Helvolic acid, an antibacterial nortriterpenoid from a fungal endophyte,Xylariasp. of orchidAnoectochilus setaceusendemic to Sri Lanka.
An endophytic fungus was isolated from surface sterilized leaf segments ofAnoectochilus setaceus,an orchid endemic to Sri Lanka, and was identified asXylariasp. by morphological characters and DNA sequencing. Bioassay-guided chromatographic fractionation of the organic extract of a laboratory culture of this fungus led to the isolation of the known antibacterial helvolic acid. Helvolic acid was active against the Gram-positive bacteria,Bacillus subtilis[minimal inhibitory concentrations (MIC), 2 μg mL-1] and methicillin-resistantStaphylococcus aureus(MIC, 4 μg mL-1).
Department of Chemistry, University of Colombo, Colombo 03, Sri Lanka ; Department of Science and Technology, Uva Wellassa University, Badulla, Sri Lanka.
Pamoda B
PB
Ratnaweera
Department of Chemistry and Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada.
David E
DE
Williams
Department of Chemistry, University of Colombo, Colombo 03, Sri Lanka.
E Dilip
ED
de Silva
Department of Plant Sciences, University of Colombo, Colombo 03, Sri Lanka.
Ravi L C
RL
Wijesundera
Department of Chemistry and Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada.
Doralyn S
DS
Dalisay
Department of Chemistry and Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, BC, Canada.
Raymond J
RJ
Andersen
Anoectochilus setaceus; Xylaria; antibacterial; endophytic fungi; helvolic acid; rainforest