Fimbristylis genus had commonly found as a dominant weed in the rice fields. The sedges have been identified as one of the invasive weed in the world and their undesirable presence disturb the growth of the crop. The presence of secondary metabolites, on the other hand, revealed that this plant is capable of a wide range of biological activities. Therefore, this study focused on the phytochemistry, antioxidant and antifungal properties of 2 weeds in the genus Fimbristylis. The methanol extracts of 2 species; Fimbristylis miliacea and Fimbristylis dichotoma were screened for phytochemical, antioxidant and antifungal activity. Phytochemical screening showed the presence of saponin, terpenoid, phenolic and flavonoid. Antioxidant activity was determined using 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) assay. The extracts have significant antioxidant activity with values of IC50 = 250.67 μg/ml (F. miliacea) and 213.72 μg/ml (F. dichotoma). Antifungal activity was validated by dual culture test; minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) using crude methanol extract 10mg/mL. The percentage of inhibition radial growth (PIRG) value by dual culture test against Colletotrichum spp for F. miliacea was 42.67%, and F. dichotoma was 38.33%. For MIC and MFC test, the lowest values against the plant pathogenic fungi showed at 1.25 mg/mL and 2.5 mg/mL. From the results, it showed that these extracts have the potential to be develop as natural products in integrated control strategies.

The use of synthetic fungicide are affecting the health, disturbing the ecosystem of the environment and has develop resistance of many pathogenic fungi. This study aimed to investigate the antifungal activity of ethanolic Piper betel (P. betel) crude leaf extracts with HOCl formulated by natural oxygenated water against selected crop pathogenic fungi which are Fusarium spp. and Phakopsora euvitis fungi. The screening test was done using well diffusion technique where the parameter observed was the Percentage Inhibition Radial Growth (PIRG). The antifungal effects of P.betel crude leaf extract with formulated HOCl minimum inhibitory concentration (MIC) were further evaluated by micro broth dilution method and minimum fungicidal concentration (MFC) were tested by agar well method. Screening results showed the P.betel extracts with HOCl have potential to inhibit the fungi radial growth when compared to positive control Kencozeb M45. MIC and MFC results portrayed the extracts with formulated HOCl displayed fungicidal activity against both fungi in the range of 2500 µg/ml until 5000 µg/ml for Fusarium spp and Phapkopsora euvitis, respectively. To the best of our knowledge this is the only natural oxygenated water source in Malaysia and first reported with combination of Piper betel extract.