<i>Enterococcus faecalis</i>-Aided Fermentation to Facilitate Edible Properties and Bioactive Transformation of Underutilized <i>Cyathea dregei</i> Leaves

<i>Cyathea dregei</i> (CD) is a weed plant that is rarely consumed. This study investigated the impact of <i>Enterococcus faecalis</i> as an agent of 3–5-day fermentation, thus stimulating the edible properties of the leaves from CD using <i>Talinum fruticosum</i> as the control. The proximate content, biochemical, antioxidant properties, and phytochemical constituents of the unfermented and fermented leaves were examined. The lactate dehydrogenase activity (LDH) activity significantly increased (<i>p</i> < 0.05) due to the fermentation, which peaked on the third day. The fat, ash, and crude fiber constituents of the fermented CD leaves were significantly higher (<i>p</i> < 0.05), especially on day 3, compared to the unfermented leaves of CD. The leaves of CD naturally possess significantly higher (<i>p</i> < 0.05) values of calcium, selenium, magnesium potassium, sodium, zinc, and vitamin C but significantly lower (<i>p</i> < 0.05) values of vitamins A and E compared to those of water leaf. The fermentation aided the synthesis of caffeic acid (61.71 mg/10 g extract), eleven other bioactive phytochemicals (0.14–60.24 mg/10 g extract), two unexplored saponins (P-Scd, 52.05 mg/10 g extract), and a phenolic compound (P-Pcd, 0.23 mg/10 g extract). Four novel intermediary compounds and six other established compounds were freshly identified with fermentation. The leaves of <i>C. dregei</i> are naturally rich in bioactive nutrients and phytochemicals that trigger their strong antioxidant qualities, which were improved by this fermentation technique. <i>E. faecalis</i> is most likely to engage LDH in driving the fermentation transforming the <i>C. dregei</i> into a potential edible vegetable.