Most of the extracts demonstrated antimicrobial activities against tested gram
positive bacteria and fungi. Antimicrobial activity against gram negative bacteria was less
potent (Table 1-2). The ethanol extract of X. indica flowering heads showed broadest
antimicrobial spectrum followed by the petroleum ether extract of E. Americana bulbs. Xyris
spp. were previously reported for their antifungal properties due to 1,8-
dihydroxyanthraquinone derivatives [20]. Crude ethanolic extract from bulbs of E.
Americana was formerly shown to be a good antimicrobial agent against foodborne grampositive
bacteria, certain gram-negative, and food spoilage organisms except Candida
albicans [21]. The present study used higher dose of the extract and different agar diffusion
technique (4 mg/well vs. 2.5 mg/disc) resulting in anti-candida potential of E. Americana
bulbs.