Xylaria species associated with termite nests or soil have been considered rare species in nature and the few which have been reported upon have been found to act as a rich source of bioactive metabolites. This study evaluated 10 ethyl acetate extracts of five new Xylaria species associated with termite nests or soil for their antioxidant activity, and cytotoxicity against different cancer and normal cell lines. DPPH and ABTS radical scavenging activities of the extracts demonstrated strong capacity with low IC50 values. The highest observed activities belonged to X. vinacea SWUF18-2.3 having IC50 values of 0.194 ± 0.031 mg/mL for DPPH assay and 0.020 ± 0.004 mg/mL for ABTS assay. Total phenolic content ranged from 0.826 ± 0.123 to 3.629 ± 0.381 g GAE/g crude extract which correlated with antioxidant activities. The high total phenolic content could contribute to the high antioxidant activities. Cytotoxicity was recorded against A549, HepG2, HeLa and PNT2 and resulted in broad spectrum to specific activity depending on the cell lines. The highest activities were observed with X. subintraflava SWUF16-11.1 which resulted in 11.15 ± 0.32 to 13.17 ± 2.37% cell viability at a concentration of 100 µg/mL. Moreover, LC-MS fingerprints indicated over 61 peaks from all isolates. There were 18 identified and 43 unidentified compounds compared to mass databases. The identified compounds were from various groups of diterpenoids, diterpenes, cytochalasin, flavones, flavonoids, polyphenols, steroids and derivatives, triterpenoids and tropones. These results indicate that Xylaria spp. has abundant secondary metabolites that could be further explored for their therapeutic properties.

Center for Advanced Studies in Nanotechnology for Chemical Food and Agricultural Industries KU Institute for Advanced Studies Kasetsart University Bangkok 10900 Thailand

Centre for Natural Products Discovery School of Pharmacy and Bimolecular Sciences Liverpool John Moores University James Parsons Building Byrom Street Liverpool L3 3AF UK

Department of Biochemistry Faculty of Science Kasetsart University Bangkok 10900 Thailand

Department of Biology Faculty of Science Nakhon Phanom University Nakhon Phanom 48000 Thailand

Department of Biology Faculty of Science Srinakharinwirot University Bangkok 10110 Thailand

Department of Microbiology Faculty of Science Srinakharinwirot University Bangkok 10110 Thailand

Laboratory of Growth Regulators Institute of Experimental Botany ASCR and Palacký University Šlechtitelů 27 78371 Olomouc Czech Republic

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