panella
authors.forename: Anna Teresa
authors.initials: AT
authors.lastname: Palamara
authors.forename: Alessio
authors.initials: A
authors.lastname: Valletta
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pasqua
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D003883:Arthrodermataceae / Q000187:drug effects; D002175:Candida / Q000187:drug effects; D048271:Chitosan / Q000378:metabolism*; D003455:Cryptococcus neoformans / Q000187:drug effects; D020902:Hypericum / Q000254:growth & development* / Q000378:metabolism*; D007210:Indoleacetic Acids / Q000378:metabolism; D007211:Indoles / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors; D044004:Xanthones / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000935:Antifungal Agents; D007210:Indoleacetic Acids; D007211:Indoles; D010936:Plant Extracts; D044004:Xanthones; C014612:indolebutyric acid; D048271:Chitosan